Download Physiology and Pathophysiology of the Calcium Store in the

Physiol Rev 85: 201–279, 2005;
doi:10.1152/physrev.00004.2004.
Physiology and Pathophysiology of the Calcium Store
in the Endoplasmic Reticulum of Neurons
ALEXEI VERKHRATSKY
The University of Manchester, Faculty of Biological Sciences, Manchester, United Kingdom
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
I. Endoplasmic Reticulum and Cellular Physiology: Historical Remarks
II. Organization of the Endoplasmic Reticulum
A. The neuronal ER as a continuous endomembrane structure
B. The ER as a universal signaling organelle
C. The ER as an excitable organelle
III. Endoplasmic Reticulum Calcium Release in Nerve Cells
A. The discovery of Ca2⫹ release from the ER
B. Ca2⫹-induced Ca2⫹ release
C. IICR in nerve cells
D. Do InsP3Rs and RyRs share a common Ca2⫹ pool?
E. Luminal Ca2⫹ as a regulator of Ca2⫹ release
F. Refilling the Ca2⫹ store and store-operated Ca2⫹ entry
G. Pharmacology of Ca2⫹ release
IV. Endoplasmic Reticulum Calcium Signaling and Regulation of Neuronal Functions
A. Neuronal excitability
B. Neurotransmitter release
C. Synaptic plasticity
D. Gene expression, ER Ca2⫹ waves, and ER Ca2⫹ tunneling
E. Neuronal growth and morphological plasticity
F. Neurohormone release
G. Circadian rhythms
V. Endoplasmic Reticulum Calcium Homeostasis and Neuronal Pathophysiology
A. ER stress response and neurodegeneration
B. ER stores and ischemia
C. ER stores and human immunodeficiency virus
D. ER stores and diabetes
E. ER stores and gangliosidoses (Gaucher’s and Sandhoff’s disease)
F. ER stores and Alzheimer’s disease
G. ER stores and ageing
H. Spinocerebellar ataxia type 1
I. ER and neuronal trauma
J. ER and Parkinson’s disease
K. ER and epileptiform activity
L. ER and Huntington’s disease
VI. Concluding Remarks
202
203
203
205
205
207
207
209
226
233
234
236
242
244
244
244
250
253
254
255
255
255
255
256
257
257
258
258
260
261
261
261
261
261
261
Verkhratsky, Alexei. Physiology and Pathophysiology of the Calcium Store in the Endoplasmic Reticulum of
Neurons. Physiol Rev 85: 201-279, 2005; doi:10.1152/physrev.00004.2004.—The endoplasmic reticulum (ER) is the
largest single intracellular organelle, which is present in all types of nerve cells. The ER is an interconnected,
internally continuous system of tubules and cisterns, which extends from the nuclear envelope to axons and
presynaptic terminals, as well as to dendrites and dendritic spines. Ca2⫹ release channels and Ca2⫹ pumps residing
in the ER membrane provide for its excitability. Regulated ER Ca2⫹ release controls many neuronal functions, from
plasmalemmal excitability to synaptic plasticity. Enzymatic cascades dependent on the Ca2⫹ concentration in the ER
lumen integrate rapid Ca2⫹ signaling with long-lasting adaptive responses through modifications in protein synthesis
and processing. Disruptions of ER Ca2⫹ homeostasis are critically involved in various forms of neuropathology.
www.prv.org
0031-9333/05 $18.00 Copyright © 2005 the American Physiological Society
201
202
ALEXEI VERKHRATSKY
I. ENDOPLASMIC RETICULUM AND CELLULAR
PHYSIOLOGY: HISTORICAL REMARKS
FIG. 1. Early drawings of intracellular reticular structures. A: original drawings of Camillo Golgi. The drawings present dorsal root ganglion
neurons of an adult horse (Figs. 1–3), bovine fetus (Fig. 4), a neonatal cat (Fig. 6), and a young dog (Fig. 8). Black reticular structures (“internal
reticular apparatus”) are visualized by metallic impregnation (188). B: original drawing of Emilio Veratti. Longitudinal section of a limb muscle of
the water beetle Hydrophilus piceus (668). The black reticular structure represents sarcoplasmic reticulum. [A from Bentivoglio et al. (37); B from
Mazzarello et al. (385).]
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
In 1674 Antonius van Leeuwenhoek, after discovering
the cross-striations of muscle fibers using one of his ingenious light microscopes, reflected “. . . who can tell,
whether each of these filaments may not be enclosed in its
proper membrane and contain within it an incredible
number of still smaller filaments.” (236). One century
later, Luigi Galvani discovered “animal electricity” (178).
To explain his observations, Galvani suggested that nerve
and muscle are capable of generating electricity by accumulating positive and negative charges on two opposite
surfaces. Moreover, the electrical flow necessary to produce voltage changes was explained by Galvani in terms
of specific fluid-filled pores between the internal and external surfaces, which were the harbingers of ion channels.
The 19th century witnessed the emergence of the
cellular theory. Furthermore, it became apparent that the
cell is a complex structure containing numerous organelles. Great histologists, such as Rudolf Virchow,
Gustav Retzius, Santiago Ramon y Cajal, and Jan Purkinje, to name but a few, developed various techniques to
look inside the cells, and it was Camillo Golgi who, using
his “black (silver chromate) reaction” technique in 1898
discovered the “fine and elegant reticulum hidden in the
cell body” of owl cerebellar Purkinje neurons (187; see
also Refs. 37, 384), the structure known to us as the “Golgi
complex.” The first detailed description of the endoplasmic reticulum was made by Golgi’s pupil, Emilio Veratti,
who, by using black reaction technique on muscle fibers,
was the first to discover a “true reticular apparatus constituted of filaments” (385, 668, 669; Fig. 1). This finding
remained almost unnoticed for 50 years, and only when
the endoplasmic reticulum (ER) was rediscovered by
Keith Porter and George Palade, who used electron microscopy (481), were Veratti’s achievements generally
recognized.
Insights into the physiological function of the ER and
the appearance of the concept of intracellular Ca2⫹ stores
resulted from studies of muscle contraction. Sidney Ringer’s experiments (535), which clearly identified Ca2⫹ as an
ion mediating muscle contraction, did not address directly the question of the Ca2⫹ source, although Ringer
noticed that contractions of skeletal muscle can be maintained in Ca2⫹-free media for hours and even days (536,
537), suggesting the existence of some barriers hampering
the exchange of ions between the muscle interior and the
external milieu. Further notions of the possible importance of intracellular Ca2⫹-containing systems were stimulated by experiments in which it was shown that move-
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
an electrochemical gradient favoring Ca2⫹ entry (334,
544). The functional importance of the neuronal ER as a
dynamic Ca2⫹ pool was first appreciated after the demonstration that neuronal microsomal fractions can accumulate Ca2⫹ via an ATP-dependent mechanism (649). Almost simultaneously it was also discovered that various
neuronal preparations, such as the squid axon (64), extruded axoplasm (21), and permeabilized synaptosomes
(51, 52), are able to sequester Ca2⫹ even when mitochondrial uptake was obliterated (see also Ref. 416 for review).
Finally, this nonmitochondrial Ca2⫹ uptake was unequivocally associated with the ER (212–214, 682), and the
latter became firmly established as a dynamic intracellular Ca2⫹ store, deeply involved in neuronal signaling.
II. ORGANIZATION OF THE ENDOPLASMIC
RETICULUM
A. The Neuronal ER as a Continuous
Endomembrane Structure
The endoplasmic reticulum is arguably the largest
single intracellular organelle, which appears as a threedimensional network formed by an endomembrane and
organized in a complex system of microtubules and cisternae. In neurons, the ER extends from the nucleus and
the soma to the dendritic arborization and, through the
axon, to presynaptic terminals. Classical histology subdivides the ER into smooth ER, rough ER, and the nuclear
envelope (32). The continuity of the endomembrane that
forms these three structures was initially deduced from
microscopic observations (130, 131, 371, 682). Further
insights into the continuity of the ER were gained by
fluorescent microscopy on cells injected with the lipophilic probe 1,1⬘-dihexadecyl-3,3,3⬘,3⬘-tetramethylindocarbocyanine perchlorate (DiIC16), which diffuses within
strictly continuous lipid membranes. When injected into
cells, DiIC16 labeled the intracellular membrane network
endowed with ER markers (632, 633). Injection of DiIC16
into rat cerebellar Purkinje neurons in acutely isolated
brain slices revealed a continuous membrane network
extending throughout all parts of the cell (Fig. 2, A and B).
The kinetics of dye spread was consistent with intramembrane diffusion; moreover, the ER labeling occurred even
when slices were fixed 2 min after dye injection, thus
excluding the possibility of active transport (634). Very
similar ER labeling was observed in cultured hippocampal neurons (634). The concept of a continuous ER was
further substantiated by experiments on nonneuronal
cells. Initially, the continuity of the intra-ER aqueous
space was directly demonstrated in pancreatic acinar
cells, where soluble molecules, such as Ca2⫹ and fluorescent dyes, were shown to move throughout the ER lumen
with remarkable ease (491, 509). Later on, it was found
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
ments of ameba are particularly sensitive to chelation of
intracellular Ca2⫹. Injection of Ca2⫹-precipitating agents
such as phosphates, sulfates, or alizarine sulfonate froze
the movements of the amebas almost instantly (513, 532).
The first direct evidence for the existence of a sizable
intracellular Ca2⫹ storage compartment was obtained by
Weise, who found that excessive physical exercise led to
the appearance of Ca2⫹ in the ultrafiltrate of rat skeletal
muscle (691). Later, an increased release of radioactive
Ca2⫹ from stimulated frog sartorius muscle was demonstrated by Woodward (698), thus proving the existence of
intracellularly stored calcium.
The idea of an intracellular Ca2⫹ store and the importance of regulated intracellular Ca2⫹ release for muscle contraction was formulated by Heilbrunn, who was
also the first to test these concepts experimentally (210,
211). His theory was not readily accepted, and for many
years K⫹ were considered to be the regulators of contraction and relaxation, a theory very much supported by
Szent-Gyorgyi (619). Only after the free intracellular Ca2⫹
in skeletal muscle was measured directly by murexide
(263) or aequorin (15, 533) could internal Ca2⫹ release be
visualized and the intracellular Ca2⫹ store became the
legitimate member of a Ca2⫹ signaling cascade. In the
meantime, the concept of intracellular Ca2⫹ pumps associated with the endomembrane was developed by W. H.
Hasselbach, Setsuro Ebashi, and Anne-Marie Weber (see
Ref. 159), explaining how the ER could accumulate Ca2⫹.
At the same time, the first indications of ER-residing
regulated ion channels, which could provide a means of
Ca2⫹ release, appeared (158).
At the beginning of the 1970s the crucial role of the
ER (in its sarcoplasmic reticulum disguise) in regulation
of contraction became generally accepted and the concepts of Ca2⫹-induced Ca2⫹ release and depolarizationinduced Ca2⫹ release firmly established (see Refs. 140,
160 for review). At the same time, the receptor-activated,
second messenger-induced intracellular Ca2⫹ release was
discovered (81, 457), and a possible role for inositol phospholipids in signal transduction was suggested (410). Another decade, however, passed before the seminal experiments of Hanspeter Streb, Robin Irvine, Irene Schulz, and
Michael Berridge (607) showed that this alternative pathway for intracellular Ca2⫹ release is mediated by the
second messenger inositol 1,4,5-trisphosphate (InsP3).
The intracellular Ca2⫹ release channels, residing within
the endomembrane, were soon molecularly characterized, revealing two main families: the Ca2⫹-gated and
InsP3-gated channels (505, 613). Thus the general concept
of intracellular Ca2⫹ stores was established, and the stage
was set for identification of their functional role in various
cell types.
The ability of nerve cells to actively buffer cytosolic
Ca2⫹ was initially associated with Ca2⫹ accumulation by
mitochondria, the latter utilizing H⫹ transport to develop
203
204
ALEXEI VERKHRATSKY
that much larger molecules of green fluorescence protein
(GFP) targeted against the ER and expressed in Chinese
hamster ovary (CHO) cells, were also able to freely diffuse within the ER lumen. Repeated local laser illumination of a spot 2 ␮m in diameter eventually bleached all
GFP present in the cell, thus demonstrating the continuity
of the ER lumen (115). Similarly, in RBL cells transfected
with even larger ER-targeted elastase-GFP fusion protein
(molecular weight 60 kDa), fluorescence recovery after
photobleaching revealed rapid (diffusion coefficient ⬃0.5
␮m2/s) movements of this, rather hefty, protein within the
entire ER lumen (610).
Although internally continuous, the ER exhibits an
extraordinary heterogeneity in both its morphology and
the functional properties. The ER can be represented as
tubular networks as well as by flattened cisternae, the
latter sometimes arranged in complex cisternal ER stacks
or even crystalloid structures found in photoreceptors
(682) and Purkinje neurons (625). In neuronal somata, the
ER network is omnipresent (Fig. 2), and part of it forms
the nuclear envelope. Portions of the ER in the soma and
Physiol Rev • VOL
in the distal dendrites are molded into specialized structures known as subsurface cisternae, which come into
close contact with the plasma membrane (620). These
cisternae exist in several shapes and forms: type I is
separated from the plasmalemma by a distance of 60 – 80
nm, whereas types II and III reside much closer, at a
distance of ⬃20 nm from the plasmalemma. These latter
types of ER cisternae often follow the contour of the
surface membrane (543). Sometimes the surface cisternae
are organized in more complex structures, the cisternal
organelles, which have been found in the proximal parts
of axons (34, 267, 305, 548).
In axons, the ER mostly has a tubular structure and
extends into the presynaptic terminals, where it often
closely enwraps the mitochondria (48, 391, 693). The ER
also spreads throughout the dendrites, terminating in the
spine apparatus and thereby connects the latter with the
entire ER lumen (604).
An important feature of the ER is its morphological
plasticity. The ER network constantly remodels itself
through multiple forms of tubular movements. These
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 2. Morphological appearance of neuronal endoplasmic reticulum (ER). A: the continuity of ER in Purkinje neurons from acutely
isolated cerebellar slices. The lipophilic dye
DiIC16 (absorption maximum 549 nm, emission
565 nm) was injected into the soma of two
Purkinje neurons (PNs) in acutely isolated slice,
and the resulting spread of fluorescence was
imaged by a confocal microscope 4 h after dye
injection. To obtain the image of the entire cellular network, a Z-series scan was performed,
and the images were superimposed. B: spread of
DiIC16 in living and fixed PNs. Images show the
spread of the dye at 30 min (a) and 2 h (b) after
the dye injection in a living cell; c and d show
the spread of DiIC16 in PN fixed 2 min after dye
injection and imaged 15 min (c) and 14 h (d)
after injection. Bars for A and B, 10 ␮m. C:
imaging of the ER in isolated sensory neuron.
The same DRG neuron cultured for 24 h after
isolation was stained with ER-Tracker (100 nM,
10 min at 24°C) and BODIPY FL-X fluorescent
ryanodine (1 ␮M, 5 min). The fluorescence was
excited at 357 nm (ER-Tracker) and at 488 nm
(BODIPY FL-X ryanodine), and emitted light
was collected at 530 ⫾ 15 nm. [A and B from
Terasaki et al. (634), copyright 1994 National
Academy of Sciences, USA; C from Solovyova et
al. (603), with permission from Nature Publishing Group.]
CALCIUM STORE IN THE ER OF NEURONS
in rapid cellular signaling, because it is a dynamic store of
Ca2⫹ that regulates the cytosolic Ca2⫹ concentration and
generates Ca2⫹ fluxes between the cytosol and the ER
lumen in response to extracellular stimulation. Finally,
the ER coordinates all these diverse processes with the
physiological state of the cell. Therefore, the ER may be
defined as a multifunctional organelle able to detect and
integrate incoming signals and generate output signals in
response to environmental changes (40, 57). For a comprehensive overview of ER functions, see References 65,
257, 364, 388, 392, 399 – 402, 479, 487, 508, 509, 591, 677.
The intimate mechanisms of ER integration remain
largely undiscovered, yet a central role for Ca2⫹ is emerging. First, Ca2⫹ is a key input and output signal of the ER.
Indeed, Ca2⫹ concentration increases in the cytosol affect
its concentration in the ER, and in turn, the ER Ca2⫹
release and uptake influence the cytosolic Ca2⫹ concentration. Second, a number of intra-ER chaperones, such as
calreticulin, calnexin, grp78/BiP, endoplasmin (or glucose-regulated protein, grp94), are Ca2⫹ binding proteins,
and changes in free Ca2⫹ concentration in the lumen of
the ER ([Ca2⫹]L) profoundly affect their functional activity (106, 409). Therefore, fluctuations in the ER Ca2⫹
content may provide the link between rapid signaling and
long-lasting cellular adaptive responses.
C. The ER as an Excitable Organelle
B. The ER as a Universal Signaling Organelle
The functions of the ER are many. First and foremost, the ER is the site of synthesis and maturation of
proteins. Protein synthesis is accomplished in the rough
ER, while posttranslational processing of proteins is governed by an extended family of ER-resident chaperones,
which form complexes with newly synthesized proteins,
assist their folding into the final tertiary structure and
prevent them from aggregation. If the process of folding
somehow fails, the chaperones remain assembled with
misfolded proteins, thereby preventing them from proceeding through the ER exit sites and towards the Golgi
complex. Whenever the concentration of unfolded proteins rises dangerously high, the ER develops a specialized reaction known as ER stress, as a result of which
transcription-affecting signals are sent to the nucleus,
which, in turn, adjusts gene expression according to environmental requirements. In addition to the synthesis of
proteins, the ER is the primary site of formation of phospholipids, glucosylphosphatidylinositols, and leukotrienes. The ER may also serve as a graveyard for various
unwanted molecules and toxins. Owing to its continuous
lumen, the ER serves as a highway allowing haulage of
transport RNAs, secretory products, numerous structural
proteins and, as we shall see later, ions between different
parts of polarized cells. The ER is also intimately involved
Physiol Rev • VOL
The basic physiology of the ER calcium store has
been extensively characterized in a variety of excitable
and nonexcitable cells (for key reviews, see Refs. 38 – 42,
56, 75, 76, 147, 177, 308, 309, 381, 507, 508, 539, 670 – 672,
712). The ER acts as a dynamic Ca2⫹ store due to concerted activity of Ca2⫹ channels and transporters residing
in the endomembrane, and intraluminal Ca2⫹-binding proteins, which serve as a high-capacity Ca2⫹ buffering system. Ca2⫹ efflux from the ER is executed by two families
of Ca2⫹ channels, the Ca2⫹-gated Ca2⫹ channels, generally referred to as the ryanodine receptors (RyRs), and the
InsP3-gated channels, commonly known as InsP3 receptors (InsP3Rs). Ca2⫹ accumulation into the ER lumen
results from the activity of Ca2⫹ pumps of the sarco(endo)plasmic reticulum Ca2⫹-ATPase (SERCA) family. The
molecular physiology of ER channels and SERCA pumps
has been comprehensively reviewed recently (RyRs, Refs.
59, 148, 161, 396, 545, 695; InsP3Rs, Refs. 44, 411, 412, 631;
SERCA pumps, Refs. 121, 134, 587, 618, 699); hence, I shall
limit myself to a brief discussion of their key features in
the context of neuronal signaling.
1. Ca2⫹ release channels
The Ca2⫹ release channels, the RyRs and the InsP3Rs,
are large tetrameric channel proteins that share a rather
peculiar four-leaf clover-like structure when observed by
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
movements occur quite rapidly; new structures emerge
within tens of seconds (57). Even large formations such
as crystalline cisternal organelles are not static and may
swiftly surface as part of a neuronal adaptive response,
for example, against hypoxia (625).
The topographical heterogeneity of the ER is
matched by its functional diversity. Protein synthesis
within the rough ER occurs in specific compartments,
with different mRNAs being specifically selected and targeted towards distinct regions of the reticulum (209, 525,
682). Sometimes mRNA is engaged in a long-distance
travel to end up in the ER in dendrites, where the actual
synthesis of a locally demanded protein (e.g., InsP3 receptors, Ref. 606) takes place (180, 566). Here, the ER closely
interacts with another reticular structure, the Golgi apparatus, the outposts of which are present in dendrites and
are involved in final trafficking of membrane proteins and
proteins destined for secretion (237, 238). Although the
precise mechanisms of the intra-ER mRNA sorting remain
unclear, they appear to be an important part of proteins
targeting cascades. The synthesis of phospholipids and
cholesterol similarly appears to be spatially heterogeneous, with different steps of the process occurring in
different ER compartments (32). The enormous functional heterogeneity of the ER is nonetheless integrated
into a coherent system by the continuous lumen.
205
206
ALEXEI VERKHRATSKY
Physiol Rev • VOL
mRNA became the major isoform in many brain regions,
while RyR1 mRNA became prominent in the dentate gyrus
and in the Purkinje cell layer. Postnatal downregulation in
the caudal cerebral cortex restricted RyR3 mRNA expression to the hippocampus, particularly the CA1 region
(427).
In vivo imaging of RyRs can be achieved using fluorescent BODIPY-ryanodine (e.g., Refs. 389, 603; Fig. 2C).
Because ryanodine binding to the RyR is use dependent,
the intensity of BODIPY-ryanodine staining may reflect
the overall density of open channels. With the use of this
technique, a redistribution of active RyRs from soma to
dendrites was observed in developing hippocampal neurons (611); moreover, L-type Ca2⫹ channel-RyR coupling
was identified at early developmental stages (611), reflecting a developmental switch between RyR1 and RyR2 expression in nerve cells (427).
Similar to RyRs, the InsP3 receptor family comprises
three homotetrameric isoforms, InsP3R1, InsP3R2, and
InsP3R3, although further diversity may arise from alternative splicing of InsP3R1 (up to 6 variants; Ref. 463) and
heteromeric expression (399). The most important difference between isoforms lies in their different sensitivity to
[Ca2⫹]i: the InsP3R1 has the “classical” bell-shaped dependence on [Ca2⫹]i with a maximal activation at ⬃300 – 400
nM (45); the InsP3R2 and InsP3R3 are also stimulated by
[Ca2⫹]i increase, but are not readily inhibited by larger
[Ca2⫹]i rises (198).
In the central nervous system, the InsP3Rs were initially discovered in the cerebellum (172, 613), but thereafter all three isoforms were identified throughtout the
brain, with particularly strong expression in Purkinje neurons and in somatas of CA1 cells (170, 171, 574). The
InsP3R1 is the most abundant isoform in the brain,
whereas InsP3R2 dominates in the spinal cord and is also
highly expressed in glial cells. The InsP3R3 are expressed
to a much lesser extent but are nonetheless clearly detectable in several brain regions, such as the cerebellar
granule layer and the medulla (575). There is a prominent
heterogeneity in the intracellular distribution of InsP3Rs.
For example, InsP3R1 is found in dendrites, dendritic
spines, cell bodies, axons, and axonal terminals of cerebellar Purkinje cells, but is mostly confined to somatic
regions and proximal dendrites in other neurons (122,
551, 575). The InsP3R3 is very much concentrated in the
neuropil and neuronal terminals (575).
2. SERCA pumps
The SERCA pump belongs to the family of P-type
Ca2⫹-ATPases and includes three gene products,
SERCA1, SERCA2, and SERCA3; alternative splicing produces two distinct isoforms of SERCA2, namely, 2a and
2b. In central neurons, the SERCA2b is ubiquitously expressed, whereas SERCA2a and SERCA3 are found al-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
electron microscopy. The RyRs were the first to receive
experimental attention due to their vital role in excitationcontraction coupling in muscle. The RyR family comprises three major receptor subtypes, which were historically classified as “skeletal muscle,” “heart,” and “brain”
types, currently referred to as RyR1, RyR2, and RyR3,
respectively. The historic classification had a certain
physiological sense, as the RyR1 type, dominant in skeletal muscle, possesses a rather unique activation mechanism; it can be activated solely by membrane depolarization by virtue of a direct link with the plasmalemmal Ca2⫹
channels through a huge cytosolic “foot” extension. All
three RyRs can be activated by Ca2⫹ from the cytosolic
side; the rank order of their sensitivity to cytosolic free
Ca2⫹ concentration ([Ca2⫹]i) being RyR1 ⬎ RyR2 ⬎ RyR3
(93, 435). On the basis of studies on reconstituted channels in lipid bilayer membranes, the RyRs can be biophysically described as not perfectly selective Ca2⫹ channels
(PCa/PK ⬃6 –7) with fast activation kinetics (␶ of activation ⬃0.5–1 ms) and a large conductance (100 –500 pS,
depending of the nature of ion carrier) (148). Yet, taking
into account the imperfect selectivity toward monovalent
cations and the virtual absence of selectivity between
divalents, the physiological unitary Ca2⫹ current through
RyRs can be as small as 0.5– 0.9 pA at 2 mM intraluminal
Ca2⫹ concentration (397).
All three types of RyRs have been detected in neurons; however, expression of the RyR2 isoform dominates. Interestingly, although the RyR3 was initially called
the “brain” subtype, its total expression in the central
nervous system does not exceed 2% of all RyRs (434). The
RyR1 is heavily expressed in cerebellar Purkinje neurons,
whereas RyR3 is found in hippocampal structures, the
corpus striatum, and the diencephalon (170, 185, 434, 474,
574).
However, these are only general trends; in reality,
many neurons coexpress either two or all three types of
RyR isoforms. RyRs are found in high densities in neuronal somatas; in axons of hippocampal (574), cerebellar
(475), and cortical (723) neurons; in cerebellar mossy
fibers (475); and in presynaptic terminals (355). RyRs are
also widely expressed in the dendritic tree; their expression is particularly high in dendritic spines of hippocampal CA1 neurons, where they represent the dominant
Ca2⫹ release channel (574). Incidentally, RyRs were visualized (with fluorescent ryanodine) in the Golgi complex
of sympathetic neurons, although the functional relevance of this discovery remains unclear (98).
The expression of RyRs changes considerably during
development; for instance, throughout the embryonic
stage, RyR1 mRNA levels are highest in the rostral cortical plate, whereas RyR3 mRNA was most prominent in
the caudal cortical plate and hippocampus. Low levels of
RyR2 mRNA were detected in the diencephalon and the
brain stem. However, from postnatal day 7 onward, RyR2
CALCIUM STORE IN THE ER OF NEURONS
3. ER Ca2⫹ buffers
ER Ca2⫹ buffering is accomplished by several Ca2⫹binding proteins; in neurons, the most abundant is calreticulin, which accounts for nearly one-half of total ER
Ca2⫹ binding. Calreticulin in the neuronal ER is endowed
with 20 –50 low-affinity Ca2⫹ binding sites (KD ⬃1 mM)
and therefore can bind a huge amount of Ca2⫹. As mentioned above, calreticulin acts not only as a Ca2⫹ buffer,
but also as an important chaperone and regulator of
SERCA pumps. Calsequestrin, the major ER Ca2⫹ buffer
in skeletal myocytes, is also present in nerve cells, and
like calreticulin may bind up to 50 Ca2⫹ with low affinity.
Several other low-affinity Ca2⫹-binding proteins, such as
endoplasmin (grp94), BiP/grp78, and proteins of the
CREC family (reticulocalbin, calumenin, Cab55, etc.) also
participate in intra-ER Ca2⫹ buffering (235, 399, 401, 409).
The most important property of the ER Ca2⫹ buffers
is their low affinity to Ca2⫹, which allows the maintenance of high intra-ER free Ca2⫹ levels. There is a fundamental difference in Ca2⫹ handling in the cytosol and
within the ER lumen. The cytoplasmic Ca2⫹ binding proPhysiol Rev • VOL
teins are characterized by a very high (10 –100 nM) affinity
to Ca2⫹; therefore, they limit Ca2⫹ diffusion and favor
localization of cytosolic Ca2⫹ signals. In contrast, the low
Ca2⫹ affinity of the ER buffers allows Ca2⫹ diffusion
throughout the lumen (423).
4. The ER as an excitable medium
The extensive complement of endomembrane Ca2⫹
channels and transporters, together with intra-ER Ca2⫹
storage proteins, gives rise to the excitable properties of
the ER. Ca2⫹ accumulation in the ER lumen creates a
large electrochemical driving force favoring Ca2⫹ movement from the ER lumen into the cytosol; hence, opening
of Ca2⫹ channels in the ER membrane causes fast efflux
of Ca2⫹ from the ER. In turn, the ER channels are sensitive to signals originating at the plasmalemma and so can
be activated by both electrical and chemical stimulation
of the cell. Furthermore, the ER channels are subject to
positive autofeedback due to their sensitivity to cytosolic
Ca2⫹, leading to a regenerative opening of RyRs and/or
InsP3Rs beyond a certain threshold of [Ca2⫹]i. This regenerative process underlies propagating waves of channel
activation along the ER membrane, very similar to the
propagating wave of opening and closing of Na⫹ and K⫹
channels that generate plasmalemmal action potentials.
Neuronal function is thus an interplay of two excitable
membranes, the outer and the inner, which are coupled
through a multitude of reciprocal signaling cascades (39).
In contrast to plasmalemma, which is mostly specialized
for integrating extracellular information, the ER uses
Ca2⫹ to couple plasmalemmal and cytosolic events with
intraluminal formation and transport of proteins, as well
as with gene expression within the nucleus. The periodic
fluctuations of the ER Ca2⫹ concentration are instrumental for this intracellular integration, because [Ca2⫹]L regulates the excitability of the ER membrane by controlling
ER Ca2⫹ release channels and SERCA pumps, and governs intra-ER enzymatic cascades.
III. ENDOPLASMIC RETICULUM CALCIUM
RELEASE IN NERVE CELLS
A. The Discovery of Ca2ⴙ Release From the ER
Historically, the first observations of the release of
Ca2⫹ from an intracellular pool were very much indebted
to the previous discovery that caffeine can activate RyRs
in muscle cells (688). The pioneering observation indicating that caffeine affects neuronal [Ca2⫹]i was made by K.
Kuba and S. Nishi in 1976 (319). When monitoring membrane potential of neurons in isolated sympathetic ganglia
of the bullfrog, Kuba and Nishi found that superfusion of
the ganglia with an extracellular solution supplemented
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
most exclusively in cerebellar Purkinje neurons (18). The
physiological role of SERCA3 remains quite mysterious,
and genetic deletion of this Ca2⫹ pump does not result in
any obvious phenotypic change, save minor deficits in
relaxation of vascular and tracheal smooth muscles (351).
An important property of the SERCA2b pump that is
relevant for ER Ca2⫹ homeostasis is the tight regulation of
its activity by the free Ca2⫹ concentration in the ER
lumen, mediated via the Ca⫹-binding proteins calreticulin
(264) and ERp57 (341). Calreticulin senses the actual level
of [Ca2⫹]L and, by directly interacting with SERCA2b,
activates Ca2⫹ pumping whenever [Ca2⫹]L decreases. The
ERp57 regulates Ca2⫹ uptake by modulating the redox
state of SERCA2b thiols in a Ca2⫹-dependent manner.
The SERCA pumps have a distinct pharmacology;
they are blocked irreversibly by thapsigargin (TG) in submicromolar concentrations (KD ⬃20 nM) and reversibly
by cyclopiazonic acid (CPA) at concentrations of ⬃20 –50
␮M. Inhibition of the SERCA pumps results in a relatively
slow emptying of releasable Ca2⫹ from the ER, with Ca2⫹
leaving the ER through poorly understood pathways (72).
It must also be noted that TG is not perfectly specific for
SERCAs; it also inhibits plasmalemmal voltage-gated
Ca2⫹ channels of L/N-types in DRG neurons at concentrations of 0.2–2 ␮M (582). Likewise, micromolar concentrations of TG substantially decreased T and L Ca2⫹ currents
in adrenal glomerulosa cells (546). The concentrations of
TG that inhibit Ca2⫹ channels are comparable to those
used in the majority of experiments in which it is intended
to block the Ca2⫹ accumulation by the ER. A certain care,
therefore, should be taken when interpreting data arising
from such experiments.
207
208
ALEXEI VERKHRATSKY
TABLE
1.
Caffeine-induced Ca2⫹ release
Species/Age/NS Region
Technique
Experimental Evidence
Rat/newborn/DRG
Primary culture
Aequorin
microphotometry
Rat/neonatal/superior cervical
ganglia
Primary culture
Frog/paravertebral ganglia
Primary culture
(up to 5 DIV)
Fura 2-AM or fura 2
microfluorimetry;
whole cell
voltage clamp
Fura 2-AM imaging
Helix pomatia/ganglia
Freshly isolated
neurons
Dog/adult/cerebrum,
cerebellum
Microsomes
Bull frog/adult/lumbar
sympathetic ganglia
Primary culture
(1–7 DIV)
Whole cell voltage
clamp; fura 2
imaging
Rat/P2–P7/DRG
Primary culture
(2 DIV)
Indo 1-AM; fura
2-AM
microfluorimetry
Rat/P14/hippocampus
Freshly isolated
cells
Whole cell voltage
clamp
Chicken/P10/DRG
Freshly isolated
neurons
Whole cell voltage
clamp/indo 1-AM
microfluorimetry
Rat/P5–P8/DRG, neocortex,
hippocampus CA1, CA3,
nucleus cuneatus
Primary culture
(2–14 DIV)
Indo 1-AM
microfluorimetry
Chicken/E16–E19/cerebellum
Freshly
dissociated
PNs
Primary
cultures
(3–17 DIV)
Fura 2-AM
microfluorimetry
Acute slices,
PN
Whole cell voltage
clamp; fura 2,
fura 2-AM
imaging
Cells microinjected with aequorin (1–3 mg/ml) responded to
caffeine (10 mM) with large [Ca2⫹]i elevation. The latter
was insensitive to 5 mM Co2⫹ applied extracellularly.
First application of caffeine (duration ⬃7 s) depleted the
store so that the second application, which arrived ⬃50 s
later, was unable to elevate [Ca2⫹]i. Store can be refilled
by 3 APs applied in a sequence, after which caffeine
triggered full-blown [Ca2⫹]i elevation.
Caffeine (10 mM) induced [Ca2⫹]i elevation in the absence
of extracellular Ca2⫹; this [Ca2⫹]i rise was completely
blocked by 1 ␮M ryanodine, 10 ␮M dantrolene, but not by
TMB-8 (10 ␮M).
Caffeine (10 mM) triggered [Ca2⫹]i elevation, which was
large in the soma, and smaller in the growth cone.
Caffeine responses did not require extracellular Ca2⫹.
In the presence of caffeine and theophylline intracellular
injections of Ca2⫹ were necessary to reach a threshold
for CICR. Incidentally, intracellular Ca2⫹ release was also
triggered by thymol.
Caffeine (6 mM) and extravesicular Ca2⫹ (20 ␮M) triggered
Ca2⫹ release inhibited by La3⫹ (4 ␮M), ryanodine (50
␮M), Mg2⫹ (IC50 6 ␮M for cerebrum and 12 ␮M for
cerebellum); ruthenium red (IC50 40 ␮M for cerebrum and
60 ␮M for cerebellum) and DAPI (IC50 90 ␮M for
cerebrum and 150 ␮M for cerebellum).
Caffeine (10 mM) triggered [Ca2⫹]i elevation, increased
frequency of SMOCs and activated an outward current.
Caffeine-induced [Ca2⫹]i elevation was inhibited by
ryanodine (0.1–10 ␮M) and procaine (5 mM). Ryanodine
by itself caused slow rise in [Ca2⫹]i. Increase in [Ca2⫹]i
levels preceding caffeine application potentiated Ca2⫹
release.
Caffeine (2–20 mM) triggered [Ca2⫹]i elevation which did
not require extracellular Ca2⫹. Caffeine-induced [Ca2⫹]i
transients were blocked by ryanodine (10 ␮M), procaine
(5 mM), dantrolene (10 ␮M), and Ba2⫹ (0.5 mM).
Caffeine (10 mM) triggered activation of Ca2⫹-dependent K⫹
current; inhibition of Ca2⫹ release by 10 ␮M ryanodine
and 0.5–1 mM procaine abolished the current.
Caffeine (10 mM) triggered activation of Ca2⫹-dependent
Cl⫺ current [ICl(Ca)] and induced [Ca2⫹]i elevation. Both
effects did not require external Ca2⫹ and were blocked
by 10 ␮M ryanodine.
Caffeine (20 mM) triggered [Ca2⫹]i responses in central
neurons only after conditioning depolarization by 50 mM
KCl; in DRG neurons caffeine was able to induce Ca2⫹
release in resting conditions.
Caffeine (10 mM) and trans-ACPD triggered [Ca2⫹]i
elevations which were considered to be the result of
Ca2⫹ release from the ER.
Caffeine (10 mM) initiated [Ca2⫹]i rise, which did not
require external Ca2⫹, and was blocked by ryanodine in
use-dependent manner. Small increase (by ⬃30 nM) of
resting [Ca2⫹]i by tonic activation of NMDA receptors (0.3
␮M glutamate ⫹ 10 ␮M glycine in Mg2⫹-free solution)
significantly (up to 3 times) potentiated caffeine-induced
[Ca2⫹]i response.
Caffeine (20 mM) caused [Ca2⫹]i elevation in small
proportion of resting neurons; when resting [Ca2⫹]i was
elevated by moderate depolarization caffeine caused
[Ca2⫹]i responses in most of the cells. The amplitude of
caffeine-induced [Ca2⫹]i elevation linearly depended from
precaffeine [Ca2⫹]i level. Caffeine-induced [Ca2⫹]i
responses were blocked by ruthenium red (10 ␮M) and
by ryanodine (10 ␮M, in a use-dependent manner).
Caffeine significantly prolonged [Ca2⫹]i transients in
response to depolarization or climbing fiber stimulation;
this prolongation was blocked by 10 ␮M ruthenium red.
Mouse/E15–E16/telencephalon
Rat/P12–P22/cerebellum
Fura 2-AM
microfluorimetry
antipirilaso III
microphotometry
Stopped-flow
photometry of
arsenaso III
Fura 2-AM imaging
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Reference
Nos.
452
637
348, 349
311
407
368
661
658
255
581
553
650
269
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Preparation
CALCIUM STORE IN THE ER OF NEURONS
TABLE
209
1—Continued
Species/Age/NS Region
Preparation
Technique
Experimental Evidence
Primary culture
(2–8 DIV)
Fura 2-AM
microfluorimetry
Chicken/E18/brain stem
Acute slices
Fura 2-AM imaging
Rat/P9–P18/hippocampus
Acute slices,
CA1
pyramidal
neurons
Whole cell voltage
clamp; fura 2;
fura 2-AM video
imaging
Rat/E19/hippocampus
Primary culture
(21 DIV)
Calcium green 1
confocal imaging;
fura 2-AM
imaging
Rat/adult/tongue
Freshly isolated Fura 2-AM
taste receptor
microfluorimetry
cells
Bullfrog/adult/sympathetic
ganglia
Primary culture
(14 DIV)
Fura 2-AM, fura
6-AM
microfluorimetry
Tiger salamander/larval stage/
retina
Freshly isolated
rods and
cones
Fura 2-AM imaging;
fluo 4-AM
confocal imaging
Mouse/P2–P5/brain stem
Acute slices,
hypoglossal
motoneurons
Fura 2 imaging;
fura 2, calcium
green 1
multiphoton
imaging
Caffeine (1–100 mM) produced Ca2⫹ release, which was
inhibited by dantrolene (10 ␮M), CPA (30 ␮M), procaine
(5 mM), and ryanodine (1 ␮M); the latter block was use
dependent (i.e., at least 1 application of caffeine has to
be performed in the presence of ryanodine in order to
inhibit developments). Multiple caffeine applications
depleted the store; store replenishment required
plasmalemmal Ca2⫹ influx. Readmission of Ca2⫹ after
depletion of the store by caffeine in Ca2⫹-free solution
triggered significant [Ca2⫹]i increase, indicative of the
activation of SOC.
Caffeine (100 mM) induced [Ca2⫹]i increase when applied in
Ca2⫹-free media; caffeine-induced [Ca2⫹]i responses were
inhibited by glutamate and trans-ACPD, suggesting GluR
control over CICR.
Caffeine (⬃10 mM) triggered [Ca2⫹]i elevation in previously
unstimulated cells; the caffeine [Ca2⫹]i response did not
require extracellular Ca2⫹, was blocked by ryanodine (20
␮M) in a use-dependent manner, and was inhibited by
CPA (30 ␮M) and TG (3 ␮M).
Application of caffeine induced [Ca2⫹]i rise in 34 of 48
spines; [Ca2⫹]i response did not require extracellular
Ca2⫹ and was blocked by TG (1 ␮M) and ryanodine (10
␮M). At the same time TG and ryanodine reduced [Ca2⫹]i
responses to glutamate; the degree of suppression was
higher in dendrites vs. spines.
Caffeine (10 mM) induced Ca2⫹ release, blocked by
preincubation with 1 ␮M TG (25–40 min); the release was
independent on extracellular Ca2⫹ and insensitive to
ryanodine (50 nM–100 ␮M).
Repetitive applications of low (2 mM) concentrations of
caffeine resulted in sensitization of CICR and gradual
increase in the amplitude of caffeine-induced Ca2⫹
release most probably due to an increase in ER Ca2⫹
content.
Caffeine (10 mM) evoked [Ca2⫹]i transients, which were
blocked by ryanodine (20 ␮M), CPA (5 ␮M), and TG (1
␮M); these drugs also attenuated [Ca2⫹]i transients in
response to KCl depolarization, indicating CICR.
Application of caffeine (5 mM) triggered large [Ca2⫹]i rises;
Ca2⫹ release was initiated in “hot spots,” which, in
somatic regions, coincided with sites of depolarizationinduced Ca2⫹ entry. Ca2⫹ release also activated
Ca2⫹-dependent K⫹ currents.
286
274
179
303
715
226
315
322
DIV, days in vitro; PN, Purkinje neuron; APs, action potentials; CICR, Ca2⫹-induced Ca2⫹ release; DAPI, 4⬘,6-diamidino-2-phenylindole; ER,
endoplasmic reticulum; CPA, cyclopiazonic acid; SOC, store-operated Ca2⫹ entry; TG, thapsigargin.
with 1– 6 mM caffeine resulted in rhythmic hyperpolarizations. Further on, they found that the caffeine-induced
effects on membrane potential (Vm) were mediated
through a Ca2⫹-dependent K⫹ conductance, because intracellular injection of EDTA inhibited the action of caffeine. Several years later, Kenji Kuba made the logical
suggestion that “rhythmic increases in the GK under the
effect of caffeine are due to oscillations of the intracellular Ca2⫹ concentration and that there may be Ca storage
sites in the bullfrog sympathetic ganglion cell which are
comparable to the sarcoplasmic reticulum in the skeletal
muscle fiber” (317). Using K⫹ permeability as a readout of
[Ca2⫹]i, several groups confirmed these observations
(219, 318, 431, 557). The advent of luminescent and fluoPhysiol Rev • VOL
rescent Ca2⫹ probes allowed direct monitoring of [Ca2⫹]i,
which became instrumental for detailed investigations of
ER Ca2⫹ release in nerve cells.
B. Ca2ⴙ-Induced Ca2ⴙ Release
1. Caffeine-induced Ca2⫹ release
As already mentioned, the methylxantine caffeine
was the first specific agent permitting identification of ER
Ca2⫹ release, and it has remained the probe of choice
(Table 1). Probably the first direct indication that another
methylxantine, theophylline, triggers [Ca2⫹]i rises in vertebrate nerve cells was obtained in bullfrog sympathetic
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Myenteric plexus/P1/guinea
pig
Reference
Nos.
210
ALEXEI VERKHRATSKY
ing and McBurney (452) showed that caffeine depletes the
Ca2⫹ store, which, however, can be rapidly replenished by
stimulating the neuron with several action potentials
(APs) (Fig. 3B). Further progress in studying caffeineinduced Ca2⫹ release was very much assisted by the
introduction of fluorescent Ca2⫹ probes (653, 654) as well
as by the widespread use of the patch-clamp technique
(200). When combined, these techniques allowed simultaneous monitoring of membrane currents and [Ca2⫹]i
dynamics. In 1988, caffeine-induced Ca2⫹ release was
identified in fura 2-loaded sympathetic neurons of the frog
(348, 349) and in sympathetic (636), sensory (637), and
central (638) neurons of the rat. Within the next several
years caffeine-induced Ca2⫹ release was discovered in all
types of neurons studied regardless of the preparation;
the phenomenon was found in freshly dissociated neu-
FIG. 3. Identification of caffeine-stimulated ER
Ca2⫹ release in nerve cell. A: effect of caffeine on
membrane potential (Vm) and [Ca2⫹]i (proportional to
changes in Ilight) in a single DRG neuron. The resting
Vm was ⫺55 mV. Extracellular solution contained 20
mM TEA. Peak of caffeine-induced [Ca2⫹]i rise was
⬃10 ␮M. B: caffeine depletes the ER calcium store.
Similarly to A, the [Ca2⫹]i and Vm were recorded from
a single DRG neuron. First application of caffeine
triggered [Ca2⫹]i rise; however, when caffeine was
applied 50 s later, no changes in [Ca2⫹]i were observed. After the cell was stimulated by three action
potentials (AP), caffeine was once more able to produce [Ca2⫹]i elevation. The time elapsed after the
beginning of the experiment is indicated on the graph.
[From Neering and McBurney (452), with permission
from Nature Publishing Group.]
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
neurons injected with the bioluminescent Ca2⫹ probe
arsenazo III (597). Yet, the first proper description of
caffeine-induced Ca2⫹ release was published in 1984,
when Ian Neering and Robert McBurney presented the
results of their experiments on DRG neurons, which were
isolated from newborn rats and injected with another
luminescent Ca2⫹ probe, aequorin (452). When 10 mM
caffeine was applied to DRG neurons, they responded by
a large light transient, reflecting an elevation of [Ca2⫹]i
(Fig. 3A). In fact, the caffeine-induced [Ca2⫹]i elevation
was three to five times larger than the [Ca2⫹]i increase
evoked by action potentials (the latter artificially prolonged by addition of 20 mM TEA). The caffeine-induced
[Ca2⫹]i response was preserved in an extracellular solution containing 5 mM Co2⫹, suggesting that it was independent of plasmalemmal Ca2⫹ entry. Furthermore, Neer-
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
2. The “quantal” nature of caffeine-induced
Ca2⫹ release
Caffeine releases Ca2⫹ from neuronal ER in a rather
peculiar manner, which has been termed “quantal” release. When the cell is challenged with a low concentration of caffeine (⬃2–5 mM), a transient Ca2⫹ response is
triggered, and even if caffeine remains in the system, the
[Ca2⫹]i recovers back toward the prestimulated level. Applications of caffeine in submaximal concentrations fail
to empty the store completely; subsequent application of
a higher caffeine concentration induces a further [Ca2⫹]i
elevation. Interestingly, it appears that a submaximal caffeine concentration can empty the store “compartment”
sensitive to this concentration: when 2 mM of caffeine is
applied repetitively, the second application no longer produces a [Ca2⫹]i response (Fig. 4). This peculiar quantal
release was found when studying [Ca2⫹]i dynamics in
cultured chromaffin cells (92), in rat (661) and mouse
(584) DRG neurons, and in myenteric neurons (286). A
similar quantal release was also found when monitoring
[Ca2⫹]L in chromaffin cells expressing ER-targeted aequorin (9; see Fig. 4A). These observations can be explained by assuming either that different neuronal Ca2⫹
release channels have different sensitivities to caffeine, or
that the ER is composed of several compartments, which
are discharged by different concentrations of caffeine
(92). Further experiments showed, however, that the
quantal caffeine-induced release is controlled by intraluminal Ca2⫹ concentration, and overcharging the stores
with Ca2⫹ following massive depolarization-induced Ca2⫹
entry significantly enhances the sensitivity of ER Ca2⫹
release to caffeine (Fig. 4D, Refs. 300, 584). In the context
of ER Ca2⫹ release, [Ca2⫹]L-dependent regulation of RyRs
appears to be a general phenomenon, as the same sort of
regulation is well established for another Ca2⫹ release
channel, the InsP3R. Similar to RyRs, elevation of luminal
Ca2⫹ increases the sensitivity of InsP3R to InsP3 (419,
465). Changes in “luminal” [Ca2⫹] in a planar lipid system
directly influenced the purified InsP3R by affecting their
inactivation (643).
3. Cytosolic Ca2⫹ regulates caffeine-induced
Ca2⫹ release
The nature of interaction of caffeine with RyRs depends on the concentration of the former: direct electrophysiological investigations of isolated ryanodine receptor channels have demonstrated that low (⬍2 mM) concentrations of caffeine sensitize the channel to
extraluminal (i.e., cytoplasmic) calcium, shifting RyR activation towards submicromolar Ca2⫹ concentrations. In
the presence of low millimolar caffeine concentrations,
the RyR channel open probability (Po) was significantly
increased mostly due to a shortening of the lifetime of the
closed state. At higher concentrations (⬎5 mM), caffeine
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
rons, neurons in primary cultures, and neurons in situ in
brain slices (see Table 1).
As a drug aimed at an intracellular target, caffeine is
rather convenient as it freely diffuses through the plasma
membrane, and its wash-in and wash-out kinetics are
quite similar. The process of caffeine entering and exiting
the cell can be directly monitored by exploring the ability
of caffeine to quench the fluorescence of various Ca2⫹
probes in a wavelength-independent manner (471, 661,
662). This quenching is most prominent for indo 1, which
allows real time recordings of intracellular caffeine concentration simultaneously with [Ca2⫹]i measurements.
The properties of caffeine-induced Ca2⫹ release are
generally similar between different neurons (Table 1).
Caffeine induces a [Ca2⫹]i rise without a requirement for
extracellular calcium, and the [Ca2⫹]i elevation is not
associated with plasmalemmal Ca2⫹ movements. Caffeine-evoked [Ca2⫹]i transients are sensitive to pharmacological modulators interacting with RyRs or with
SERCA pumps; specifically, these [Ca2⫹]i responses are
blocked by ryanodine, dantrolene, ruthenium red, and
procaine and disappear after inhibition of ER Ca2⫹ uptake
with TG or CPA (Table 1). Caffeine responses are found in
all parts of neurons, from soma to dendrites and presynaptic terminals. Caffeine-induced Ca2⫹ release that is sensitive to TG and ryanodine has even been observed in
individual spines of cultured hippocampal neurons, which
are rich in ryanodine receptors (303).
Incubation of neurons isolated from bullfrog sympathetic ganglia with 10 mM caffeine frequently induces
[Ca2⫹]i oscillations (e.g., Refs. 164, 166, 462), which are
often quite diverse in different neurons, ranging from
high-amplitude regular oscillatory activity to low-amplitude decaying [Ca2⫹]i fluctuations (111). This diversity of
oscillatory patterns reflects complex mechanisms responsible for their generation, which involve ER (Ca2⫹-induced Ca2⫹ release and SERCA-dependent Ca2⫹ uptake,
etc.) as well as non-ER (mitochondrial Ca2⫹ accumulation, plasmalemmal Ca2⫹ extrusion) cascades.
When using caffeine in nerve cell preparations, a
certain caution is needed, because caffeine (and other
methylxanthines) directly affects potassium channels
(660) and effectively inhibits delayed rectifier and A-type
potassium currents in vertebrate neurons (529). In certain
types of neurons, caffeine may also activate plasmalemmal Ca2⫹ influx, for example, as demonstrated in
acutely dissociated rabbit nodose ganglion neurons (229)
and leech mechanosensitive neurons (565). The KD values
for the activation of ER Ca2⫹ release and plasmalemmal
Ca2⫹ influx by caffeine were close (1.5 and 0.6 mM, respectively); this needs to be taken into account when
interpreting caffeine-induced [Ca2⫹]i responses as a sole
consequence of ER Ca2⫹ release.
211
212
ALEXEI VERKHRATSKY
opens RyRs even at picomolar [Ca2⫹]i and dramatically
increases the open time of the channel (e.g., Refs. 221,
547, 593).
These biophysical properties of the caffeine-RyR interactions are also reflected by the [Ca2⫹]i dependence of
caffeine action on nerve cells. The amplitude of the
[Ca2⫹]i elevation induced by 10 mM caffeine increased
sharply when the [Ca2⫹]i preceding the application of the
drug was elevated by a conditioning KCl depolarization of
rat sympathetic neurons (221). By changing the duration
of the KCl application between 0.3 and 7 s, the conditioning [Ca2⫹]i rise could be graded, therefore making it possible to characterize the relation between [Ca2⫹]i and the
amplitude of caffeine-induced Ca2⫹ release (Fig. 5A). This
relation appeared bell-shaped: an increase of [Ca2⫹]i from
the resting level of ⬃50 –70 to 100 –300 nM markedly
potentiated caffeine-induced [Ca2⫹]i response, but a further increase of [Ca2⫹]i to ⬎400 nM led to an inhibition of
the caffeine-evoked [Ca2⫹]i elevation. A similar effect of
[Ca2⫹]i on the response to a submaximal (2 mM) caffeine
challenge was observed in rat sensory neurons (Fig. 5B),
where an increase in [Ca2⫹]i preceding caffeine application greatly potentiated Ca2⫹ release (584). Moreover,
when precaffeine [Ca2⫹]i reached a level of ⬃350 nM, 2
mM caffeine induced a full-blown Ca2⫹ release that almost completely emptied the ER.
An even more striking dependence of caffeine responses on precaffeine [Ca2⫹]i was observed in central
neurons. In Purkinje cells studied in rat cerebellar slices,
Physiol Rev • VOL
application of 20 mM caffeine to the resting cell (resting
[Ca2⫹]i ⬃20 – 40 nM) rarely resulted in Ca2⫹ release. Yet,
when [Ca2⫹]i was slightly elevated by moderately depolarizing the cell (experiments were done under voltageclamp) caffeine produced robust [Ca2⫹]i elevations (Fig.
6). The amplitude of the caffeine-induced [Ca2⫹]i response was linearly dependent on the preceding [Ca2⫹]i
level (269). Similarly, in hippocampal neurons, an elevation of precaffeine [Ca2⫹]i from ⬃40 to 284 nM led to a
3.5-fold increase of the caffeine-induced [Ca2⫹]i response
(179).
4. Physiological CICR
A) THE ER AS A SOURCE OF AND SINK FOR CYTOSOLIC CA2⫹.
Although the ability of the ER to buffer [Ca ]i and at the
same time to release Ca2⫹ into the cytosol was recognized
already by the mid 1980s (213, 214, 386), the concept of
the ER Ca2⫹ store acting as a “Ca2⫹ sink and Ca2⫹ source”
was for the first time clearly formulated by David Friel
and Richard Tsien in 1992 (165). They backed up this
concept with a rather thorough analysis of changes in
depolarization-induced Ca2⫹ transients occurring upon
various manipulations of the ER Ca2⫹ store. First, they
convincingly demonstrated that ER Ca2⫹ release participates in the delivery of Ca2⫹ to the cytosol during cell
depolarization, i.e., that CICR indeed acts as an amplifier
of Ca2⫹ signals resulting from plasmalemmal Ca2⫹ entry.
They employed a protocol, which later became a gener-
85 • JANUARY 2005 •
2⫹
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 4. “Quantal” release of Ca
by
caffeine. A: “quantal” caffeine-induced
2⫹
release of ER Ca
as measured by
[Ca2⫹]L recordings in bovine chromaffin
cells expressing ER-targeted low-affinity
aequorin. The ER was refilled by incubation with medium containing 1 mM Ca2⫹,
and the increasing concentrations of caffeine were applied as indicated. B and C:
examples of [Ca2⫹]i recordings from
acutely isolated mouse DRG neurons in
response to different concentrations of
caffeine. Note that (C) the second application of 2 mM caffeine fails to induce
[Ca2⫹]i increase, although 5 mM of caffeine applied shortly after triggers Ca2⫹
release. D: increase in intraluminal Ca2⫹
content increases the sensitivity of ER
Ca2⫹ release to caffeine. The graph
shows the concentration dependence of
caffeine-induced [Ca2⫹]i responses. The
amplitudes of caffeine-induced [Ca2⫹]i
transients measured at rest (E) and after
conditioning depolarization (F; the example of [Ca2⫹]i trace is shown in inset)
are plotted against caffeine concentration. Data are pooled from 24 mouse
DRG neurons; bars denote ⫾SD. [A from
Alonso et al. (9) by copyright permission
from The Rockefeller University Press.
B–D from Shmigol et al. (584), copyright
1996 with permission from Elsevier.]
CALCIUM STORE IN THE ER OF NEURONS
213
2⫹
2⫹
FIG. 6. Effects of [Ca ]i on caffeine-induced Ca
release in Purkinje neurons. A: pseudocolor fluorescence images of [Ca2⫹]i illustrating the
[Ca2⫹]i dependence of caffeine-induced Ca2⫹ release in various cellular compartments. The gain of intensified CCD camera was set at values that
optimized detection from dendrites, but partially saturated the fluorescence signal from the soma (darkened area in the central part of the soma).
B: [Ca2⫹]i recordings from the soma and proximal and distal dendrites of Purkinje neuron shown in A. The regions from which the mean [Ca2⫹]i
values were calculated are indicated by rectangles on images shown in A. Arrows marked with a, b, and c indicate the time at which the digital
fluorescence images in A, labeled a, b, and c, were taken. The baseline [Ca2⫹]i was changed by applying 6 depolarizing pulses (from ⫺60 to 0 mV
for 500 ms) immediately before the application of caffeine. [From Kano et al. (269), with permission from Blackwell Publishers Ltd.]
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 5. Effects of [Ca ]i on caffeine-induced Ca2⫹ release in peripheral
neurons. A: the [Ca2⫹]i recordings were
performed on cultured rat sympathetic
neurons. Left: examples of [Ca2⫹]i transients illustrating the effects of applying
a conditioning pulse of high KCl of increasing durations (as indicated under
the traces) just before a caffeine application of 5 s. The interval between the end
of KCl pulse and the caffeine application
remained constant at 1.5 s. Right: amplitudes of caffeine (⌬[Ca2⫹]caff) measured
from the records shown on the left and
plotted against the “pedestal” [Ca2⫹]i (P),
reached immediately before caffeine administration. B: two [Ca2⫹]i recordings
taken from the same freshly isolated
mouse DRG neuron. Note that increase
in [Ca2⫹]i significantly potentiated the
amplitude of 2 mM caffeine-induced response (left trace); further increase in
[Ca2⫹]i (right trace) triggered even
larger response to 2 mM caffeine, which
emptied the ER, as judged by very small
response to subsequent application of 20
mM caffeine. Timing of caffeine and KCl
applications is indicated on the graph. [A
from Hernandez-Cruz et al. (221), with
permission from Blackwell Publishers
Ltd. B from Shmigol et al. (584), copyright 1996 with permission from Elsevier.]
214
ALEXEI VERKHRATSKY
ally accepted test for CICR. This protocol compared depolarization-induced [Ca2⫹]i transients in control conditions and in conditions when 1) ER is recovering following treatment with a high (10 –20 mM) concentration of
caffeine, 2) RyRs are sensitized by a low (1 mM) concentration of caffeine, and 3) RyRs are activated by 1 ␮M
ryanodine and the stores are permanently depleted. In
perfect concordance with the idea of the ER having the
dual role of [Ca2⫹]i buffer and Ca2⫹ source, these manip-
ulations affected both the rising phase and the recovery of
[Ca2⫹]i elevations in response to membrane depolarization with 30 –50 mM KCl (Figs. 7 and 8). A complete
depletion of the stores decreased the amplitude and rate
of rise of KCl-induced [Ca2⫹]i transients, and accelerated
their recovery by 1) removing the CICR contribution and
2) upregulating Ca2⫹ uptake into the depleted ER. Sensitization of RyRs by 1 mM caffeine increased the rate of
rise and the amplitude of the depolarization-induced
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 7. ER Ca
store as a source of and sink for
Ca2⫹. Top panel represents [Ca2⫹]i traces evoked by 30
mM KCl in control conditions and upon pharmacologically modulated ER Ca2⫹ store (b– e) as explained by
drawings below. Arrows indicate direction and relative
magnitude of the net Ca2⫹ flux across the surface
membrane and between the cytosol and the store,
during the onset and recovery phases of the response.
Under control conditions (a), depolarization stimulates Ca2⫹ entry and a rise in [Ca2⫹]i, which promotes
Ca2⫹ release from the store (onset). Repolarization
permits the Ca2⫹ contents of both the cytosol and the
store to relax towards their prestimulation levels (recovery); since the store released Ca2⫹ during the onset, it must accumulate Ca2⫹ during the recovery. b:
When continuously present, caffeine (1 mM) enhances
Ca2⫹-induced Ca2⫹ release (CICR) from the store (onset) so that [Ca2⫹]i increases more rapidly than it does
under control conditions. To restore its initial Ca2⫹
content, the store also accumulates Ca2⫹ more avidly
during the recovery; as a result, [Ca2⫹]i declines more
rapidly following repolarization. If Ca2⫹ entry is induced while the store is filling as in c, net Ca2⫹ uptake
by the store slows the rate at which [Ca2⫹]i rises during
the onset. However, if [Ca2⫹]i is elevated long enough
for the Ca2⫹ content of both the cytosol and the store
to approximate the steady-state values achieved under
control conditions (a), then [Ca2⫹]i will recover just as
it does in the control (compare a and c, recovery). By
increasing passive Ca2⫹ exchange between the store
and cytosol, ryanodine prevents net Ca2⫹ accumulation by the store (d and e). Without the added effect of
CICR, [Ca2⫹]i rises more slowly in response to stimulated Ca2⫹ entry (compare a and d, onset) and falls
more slowly during recovery (compare a and d) than it
does under control conditions. Since the store remains
discharged in the presence of ryanodine, caffeine has
no further effect. Therefore, the postcaffeine response
in the presence of ryanodine (e) is essentially the same
as the response elicited in the presence of ryanodine
without caffeine pretreatment (d). [From Friel and
Tsien (165), with permission from Blackwell Publishers Ltd.]
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
manipulations resulted in large and frequent [Ca2⫹]i responses in freshly dissociated neurons (697) (however a
caveat: the cultures were prepared from the embryonic
cerebellum, E16-E18, whereas neurons were acutely isolated from mice at postnatal days 10 –16). Conversely, no
CICR in response to a single AP or trains of APs (tetanic
stimulation) was observed in bullfrog sympathetic neurons, when studied in whole ganglia (462), but a prominent CICR in response to Ca2⫹ entry was invariably observed when the same cells were kept in culture conditions (240).
In certain cell types, physiological CICR exhibits a
remarkable spatial heterogeneity. In leech Retzius neurons, for instance, depletion of the ER by 10 ␮M CPA
reduced AP-induced [Ca2⫹]i transients in dendrites, but
not in axons (33). In frog sympathetic ganglion neurons,
either within the whole ganglia or in culture, a single AP
was able to trigger several local CICR events concentrated in the ER-rich perinuclear region or around axon
hillocks, as was revealed by fast fluo 4 confocal imaging
(112).
At the subcellular level, activation of CICR is represented by local release events, resulting from spontaneous activation of RyRs and subsequent recruitment of
RyR clusters. These elementary [Ca2⫹]i signals [observed
in nerve growth factor-differentiated PC12 cells and in
cultured hippocampal neurons (298, 398)] are analogs to
“sparks” in muscle cell preparations. Neuronal [Ca2⫹]i
sparks occur spontaneously, and their frequency increases upon addition of low concentrations of caffeine
or following loading of the ER store by conditioning depolarization-induced Ca2⫹ entry. In contrast to other
preparations, neuronal release sites appear to contain
both InsP3Rs and RyRs, since metabotropic stimulation
affected elementary Ca2⫹ release frequency at the same
sites as caffeine (298). Spontaneous [Ca2⫹]i sparks were
also found in presynaptic boutons of the lizard neuromuscular junction (398) and in cerebellar basket neurons
(105, 355).
More accurate characterization of CICR in nerve
cells requires a direct comparison between plasmalemmal
Ca2⫹ entry and [Ca2⫹]i elevation. This necessitates simultaneous monitoring of Ca2⫹ currents (under voltageclamp) and [Ca2⫹]i; the amount of Ca2⫹ entering the cell
can be precisely calculated by integrating Ca2⫹ current
(ICa) over time, and hence the ⌬[Ca2⫹]i can be directly
related to 兰ICa/⌬t. Such an experiment was performed for
the first time in rat sympathetic neurons (636), revealing a
fairly linear relation between Ca2⫹ entry and ⌬[Ca2⫹]i at
short test pulses and its saturation at long test pulses
(range of ICa durations varied between 10 and 640 ms).
When the same experiment was repeated in the presence
of 10 mM caffeine and 10 ␮M ryanodine, suppression of
⌬[Ca2⫹]i was detected; however, this phenomenon was
not very robust, leading the authors to conclude that
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
[Ca2⫹]i transient, and moderately accelerated the recovery of the [Ca2⫹]i elevation by 1) enhancing the CICR
contribution and 2) augmenting Ca2⫹ uptake because
increased CICR depleted the store to a higher extent
compared with control. Finally, permanent emptying of
the ER by 1 ␮M ryanodine decelerated the KCl-induced
[Ca2⫹]i transient and slowed down the recovery by 1)
removing the CICR contribution and 2) occluding the ER
Ca2⫹ uptake, because the store remained permanently
leaky due to constantly open RyRs.
The concept of “sink and source” quite adequately
explains CICR behavior in nerve cells, and, most importantly, it emphasizes the role of the intra-ER Ca2⫹ content,
which appears to be an essential regulator of ER function,
controlling the mode (source or sink) of Ca2⫹ store operation. The relatively low ER Ca2⫹ content would therefore promote [Ca2⫹]i buffering as for example happens in
hypoglossal motoneurons, where depletion of the store by
caffeine prolonged the recovery, but did not alter the
amplitude of AP-evoked [Ca2⫹]i transients (127).
B) EVIDENCE FOR PHYSIOLOGICAL CICR IN NEURONS. With the use
of the paradigm described above, the contribution of
CICR to the [Ca2⫹]i elevation triggered by plasmalemmal
Ca2⫹ entry has been demonstrated for many types of
neurons, in both the peripheral and the central nervous
system (Table 2). In addition to the protocols used by
Friel and Tsien, several other experimental approaches
were developed, e.g., CICR can be completely blocked by
high concentrations of ryanodine, or the ER store can be
depleted using the SERCA pump blockers TG or CPA. The
changes observed in the depolarization-induced [Ca2⫹]i
transients caused by these interventions are very much as
expected from the sink and source theory: inhibition of
CICR by ryanodine slows down the rate of rise and decreases the amplitude of KCl-induced [Ca2⫹]i transients,
whereas inhibition of ER Ca2⫹ uptake has the same effect
on the onset of [Ca2⫹]i signals in response to depolarization and significantly decelerates their recovery.
With the use of these methods, the contribution of
CICR to depolarization-evoked [Ca2⫹]i signaling was discovered in many, but not in all, neurons (e.g., it was
absent in cerebellar granule neurons, Refs. 250, 292).
Furthermore, in experiments on brain slices with preserved synaptic inputs, a very significant CICR was recorded in response to synaptic stimulation in dendrites
(Fig. 8B) and even spines of hippocampal neurons (6,
138). In these cases the trigger Ca2⫹ entered the cytosol
via Ca2⫹-permeable NMDA receptors.
It is worth pointing out that the functionality of the
CICR pathway may critically depend on the experimental
conditions. For instance, in Purkinje neurons, the parameters of ER Ca2⫹ release are greatly affected by cell
culture. Photorelease of InsP3 or administration of caffeine induced only a tiny [Ca2⫹]i response in a small
fraction of cultured Purkinje neurons, whereas the same
215
216
TABLE
ALEXEI VERKHRATSKY
2.
Physiological CICR in nerve cells
Species/Age/NS Region
Preparation
Technique
Evidence for CICR
Reference
Nos.
CICR in response to Ca2⫹ entry
Primary culture Microelectrodes Vm
(up to 7 DIV)
recordings;
fura 2-AM
microfluorimetry
Rat/P2–P7/lumbar DRG
Primary culture
(⬎2 DIV)
Snail Helix aspersa/
circumoesophagial
ganglia
Whole ganglia
Rabbit/P1–P3/otic ganglia
Primary culture
(1–3 DIV)
Bullfrog/12–18 cm long/
sympathetic ganglia
Whole ganglia
preparation
Rat/E20/cerebellum
Primary
cultured
Purkinje
neurons
Primary culture
Rat/P3/hippocampus
Rat/P1–P3/DRG
Primary culture
(2–3 DIV)
Rabbit/nodose ganglia
Primary culture
(3–4 DIV)
Rat/P10–P17/hippocampus Acutely
isolated
slices, CA1
neurons
Rat/P10–P18/cortex
Acutely
isolated
slices
Depletion of ER store with 20 mM caffeine reduced the amplitude
165
and speed of subsequent [Ca2⫹]i response to 50 mM KCl
depolarization. Cell treatment with 1 mM caffeine increased the
rate of rise and the amplitude of KCl-induced [Ca2⫹]i elevation,
whereas ryanodine (1 ␮M) inhibited caffeine-induced Ca2⫹
release and slowed down and attenuated the amplitude of
KCl-triggered [Ca2⫹]i transient.
Fura 2-AM,
Depletion of Ca2⫹ stores with 20 mM caffeine or RyRs inhibition
661
indo 1-AM
by ryanodine (10 ␮M) significantly decreased the rate of rise
microfluorimetry
and the amplitude of the subsequent [Ca2⫹]i responses to KCl
(40–50 mM). Sensitization of RyRs by 1 mM caffeine
accelerated the rise and increased the amplitude of [Ca2⫹]i
transients evoked by KCl.
Microelectrodes Vm Low doses of caffeine (0.2–1 mm) increased the amplitude of
472
recordings; fura 2
depolarization-induced [Ca2⫹]i transients. Ryanodine (10 ␮M)
2⫹
microfluorimetry
and CPA (50 ␮M) reduced the size of [Ca ]i responses to
depolarization and blocked effects of caffeine.
Fura 2-AM
Ryanodine (10 ␮M) decreased the amplitude (to ⬃70% of the
711
microfluorimetry
control) and the rate of rise (to 160% of the control) of [Ca2⫹]i
2⫹
elevation induced by 30 mM KCl and abolished [Ca ]i
oscillations in the presence of KCl.
Fura 2
Sympathetic terminals were loaded by indicator by placing a grain
502
microfluorimetry
of fura 2K5 at the end of sympathetic chain; terminals were
filled with the dye within 2–10 h. Ryanodine (10 ␮M) decreased
the amplitude of [Ca2⫹]i transients triggered by 100–400
electrical stimuli (20 Hz) by 46% on average (range 12–83%).
Fura 2-AM imaging Dantrolene (10 ␮M), ryanodine (10 ␮M), preincubation with
193
caffeine (10 mM), and BHQ (10 ␮M) significantly reduced
2⫹
AMPA-mediated [Ca ]i elevation being thus suggestive of
CICR.
Fluo 3-AM confocal Field stimulation of cultures triggered somatic [Ca2⫹]i responses
256
imaging
which rose linearly with an increase in number of APs.
3⫹
“. . . significantly more La has to be added extracellularly for
blocking Ca2⫹ responses, as predicted from the reported La3⫹
dependence of voltage-gated Ca2⫹ channels,” which led to a
conclusion that “ . . . the opening of intracellular Ca2⫹ release
channels plays a crucial part in shaping the action
potential-induced neuronal Ca2⫹ response.”
Whole cell
In the presence of 5 mM caffeine (acting as a “sensitizer” of
663
current-voltage
CICR) bursts of APs or Ca2⫹ currents triggered all-or-none
2⫹
2⫹
clamp; indo 1
Ca release from the ER when [Ca ]i reached the threshold
microfluorimetry
level of ⬃120 nM). cADPR applied through the pipette was not
calcium green-1
effective as a substitute to caffeine. In confocal experiments,
confocal imaging
CICR was shown to facilitate the spread of Ca2⫹ signal from
plasmalemma to cell interior.
103, 426
Sharp
Amplitude of Ca2⫹-dependent afterhyperpolariztion and [Ca2⫹]i
transient induced by a train of APs (1–8–65) were markedly
microelectrode
inhibited by ryanodine (10 ␮M), TG (100 nM), BHQ (10 ␮M),
voltage clamp;
or CPA (10 ␮M). These agents also inhibited caffeine-induced
fura 2-AM
[Ca2⫹]i response. In the presence of ER blockers at least 8 APs
microfluorimetry
were necessary to evoke measurable [Ca2⫹]i elevation, whereas
in control conditions 1 AP was already sufficient to evoke
[Ca2⫹]i response.
Whole cell current
CA1 neurons were excited by antidromic field stimulation or
560
clamp; fura 2-AM/
directly under current clamp. Low concentrations of caffeine (5
2⫹
bis-fura 2 imaging
mM) potentiated AP-driven [Ca ]i signals, whereas incubation
with high (20 mM) concentration of caffeine depressed [Ca2⫹]i
elevations. AP-driven [Ca2⫹]i signals were also suppressed by
TG (3␮M) and ryanodine (20 ␮M).
Fura 2/fluo 3
Stimulation of cortical neurons with depolarization for 2 s evoked
277
imaging/
burst of APs and biphasic [Ca2⫹]i elevation, with sharply rising
microfluorimetry
delayed 2nd phase. This 2nd phase was completely abolished
by intracellular perfusion with mixture of ryanodine (30 ␮M) ⫹
heparin (2 mg/ml) or by TG (10 ␮M).
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Bullfrog/sympathetic
ganglia
CALCIUM STORE IN THE ER OF NEURONS
TABLE
217
2—Continued
Species/Age/NS Region
Preparation
Technique
Evidence for CICR
Whole plexus
227
655
63
586
CICR in response to synaptic stimulation
Rat/P11–P17/hippocampus Acutely
isolated
slices, CA1
neurons
Rat/P9/hippocampus
Organotypic
(slice)
culture
Tetanic stimulation of SC triggered postsynaptic dendritic [Ca2⫹]i
response accompanied with NMDAR-mediated EPSC.
Ryanodine (10 ␮M) and TG (10 ␮M) reduced [Ca2⫹]i elevation
by ⬃70% without affecting EPSC.
Microelectrode
Synaptically evoked [Ca2⫹]i transients were measured in
current clamp;
individual spines using line-scan mode. These [Ca2⫹]i transients
Oregon green 488
resulted from activation of NMDA receptors and subsequent
BAPTA-1 confocal
CICR. Inhibition of ER Ca2⫹ release by CPA (15 ␮M) or
imaging
ryanodine (10–20 ␮M) greatly reduced or even abolished
synaptically evoked [Ca2⫹]i signals.
Whole cell voltage
clamp; fluo 3
confocal imaging
6
138
Unitary Ca2⫹ transients recordings
Bullfrog/adult/sympathetic Primary culture Whole cell voltage
ganglia
(up to 50
clamp; fura 2
DIV)
microfluorimetry;
indo 1 confocal
imaging
Rat/P8–P14/cerebellum
Acute slice, PN Whole cell voltage
clamp; fura 2
microfluorimetry
Rat/P2–P7/DRG
Freshly isolated Whole cell voltage
cells
clamp; indo 1
microfluorimetry
Rat/P10–P25/dorsolateral
geniculate nucleus
Acute slice;
Whole cell voltage
freshly
clamp; fura
isolated
2/bis-fura 2
neurons
imaging
Freshly isolated Whole cell voltage
cells
clamp; fura 2
microfluorimetry
Cockroach Periplaneta
americana/dorsal
unpaired median
(DUM) neurons
When Ca2⫹ entry was graded by changing the duration of ICa
240
(20–450 ms), the unitary Ca2⫹ transient showed a supralinear
2⫹
dependence on Ca entry when ICa exceeded ⬃300 ms.
Ryanodine (10 ␮M) depressed [Ca2⫹]i elevation without
affecting ICa. Sequence of two or three depolarizations
potentiated [Ca2⫹]i increase; this effect was blocked by
dantrolene. The UT also increased with an increase in resting
[Ca2⫹]i.
The amplitude of [Ca2⫹]i transients in response to ICa of
353
different durations (20–100 ms) increased supralinearly at
depolarizations ⬎60 ms. This supralinearity was blocked by
ruthenium red (20 ␮M) and was potentiated by ryanodine (20
␮M). The supralinearity was more pronounced in dendrites.
585, 673
Unitary Ca2⫹ transient was increased by elevation of [Ca2⫹]o
from 2 to 8 mM, and by 1 mM caffeine. The UT increased
supralinearly with an increase of ICa duration ⬎200 ms (range
20–500 ms). The supralinearity was blocked after stores
depletion with caffeine (20 mM) and UT in response to 500 ms
was greatly suppressed by ryanodine (10 ␮m) or after stores
depletion with caffeine (20 mM).
Grading of Ca2⫹ entry by an increase in the duration of ICa
68
(60–1,460 ms) resulted in a supralinear increase of the unitary
2⫹
[Ca ]i transient at ICa longer than 460 ms. This supralinear
relation was completely blocked by 20 ␮M ryanodine.
Unitary Ca2⫹ transients showed supralinearly with an increase
406
in ICa duration from 20 to 1,000 ms; this supralinearity was
blocked by ryanodine (100 ␮M) or ruthenium red (1 ␮M). CICR
also amplified [Ca2⫹]i responses induced by neurohormone D,
which triggered inward Ca2⫹ current.
Intraluminal ([Ca2⫹]L) recordings
Bovine/adrenal
chromaffin cells
Primary culture Luminometry of the
ER-targeted
aequorin
Physiol Rev • VOL
The resting [Ca2⫹]L was estimated at ⬃500–800 ␮M. Caffeine and
KCl (50 mM) depolarization triggered [Ca2⫹]L decrease being
thus indicative of CICR.
85 • JANUARY 2005 •
www.prv.org
9
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Microelectrode
CICR in myenteric neurons was graded by Ca2⫹ entry; each AP
current clamp;
triggered a release resulting in ⬃30 nM [Ca2⫹]i increase (which
bis-fura 2 imaging
accounted to ⬃50% of total [Ca2⫹]i rise). CICR controlled the
amplitude of AHP; ryanodine (10 ␮M) caused ⬃60% reduction
in both amplitude of AP-induced [Ca2⫹]i transient and AHP
amplitude.
Mouse WT and ␤2 NChR Acute isolated Fura 2-AM imaging Ca2⫹ influx through neuronal ␣7-NChR triggers CICR; inhibition
KO/9–15 days/substantia
slices
of the ER by dantrolene (10 ␮M) or CPA (30 ␮M) significantly
nigra pars compacta
reduced NChR-mediated [Ca2⫹]i elevation.
Mouse/vas
Freshly isolated Oregon
Perfusion with nicotine (2–30 ␮M) triggered small [Ca2⫹]i spikes,
deferense/postganglionic
tissue
green-BAPTA
which were blocked by ryanodine (100 ␮M) and caffeine (3
sympathetic terminals
1-AM confocal
mM). Authors suggested that activation of NChRs triggers Ca2⫹
imaging
influx via VGCC, which in turn induces CICR.
Chicken (E15 and P21)/
Freshly isolated Oregon green-1
Treatment with ryanodine (10 ␮M) and TG (1 ␮M) decreased
ciliary ganglia
whole
dextran (10,000
NChR-dependent [Ca2⫹]i plateau induced by high-frequency
ganglia
Da) confocal
synaptic stimulation. It is assumed that CICR is triggered by
imaging; dye
Ca2⫹ entry through Ca2⫹-permeable ␣7-NChRs.
delivered by
back-loading
Guinea pig/myenteric
plexus
Reference
Nos.
218
TABLE
ALEXEI VERKHRATSKY
2—Continued
Species/Age/NS Region
Rat/P1–P3/DRG
Preparation
Technique
Primary culture Mag-fura 2-AM/fluo
(1–2 DIV)
3 imaging
Evidence for CICR
Resting [Ca2⫹]L was estimated at ⬃300 ␮M. Short applications of
caffeine (20 mM) triggered [Ca2⫹]L decrease; [Ca2⫹]L recovery
was achieved chiefly by TG-sensitive uptake. The ICa triggered
by cell depolarization resulted in transient decrease in [Ca2⫹]L,
which was potentiated by 1 mM caffeine and blocked by 50 ␮M
ryanodine. The relation between Ca2⫹ entry and [Ca2⫹]L
decrease was linear, indicating graded CICR.
Reference
Nos.
603
Depolarization-induced Ca2⫹ release through RyRs
Mouse/adult/nerve
terminals
Acutely
isolated
116
RyR, ryanodine receptor; CICR, Ca2⫹-induced Ca2⫹ release; TG, thapsigargin; VGCC, voltage-gated Ca2⫹ channels; EPSC, excitatory postsynaptic current; CPA, cyclopiazonic acid; ICa, Ca2⫹ current.
CICR involvement in amplification of voltage-gated
[Ca2⫹]i transients is rather modest, if it exists at all.
Several years later, Shao-Yng Hua, Mitsuo Nohmi, and
Kenji Kuba (240) added a degree of sophistication to this
protocol by inventing a “unitary Ca2⫹ transient” (UT),
which legitimized the ⌬[Ca2⫹]i/兰ICa/⌬t equation being in
essence a measure of how many nanomolar Ca2⫹ will
appear in the cytoplasm per nanoCoulombs of Ca2⫹-carried current entering the cell. If the transmembrane calcium current would be the only source for the [Ca2⫹]i
increase, the UT should be constant irrespective of the
duration or amplitude of ICa. An increase in UT thus
reflects either the occurrence of CICR that delivers additional Ca2⫹, or saturation of cytoplasmic Ca2⫹ buffers
and/or fast Ca2⫹ extrusion systems. Several groups, starting with Hua et al. have measured UT or else quantified
the relation between Ca2⫹ entry and ⌬[Ca2⫹]i in peripheral (240, 406, 585, 673) and central (68, 353) neurons, and
all groups obtained virtually identical results (Table 2).
When Ca2⫹ entry was graded by lengthening the depolarization step, the UT would eventually begin to increase,
indicating a supralinear relation between Ca2⫹ entry and
⌬[Ca2⫹]i (Fig. 9); the UT was similarly increased when
Ca2⫹ entry was graded by increases in extracellular free
Ca2⫹ concentration ([Ca2⫹]o) or by varying the depolarization amplitude (Figs. 9 and 10). Pharmacological inhibition of RyRs, or emptying the ER by preincubation with
20 mM caffeine, would depress UT and remove the supralinear relation between ⌬[Ca2⫹]i and Ca2⫹ entry. Conversely, sensitization of RyRs by 1 mM caffeine results in
an increase of UT (i.e., in increase of ⌬[Ca2⫹]i in response
to the same ICa; Fig. 10). These data strongly imply the
existence of physiological CICR in nerve cells.
Physiol Rev • VOL
The final proof that CICR can be activated by physiological Ca2⫹ entry came from direct monitoring of
[Ca2⫹]L in neural cells (the technique will be discussed in
more details below). When performing these [Ca2⫹]L recordings in chromaffin cells (9) and in sensory neurons
(603), it was demonstrated that cell depolarization with
KCl in the former case, or activation of ICa under voltageclamp conditions in the latter, resulted in a clear decrease
in the [Ca2⫹]L, which reflected Ca2⫹ efflux from the ER
lumen (Fig. 11). Furthermore, these [Ca2⫹]L transients
can be enhanced by low caffeine concentrations and fully
inhibited by ryanodine, thus unequivocally linking the
[Ca2⫹]L decrease to the activation of RyRs.
C) NEURONAL CICR IS GRADED BY CA2⫹ ENTRY. The activation of
neuronal CICR proportionally follows the plasmalemmal
Ca2⫹ entry, as was shown in experiments correlating
兰ICa/⌬t and [Ca2⫹]i as described above. The “grading” of
CICR by plasmalemmal Ca2⫹ influx was demonstrated
even more directly in experiments where ICa, [Ca2⫹]i, and
[Ca2⫹]L were simultaneously monitored (Fig. 12, Ref.
603). The relationship between 兰ICa/⌬t and the magnitude
of the transient [Ca2⫹]L decrease activated by Ca2⫹ entry
was perfectly linear for ICa of increasing (from 50 ms to
3 s) durations. When the “unitary release potency” of ICa
(defined as the amount of charge translocated necessary
to decrease [Ca2⫹]L by 1 ␮M) was calculated, it remained
the same for Ca2⫹ currents of different durations. This
means that a small Ca2⫹ entry may generate only a moderate CICR, which may not significantly affect [Ca2⫹]i.
This most likely explains the apparent threshold for CICR
observed in unitary [Ca2⫹]i transient measurements (68,
240, 353, 406, 585).
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Whole terminal
Spontaneous localized [Ca2⫹]i transients (“Ca2⫹ syntillas”) were
voltage-clamp/fluo
observed in the terminals held at ⫺80 mV and bathed in
3 imaging
Ca2⫹-free solution. These events were also observed in
Ca2⫹-containing solution and in the presence of 200 ␮M Cd2⫹.
Frequency of Ca2⫹ syntillas was increased by caffeine and by
depolarization of the terminal in conditions of blocked
plasmalemmal Ca2⫹ influx; ryanodine (100 ␮M) inhibited
spontaneous Ca2⫹ transients. Stronger depolarization (from
⫺80 to 0 mV) can trigger global [Ca2⫹]i rise (inhibited by
ryanodine) even in the absence of extracellular Ca2⫹.
CALCIUM STORE IN THE ER OF NEURONS
219
The sensitivity of CICR to Ca2⫹ entry differs very
significantly between different neuronal types. For example, in sensory neurons, the contribution of CICR (determined as the ryanodine-sensitive component of the
[Ca2⫹]i transient) during physiological electrical activity
became apparent only when ⬎50 APs were generated in
close succession (20-Hz frequency) (585). Likewise, in
thalamocortical neurons, the contribution of CICR began
to materialize only when bursts of APs exceeded 25
spikes with inter-AP interval of 7.5 ms (68). Conversely, in
myenteric neurons, every single AP triggered a significant
CICR, which, however, remained graded because each AP
induced the same amount of Ca2⫹ release (227).
Nonetheless, in certain conditions, and in certain
cells, neuronal CICR may acquire a regenerative character, when after reaching a threshold the release develops
in an all-or-none fashion. A particularly strong CICR in
Physiol Rev • VOL
response to a single AP was observed in nodose neurons,
where Ca2⫹ entry produced by a single AP was amplified
5- to 10-fold by CICR, suggesting a regenerative process.
In fact, the inhibition of CICR in these cells resulted in
complete disappearance of [Ca2⫹]i elevations in response
to less than eight APs (103). In sensory neurons regenerative CICR was also reported, although it required pharmacological sensitization of RyRs. In the presence of 5
mM caffeine, suprathreshold [Ca2⫹]i elevations produced
by Ca2⫹ entry through plasmalemmal channels invariably
triggered all-or-none CICR (663). Conversely, when the
same protocol was applied to hippocampal neurons in
slices, it did not reveal any regenerative CICR (446).
In fact, CICR is tightly regulated by the amount of
trigger Ca2⫹ entering the cell and the rate of rise of [Ca2⫹]i
in the close neighborhood of RyRs (222). In the presence
of caffeine, the rise of [Ca2⫹] in the vicinity of RyRs is fast
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 8. Evidence for CICR in neurons: pharmacological modulation of depolarization- and synaptically induced [Ca2⫹]i elevation by caffeine and ryanodine. A: depletion of ER attenuates depolarizationinduced [Ca2⫹]i response in indo 1-AM-loaded
cultured rat DRG neurons. The [Ca2⫹]i trace shows
high-K⫹-induced [Ca2⫹]i transients before and after
store depletion by long application of 10 mM caffeine. The inset shows initial phase of depolarizationinduced [Ca2⫹]i response before and immediately after caffeine application. The amplitude and the rate
of rise of KCl-evoked [Ca2⫹]i transients were 603 nM
and 202 nM/s before and 393 nM and 122 nM/s after
depletion of the Ca2⫹ store. B: CICR accounts for
major part of [Ca2⫹]i elevation following titanic stimulation of synaptic inputs to CA1 neurons in hippocampal slices. Incubation of slice with 10 ␮M ryanodine or 10 ␮M thapsigargin markedly suppresses
[Ca2⫹]i elevation without affecting excitatory
postsynaptic currents. [A modified from Usachev et
al. (661); B modified from Alford et al. (6).]
220
ALEXEI VERKHRATSKY
enough to trigger a regenerative response, which, by recruiting adjacent RyRs (already sensitized by caffeine),
fully depletes the store. In the absence of caffeine, [Ca2⫹]i
rises are slower and inactivation of RyRs prevents the
occurrence of all-or-none CICR. One also has to remember the [Ca2⫹]i-sequestering ability of the ER, which balances the release, and sometimes may even overcome the
latter. Indeed, as was elegantly shown by David Friel and
colleagues (4, 234), the ER may switch between net Ca2⫹
release and net Ca2⫹ accumulation depending on the
amount of Ca2⫹ entering the cell.
The mechanism that allows smoothly graded CICR in
nerve cells is not entirely clear, although the very same
phenomenon has been known for a long time from experiments on cardiomyocytes (149). Several theories (e.g.,
RyR adaptation, Ca2⫹-dependent inactivation of RyRs,
[Ca2⫹]L depletion, [Ca2⫹]L regulation of RyRs, etc.) have
been proposed to explain the inhibition of autocatalytic
CICR (149, 326, 595); most likely a combination of many if
not all of these factors is responsible for Ca2⫹ entrydependent grading of Ca2⫹ release.
5. Depolarization-induced CICR in nerve cells
Although many neurons express the “skeletal”
RyR1, identification of direct depolarization-induced
Ca2⫹ release, which does not involve plasmalemmal
Ca2⫹ entry, has long been missing. Some recently published data indicate that direct coupling between the
plasmalemmal and ER Ca2⫹ channels in neurons may
Physiol Rev • VOL
indeed exist. At the molecular level, for instance, direct
coupling between the Ca2⫹ channels Cav1.2 or Cav1.3
and RyR1 was identified in solubilized rat brain membrane preparations (433). Some indirect evidence favoring the expression of depolarization-induced CICR
in axons was presented by Ouardouz et al. (473), who
demonstrated that inhibition of the voltage sensor of
Ca2⫹ channel provides the same degree of protection
against ischemic axonal damage as inhibition of RyRs.
These authors also observed coimmunoprecipitation
(suggestive of a direct physical link) of RyR1 and
Cav1.2 and of RyR2 and Cav1.3, both in the whole brain
and in the dorsal spinal cord column (such combinations are quite different from skeletal muscle where
RyR1 is linked to Cav1.1). Finally, elementary Ca2⫹
release events, which occurred in the absence of Ca2⫹
entry but were potentiated by depolarization, were
identified in isolated nerve terminals of magnocellular
hypothalamic neurons (116). The localized [Ca2⫹]i transients that resulted from these elementary Ca2⫹ releases were named Ca2⫹ scintillas (a spark or a glimmer
in latin). They were not affected by the removal of
extracellular Ca2⫹, they were sensitive to ryanodine,
and their frequency increased upon depolarization.
6. Endogenous CICR modulators
A) CYCLIC ADP RIBOSE. The effects of cyclic ADP ribose
(cADPR) on Ca2⫹ homeostasis were initially discovered
in sea urchin eggs microsomes where this pyridine nucle-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 9. Evidence for CICR in neurons: modulation of unitary Ca2⫹ transients by graded Ca2⫹ entry. A and B:
nonlinear relations between Ca2⫹ entry
and ⌬[Ca2⫹]i in Purkinje neurons in cerebellar slice. The amount of Ca2⫹ influx
was graded by changing either the duration of Ca2⫹ current (ICa; A) or the amplitude of test potentials evoking ICa
(from ⫺70 to ⫺40 mV to 0 mV, B). Plots
show peak ⌬[Ca2⫹]i values as a function
of ICa integral. The insets show selected
ICa (in response to depolarizations of different durations or different amplitudes)
and corresponding [Ca2⫹]i traces. C: similarly to A, the UT was measured from
single DRG neurons. Ca2⫹ entry was
graded by varying the duration of ICa
(evoked by test depolarization from ⫺60
to 0 mV, duration 20 –500 ms). Note the
clear supralinear increase in ⌬[Ca2⫹]i at
ICa longer than 200 ms. This supralinearity was completely obliterated when the
experiments were repeated in the presence of 20 mM caffeine, which depleted
the ER. [A and B modified from Llano et
al. (353); C from Verkhratsky and
Shmigol (673), copyright 1996 with permission from Elsevier.]
CALCIUM STORE IN THE ER OF NEURONS
221
otide applied in low micromolar concentrations was
found to trigger Ca2⫹ release (99, 333). The primary target
of cADPR is the ryanodine receptor type 2, and cADPR
triggers opening of RyR2 in various nonexcitable cells
(176, 177). In neuron-related cells or in neuron-derived
cell lines, the injection of cADPR was reported to induce
Ca2⫹ release. Such direct cADPR-triggered CICR was observed in permeabilized bovine chromaffin cells (430),
and PC12 pheochromocytoma cells (100), as well as in
neuroblastoma ⫻ fibroblast hybrid cells injected with
cADPR (251). An increase in [Ca2⫹]i due to Ca2⫹ release
was also observed in buccal Aplysia neurons injected
with cADPR (432); moreover, cADPR also potentiated the
release of ACh from cholinergic synapses belonging to
Physiol Rev • VOL
these neurons. Apart from affecting the ER, cADPR may
exert several other effects not connected with RyRs at all,
e.g., cADPR was reported to interact with M-type potassium channels by affecting the ACh-induced inhibition of
IK(M) (61). It has to be noted also that cADPR competes
with ATP for the same binding site on the RyR2 (592).
In mammalian neurons, cADPR usually does not induce Ca2⫹ release by itself, yet it potentiates CICR in
response to plasmalemmal Ca2⫹ entry. In the majority of
neurophysiological experiments, administration of
cADPR into the nerve cells was not accompanied by acute
changes in [Ca2⫹]i. Injection of cADPR via patch pipette
into NG108 –15 neuroblastoma cells did not affect resting
[Ca2⫹]i, but greatly potentiated depolarization-induced
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 10. Evidence for CICR in neurons: effects of increase in Ca
influx and pharmacological modulators. A: elevation of extracellular Ca2⫹
(from 2 to 8 mM) and hence increase in ICa (evoked by cell depolarization from ⫺60 to 0 mV) leads to an increase in urinary Ca2⫹ transient (UT)
in a single DRG neuron. B: incubation of DRG neuron with 1 mM caffeine results in dramatic increase of ⌬[Ca2⫹]i and UT in response to ICa; after
store depletion in the presence of 20 mM caffeine, both UT and ⌬[Ca2⫹]i are markedly depressed. Throughout the experiment ICa did not change
significantly. C: effects of pharmacological inhibition of ryanodine receptors (RyRs) by ryanodine on depolarization-induced [Ca2⫹]i transients.
Ryanodine (10 ␮M) was added into the intrapipette solution, and [Ca2⫹]i and ICa were recorded simultaneously from DRG neuron. First
depolarization (from ⫺60 to 0 mV, 500 ms) delivered 5 min after the beginning of intracellular perfusion triggered large [Ca2⫹]i transient (left trace).
Subsequent application of 20 mM caffeine (middle trace) failed to induce [Ca2⫹]i elevation. The second depolarization (right trace) resulted in ICa
very similar to the first, yet ⌬[Ca2⫹]i was reduced by ⬃80%, indicating CICR eradication by ryanodine. [A and C modified from Shmigol et al. (585);
B modified from Verkhratsky and Shmigol (673).]
222
ALEXEI VERKHRATSKY
[Ca2⫹]i elevation, the effect being, at least in part, blocked
by ryanodine. Apart from facilitating CICR, in these experiments cADPR also potentiated Ca2⫹ entry via L-type
channels (204). In another set of experiments on the same
neuroblastoma NG108 –15, the inclusion of 10 ␮M cADPR
into the pipette solution potentiated [Ca2⫹]i transients
evoked by Ca2⫹ currents and resulted in a strong nonlinearity between Ca2⫹ entry and [Ca2⫹]i transient amplitude
(thus indicating potentiated CICR, Fig. 13A, Ref. 137).
Similarly, intracellular administration of cADPR facilitated depolarization-induced [Ca2⫹]i transients in CA1
hippocampal pyramidal cells (612) and in thalamocortical
neurons (68).
Physiol Rev • VOL
In bullfrog sympathetic neurons, the inclusion of
cADPR into the intracellular solution enhances the amplitude of depolarization- and caffeine-induced [Ca2⫹]i
elevations (241). Similar facilitation of CICR by cADPR
was found in DRG neurons studied under whole cell
voltage-clamp with simultaneous monitoring of [Ca2⫹]i
using fura 2. The inclusion of cADPR into the dialyzing
solution significantly enhanced the unitary Ca2⫹ transient, thus reflecting increased nonlinearity between
Ca2⫹ entry through voltage-gated Ca2⫹ channels
(VGCCs) and the amplitude of the resulting [Ca2⫹]i
elevation (Fig. 13B, Ref. 580). The opposite results,
however, were obtained by Usachev and Thayer (663),
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 11. CICR as seen from the ER lumen. A:
CICR-induced changes in [Ca2⫹]L measured in bovine chromaffin cells transfected by ER-targeted aequorin. a: Activation of CICR by the Ca2⫹ entry elicited by high-K⫹-induced cell depolarization. The ER
was refilled by perfusing medium containing 1 mM
Ca2⫹. Then, standard medium containing 70 mM KCl
was applied as indicated. b: Potentiation of CICR by
1 mM caffeine. B: direct visualization of CICR in DRG
neurons. Simultaneous recordings of [Ca2⫹]i (normalized fluo 3 fluorescent intensity, black trace) and
[Ca2⫹]L (ratiometric recordings with Mag-fura 2, gray
trace) dynamics recorded from the same neuron are
presented. The cell was challenged subsequently by
an application of caffeine (20 mM) and by a 3-s step
depolarization from ⫺70 to 0 mV (the corresponding
Ca2⫹ current is shown in the inset on the top of the
fluo 3 trace). Note that depolarization triggers an
increase in cytoplasmic Ca2⫹ and a decrease in
[Ca2⫹]L. C: pharmacological manipulation with
CICR-induced changes in [Ca2⫹]L. a: Low (1 mM)
caffeine concentration enhances the CICR. The
[Ca2⫹]i (black traces) and [Ca2⫹]L (gray traces) were
measured from the same DRG neuron. The neuron
was stimulated by 3-s depolarizations in control conditions and in the presence of 1 mM caffeine (the
instants of depolarizations are indicated by arrows).
Note the significant rise in the amplitude of the
[Ca2⫹]L transient in the presence of caffeine. The
corresponding ICa are shown on the bottom panel at
a higher time resolution. b: Ryanodine completely
inhibits both caffeine- and Ca2⫹-induced Ca2⫹ release. The top panel shows control [Ca2⫹]i and
[Ca2⫹]L traces (depicted in black and gray, respectively) in response to 20 mM caffeine and 3-s depolarization. The lower panel demonstrates the same
experiment performed on another neuron from the
same culture after 10-min incubation with 50 ␮M
ryanodine. ICa are shown in the insets. [A modified
from Alonso et al. (9); B and C modified from Solovyova et al. (603).]
CALCIUM STORE IN THE ER OF NEURONS
223
who did not observe any potentiation of CICR following
intracellular dialysis of rat DRG neurons with 1–10 ␮M
cADPR.
To act as a second messenger, production of cADPR
must be controlled by relevant neurotransmitter-activated
signaling cascades. Indeed, the activity of ADP-ribosyl
cyclase may be regulated by metabotropic receptors, such
as muscarinic cholinoreceptors (MChRs) or even glutamate receptors. Coupling between MChR and ADP-ribosyl
cyclase was identified in the NG108 –15 neuroblastoma,
indicating that ACh may regulate cADPR production
(225). The neurotransmitter-regulated cADPR-dependent
Ca2⫹ release pathway was also implicated in glutamateinduced [Ca2⫹]i signaling in midbrain dopamine neurons:
local activation of mGluRs triggered propagating Ca2⫹
waves that were mediated by both InsP3Rs and RyRs, and
were blocked by concerted action of heparin and the
cADPR antagonist 8-NH2-cADPR. Quite naturally, the idea
of mGluRs controlling both phospholipase C (PLC) and
ADP-ribosyl cyclase was born (429), although more direct
data supporting such a suggestion would be very
welcome.
Physiol Rev • VOL
In addition, the activity of ADP ribosyl cyclase may
be controlled by the nitric oxide (NO)/cGMP/cGMPdependent protein kinase cascade (224); NO and cGMP
do enhance the formation of cADPR in homogenates
of sea urchin eggs (176). Photorelease of cGMP from
a caged precursor delivered into cultured DRG neurons
via intracellular dialysis triggered a delayed Ca2⫹dependent inward current in ⬃50% of all neurons
tested (514). This was interpreted as an indication of
cADPR-induced Ca2⫹ release resulting from the activation of ADP ribosyl cyclase caused by cGMP-dependent
phosphorylation. In support of this suggestion, the inclusion of the cADPR antagonist 8-NH2-cADPR into the
pipette solution inhibited the effects of cGMP. Finally,
there is some evidence that cADPR may be involved in
assisting CICR necessary for LTP generation in Schaffer collaterals-CA1 neuron synapses in rat hippocampus (531).
All in all, cADPR remains a strong candidate as an
endogenous modulator of CICR. In particular, neurotransmitter-regulated synthesis of cADPR in synaptic
regions may be very important for local modulation of
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 12. CICR is graded by Ca
entry. A: changes in [Ca2⫹]L (top panel, gray traces) and [Ca2⫹]i (bottom panel, black traces) in response to
step depolarizations from ⫺70 to 0 mV of increasing duration. B: voltage protocol and Ca2⫹ currents from the experiment shown in A. C: the
relationship between the amplitude of the [Ca2⫹]L decrease (⌬[Ca2⫹]L) and the charge carried by Ca2⫹ current (兰ICa/⌬t) derived from the traces
shown in A and B. D: the ratio between the charge carried by ICa and the amplitude of [Ca2⫹]L decrease plotted against duration of corresponding
Ca2⫹ currents. Data are means ⫾ SD derived from 5 independent experiments similar to those shown in A. [From Solovyova et al. (603), with
permission from Nature Publishing Group.]
224
ALEXEI VERKHRATSKY
[Ca2⫹]i signals and hence relevant for synaptic
plasticity.
B) NICOTINIC ACID ADENINE DINUCLEOTIDE PHOSPHATE. Another
nucleotide involved in the regulation of ER Ca2⫹ release
in many types of nonexcitable cells is nicotinic acid adenine dinucleotide phosphate (NAADP). This molecule
is believed to trigger Ca2⫹ release through specific, but
so far unidentified, channels, the NAADPRs (75, 77, 96,
177, 374), although NAADP may also directly activate
RyRs (182). In the neural tissue, the NAADP-induced
Ca2⫹ release was described in brain microsomes (20) and
Physiol Rev • VOL
in neurons from buccal ganglion of Aplysia californica
(86). The existence and importance of NAADP-dependent
signaling cascade in vertebrate neurons remains
unknown.
2⫹
C) CALEXCITIN. Calexcitin (CE), a Ca
and GTP-binding
protein, is a recently discovered endogenous modulator
of neuronal RyRs and CICR. This protein was initially
isolated from neurons of conditionally trained Hermissenda (451). CE binds Ca2⫹ by virtue of an EF Ca2⫹binding domain and undergoes considerable and reversible conformational changes when [Ca2⫹] fluctuates be-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 13. cADPR-dependent potentiation of CICR. A, a: whole cell voltage-clamp
electrophysiological recording of a cell
showing ICa traces evoked upon depolarization of the membrane from ⫺70 to ⫺10
mV. Below the current records are the simultaneously measured [Ca2⫹]i traces
shown at a different time scale. The colors
of the [Ca2⫹]i traces correspond to the colors of the current traces. The arrow shows
the time the voltage step was applied. The
pipette used to record this cell contained
10 ␮M cADPR that potentiated the measured [Ca2⫹]i rises when longer voltage
steps, leading to prolonged inward currents (red, green, and yellow), triggered an
enhanced Ca2⫹ release. By measuring the
area beneath the current trace, pA multiplied by seconds, the charge carried by ICa
was derived. b: The unit transient
(⌬[Ca2⫹]i/兰ICa/⌬t) calculated for this cell at
each duration voltage step (from three separate voltage step applications) is plotted
against the duration of the step. Also
shown, in black, are values from a representative control cell. c: Pseudocolor images of a control cell and a cell treated with
10 ␮M cADPR. Images are sequential left to
right and taken at 1.4-s intervals; the white
arrow represents the time at which the
voltage step was applied. The charge entry
was similar in both cells. The pseudocolor
images show that the edges of the cells
were always the first regions to increase,
presumably as Ca2⫹ entered the cell following the depolarization. In the cADPRtreated cell there was a significant rise of
[Ca2⫹]i in the center of the cell after the
influx, whereas in the control cell the rise
in [Ca2⫹]i in the center was less apparent
and more confined to the edges. B: results
of a similar experiment performed on isolated DRG neurons perfused with intrapipette solution supplemented with 10 ␮M
cADPR. The examples of ICa and corresponding [Ca2⫹]i transients with and without 100 ␮M ryanodine in the bath are
shown in a. The dependence of UT from
pulse duration measured for control cells
(without cADPR in the pipette), for cells
intracellularly exposed to cADPR and for
the same cells treated with 100 ␮M ryanodine is shown on b. [A modified from Empson and Galione (137); B from Kostyuk and
Verkhratsky (309), with the actual experiments performed by Shmigol, Eisner, and
Verkhratsky.]
CALCIUM STORE IN THE ER OF NEURONS
1
Assistance from Jane Austin also should be acknowledged: “It is
a truth universally acknowledged that a single man in possession of a
good fortune must be in want of a wife” (Pride and Prejudice, p. 1).
Physiol Rev • VOL
various cell types are sensitive to the concentration of
protons (e.g., Refs. 128, 395). In neurons, acidosis inhibits
CICR and increases ER Ca2⫹ content (641), whereas alkaline shifts stimulate the release of Ca2⫹ and/or inhibit
reuptake of Ca2⫹ into the ER (696).
F) GLUTAMATE. It is generally accepted that the action of
extracellular glutamate on ER Ca2⫹ release is accomplished via activation of group I metabotropic glutamate
receptors (mGluRs) coupled, through G protein pathways, to PLC and InsP3 metabolism. Data accumulated
during the past decade, however, indicate the existence of
an alternative route that involves direct interactions of
mGluRs and RyRs (145). Initial evidence in support of this
pathway was obtained in cell-attached patch-clamp experiments on cultured cerebellar granule cells (90). This
study demonstrated mGluR-dependent activation of L-type
VGCCs, which could not be mimicked by intracellular
dialysis with InsP3, was not blocked by heparin, but was
completely obliterated by 1 ␮M ryanodine and simulated
by caffeine. Subsequently, it was found that ryanodine
effectively (⬃90%) inhibited 1-aminocyclopentane-trans1,3-dicarboxylic acid (trans-ACPD)-induced [Ca2⫹]i elevation, while it was much less potent against [Ca2⫹]i signals
triggered by the other metabotropic agonists carbachol
and histamine (119). These data led to an interesting idea
about direct functional coupling between mGluRs and
RyRs, thought to be mediated by Homer proteins (145).
This assembly may be even more complex and may involve voltage-gated Ca2⫹ channels and Ca2⫹-dependent
potassium channels. Although extremely stimulating, this
hypothesis still requires additional experimentation.
Further evidence for glutamate-mediated regulation
of CICR was obtained on neurons from the avian nucleus
magnocellularis, in which activation of mGluRs inhibited
both CICR and InsP3-induced Ca2⫹ release (IICR). It is
hypothesized that this inhibition provides a mechanism
by which glutamate protects highly active neurons from
calcium overload (275).
G) NEUROTROPHINS. Neurotrophins, which include nerve
growth factor (NGF), brain-derived neurotrophic factor
(BDNF), and neurotrophins 3/4/5 (NT-3, -4, and -5), operate through an extended family of TrkA, -B, and -C receptors, tumor necrosis factor (TNF) receptors, and p75 and
Fas receptors (89). Among these receptors TrkA and p75
are abundantly expressed in the brain, and their activation is important for neuronal physiological activity; for
example, BDNF-dependent neuronal excitation, synaptic
plasticity, and release of neurotransmitters have been
reported (265, 340, 359, 685, 701). Several of these effects
involve intracellular Ca2⫹ release mediated by RyRs. For
instance, NGF induces release of glutamate from cultured
cerebellar neurons through activation of p75 receptors
and ryanodine-sensitive Ca2⫹ mobilization (464). Similar
activation of glutamate release, sensitive to dantrolene
and to store depletion by caffeine, was observed in cor-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
tween 0.1 and 10 ␮M (14). The physiological effects of CE
are exerted through modulation of K⫹ channels and RyRs.
CE binds to RyRs in a Ca2⫹-dependent manner (7, 453)
and facilitates Ca2⫹ release; injection of CE into hippocampal neurons resulted in a slow-developing [Ca2⫹]i
elevation, which originated from the ER (454). CE also
stimulated Ca2⫹ release from squid optic lobe microsomes; this release was blocked by dantrolene and an
anti-RyR antibody (454). CE is known to be phosphorylated upon memory consolidation, which raises the interesting possibility that RyRs are involved in this process.
D) VANILLOID RECEPTORS. The effects of capsaicin on nerve
cells are executed through the TRPV1/VR1 vanilloid receptor, which belongs to a broad family of TRP channels
(35, 49). In cultured DRG neurons, capsaicin increased
[Ca2⫹]i in a dose-dependent manner with ED50 ⬃13.5 ␮M.
This [Ca2⫹]i elevation was mimicked by the capsaicin
analog resiniferatoxin (100 nM) and blocked by the VR1
receptor antagonist capsazepine (10 mM). Capsaicin-induced [Ca2⫹]i signaling did not require extracellular Ca2⫹
and disappeared after the ER was depleted by incubating
cells with a mixture of 10 mM caffeine and 12 ␮M ryanodine (144). The [Ca2⫹]i transients evoked by capsaicin
were also inhibited by 10 ␮M dantrolene or by 10 ␮M
ruthenium red (144), as well as by 2 ␮M TG (271). Taken
together, these data indicate that capsaicin stimulates
CICR in sensory neurons.
A rather unusual suggestion of direct involvement of
TRPV1/VR1 in Ca2⫹ release from the ER was made recently by Liu et al. (352), who confirmed that capsaicin,
when applied in Ca2⫹-free media, produces [Ca2⫹]i elevation in small DRG neurons. In contrast to previous findings, however, this [Ca2⫹]i signaling pathway was not
affected by TG but was sensitive to the TRPV1/VR1 receptor antagonist capsazepine. Morphological examination revealed a substantial overlap between polyclonal
antibody (TRITC labeled) TRPV1/VR1 staining of small
DRG neurons and staining of the same cells with ERtracker or ER marker DiOC5 (352). This overlap in staining was considered to indicate specific localization of
TRPV1/VR1 in the ER membrane. These data prompted the
intriguing speculation that TRPV1/VR1s may act as ER-resident Ca2⫹ release channel. These authors also proposed
that the vanilloid receptors act as store-operated channels
(but this is disputed by Karai and co-workers, Ref. 271).
E) PROTONS. “It is a truth universally acknowledged that
all intracellular reactions are sensitive to pH” wrote Roger
Thomas (641),1 and RyR function as well as CICR in
225
226
ALEXEI VERKHRATSKY
C. IICR in Nerve Cells
1. Direct evidence for neuronal IICR
The initial suggestion of InsP3-induced release of
Ca2⫹ in neurons arose from electrophysiological studies,
which demonstrated that injection of InsP3 into various
neurons or neuronlike cells [e.g., neuroblastoma ⫻ glioma
Physiol Rev • VOL
cells (223), rat hippocampal neurons (387), rat dorsal
raphe neurons (162), etc.] resulted in activation of Ca2⫹dependent K⫹ currents. This suggestion was immediately
confirmed by measuring [Ca2⫹]i (Fig. 14A, Ref. 151),
which demonstrated directly that intracellular administration of InsP3 induces a [Ca2⫹]i elevation due to Ca2⫹
release from the intracellular compartments (Table 3).
Similar experiments, in which InsP3 was administered intracellularly by photorelease from a caged precursor or by InsP3 application to permeabilized cells, revealed relatively poor sensitivity of neuronal IICR to the
agonist. In Purkinje neurons in situ, for example, even 80
␮M InsP3 did not result in an obvious saturation of the
[Ca2⫹]i response (Fig. 14B; Ref. 284). Likewise, the EC50
for InsP3-mediated decrease in [Ca2⫹]L determined in permeabilized embryonic Purkinje neurons loaded with Magfura 2 was 25.8 ␮M (169). In single permeabilized DRG
neurons, maximal depletion of the ER was observed at
InsP3 concentrations of ⬃20 ␮M (602). These values are
many times greater that effective InsP3 concentrations
determined for purified cerebellar InsP3Rs (EC50 ⬃1 ␮M;
Refs. 45, 362) and InsP3R1 heterologously expressed in
artificial systems (EC50 ⬃0.2–2 ␮M; Refs. 133, 420). Similarly, in many nonexcitable cells, such as astrocytes,
hepatocytes, exocrine cells, and vascular epithelium, the
maximal IICR was observed at InsP3 concentrations not
exceeding 5–10 ␮M (285); however, very high doses of
InsP3 (up to 100 ␮M) were required to trigger maximal
response in pancreatic acinar cells (681).
The reasons for low sensitivity of IICR in nerve cells
are not quite clear. The effective InsP3 concentrations in
the cytosol can be substantially reduced by an extensive
InsP3 buffering, or else InsP3 can be quickly degraded by
enzymatic systems. These two possibilities, however, are
questioned by the experiments on permeabilized cells,
where cytoplasm is essentially washed out together with
the InsP3 buffers and InsP3-degrading enzymes. Alternatively, the InsP3 binding to the receptor may be inhibited
by endogenous inositol trisphosphate receptor inhibitor
(IRI), recently discovered in the cerebellum (686). The
low sensitivity of neuronal IICR could be important for
the maintenance of synaptic specificity by localization of
InsP3-induced signaling.
2. Metabotropic receptors and neuronal IICR
Physiological activation of IICR requires stimulation
of plasmalemmal receptors coupled to PLC, which in turn
hydrolyzes phosphatidylinositol 4,5-bisphosphate and
gives birth to InsP3. These plasmalemmal receptors,
which usually share a common seven-transmembrane domains structure, are coupled to G proteins and are generally known as metabotropic receptors. Neurons express
an impressive complement of metabotropic receptors,
many of which are coupled to the InsP3 signaling cascade.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
tical synaptosomes; in this case, NGF acted through TrkA
receptors, and glutamate release was sensitive to heparin
(527).
Another neurotrophin, NT-3, significantly potentiated
the spontaneous neurotransmitter release in the neuromuscular junction; this action required both Ca2⫹ release
via RyR/InsP3Rs and the activation of Ca2⫹/calmodulindependent kinase II (208). In pyramidal neurons from the
visual cortex, NT-4 potentiated depolarization-induced
[Ca2⫹]i elevations partly though enhancement of CICR (278).
Alternatively, neurotrophins may regulate CICR by
affecting the expression of RyRs. For instance, NGF treatment of cultured adrenal chromaffin cells significantly
elevated the expression of RyR2 and dramatically
(⬎1,000% over 10 days) increased the amplitude of caffeine-induced [Ca2⫹]i responses (260). In cerebellar granule cells, the addition of 10 ng/ml BDNF from the first day
in culture augmented the contribution of CICR to depolarization-induced [Ca2⫹]i transients by a yet unknown
mechanism (408).
H) TNF-␣/SPHINGOSINE-1-PHOSPHATE. Treatment of cultured
rat DRG neurons with TNF-␣ induced a Ca2⫹-dependent
current in ⬃70% of cells and triggered [Ca2⫹]i increase in
⬃35% of cells tested; both the current and [Ca2⫹]i elevation were inhibited by TG (10 –50 ␮M) and ryanodine (10
␮M). The action of TNF-␣ was mimicked by the uncaging
of sphingosine or by addition of 0.4 U/ml sphingomyelinase (515). In parallel, two subtypes of TNF-␣ receptors,
TNFR1 and TNFR2, were identified in DRG neurons by
immunohistochemical and RT-PCR techniques. Whether
the2⫹activation of TNFRs represents a novel pathway for
Ca
release mediated by sphingosine-1-phosphate
through separate ER channels or through modulation of
RyRs remains rather unclear (712).
I) NO. NO, which acts as a rapidly diffusible gaseous
messenger in many tissues including the brain, seems to
be another endogenous regulator of RyRs (143). NO-induced activation of RyR-mediated Ca2⫹ release was observed in hippocampal CA1 neurons; this Ca2⫹ release
was important for both CREB phosphorylation and LTP
induction (360). NO-induced activation of Ca2⫹ release
from a ryanodine-sensitive store was also implicated in
hypoxic [Ca2⫹]i rises in brain slices (394). Similarly, NOmediated ER Ca2⫹ release via RyRs is considered to be an
important pathological step in interleukin (IL)-1␤-induced
pyrogenic effects (485).
CALCIUM STORE IN THE ER OF NEURONS
227
Numerous observations have shown that activation of
many different types of neuronal metabotropic receptors
trigger IICR (Table 4).
The metabotropic receptors are activated upon synaptic transmission (Table 5, Fig. 15) and initiate IICR
responsible for several distinct forms of [Ca2⫹]i responses, manifested either as propagating Ca2⫹ waves,
discussed below, or in a form of highly localized [Ca2⫹]i
elevations. The local [Ca2⫹]i microdomains are particularly important in cerebellum, where synaptic stimulation
of mGluRs results in Ca2⫹ release strictly confined to
postsynaptic spines or defined dendritic areas of the Purkinje neurons (150, 624). This localization of [Ca2⫹]i signaling seems to be an intrinsic property of the IICR mechanism, because focal photorelease of InsP3 triggered
[Ca2⫹]i elevation which did not spread far away from the
site of InsP3 appearance (150). This localization may reflect specific properties of the Purkinje neurons such as
low sensitivity of IICR to InsP3; high level of cytosolic
Ca2⫹ buffering; large densities of InsP3 receptors/buffers,
which bind InsP3; speed of InsP3 degeneration, or the
effects of IRI discussed in the previous section. This local
IICR modulates the neighboring synapses by inducing
long-term depression (LTD); the localized [Ca2⫹]i signaling can be important for spatial segregation of synaptic
plasticity events.
Physiol Rev • VOL
A further degree of complexity is added by the fact
that neuronal InsP3Rs can be directly linked to plasmalemmal mGluRs via Homer proteins (656). This physical
link may have important functional consequences, because the expression of a modified form of Homer protein, lacking the ability to cross-link with InsP3R, reduces
amplitude and speed of [Ca2⫹]i transients mediated by
activation of mGluRs (656).
3. CICR-assisted IICR
An important property of InsP3 receptors and IICR is
their regulation by [Ca2⫹]i. An increase in the latter facilitates IICR and may trigger Ca2⫹ release through InsP3Rs
in the presence of a constant level of the second messenger. The synergism between [Ca2⫹]i and InsP3 may act as
a coincidence detector allowing the system to identify the
simultaneous activation of both signaling cascades; furthermore, pairing of InsP3 and [Ca2⫹]i elevations may be
important in converting local signaling events into propagating waves of ER membrane excitation.
Indeed, IICR was found responsible for generation of
propagating Ca2⫹ waves triggered by synaptic excitation
of hippocampal pyramidal neurons. These Ca2⫹ waves
were found almost exclusively in the thick apical shafts of
CA1 neurons (445). The generation of the Ca2⫹ wave has
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG.
14. Inositol trisphosphate
(InsP3)-induced Ca2⫹ release in neurons
in response to direct activation of InsP3
receptors. A: one of the first recordings
of InsP3-induced Ca2⫹ release (IICR) in
nerve cell. The Aplysia californica neuron was loaded with fura 2 and injected
with InsP3 (0.8 mM InsP3 in the electrode). Pseudocolor fluorescence images
of [Ca2⫹]i show intracellular calcium dynamics at different times during and after
InsP3 injection. B: low sensitivity of neuronal IICR. Left panel shows [Ca2⫹]i
traces recorded from Purkinje neuron in
cerebellar slice after photorelease of different InsP3 concentrations. On the right
panel, the amplitudes of normalized peak
[Ca2⫹]i responses are plotted against
InsP3 concentrations attained during
photorelease. [A modified from Fink et
al. (151); B modified from Khodakhah
and Ogden (284).]
228
ALEXEI VERKHRATSKY
TABLE
3.
InsP3-induced Ca2⫹ release in neurons
Species/Age/NS Region
Preparation
Technique
Aplysia californica/
abdominal ganglia
Primary
cultures bag
cells
Microelectrode
current clamp;
fura 2 imaging
Rat/P12–P22/cerebellum
Acute slice, PN
Whole cell voltage
clamp; fluo 3,
Mag-fura 2
microfluorimetry
Rat/E17/hippocampus
Primary culture
(8–14 DIV)
Acute slice, PN
Fura 2-AM imaging
Rat/P14–P21/cerebellum
Acutely
isolated
slices
Mouse/E18/cerebellum
Primary culture
(DIV 21–28),
PN
Acute slice
Mouse/P17–P25/cortex
Rat/P1–P3/DRG
Primary culture
(1–2 DIV)
Mag-fura 2 imaging
of [Ca2⫹]L
Whole cell voltage
clamp; fura 2
two-photon
confocal
imaging
Mag-fura 2-AM
imaging of [Ca2⫹]L
Microinjection (iontophoresis or pressure) of InsP3 (intrapipette
concentration 0.8 mM, injection time, 1 s) triggered [Ca2⫹]i
elevation and neuronal hyperpolarization. The [Ca2⫹]i
elevation remained in Ca2⫹-free media.
Photorelease of InsP3 triggered [Ca2⫹]i increase when InsP3
concentration exceeded ⬃9 ␮M; the amplitude of [Ca2⫹]i
response increased with InsP3 concentrations of up to 80 ␮M.
Maximal amplitude of [Ca2⫹]i elevation was 10–80 ␮M and
maximal rate of rise of 1,400 ␮M/s at 40 ␮M InsP3.
Microinjection of 1 ␮M InsP3 triggered [Ca2⫹]i elevation.
Reference
Nos.
151
284, 285,
467
417
Focal (3–5 ␮m in diameter) photorelease of InsP3 triggered
localized [Ca2⫹]i elevation in PN dendrites; [Ca2⫹]i increase
dependent on the InsP3 concentration (⬃1 to 160 ␮M) and
did not propagate through the dendrite.
150
Photorelease of InsP3 (1-ms ultraviolet flash; produced
concentrations of 0.75–30 ␮M) triggered [Ca2⫹]i rise and
evoked apamin-sensitive Ca2⫹-dependent K⫹ currents (SK
channels).
Application of InsP3 to permeabilized cells induced decrease in
[Ca2⫹]L; EC50 for InsP3-induced store depletion was 25.8 ␮M.
428
Photorelease of InsP3 triggered [Ca2⫹]i transients in layer V
pyramidal neurons. These [Ca2⫹]i elevations were potentiated
by Ca2⫹ entry triggered by APs. [Ca2⫹]i elevations resulted
from IICR regulated neuronal excitability by activation of
strong outward K⫹ currents.
Application of InsP3 (5–20 ␮M) to permeabilized DRG neurons
induced decrease in [Ca2⫹]L. InsP3-induced [Ca2⫹]L responses
saturated at ⬃20 ␮M of agonist.
609
169
602
InsP3, inositol 1,4,5-trisphosphate; IICR, InsP3-induced Ca2⫹ release.
a threshold nature, which most likely reflects InsP3 accumulation (717) and amplification of the release by CICR
through InsP3Rs. This amplification can be seen directly.
Pairing of mGluR stimulation (either by synaptic stimulation or by application of a metabotropic receptors agonist) with plasmalemmal Ca2⫹ entry, activated by backpropagating action potentials, greatly enhanced [Ca2⫹]i
signals (Fig. 16, Refs. 444, 446). In fact, the degree of
mutual potentiation was quite remarkable: a backpropagated AP by itself resulted in a fast low-amplitude [Ca2⫹]i
increase, and the application of mGluR antagonists alone
did almost nothing to [Ca2⫹]i, yet when an AP was generated in the presence of continuous mGluR stimulation,
a large (up to 40 ␮M) [Ca2⫹]i increase was produced
(446). Similarly, [Ca2⫹]i waves could be induced in response to electrical stimulation of mossy fibers, which
form synaptic input to CA3 hippocampal neurons. These
waves were inhibited by 1 ␮M heparin and were potentiated by pairing mossy fiber stimulation with AP-driven
Ca2⫹ influx through VGCC (270). Comparable synaptically
activated propagating [Ca2⫹]i waves resulting from IICR
were also observed in neocortical pyramidal neurons
from layers II/III and V. These [Ca2⫹]i waves were dependent on stimulation of metabotropic glutamate receptors
Physiol Rev • VOL
and were blocked not only by intracellularly applied heparin, but also by 5–20 ␮M ryanodine, but not by ruthenium
red (331). These results may indicate either an amplifying
role of RyR-mediated CICR or depletion of a single store
shared by RyRs and InsP3Rs.
Activation of muscarinic cholinoreceptors in hippocampal CA1 neurons by electrical stimulation of cholinergic synaptic inputs induced [Ca2⫹]i waves propagating
from dendrites towards soma. These [Ca2⫹]i waves were
potentiated by AP-induced Ca2⫹ entry, disappeared after
inhibition of ER Ca2⫹ accumulation with TG (100 nM) or
CPA (30 ␮M), and were blocked by intracellular administration of heparin (500 ␮g/ml), demonstrating the involvement
of InsP3Rs (518). The CICR from InsP3Rs was also described
in layer II/III neocortical neurons in which AP-induced
[Ca2⫹]i transients were remarkably augmented upon stimulation of MChRs; the latter apparently provided an increase
in InsP3, which sensitized InsP3Rs to Ca2⫹ entering through
the plasmalemma (704). Most interestingly, this CICR via
InsP3Rs was absent in very young (⬍P7) rats, although in
these young neurons direct application of InsP3 resulted in
IICR, and cell depolarization produced [Ca2⫹]i elevation of
an appreciable amplitude (705). This developmental difference prompted the suggestion that during development, the
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Rat/P1–P21/midbrain
Whole cell voltage
clamp; calcium
green 1; Oregon
green BAPTA-1
confocal imaging
Whole cell voltage
clamp; fura 6F
microfluorimetry
Parameters of Release
CALCIUM STORE IN THE ER OF NEURONS
TABLE
4.
229
Metabotropic receptors and InsP3-induced Ca2⫹ release in neurons
Species/Age/NS Region
Preparation
Technique
Experimental Evidence
Reference
Nos.
Metabotropic glutamate receptors
Primary culture
(3–17 DIV)
Fura 2-AM
microfluorimetry
Rat/P12–P20/cerebellum
Acute slice, PN
Whole cell patch
clamp; fura 2
imaging
Rat/E20/cerebellum
Primary culture
(⬎20 DIV), PN
Fura 2-AM imaging
Rat/P3/olfactory bulb
Primary neuronalglial culture
Fluo 3-AM imaging
Rat/P13–P27/supraoptic
nucleus
Freshly isolated
presumed
oxytocin/
vasopressin
neurons
Fura 2-AM imaging
Rat/E18/hippocampus
Primary culture
(7–20 DIV)
Primary culture,
granule cells
Fura 2-AM imaging
Fura 2-AM
microfluorimetry
Rat/P1–P3/hippocampus
Primary culture
(6–36 DIV)
Indo 1-AM
confocal imaging
Rat/P3–P30/spiral
ganglion
Freshly isolated
cells
Indo 1-AM
microfluorimetry
Chicken/E18/DRG
Primary culture
Fura 2-AM
microfluorimetry
Rat/E17/hippocampus
Primary culture
(8–14 DIV)
Fura 2-AM imaging
Guinea
pig/P1/myenteric
plexus
Primary culture
(2–8 DIV)
Fura 2-AM
microfluorimetry
Glutamate, NMDA, KA, and quisqualate triggered [Ca2⫹]i
elevations; removal of extracellular Ca2⫹ obliterated
responses to NMDA and KA, but not to glutamate and
quisqualate. Similarly, phenylephrine produced [Ca2⫹]i
transients in Ca2⫹-free media.
Applications of glutamate and quisqualate triggered
inward currents and [Ca2⫹]i rise in PN dendrites;
[Ca2⫹]i elevation persisted in Ca2⫹-free media. When
slices were incubated in Ca2⫹-free solution, only 1st
agonist application triggered [Ca2⫹]i signal indicating
depletion of the store.
Stimulation of PN by trans-ACPD (100–300 ␮M), DHPG
(200–500 ␮M), and a mixture of quisqualate (1–5 ␮M)
and DNQX (50 ␮M) induced [Ca2⫹]i elevation in
Ca2⫹-free media; these [Ca2⫹]i signals were inhibited
by TG (1 ␮M), BHQ (10 ␮M), and dantrolene (10 ␮M).
Stimulation of neurons with glutamate (10–20 ␮M) or
quisqualate (10 ␮M) triggered Ca2⫹ responses in
Ca2⫹-free media; these responses were blocked by TG
(10 ␮M).
Glutamate, quisqualate, and trans-ACPD evoked [Ca2⫹]i
increase in Ca2⫹-free media.
437, 438
354
193
79
205
Muscarinic cholinoreceptors
Rat/P7–P8/cerebellum
Acetylcholine (⬎10 ␮M) triggered [Ca2⫹]i elevation that
was partly independent from extracellular Ca2⫹.
Application of CCh (1 mM) triggered [Ca2⫹]i transient,
which was inhibited by preincubation with TG (10
␮M), dantrolene (25 ␮M), and ryanodine (10 ␮M).
Cell preincubation with caffeine (50 mM) greatly
reduced CCh [Ca2⫹]i response, and vice versa,
pretreatment with CCh inhibited following caffeine
[Ca2⫹]i response.
Carbachol (1–10 ␮M) triggered [Ca2⫹]i elevation in
⬃20% of resting neurons; conditioning KCl (16.2–25
mM) depolarization made almost all cells respond.
Carbachol responses were blocked by TG (2 ␮M).
Replenishment of stores required plasmalemmal Ca2⫹
entry mediated through nifedipine (10 ␮M)-sensitive
L-type VGCC.
ACh (KD ⬃8 ␮M) and muscarine (KD ⬃10 ␮M) triggered
[Ca2⫹]i elevation mostly due to ER Ca2⫹ release;
responses were slightly attenuated by extracellular
Ca2⫹ removal and were blocked by 10 ␮M TG.
Muscarinic agonists (1 mM muscarine or 1 mM
oxotremorine) triggered [Ca2⫹]i increase mediated
through InsP3-induced Ca2⫹ release, as [Ca2⫹]i
transients were blocked by 10 ␮M TG and did not
require extracellular Ca2⫹.
320
590
249
540
629
P2Y purinoreceptors
Physiol Rev • VOL
ATP (3–30 ␮M) produced [Ca2⫹]i elevation; removal of
external Ca2⫹ did not affect peak but reduced plateau
of the response. ATP did not produce measurable
membrane current; ATP responses were not affected
by Cd2⫹ (1 mM) but were blocked by TG (1 ␮M).
ATP (0.01–1,000 ␮M) induced [Ca2⫹]i elevation that was
independent on extracellular Ca2⫹ and nifedipine (10
␮M), hence reflecting Ca2⫹ release. The ATP-induced
[Ca2⫹]i responses were blocked by preapplication of
CPA (30 ␮M), by the PLC inhibitor U-73122 (10 ␮M),
and by phorbol ester preincubation (100 nM).
Treatment with pertussis toxin (100 ng/ml, 24 h) did
not affect Ca2⫹ mobilization.
85 • JANUARY 2005 •
www.prv.org
417
287
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Mouse/E17/hippocampus
230
TABLE
ALEXEI VERKHRATSKY
4—Continued
Species/Age/NS Region
Technique
Experimental Evidence
Mouse/P60–P90/DRG
Freshly isolated
large
(proprioceptive)
and small
(nociceptive)
neurons
Whole cell voltage
clamp; indo 1,
indo 1-AM
microfluorimetry
Rat/P1/cortex
Primary culture
(7–14 DIV)
Whole cell voltage
clamp; fura
2-AM imaging
Rat (14 days
old)/neocortex
Acute slices
Fura 2-AM
microfluorimetry
Guinea pig/adult/Corti
organ
Isolated cochlea
preparation;
outer hair cells
Calcium green-1
imaging
Rat/P7–P14/intracardiac
ganglia
Primary culture
Fura 2-AM
microfluorimetry
Rabbit/nodose ganglia
Primary culture
(3–4 DIV)
Whole cell voltage
clamp; fura 2AM, fluo 3-AM
microfluorimetry
Rat/P56–P98/DRG
Primary culture
(2–3 DIV)
Fura 2-AM
microfluorimetry
ATP (100 ␮M) triggered inward current and [Ca2⫹]i
elevation only in proprioceptive, but not in nociceptive,
neurons (in the latter, ATP induced inward current only).
Both ATP-induced currents and [Ca2⫹]i transients
persisted in Ca2⫹-free media. The [Ca2⫹]i transient, but
not the current, was blocked by intracellular dialysis
with 20 ␮M heparin, TG (200 nM), and ryanodine (50
␮M).
Application of UTP (10 ␮M) triggered potassium current
and [Ca2⫹]i elevation, which were blocked by
intracellularly dialyzed heparin (1 mg/ml) or neomycin
(PLC inhibitor, 500 ␮M).
ATP-induced [Ca2⫹]i responses were in part mediated
through P2Y metabotropic pathway; removal of
extracellular Ca2⫹ reduced the amplitude of ATP-induced
[Ca2⫹]i elevation by ⬃40%; incubation with 1 ␮M TG
decreased ATP-induced [Ca2⫹]i elevation by ⬃50% in 2.5
mM [Ca2⫹]o. The P2Y-mediated ATP responses decreased
during development: at P14, 90% of neurons were in
possession of this mechanism, whereas at P30, only 30%
of cells displayed P2Y component of [Ca2⫹]i response.
ATP (local puff application of 1 mM for 100 ms) triggered
inward current and two-component (fast and slow)
[Ca2⫹]i transient. The slow component of [Ca2⫹]i
response persisted in Ca2⫹-free solution and was
inhibited by heparin (7 mg/ml).
ATP and UTP triggered transient [Ca2⫹]i elevation in
concentration-dependent manner (EC50 ⬃20 and ⬃40
␮M, respectively). These [Ca2⫹]i responses did not
require extracellular Ca2⫹ and were blocked by 10 ␮M
CPA.
ATP (100 ␮M) and InsP3 photorelease triggered [Ca2⫹]i
responses in Ca2⫹-free media; ATP-induced [Ca2⫹]i
transients were inhibited by U73122 (1 ␮M), neomycin (2
mM), heparin (1 mg/ml), and PPADS (10 ␮M). Ryanodine
(10 ␮M) eliminated ⬃30% of the ATP-induced response,
suggesting a secondary CICR amplifying the IICR.
ATP and UTP (100 ␮M) triggered [Ca2⫹]i elevation in small
(⬍30 ␮m diameter) neurons. [Ca2⫹]i responses were
blocked by TG (100 nM), suramine (100 ␮M), and PPADS
(10 ␮M), suggesting P2Y-mediated IICR.
Reference
Nos.
615, 616
460
324, 325
366
350
230
559
Adenosine A1 receptors
Rat/adult/basal
forebrain/cholinergic
neurons
Acute slices
Calcium orange/
AM multiphoton
confocal imaging
Adenosine triggered [Ca2⫹]i elevation selectively in
cholinergic neurons; the responses were mimicked by A1
agonist CHA (100 nM) and inhibited by A1 antagonist
CPT (1 ␮M). Adenosine-evoked [Ca2⫹]i responses were
preserved in Ca2⫹-free media, were blocked by 50 ␮M
TG, and were inhibited by 2-APB (50 ␮M) and XeC (20
␮M).
31
Dopamine D1/D5 receptors
Rat/P1/cortex,
hippocampus,
striatum
Primary culture
(4–10 DIV)
Fura 2-AM imaging
D1/D5 receptors agonists SKF81297 (10 ␮M) or SKF38393
(500 ␮M) triggered [Ca2⫹]i transients associated with
Ca2⫹ release after cultured cortical or hippocampal
neurons were primed by conditioning stimulations with
mGluR agonist DHPG, carbachol, or 100 mM KCl. In
striatal neurons, D1/D5 responses were completely
absent.
339
Trk receptors
Xenopus/E1/neural tube
Primary culture (1
DIV)
Rat/adult/nodose
ganglia
Primary culture
(16–24 HIV)
Calcium-green
dextran confocal
imaging
Fura 2-AM imaging
Physiol Rev • VOL
NT-3 induced [Ca2⫹]i elevation, which was blocked by
heparin, XeC (1 ␮M), or PLC-␥ inhibitor U73122 (5 ␮M).
706
NGF, BDNF, and GDNF (all at 100 ng/ml) triggered slow
[Ca2⫹]i increase in ⬃30% of neurons, which remained in
Ca2⫹-free media and was blocked by TG (500 nM) and
tyrosine kinase inhibitor K252 (1 ␮M).
327
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Preparation
CALCIUM STORE IN THE ER OF NEURONS
TABLE
231
4—Continued
Species/Age/NS Region
Chicken/E5.5/spinal
cord
Preparation
Technique
Experimental Evidence
Primary culture;
motoneurons
Fluo 4-AM
confocal imaging
GDNF (100 ng/ml) induced [Ca2⫹]i elevation, which did
not require extracellular Ca2⫹ and was blocked by TG
(1 ␮M, 30 min) and dantrolene (40 ␮M, 30 min). Ca2⫹
released by GDNF facilitated survival of neurons via
CaM/PI 3-kinase pathway.
Reference
Nos.
504
Histamine H1 receptors
Acute slices
Whole cell voltage
clamp
343
Rat/adult/DRG
Primary culture
(up to 8 DIV)
Fura 2-AM imaging
Guinea
pig/P1/myenteric
plexus
Primary culture
(2–8 DIV)
Indo 1-AM
microfluorimetry
Rat/P3–P30/spiral
ganglion
Freshly isolated
cells and
clusters of
cells
Indo 1-AM
microfluorimetry
Rat/neonatal/DRG
Primary culture
Fura 2-AM
microfluorimetry
Murine neuroblastoma
2a stably expressing
␦-, ␮-, or ␬-opioid
receptors
Rat/P9–P14/brain stem/
nucleus raphe
magnus
Cultured cell
line
(neuroblastoma)
Fura 2-AM imaging
Stimulation of opioid receptors triggered Ca2⫹ release
in neuroblastoma cells stably expressing opioid
receptors.
605
Acute slice
Whole cell voltage
clamp
Hyperpolarization-activated current (Ih) was used as a
readout of [Ca2⫹]i. ␬-Opioid receptor agonist U69593
(300 nM) enhanced Ih, this action being inhibited by
receptor antagonist BNI (100 nM). Effects of
␬-receptor activation were antagonized by caffeine
(10 mM), TG (3 ␮M), and heparin (500 ␮M).
486
456
Substance P tachykinin receptors
Substance P induced Ca2⫹ release (blocked by
preincubation in TG, 5 ␮M, 1 h and independent of
extracellular Ca2⫹). No SOC was observed in TG
pretreated neurons, although it was present in
nonneuronal cells from the same culture.
Substance P (EC50 ⫽ 8.8 ␮M) initiated [Ca2⫹]i elevation,
which did not require extracellular Ca2⫹ and was
blocked by U-73122 indicating tachykinin receptor
(NKR3)-induced ER Ca2⫹ release.
666
253
Bradykinin receptors
Bradykinin stimulates InsP3 synthesis and releases Ca2⫹
from the intracellular store.
637
Opioid receptors
Spontaneous [Ca2⫹]i oscillations
Mouse
(E9.5–E10)/neural
crest
Primary culture
(⬎4 DIV)
InsP3-induced Ca2⫹ release mediated spontaneous
[Ca2⫹]i oscillations; Ca2⫹ oscillations were blocked by
increased intracellular Mg2⫹ (the latter
noncompetitively inhibits InsP3-mediated Ca2⫹
release) or by ER store depletion with 10 ␮M BHQ.
Slight increase in [Ca2⫹]i by reversing Na/Ca2⫹
exchanger (removal of Nao⫹) facilitated oscillations,
suggesting therefore CICR through InsP3Rs.
Oregon greenBAPTA-1-AM
imaging
plasmalemmal Ca2⫹ channels and InsP3Rs become closer
spatially, allowing modulation of InsP3Rs by Ca2⫹ influx.
4. Endogenous IICR modulators
A) PROTEIN KINASES AND CALCINEURIN. Endogenous regulation of InsP3Rs is mainly achieved through phosphorylation/dephosphoryaltion of the receptor molecule. Phosphorylation of the InsP3R, which results in enhanced
channel activity, is catalyzed by protein kinases A, C, and
Physiol Rev • VOL
78
G (412, 413) and by tyrosine kinase (258). The latter is
also coupled to InsP3 metabolism and therefore may affect the IICR via several routes. Dephosphorylation of
InsP3R and hence reduction of the channel activity is
catalyzed by the Ca2⫹/calmodulin-dependent phosphatase
calcineurin (73), which also regulates the expression of
InsP3R at the transcriptional level, because pharmacological blockade of calcineurin abolished the expression of
InsP3Rs in cerebellar granule neurons (181).
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Histamine (1–2.5 ␮M) enhanced Ca2⫹-dependent slow
inward current in almost all neurons tested. This
enhancement was blocked by intracellular
administration of heparin (2–3 mg/ml), suggesting
H1-mediated IICR.
Histamine induced an elevation in InsP3 and in [Ca2⫹]i;
the peak of [Ca2⫹]i elevation did not require
extracellular Ca2⫹, suggesting ER release.
Rat/adult/supraoptic
nucleus
232
ALEXEI VERKHRATSKY
TABLE
5.
Synaptically induced IICR in neurons
Species/Age/NS
region
Synaptic
Contact
Rat/P11–P17/
hippocampus
Technique
Experimental Evidence
SC-CA1
Acute slice, CA1
neurons
Whole cell voltage
clamp; fluo 3
confocal
imaging
Rat/adult/
hippocampus
MF-CA3
Organotypic
(4–10 DIV)
and acute
slices, CA3
neurons
Whole cell voltage
clamp; fura 2/
fura 2 dextran
imaging
Rat/P14–21/
cerebellum
PF-PN
Acute slice, PN
Calcium green 1;
Oregon green
BAPTA-1
confocal
imaging
Mouse/
P20–P32/
cerebellum
PF-PN
Acute slice, PN
Whole cell voltage
clamp; Oregon
green BAPTA-1
confocal
imaging
Rat/P21–P28/
hippocampus
SC-CA1
Acute slice, CA1
neurons
Whole cell voltage
clamp; bis-fura
2, Mag-fura 2
imaging
Rat/P19–P25/
hippocampus
CA3
MF-CA3
Acute slice, CA3
neurons
Whole cell voltage
clamp; fura 2
imaging
Tetanic stimulation of SC triggered EPSC and
[Ca2⫹]i elevation in dendrites of CA1
neurons (clamped at ⫺35 mV to exclude
VGCC activation). The [Ca2⫹]i elevation
was blocked by mGluR antagonist M CPG
(250–500 ␮M); EPSCs were not
significantly affected by the drug.
Synaptic stimulation triggered [Ca2⫹]i
transients in conditions of pharmacological
block of ionotropic GluRs (CNQX 10–50
␮M ⫹ MK-801, 2–5 ␮M); these [Ca2⫹]i
responses were blocked by TG (5 ␮M, 15
min of incubation). Successful induction of
Ca2⫹ release required conditioning training
with several depolarizations to load the
stores with Ca2⫹.
Stimulation of PF induced local [Ca2⫹]i
signaling in PN dendrites; the [Ca2⫹]i
response comprised of two components
associated with AMPAR mediated Ca2⫹
entry and IICR; the latter component was
blocked by mGluR antagonist MCPG (1
mM) and intracellularly applied heparin (50
␮g/ml).
Short repetitive stimulation (5 stimuli, 50 Hz)
of PF triggered EPSP and local biphasic
[Ca2⫹]i elevation in dendrites. Rapid phase
of Ca2⫹ signal was blocked by CNQX (10
␮M), whereas delayed phase was inhibited
by MCPG (1 mM), intracellular heparin (4
mg/ml) or CPA (20 ␮M), indicating thus
IICR.
Synaptic stimulation in conditions of
blockage of AMPA and NMDA receptors
(CNQX 10 ␮M, AP-5, 100 ␮M) triggered
small dendritic [Ca2⫹]i transients. When
synaptic stimulation was paired with 5–10
APs, the [Ca2⫹]i transient increased
dramatically. Pairing of APs with transACPD (30 ␮M) resulted in big [Ca2⫹]i
elevations, while APs alone triggered small
[Ca2⫹]i rise. The [Ca2⫹]i responses
triggered by paired synaptic stimulation
and APs were inhibited by heparin (1 mg/
ml), CPA (20 ␮M) and ryanodine (10 ␮M),
but not by ruthenium red (120 ␮M).
Stimulation of mossy fibers by low-intensity
trains of 10- to 100-Hz frequency resulted
in [Ca2⫹]i elevations not associated with
AP firing and plasmalemmal Ca2⫹ entry.
[Ca2⫹]i responses were blocked by
intracellularly applied heparin (1 mM) and
potentiated by pairing of mossy fiber
stimulation with postsynaptic AP.
Reference
Nos.
163
415
150
624
444
270
MF, mossy fibers; PF, parallel fibers; SC, Schaffer collateral; VGCC, voltage-gated Ca2⫹ channels; EPSC, excitatory postsynaptic currents.
B) IMMUNOPHILIN FK506 BINDING PROTEIN 12. Immunophilin
FK506 binding protein 12 (FKBP12), which is abundantly
expressed in brain tissue, was shown to be associated with
InsP3R1. This complex is disrupted upon the addition of the
immunodepressants FK506 or rapamycin. Dissociation of
InsP3R1-FKBP12 causes an increase of Ca2⫹ flux through
the channel, and this can be reversed by adding FKBP12
Physiol Rev • VOL
(74). It seems that the latter serves as a physiological regulator of the conductive properties of InsP3Rs. In biophysical
experiments on purified InsP3R1s in planar lipid bilayers, the
addition of exogenous recombinant FKBP12 substantially
increased the open time of the channels (113).
C) CALMODULIN. The InsP3R type 1, but not type 3, possesses a high-affinity binding site for calmodulin, occupa-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Preparation
CALCIUM STORE IN THE ER OF NEURONS
233
tion of which inhibits the channel. Inhibition of calmodulin by calmodulin inhibitory peptide sensitizes IICR in
Xenopus oocytes (376).
D) CALDENDRIN. The InsP3Rs are also regulated by the
cytoplasmic Ca2⫹-binding proteins caldendrins, which,
depending on their structure, may either activate or inhibit IICR. A splice variant of caldendrin was found to
bind specifically to all three InsP3R subtypes. This binding
activated InsP3Rs, suggesting the possibility of IICR initiation even in the absence of the natural agonist (707). At
the same time a long-splice variant of caldendrin, when
expressed in PC12 or HeLa cells, inhibited IICR triggered
by activation of histamine and purinoreceptors (206).
D. Do InsP3Rs and RyRs Share a Common
Ca2ⴙ Pool?
Although morphological and functional evidence
(see sect. II) clearly defined the ER as a single continuous
Physiol Rev • VOL
space, the analysis of Ca2⫹ release divided the field into
supporters of a single functional Ca2⫹ pool available for
both CICR and IICR, and supporters of at least two separate pools, selectively sensitive to either InsP3 or Ca2⫹/
caffeine (see Table 6). The experimental strategy employed by both camps is similar: the cells are treated with
maximal concentrations of CICR agonists and thereafter
the ability of IICR-stimulated agents to produce Ca2⫹
release is tested, and vice versa. Provided the cell has a
single Ca2⫹ pool, each agonist should be able to deplete it
completely, thus rendering subsequent stimulations with
other agents ineffective. Alternatively, if the cell expresses more than one functional pool, each agonist
would discharge a compartment with appropriate complement of receptors. The story is old and at the moment
opposing factions are far from a consensus. As far as
neurons are concerned, it looks as if more data are in favor
of a single continuous ER Ca2⫹ store. Furthermore, some
studies supporting separate Ca2⫹ pools mention peculiar
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 15. Synaptically evoked localized IICR in Purkinje neuron. A: local
dendritic [Ca2⫹]i signals mediated by repetitive parallel fiber stimulation. a: Confocal image of Purkinje neuron voltageclamped and loaded with Oregon-green
BAPTA-1. The dendritic regions 1 and 2
correspond to sites of stimulation (position of stimulation pipettes are depicted
by dotted lines). b: These regions at
higher magnification and also shows the
kinetics of [Ca2⫹]i responses to repetitive
parallel fiber stimulation (5 stimuli, 50
Hz). B: dependence of synaptic [Ca2⫹]i
responses on ER Ca2⫹ release. a: Almost
complete elimination of the delayed
phase of [Ca2⫹]i transient by intracellularly applied heparin (4 mg/ml). b: Same
effect of ER depletion by incubation of
slices with cyclopiazonic acid (CPA; 20
␮M). [Modified from Takechi et al. (624).]
234
ALEXEI VERKHRATSKY
unidirectional relations between RyR-bearing and InsP3Rs
bearing stores: either ryanodine occluded IICR but not vice
versa (541), or else stimulation of IICR depletes caffeinesensitive pool but stimulation of RyRs does not affect the
InsP3-sensitive one (528). Moreover, in most cases, the separate pools were observed in cell lines or in embryonic
cultures, whereas the existence of a single Ca2⫹ store is
supported by experiments on primary cultures and brain
slices, the latter preparations being rather more physiological (Fig. 17A). When directly investigating intra-ER Ca2⫹
dynamics in sensory neurons, a very clear and full overlap
between InsP3/ryanodine/caffeine/Ca2⫹ and TG/CPA pools
was observed (Fig. 17B, Ref. 602).
E. Luminal Ca2ⴙ as a Regulator of Ca2ⴙ Release
The level of free Ca2⫹ concentration within the ER
lumen is critically important for regulation of Ca2⫹
Physiol Rev • VOL
release as it creates the driving force for Ca2⫹ exit and
regulates the functional availability of Ca2⫹ release
channels. That [Ca2⫹]L in nerve cells is a labile parameter became obvious from the very beginning of experimental investigations of the ER Ca2⫹ store. The first
attempts to induce Ca2⫹ release in single central neurons, either by caffeine or by metabotropic agonists,
demonstrated that application of stimulating agents to
resting cells triggered very tiny [Ca2⫹]i increases in a
small proportion of neurons. However, when caffeine
or a metabotropic agonist was applied shortly after the
cell was depolarized, and thus had experienced a large
Ca2⫹ influx into the cytosol, a considerable [Ca2⫹]i
elevation due to Ca2⫹ release was apparent in a large
proportion of neurons (249, 250, 375, 437, 526, 581). A
small depolarization (i.e., with ⬃10 mM KCl or with low
concentrations of NMDA) which led to a steady-state
[Ca2⫹]i increase had the same effect (249).
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 16. Ca -assisted InsP3-induced
Ca2⫹ release. A: backpropagated action
potentials cause large [Ca2⫹]i elevation
and propagating [Ca2⫹]i wave in the presence of the mGluR agonist 1-aminocyclopentane-trans-1,3-dicarboxylic acid (tACPD). In control conditions (first trace
from the left), a pair of spikes caused
rapid, almost simultaneous, increases in
[Ca2⫹]i at all locations in the cell, as
shown by [Ca2⫹]i responses measured
from green and red boxes on the cell
image shown on the right. When the slice
was incubated with 30 ␮M t-ACPD, the
same pair of spikes caused the same synchronous increases in [Ca2⫹]i, followed
by larger propagating [Ca2⫹]i signal (second trace). Five spikes (third trace)
caused a similar secondary response that
initiated earlier and more synchronously
at different dendritic locations. B: synaptic
stimulation followed by action potentials
causes release of Ca2⫹ in the apical dendrites. Left panel shows bis-fura 2-filled
pyramidal neuron, with regions of interest
and electrode positions marked. AP-5 (100
mM) and CNQX (10 mM) were added to
the bath. Scale bar, 50 ␮m. a: Synaptic
stimulation at 100 Hz for 1 s caused no
detectable change in fluorescence at any
somatic or dendritic location. The membrane potential hyperpolarized because inhibition was not blocked. b: Synaptic stimulation (same stimulation parameters) followed immediately by action potentials,
evoked by 1-ms intrasomatic pulses at
30-ms intervals, caused fast fluorescence
increases at all locations and slower, larger
increases, predominantly in the proximal
apical dendrites. c: A train of 10 action
potentials without synaptic stimulation
evoked fluorescence increases that peaked
at the time of the last spike at all locations.[A from Nakamura et al. (446), copyright 2000 by the Society for Neuroscience.
B from Nakamura et al. (444), copyright
1999 with permission from Elsevier.]
235
CALCIUM STORE IN THE ER OF NEURONS
TABLE
6.
Evidence for single versus separate ER Ca2⫹ store in neurons
Separate or Partially Separate Store
Single Store Shared by RyRs and InsP3Rs
Preparation
Reference
nos.
Cultured parasympathetic neurons from rat intracardiac ganglia
Cultured rat DRG neurons (partial overlap)
Cultured mouse embryonic hippocampal neurons
Cultured rat embryonic hippocampal neurons*
Neuroblastoma ⫻ glioma hybrid Ng108-15, varicosities†
PC12 cell line‡
350
637
438
417
541
528
Reference
nos.
PC12 cell lines
Cultured rat DRG neurons
Cultured rat hippocampal neurons
Freshly isolated CA1 hippocampal neurons
Cultured rat cerebellar granule neurons
Dopamine neurons in rat horizontal midbrain slices
CA1 neurons in rat hippocampal slices
Adrenal chromaffin cells
Purkinje neurons in rat cerebellar slices
Cultured guinea pig myenteric neurons
Cultured rat DRG neurons, [Ca2⫹]L recordings
714
109
393, 571
245
250, 590
428
444, 518
9, 246, 517
283
286, 287
602
* Although full separation between InsP3 and ryanodine receptor (RyR) stores was suggested, ryanodine blocked InsP3-mediated Ca2⫹ release.
† TG inhibited [Ca2⫹]i responses to bradykinin but did not affect caffeine-induced Ca2⫹ release at all; in contrast, ryanodine substantially (⬃70%)
inhibited bradykinin-evoked [Ca2⫹]i transients.
‡ Bradykinin-evoked Ca2⫹ release significantly depleted caffeine-sensitive pool, but caffeine did
not affect bradykinin responses.
The stimulating effect of the conditioning depolarization was transient because the amplitude of Ca2⫹ release
decreased progressively when increasing the time gap
between the depolarization and the application of a Ca2⫹release stimulator (Fig. 18). Quite logically, this peculiar
behavior was explained in terms of a low releasable Ca2⫹
content of the ER in resting central neurons. The empty
Ca2⫹ store favors Ca2⫹ accumulation and therefore Ca2⫹
entering the cell following depolarization is taken up by
the ER, thus increasing the Ca2⫹ content within the store
and permitting Ca2⫹ release. An extreme situation, in
which the store is empty or almost empty at rest, is
usually observed in cultured cells. Application of caffeine
to resting neurons in acute hippocampal slices (179) or in
acutely isolated thalamocortical neurons (68) routinely
evokes [Ca2⫹]i responses; similarly stimulation of IICR
triggered [Ca2⫹]i elevation in Purkinje neurons (624) and
in pyramidal cortical neurons (609) in situ. Nonetheless,
the conditioning depolarization dramatically (by 500%)
increased the amplitude of a subsequent caffeine-induced
[Ca2⫹]i transient in central neurons studied in acute slices
(179); and similarly to what was found in cultured neurons this potentiation was short-lived (Fig. 18B). In peripheral neurons, the effect of conditioning depolarization
also existed, although it was much less dramatic; conditioning depolarization increased the amplitude of subsequent Ca2⫹ release by 10 –30% (583, 661). The nature of
this rather prominent difference between central and peripheral neurons is unclear; similarly unclear are the
mechanisms responsible for the loss of surplus Ca2⫹ in
the ER after the store has been charged.
The ability of the ER of central neurons to rapidly
accumulate huge amounts of Ca2⫹ was confirmed in direct recordings of total ER Ca2⫹ content using energy
dispersive X-ray microanalysis. In these experiments, hippocampal slices were rapidly frozen at different time
Physiol Rev • VOL
intervals after tetanic afferent stimulation. It was observed that 30 s after stimulation, the total ER Ca2⫹
content had increased up to 20 times and stayed elevated
for 15–30 min (519, 520). The authors concluded that the
ER acts as a major Ca2⫹ buffering system in dendrites
upon synaptic stimulation. However, this may vary between different regions and may depend on heterogeneous distribution of SERCA pumps (365). Importantly,
the X-ray microanalysis also showed a remarkable heterogeneity of dendritic ER with respect to Ca2⫹ accumulation; only ⬃40% of the reticulum demonstrated an increase in total Ca2⫹ content. These data once more raise
questions about the functional continuity of the ER, although a heterogeneous increase in total Ca2⫹ may reflect
specific concentration of Ca2⫹ binding proteins in particular ER regions.
The transient Ca2⫹ loading of the Ca2⫹ store in central neurons certainly has very important implications.
Indeed, a transient increase in [Ca2⫹]L and the consequent
enhancement of Ca2⫹ release would provide the ER with
a coincidence detection mechanism and with (at least
short-term) memory. Further understanding of the mechanisms controlling changes in the ER Ca2⫹ concentration
ultimately requires direct monitoring of the free Ca2⫹
dynamics in the ER lumen.
Several experimental approaches permitting real time
measurements of [Ca2⫹]L have been developed during the
last two decades (Table 7). These techniques employ either
ER-targeted Ca2⫹-sensing luminescent or fluorescent proteins (10, 120) or conventional fluorescent Ca2⫹ probes with
a sufficiently low Ca2⫹ affinity (232, 492, 601). The [Ca2⫹]L
measurements in neurons began only recently (Table 7; Fig.
19), and our knowledge about ER Ca2⫹ dynamics in nerve
cells remains very incomplete. The quantitative [Ca2⫹]L measurements performed in PC12 cells and isolated sensory
neurons showed a high resting [Ca2⫹]L ranging between 100
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Preparation
236
ALEXEI VERKHRATSKY
and 800 ␮M and demonstrated that activation of Ca2⫹ release channels by Ca2⫹, caffeine, ryanodine, and InsP3 results in a rapid decrease of [Ca2⫹]L reflecting Ca2⫹ release.
Direct [Ca2⫹]L measurements in physiologically intact central neurons have not yet been performed.
F. Refilling the Ca2ⴙ Store and Store-Operated
Ca2ⴙ Entry
Control of [Ca2⫹]L and refilling of the Ca2⫹ store after
depletion is accomplished by SERCA pumps. Numerous
experiments (see Tables 1–5) have demonstrated that
inhibition of the latter prevents Ca2⫹ accumulation and
Physiol Rev • VOL
results in progressive depletion of the Ca2⫹ store due to
unopposed leakage of Ca2⫹ from the ER lumen. Occasional reports mention the possible existence of a TGresistant Ca2⫹ store in nerve cells, and a TG-resistant
Ca2⫹ transport was found in brain microsomes and in
certain cell lines (687). The relevance of this type of Ca2⫹
pool for neuronal physiology remains unclear.
Intraluminal Ca2⫹ recordings revealed an important
role of the [Ca2⫹]L level in the regulation of the velocity of
ER Ca2⫹ uptake. Decreases in [Ca2⫹]L significantly (5–7
times) increased the speed of Ca2⫹ uptake; replenishment
of the ER slowed the rate of Ca2⫹ uptake (603). Most
importantly, at least in sensory neurons, the influence of
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
FIG. 17. Neuronal ER as a single functional Ca2⫹ store shared by RyRs and InsP3Rs.
A: ryanodine abolishes InsP3-induced [Ca2⫹]i
elevation in Purkinje neuron studies in cerebellar slices. Left panel shows three [Ca2⫹]i
responses to photorelease of various concentrations of InsP3 (as indicated over the recordings; instances of ultraviolet flash are indicated by solid circles). Right panel shows
complete inhibition of InsP3-induced Ca2⫹
mobilization in a neuron that was internally
dialyzed with 50 ␮M ryanodine. Slow equilibration of ryanodine through the Purkinje
neuron most likely resulted in depletion of the
store. B: complete overlap of InsP3/caffeine/
ryanodine and TG/CPA-sensitive Ca2⫹ store in
single DR neurons as judged by [Ca2⫹]L recordings. a– d: [Ca2⫹]L recordings taken from
different neurons that were challenged with
ER depleting/Ca2⫹-release channels activating
agents in a sequences indicated on the graph.
[A from Khodakhah and Armstrong (283),
with permission from the Biophysical Society;
B from Solovyova and Verkhratsky (602), with
permission from Springer-Verlag.]
CALCIUM STORE IN THE ER OF NEURONS
237
an increased [Ca2⫹]i on the Ca2⫹ uptake velocity seems to
be negligible (Fig. 20). To quantify Ca2⫹ uptake velocity,
Ca2⫹ release was stimulated by brief application of caffeine, and the recovery kinetics of [Ca2⫹]L were monitored during the washout period. After [Ca2⫹]L reached
the prestimulation level, the SERCA pumps were inhibited by TG, which resulted in a relatively slow decrease in
[Ca2⫹]L due to Ca2⫹ leakage. The rate of leakage declined
in proportion to the decrease in [Ca2⫹]L, presumably reflecting a falling electrochemical driving force for Ca2⫹. It
turned out that neither the rate of Ca2⫹ uptake nor the
velocity of Ca2⫹ leakage was affected when a BAPTA/
Ca2⫹ (10 mM/2 mM) buffer was washed into the cytosol
Physiol Rev • VOL
(Fig. 20, A and B). In the latter condition [Ca2⫹]i is
clamped, yet plenty of Ca2⫹ is available for ER accumulation. Therefore, in peripheral neurons store refilling
does not require an increase in [Ca2⫹]i, albeit it requires
Ca2⫹ availability in the cytosol. This seems to be a general
mechanism for many cell types, and the very similar
dependence of ER Ca2⫹ uptake on [Ca2⫹]L and independence on [Ca2⫹]i rises, was shown for pancreatic acinar
cells (425; see Fig. 20C) and BHK-21 fibroblasts (231).
In frog sympathetic ganglion neurons, a special
mechanism which greatly assists the refilling of the stores
after their depletion, the release-activated calcium transport (RACT) was also suggested (110). The nature of this
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 18. Transient overcharging of ER Ca
stores in central neurons. A: left panel shows representative [Ca2⫹]i recordings from cultured
hippocampal neurons challenged with 20 mM caffeine and 50 mM KCl as indicated on the graph. Note that initial application of caffeine to the resting
cell fails to trigger [Ca2⫹]i elevation, yet caffeine applied immediately after the end of KCl depolarization produces substantial [Ca2⫹]i response.
Increase in the time gap between conditioning KCl depolarization and application of caffeine leads to progressive decrease in the amplitude of
caffeine-induced [Ca2⫹]i elevation (right panel shows a summary of similar experiments performed on different types of cultured central neurons),
indicating that ER loses surplus Ca2⫹. The columns on the graph are means ⫾ SD for the amplitudes of caffeine-induced [Ca2⫹]i elevation; caffeine
was applied 30, 210, and 600 s after the end of KCl depolarization. B: experiment very similar to that described in A except it was performed on CA1
pyramidal neurons in acutely isolated hippocampal slices. Left panel shows examples of [Ca2⫹]i recordings demonstrating the changes in
caffeine-induced [Ca2⫹]i response depending on conditioning KCl (40 mM) challenge. On the right, the bar histogram depicting the relation between
the size of caffeine-induced [Ca2⫹]i transient versus the time elapsed after a KCl-induced [Ca2⫹]i elevation (⌬t). The ⌬t was measured between the
peaks of KCl-mediated and caffeine-mediated [Ca2⫹]i transients. Each bar represents a mean of 6 –11 data points. The amplitudes of caffeine-induced
[Ca2⫹]i transients evoked after KCl depolarization were normalized with respect to the control (i.e., before KCl) [Ca2⫹]i transient. [A from Shmigol
et al. (581), with permission from Blackwell Publishers Ltd.; B from Garaschuk et al. (179), with permission from Springer-Verlag.]
238
TABLE
ALEXEI VERKHRATSKY
7.
Monitoring of [Ca2⫹]L in neurons
[Ca2⫹]L Indicator
Experimental Approach/Data
Rat/P35/pituitary
gonadotropes
Freshly isolated
identified
cells
Mag-indo 1-AM
(KD ⬃35 ␮M)
Frog/adult/sympathetic
ganglia
Primary culture
(2–6 DIV)
Fluo 3FF-AM
(KD ⬃42 ␮M)
Bovine/adrenal medulla
rat/cerebellum
Primary
cultures of
chromaffin
cells and
cerebellar
granule
neurons
ER-targeted
aequorin
Mouse/E18/cerebellum
Primary culture
of PN (21–28
DIV)
Mag-fura 2-AM
(KD ⬃50 ␮M)
Rat/P1–P3/DRG
Primary culture
(1–2 DIV)
Mag-fura 2-AM
(KD ⬃50 ␮M)
Cells were loaded with Mag-indo 1-AM by 45-min exposure to 9–18
␮M of the dye at 37°C followed by washout for 30–60 min at
28°C. Cytosolic portion of the dye was removed by intracellular
dialysis via patch pipette; 1 mM MnCl2 was added to
intracellular solution to quench remnants of cytosolic dye
fluorescence. Stimulation of gonadotropes with
gonadotropin-releasing hormone triggered rhythmic transient
[Ca2⫹]L decreases on top of slow decrease in [Ca2⫹]L.
Cells were loaded with fluo 3FF-AM (4 ␮M for 90 min). The dye
was considered to report exclusively [Ca2⫹]L; no attempts to
remove cytosolic dye were performed. Recordings reveal rather
poor dynamic range (maximal depletion by caffeine was ⬃0.1
⌬F/F unit). More importantly, “on” and “off” kinetics of
fluorescence drop in response to caffeine application/washout
were almost identical and very rapid. Only responses to caffeine
and one small response to chloro-m-cresol were shown without
any further pharmacological identification of the mechanisms
involved.
Cells were transfected (HSV-1 virus) with ER-targeted low-affinity
aequorin (which allow [Ca2⫹] measurements in a range of 20
␮M–1 mM). Expression required ⬃16 h. Before the experiment,
cells were incubated for 1 h at room temperature in standard
medium containing 0.5 mM EGTA, 10 ␮M BHQ, and 1 ␮M
coelenterazine. In some experiments, the plasmalemma was
permeabilized with 20 ␮M digitonin. To fill up the stores, cells
were incubated with 100 nM EGTA-Ca2⫹ buffer. Both IICR
(histamine stimulated) and CICR (Ca2⫹ and caffeine stimulated)
were identified.
Cells were loaded with Mag-fura 2-AM by 60-min incubation with
30 ␮M of the dye at 24°C. Experiments were performed on cells
permeabilized with 60 ␮M ␤-escin (6–10 min); cells were kept in
Ca2⫹-free/EGTA solutions; to load ER, MgATP and Ca2⫹ were
added. Application of InsP3 induced depletion of the store; no
recovery was shown. No attempt to calibrate the system was
made.
Cells were loaded with Mag-fura 2-AM by 30-min incubation with 5
␮M of the dye at 37°C followed by washout for 60 min at 37°C.
Cytosolic portion of the dye was removed by either intracellular
dialysis or by plasmalemmal permeabilization with 0.001%
saponin applied for 7–10 s. Introduction of fluo 3K5 into
intrapipette solution (in patch-clamp experiments) allowed
simultaneous measurements of [Ca2⫹]L and [Ca2⫹]i. Both CICR
and IICR were identified.
pathway remains enigmatic, and it is possible that it simply reflects greater activation of SERCA pumping following severe depletion of the ER (although according to
the initial description RACT appeared to be insensitive
to TG).
All in all, the regulation of [Ca2⫹]L in peripheral neurons seems to be quite straightforward; these stores are
full in the resting conditions, and an efficient [Ca2⫹]L
dependent regulation of SERCA pumping keeps [Ca2⫹]L
under tight control. This control is assisted by a [Ca2⫹]Ldependent leakage such that every increase in [Ca2⫹]L
immediately increases the Ca2⫹ leak and decreases
SERCA activity. Store depletion leads to the opposite
effect, i.e., a decrease in Ca2⫹ leak and rapid upregulation
of SERCA pumping velocity. Intuitively, the mechanism
controlling [Ca2⫹]L in central neurons must be very difPhysiol Rev • VOL
Reference
Nos.
651
110
8–10
169
600–603
ferent as it should permit a high flexibility of the [Ca2⫹]L
regulation to tolerate the relatively low resting ER Ca2⫹
content. Nevertheless, this low resting [Ca2⫹]L seems to
prime SERCAs for rapid accumulation of the bulk of the
Ca2⫹ entering the cytosol upon depolarization or synaptic
stimulation. This also assumes the high sensitivity of the
Ca2⫹ uptake mechanism to increases in [Ca2⫹]i, which
represents another clear difference between central and
peripheral nerve cells.
The problem of store refilling is also inseparable from
the question of neuronal expression of the store-operated
Ca2⫹ entry pathway. This pathway, discovered by Jim
Putney (522), is a general feature of nonexcitable cells,
which lack other means of Ca2⫹ entry. A direct relation
between ER depletion and SOC activation is firmly established (458, 488, 490, 523). In nerve cells, the replenish-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Preparation
Species/Age/NS Region
CALCIUM STORE IN THE ER OF NEURONS
239
ment of the Ca2⫹ store after depletion by either several
consecutive applications of caffeine/metabotropic agonists or prolonged incubation of cells with Ca2⫹ release
stimulating agents, requires plasmalemmal Ca2⫹ influx
(179, 661). Does this Ca2⫹ influx employ a classical storeoperated mechanism? Or, does the Ca2⫹ enter the cell via
numerous Ca2⫹-permeable channels present in the neuronal plasmalemma? This remains a debatable matter. From
the general logic of neuronal physiology, the SOC pathway can hardly be justified. Indeed, neurons possess
plenty of Ca2⫹ channels, and moreover, these channels
are repeatedly activated, as neurons rarely enjoy complete idleness. Furthermore, activation of SOC, according
to several reports, has a threshold nature, i.e., it requires
Physiol Rev • VOL
a very substantial depletion of the store (202, 489, 490).
This is very difficult to reconcile with the observations of
empty stores in central neurons; if SOC exists it surely
would increase [Ca2⫹]i up to the point when the stores
become replenished.
Nonetheless, several groups have suggested that neurons possess a store-operated Ca2⫹ influx pathway very
similar to that of nonexcitable cells (Table 8, Ref. 524), yet
the data gathered are not entirely convincing. Quite often
SOC expression is judged upon pharmacological sensitivity of [Ca2⫹]i transients produced by Ca2⫹ readmission
after store depletion in Ca2⫹-free media. Because the
pharmacology of store-operated channels is not very well
defined, this interpretation is open to criticism. The exis-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
2⫹
FIG. 19. Examples of [Ca ]L recordings. A: an example of [Ca ]L recording in bovine chromaffin cells transfected by ER-targeted aequorin
showing complete overlap of InsP3/ryanodine and TG-sensitive store. Left trace shows effects of caffeine (50 mM) and histamine (10 ␮M) on [Ca2⫹]L
after the ER was refilled by incubation with medium containing 1 mM Ca2⫹. On the right, the effects of caffeine, histamine, and bradykinin (1 ␮M)
on [Ca2⫹]L in control conditions and after pretreatment with either ryanodine (10 ␮M) or thapsigargin (1 ␮M) are demonstrated. B: example of
[Ca2⫹]L recording using fluo 3FF. The cells were loaded with fluo 3FF-AM, and no attempts to washout the cytosolic portion of the dye were made,
which may account for a poor dynamic range of measurements (maximal response ⬃0.1 ⌬F/F). Cells were treated with 10 mM caffeine, 50 mM KCl,
or 1 mM chloro-m-cresol as indicated on the graph. Caffeine triggered [Ca2⫹]L response where recovery was as fast (left trace) or even faster (right
trace) that the initial [Ca2⫹]L decrease. C: simultaneous visualization of [Ca2⫹]i and [Ca2⫹]L dynamics in DRG neurons. On the left, a series of selected
images of the Mag-fura 2 ratio (Ex. 340/380 nm, top panel) taken simultaneously with images of fluo 3 fluorescent intensity (Ex. 488 nm) from the
DRG neuron exposed to 20 mM caffeine is shown. Right panel shows calibrated recordings of [Ca2⫹]L and normalized fluo 3 fluorescent intensity
(reflecting changes in [Ca2⫹]i) taken from the cell shown on the left. Caffeine was applied as indicated on the graph; the positions of the images
presented on the left panel are shown near the [Ca2⫹]L trace. [A from Alonso et al. (9) by copyright permission from The Rockfeller University Press;
B from Cseresnyes et al. (110), copyright 1997 with permission from Elsevier; C from Solovyova et al. (603), with permission from Nature Publishing
Group.]
240
ALEXEI VERKHRATSKY
tence of SOC in central neurons, for example, was postulated by Baba et al. (17) based on [Ca2⫹]i imaging of
primary cultured pyramidal and granule neurons isolated
from Ammon’s horn and dentate gyrus, respectively. After
these neurons were incubated with 1 ␮M TG for 5 min in
Ca2⫹-free solution, readmission of external Ca2⫹ triggered [Ca2⫹]i elevation, which was inhibited by 100 ␮M
La2⫹, 3 ␮M SKF96365, or 30 ␮M 2-aminoethoxydiphenyl
borate (2-APB). No attempts, however, were made to
activate SOC by more physiological depletion of the ER
store such as administration of caffeine or stimulation of
metabotropic receptors, yet a conclusion about SOC activation by synaptic transmission (based on partial and
rather slight inhibition of [Ca2⫹]i transients evoked by
Physiol Rev • VOL
tetanic field stimulation of cultured neurons by 2-APB or
SKF96365) was announced. As 2-APB and SKF96365 also
attenuated LTP recorded in hippocampal slices, another
fundamental conclusion of SOC involvement in synaptic plasticity was made by the same authors (17). Interestingly, La2⫹, 2-APB, and SKF96365 also inhibited the
plateau phase of NMDA-induced [Ca2⫹]i elevation,
which may reflect their poor selectivity, rather than
activation of SOC upon stimulation of ionotropic glutamate receptors.
The protocols of inducing SOC in neurons vary,
e.g., cultured cortical neurons were incubated in a
Ca2⫹-free, 50 ␮M EGTA and 2 ␮M CPA containing
solution for 30 min, and [Ca2⫹]i elevation developing
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 20. [Ca ]L regulates the rate of
Ca2⫹ uptake onto the ER. A: top panel
shows simultaneous [Ca2⫹]L (black
trace) and [Ca2⫹]i (gray trace) recordings from single DRG neurons treated
with 20 mM caffeine and 5 ␮M TG as
indicated on the graph. Bottom panel
shows the relationship between Ca2⫹ uptake/Ca2⫹ leakage rates and [Ca2⫹]L. The
intrapipette solution did not contain any
Ca2⫹ buffers, except 0.1 mM Ca2⫹ indicator fluo 4. B: the same experiment was
repeated on another cell, when intrapipette solution was supplemented with 10
mM BAPTA/2 mM Ca2⫹ buffer, which
clamped the [Ca2⫹]i at ⬃90 nM (note
absence of [Ca2⫹]i changes on gray
trace). The Ca2⫹ uptake/Ca2⫹ leakage
rates shown on the bottom panel of the
graph do not differ significantly from
those on A, demonstrating thus that an
increase in [Ca2⫹]i does not affect Ca2⫹
movement into and out of the ER. C: an
example of similar relations between
[Ca2⫹]L and uptake rate obtained in pancreatic acinar cell. The Ca2⫹ reuptake
into intracellular stores following AChevoked Ca2⫹ release was not prevented
by clamping the cytoplasmic Ca2⫹ concentration at the normal resting level. In
this experiment, the patch pipette solution was heavily buffered by a BAPTA/
Ca2⫹ mixture, clamping [Ca2⫹]i at a concentration of 90 nM. Left panel shows the
ACh-evoked loss of Ca2⫹ from the ER
store and the subsequent rise of [Ca2⫹]L
after removal of the agonist. After a period of Ca2⫹ reaccumulation, thapsigargin is added to arrest the ER Ca2⫹ ATPase, and a slow reduction in [Ca2⫹]L follows. Right panel shows the relationship
between apparent calcium transport
rates and [Ca2⫹]L derived from the data
shown on the left. Note similar behaviors
of ER Ca2⫹ uptake rate in acinar cell and
in DRG neuron (A and B). [A from Solovyova et al. (603), with permissiion
from Nature Publishing Group; C from
Mogami et al. (425), with permission
from Nature Publishing Group; B represents unpublished data from Solovyova
and Verkhratsky.]
CALCIUM STORE IN THE ER OF NEURONS
TABLE
8.
241
Evidence for store-operated Ca2⫹ entry in neurons
Preparation
Technique
Evidence for SOC
Rat/E17/hippocampus,
thalamus
Primary culture
(8–14 DIV)
Myenteric plexus/P1/
guinea pig
Primary culture
(2–8 DIV)
Fura 2-AM imaging;
Mn2⫹-dependent fura 2
quenching
Fura 2-AM
microfluorimetry
Chicken/E3–E13/neural
retina
Acutely
isolated
preparation
Fura 2-AM
microfluorimetry
Immortalized
hypothalamic GT1
neural cells
Rat/P1–P3/DRG
Culture
Whole cell voltage clamp;
indo 1
microfluorimetry
Whole cell voltagecurrent clamp; indo
1/indo 1-AM
microfluorimetry;
Mn2⫹-dependent fura 2
quenching
Mn2⫹ influx into neurons was detected after initiation of
Ca2⫹ release by intracellular injection of InsP3 or
stimulation of metabotropic purinoerecptors.
Reintroduction of extracellular Ca2⫹ after the stores
were depleted by application of caffeine (10 mM) in
Ca2⫹-free solution triggered substantial [Ca2⫹]i
elevation.
Readmission of Ca2⫹ after ER depletion by TG (500 nM)
in Ca2⫹-free media triggered [Ca2⫹]i rise sensitive to
10 ␮M SKF96365, 1 mM Zn2⫹, or 5 mM Ni2⫹. This
[Ca2⫹]i rise was prominent at E3 and disappeared at
E13. It was also inhibited by genistein, suggesting the
involvement of tyrosine phosphorylation in activation
of the presumed SOC.
ER store depletion with TG (5 ␮M) induced lowamplitude (⬃20 pA) Ca2⫹-conducting inward current.
Rat/P3–P5/
hippocampus
Primary
neuronal-glial
cultures
Fluo 3-AM confocal
imaging
Mouse/E15.5/cortex
Primary culture
(⬎1 DIV)
Fura 2-AM imaging
Rat/P3/hippocampus,
Ammom’s horn, and
dentate gyrus
Primary culture
(7–9 DIV)
Fura 2-AM imaging
Rat/P22–P28/midbrain
Acute slice
Whole cell voltage clamp;
fura 2 imaging
Primary culture
Refilling of Ca2⫹ store after caffeine-induced depletion
required Ca2⫹ influx, which was inhibited by 2 mM
Ni2⫹; other VGCC blockers (10 ␮M nimodipine, 10 ␮M
nicardipine, or 1 ␮M ␻-grammotoxin SIA) were
ineffective. Refilling of the store was potentiated by
hyperpolarizing the cells from ⫺55 to ⫺80 mV. The
[Ca2⫹]i transient elevation upon readmission of Ca2⫹
following discharging the store by caffeine/Ca2⫹-free
solution was found in 68% of cells. Finally, caffeine
and CPA potentiated Mn2⫹ influx in DRG neurons.
Application of 200 ␮M carbahol and 0.4 ␮M TG
triggered [Ca2⫹]i elevation in Ca2⫹-free solution;
readmission of external Ca2⫹ resulted in secondary
[Ca2⫹]i elevation, which was blocked by 50 ␮M La3⫹.
Readmission of extracellular Ca2⫹ after 30 min of cell
incubation in Ca2⫹-free 50 ␮M EGTA and 2 mM CPA
triggered [Ca2⫹]i elevation, which was considered to
reflect SOC activation.
[Ca2⫹]i elevation in response to Ca2⫹ readmission after
5 min of incubation with TG/0 Ca2⫹; this [Ca2⫹]i
elevation was blocked by 100 ␮M La3⫹ or 30 ␮M 2APB.
Activation of mGluR I (DHPG, 100 ␮M) resulted in
cationic current ⬃300–400 pA at ⫺70 mV. The
currents were inhibited by SKF96365 (100 ␮M), Gd3⫹
(100 ␮M), ruthenium red (20 ␮M), and 2-APB (30–100
␮M). When the cells were treated with 10 ␮M TG in
Ca2⫹-free media, Ca2⫹ readmission resulted in steadystate [Ca2⫹]i elevation sensitive to 2-APB. RT-PCR
revealed expression of multiple TRP channels, with
TRPC1 and TRPC5 being the most abundant.
417
286
556, 718
667
664
60
709
17
648
2-APB, 2-aminoethoxydiphenyl borate; DHPG, S-(3,5)-dihydroxyphenylglycine.
after external Ca2⫹ restoration was regarded as a SOCrelated phenomenon (709), yet the possibility that prolonged treatment with a Ca2⫹-free solution may affect
neuronal status and viability was not explored. Sometimes the existence of SOC, as well as its physiological
significance, is deduced from indirect data such as an
increase in miniature excitatory postsynaptic potential
frequencies in Ca2⫹-containing solutions after treatment with CPA (139). These observations favoring neuronal SOC should be balanced by very many experiments, that employed TG/CPA for inhibition of Ca2⫹
release in nerve cells. In most of these cases, no signifPhysiol Rev • VOL
icant changes in resting [Ca2⫹]i, indicative of SOC were
observed (e.g., Refs. 179, 303, 418, 582, 583, 629, 655 to
name but a few). All in all, the evidence for neuronal
SOC derived from pharmacological inhibition of postTG/CPA-induced [Ca2⫹]i elevation remains, in my view,
unconvincing, and conjectures about the role of SOC in
synaptic plasticity, though very stimulating, currently
lack real experimental basis.
Perhaps the most convincing case for SOC expression in neurons was presented by Usachev and Thayer,
who investigated the process of store replenishment in rat
cultured DRG neurons. They demonstrated that Ca2⫹ en-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Species/Age/NS Region
242
ALEXEI VERKHRATSKY
G. Pharmacology of Ca2ⴙ Release
1. Ryanodine receptors/CICR
Mechanisms of pharmacological modulation of RyRs
have received much attention, and the properties of drugs
that selectively modulate RyRs have been summarized in
numerous reviews (e.g., Refs. 135, 216, 217, 259, 308, 310,
483, 614, 703, 720). Therefore, I shall limit myself to a brief
discussion of some of these tools, which are instrumental
for studying CICR in nerve cells.
A) RYANODINE. Ryanodine was probably the first and the
foremost pharmacological agent used for probing for
Ca2⫹ stores and Ca2⫹ release. Its action on skeletal and
cardiac muscle had been known for the last 35 years
(259), and its ability to specifically bind to Ca2⫹-gated
Ca2⫹ release channels led to naming the latter “ryanodine
receptor” (505) a little confusing (as no ryanodine was
ever in attendance in living tissues, save in roots and stem
of the plant Ryania speciosa, which is the natural source
of ryanodine), but generally accepted. Ryanodine exerts
multiple actions on the RyRs, depending on its concentration. At very low concentrations (5– 40 nM), ryanodine
was reported to increase the frequency of RyR channel
opening, without affecting its conductance (67). At low
micromolar (1 to ⬃5 ␮M) concentrations, ryanodine promotes RyR channel opening in a subconducting (⬃40 –
60% compared with a normal) state, which is also charPhysiol Rev • VOL
acterized by a dramatic (⬃20 times) increase in the channel open time. At higher concentrations (50 to ⬎100 ␮M)
ryanodine completely blocks the channel (67, 440). These
multiple actions most likely reflect the existence of highand low-affinity binding sites for ryanodine within the
RyR. Notably, ryanodine binding to the low-affinity site is
almost irreversible. An important feature of ryanodine is
its “use dependence” (440), i.e., preferential binding of the
drug to the open channel. In practical terms, this became
apparent as a facilitation of ryanodine action by repetitive
activation of RyRs (either by caffeine or by [Ca2⫹]i increase), a phenomenon that is often observed in nerve
cells (29, 92, 269, 308, 636, 661). Ryanodine is still the
most specific pharmacological tool used for probing CICR
in neurons (see Tables 1 and 2).
B) RUTHENIUM RED. A polycationic dye, ruthenium red, is
widely used as CICR blocker in nerve cells (see Tables 1
and 2). Its effective concentrations for CICR inhibition in
muscle preparations range between 1 and 20 ␮M (720). At
the single-channel level, ruthenium red effectively reduces Po by prolonging the closed state of the RyR. Unfortunately, as an inhibitor ruthenium red is rather nonspecific as it also inhibits VGCC (97) epithelial Ca2⫹ channels ECaC1 (459), TRPV channels (194), GABA release
from hippocampal synaptic terminals (568), and mitochondrial calcium uptake (534). Moreover, when applied
to permeabilized chicken atria, ruthenium red prevented
contractile responses induced by InsP3 and potentiated
responses to caffeine (676), which makes its employment
as a specific CICR inhibitor even more dubious.
C) DANTROLENE. Dantrolene was originally synthesized
in 1967 (598) as a potent muscle relaxant, and it is currently the only available drug for the specific treatment of
malignant hyperthermia, a life-threatening complication
of general anesthesia (313). Incidentally, dantrolene may
also help against ecstasy intoxication (28). The action of
dantrolene on the ER consists of reducing the Po of RyRs,
thereby inhibiting CICR; the effective concentrations of
the drug lie between 10 and 90 ␮M (469). Dantrolene is
widely used as a CICR inhibitor in neurons (Tables 1 and
2), although there are some indications that dantrolene is
effective only against RyR1 and does not inhibit RyR2
(167).
D) GENERAL ANESTHETICS. Halothane and enflurane enhance Ca2⫹ release in cardiac preparation at low micromolar (i.e., in subtherapeutic) concentrations and increase Po of RyR channels (720). In the neural cholinergic
cell line SN56, halothane triggered Ca2⫹ release from the
ryanodine-, dantrolene- and CPA-sensitive calcium store
(189). Considering that volatile anesthetics affect synaptic
transmission (94, 95, 293) and neuronal excitability (414),
the possibility that they act by modulating CICR should
not be forgotten. In addition, however, halothane also
inhibits plasmalemmal Ca2⫹-ATPase (157, 683), so the
resulting effects on intracellular Ca2⫹ dynamics and Ca2⫹-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
try, essential for the refilling of ER stores after they have
been discharged with caffeine, can be blocked by 2 mM
Ni2⫹, and the refilling of the store is potentiated when the
cells are hyperpolarized from ⫺55 mV to ⫺80 mV. Furthermore, Usachev and Thayer (664) substantiated their
claim for SOC in nerve cells by demonstrating that ER
store depletion potentiates Mn2⫹ entry into neurons. Still,
these data may be explained by a very different mechanism, i.e., Ca2⫹ entry through T-type Ca2⫹ channels,
which have a “window” current region around ⫺75 to ⫺80
mV, where they may provide for unstimulated Ca2⫹ influx.
Calcium entry through conventional Ca2⫹ channels following ER depletion was, for instance, observed in cultured guinea pig myenteric neurons, in which the treatment with TG (1 ␮M) induced long-lasting irregular
[Ca2⫹]i oscillations arising solely from Ca2⫹ influx, yet
these oscillations were completely blocked by ␻-conotoxin MVIIA, suggesting that these neurons may use Ntype Ca2⫹ channels for store refilling (665). In the same
neurons, application of ATP triggered a biphasic (peak ⫺
plateau) [Ca2⫹]i response; the plateau required extracellular Ca2⫹ but was blocked by 10 ␮M nifedipine (287).
Likewise, the plasmalemmal voltage-gated Ca2⫹ channels
were responsible for ER store refilling in cultured cerebellar granule cells (249) as well as in cultured motoneurons from larval lampreys (280).
CALCIUM STORE IN THE ER OF NEURONS
2. Pharmacology of IICR
IICR pharmacology is less well defined than the pharmacology of CICR. From the very beginning of InsP3R
studies it became apparent that a number of quite different pharmacological agents, including heparin, p-chloromercuribenzoic acid, cinnarisine, flunarisine, local anesthetics, such as tetracaine and lidocaine, and potassium
Physiol Rev • VOL
channel blockers such as TEA, can effectively inhibit
InsP3-iduced Ca2⫹ release from microsomal ER preparations (see, e.g., Refs. 482, 484). Further complexity was
added when it became clear that caffeine, which was
believed to selectively interact with RyRs, inhibits
InsP3Rs (135, 680), and heparin, the most widely used
InsP3R blocker, activates RyRs (46, 135). As if this was
not enough, caffeine also effectively inhibits InsP3 production (645). All in all, the ideal inhibitor of IICR, which
would penetrate biological membranes and demonstrate
high selectivity against InsP3R, remains in the realm of
dreams.
A) HEPARIN. Heparin was shown to bind to InsP3Rs (613)
and block the activity of InsP3-gated channels incorporated into lipid bilayers (43). Heparin was also shown to
inhibit IICR in many types of nonexcitable and excitable
cells, and it is constantly used as a pharmacological probe
for neuronal IICR (see Tables 3–5). A big disadvantage of
heparin is its membrane impermeability; hence, it must be
delivered into the cell interior either by injection or via
intracellular dialysis. Although heparin activates RyRs in
artificial membranes, I failed to find a single report that
would describe heparin-induced Ca2⫹ release in nerve
cells. If that would be the case, however, heparin may still
inhibit IICR by depleting ER via activated RyRs, although
the interpretation of such data can be difficult.
B) CAFFEINE. The inhibitory action of caffeine on IICR
was first discovered by Ole Petersen and co-authors (680)
who studied agonist-mediated Ca2⫹ signaling in pancreatic acinar cells. Later on, the inhibition of IICR by millimolar concentrations of caffeine was found in Xenopus
oocytes (493), cerebellar microsomes (66), and permeabilized smooth muscle cells (228). Direct electrophysiological investigations of purified InsP3Rs supported these
findings by showing inhibition of unitary InsP3R current.
The KD of caffeine action on InsP3R currents was ⬃1.6
mM, and at 10 mM caffeine, a complete block of InsP3R
currents was attained (228).
C) 2-APB. The ability of 2-APB to inhibit IICR was initially found in cerebellar microsomes stimulated with 100
␮M InsP3; 2-APB blocked Ca2⫹ release with an IC50 value
of ⬃40 ␮M. Incubation with 2-APB also inhibited agoniststimulated IICR in human platelets and neutrophils (373)
and in HeLa cells (503). However, further investigations
demonstrated that 2-APB lacks selectivity as it affects not
only IICR but also Ca2⫹ pumps and store-operated Ca2⫹
entry in nonexcitable cells (55, 503).
D) XESTOSPONGINES. Some hope for a selective, membrane-permeable InsP3R antagonist appeared in 1997
when Isaac Pessah’s group purified and characterized a
group of macrocyclic bis-1-oxaquinolizidines isolated
from the Australian sponge Xestospongia species (174).
Several of these agents, dubbed Xestospongines (Xes),
namely, XeA, C, and D, were reported to be powerful
membrane-permeable blockers of IICR when tested on
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
dependent processes may be rather complex and difficult
to interpret.
E) LOCAL ANESTHETICS. Most of the local anesthetics, such
as procaine, tetracaine, lidocaine, prilocaine, the quaternary amines QX 572 and QX 314, and benzocaine, inhibit
caffeine-induced Ca2⫹ release and CICR in millimolar
concentrations (720), and this action was also observed in
nerve cells (308, 661).
F) DIHYDROPYRIDINES. Nifedipine, a well-known voltagegated channel antagonist, was reported to increase the
frequency of miniature end-plate potentials in synaptic
terminals studied in the muscular junction of neonatal (up
to 3 wk) rats. Effects of nifedipine persisted in Ca2⫹-free
media and were inhibited by TG (2 ␮M) and ryanodine (10
␮M), which allowed the authors to suggest possible stimulatory action of the drug on RyRs (512).
G) HEPARIN. Heparin, which is customarily used as a
selective inhibitor of IICR, does affect RyRs at the very
same concentrations that are effective against InsP3Rs.
The effects of heparin on RyRs were initially suggested
when it was found that heparin stimulates Ca2⫹ release
from skeletal muscle SR vesicles (404, 538). Further experiments on purified RyR channels demonstrated that
heparin increases channel openings with EC50 values of
⬃0.23 ␮g/ml (compared with 1– 4 mg/ml concentrations
usually employed for IICR inhibition) in a Ca2⫹-dependent manner (46, 135).
H) OTHER PHARMACOLOGICAL CICR REGULATORS. The interaction
with RyRs and modulation of CICR have been reported
for many other pharmacological agents, which generally
are not considered to possess such ability. For example,
cardiac glycosides and, in particular, digoxin in therapeutic concentrations increase the rate of CICR in cardiac
preparations through sensitizing RyRs to [Ca2⫹]i and increasing channel Po (390). Suramin, widely used as a
purinoreceptor blocker, induces CICR and increases Po of
RyRs (594). Another agent, believed to activate CICR and
the RyR3 channel, in particular, is chloro-m-cresol, which
triggers Ca2⫹ release in skeletal muscle (719), and in glial
cells (383). So far, however, no systematic attempts to use
chloro-m-cresol in nerve cells were made. Another class
of drugs often employed in experiments with cultured
neurons, the aminoglycoside antibiotics neomycin and
gentamycin, are potent inhibitors of CICR with effective
concentrations in a range between 50 nM and 10 ␮M
(720).
243
244
ALEXEI VERKHRATSKY
IV. ENDOPLASMIC RETICULUM CALCIUM
SIGNALING AND REGULATION OF
NEURONAL FUNCTIONS
A. Neuronal Excitability
Calcium release from the ER regulates neuronal excitability through several types of plasmalemmal Ca2⫹activated channels, responsible for K⫹, Cl⫺, and nonselective currents (see Tables 9 and 10). In addition, Ca2⫹
release may (at least theoretically) suppress VGCC by
increased Ca2⫹-dependent inactivation. The best-characterized effect of CICR is activation of K(Ca) channels,
which control postspike afterhyperpolarization (AHP).
The AHP comprises three distinct components (554), the
fast AHP (mediated by BK channels), the AHP (mediated
by SK channels), and the (ultra)slow AHP (mechanism
not yet identified). Activation of the fast AHP is mediated
solely by plasmalemmal Ca2⫹ entry, while both AHP and
slow AHP are sensitive to CICR inhibitors. The contribution of CICR to the AHP is quite substantial: up to 50% of
the AHP current is activated by Ca2⫹ released from the
ER. The mechanism of CICR-mediated regulation of the
Physiol Rev • VOL
(ultra)slow AHP remains entirely unknown. In vagal afferent neurons, Ca2⫹ release activates IAHP only when
CICR is triggered by Ca2⫹ entry through N-type VGCC,
which may reflect a very special colocalization of N-type
Ca2⫹ channels, RyRs, and Ca2⫹-dependent K⫹ channels
(107). A similar functional colocalization of RyRs and
voltage-gated N-type Ca2⫹ channels was also demonstrated in bullfrog sympathetic neurons, where Ca2⫹ entry
through N-type VGCC triggers regenerative CICR near the
plasma membrane (2). In these cells, RyRs also seem to
be functionally coupled to BK channels, thus providing a
feedback between ER Ca2⫹ release, membrane excitability, and AP frequency. Finally, the same functional interactions between N-type Ca2⫹ channels and RyRs were
confirmed in PC12 cells, where CICR is triggered by Ca2⫹
influx through N-type but not through L-type Ca2⫹ channels (657).
CICR also regulates membrane excitability through
Ca2⫹-dependent Cl⫺ channels underlying depolarizing afterpotentials (DAPs) found in the magnocellular neurons
of the supraoptic nucleus, in sympathetic neurons, and in
vagal nodose neurons subjected to vagotomy (328, 342,
370).
B. Neurotransmitter Release
The crucial importance of Ca2⫹ for neurotransmission was initially demonstrated by F. S. Locke for the
neuromuscular junction (356), and the concept of Ca2⫹dependent neurotransmitter release was coined by Bernard Katz and colleagues (118, 146). According to this
theory, regulated exocytosis, of which neurotransmitter
release represents a particular case, requires activation of
numerous Ca2⫹-regulated transduction cascades that
eventually result in the fusion of vesicles with the plasmalemma and release of vesicle contents into the extracellular space (in the case of neurotransmission, the synaptic cleft). Activation of exocytotic cascades requires a
large (up to 100 ␮M) local [Ca2⫹]i concentration, and the
role of plasmalemmal Ca2⫹ entry in neurotransmitter release is well established (36). The possible role of Ca2⫹
originating from the ER store is much less understood.
Certainly, exocytosis in several types of nonexcitable and
excitable cells almost exclusively depends on ER Ca2⫹
release [good examples are pancreatic acinar cells (506)
and pituitary gonadotrophs (652)]. In a nerve-related cell
preparation, neuroblastoma cocultured with rat skeletal
muscle cells, bradykinin-induced IICR elevated [Ca2⫹]i
and triggered acetylcholine release (468). However,
whether ER Ca2⫹ release by itself can trigger exocytosis
in presynaptic terminals in vivo remains an unanswered,
albeit challenging, question.
Numerous morphological studies confirmed that
functional ER is present in presynaptic terminals [e.g.,
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
ER vesicles isolated from the cerebellum; of these, XeC
was the most potent inhibitor with a KD of ⬃360 nM.
Further experiments have demonstrated that XeC blocks
[Ca2⫹]i transients mediated by metabotropic pathways in
the PC12 cell line and in primary rat cortical astrocytes.
Incubation of cells with 5–20 ␮M XeC effectively abolished [Ca2⫹]i responses to bradykinin and carbachol
(174). Yet more detailed investigations performed later
somewhat dampened the optimism for the action of xestospongines as selective membrane-permeable blockers
of InsP3Rs because it emerged that XeC acts as an effective blocker of SERCA pumps and thus empties the ER of
Ca2⫹ (84, 123, 600). It is noteworthy that an indication
that XeC interacts with SERCA pumps was already
present in the initial paper by Gafni et al. (174); Figure 4
of this study clearly shows that incubation of PC12 cells
with XeC decreases the amplitude of consequent TGinduced [Ca2⫹]i rise (which was interpreted by authors as
an inhibition of leak pathway, yet it may reflect depletion
of the ER as a result of SERCA blockade).
E) ADENOPHOSTINES. The adenophostines A and B were
isolated from metabolites of fungi Penicillium brevicompactum (622) and found to be extremely potent (10 –100
times more potent than InsP3) agonists of InsP3Rs (694).
They were tested in turtle olfactory sensory neurons (272)
and in single InsP3Rs isolated from fish olfactory cilia
(70). In both cases adenophostines acted as powerful
agonists of InsP3Rs inducing channel opening (70) and
promoted IICR as judged by the appearance of InsP3/
[Ca2⫹]i-dependent currents.
245
CALCIUM STORE IN THE ER OF NEURONS
TABLE
9.
Neuronal functions regulated by Ca2⫹-induced Ca2⫹ release
Function
Brain Region
Experimental Evidence
Reference
Nos.
Control of neuronal excitability
Activation of IK(Ca);
control of AHP
Activation of IK(Ca)
Otic ganglion
Activation of IK(Ca);
control of AHP
Superior cervical
ganglion; sympathetic
neurons
Parasympathetic
cardiac neurons
Myenteric
afterhyperpolarizing
neurons
Hippocampal pyramidal
neurons
Myenteric plexus
ganglia
Dentate gyrus; granule
neurons
Activation of SMOCs
Control of slow AHP
Control of slow AHP
Control of slow AHP
Activation of STOCs
Activation of SMOCs
Meunert nucleus basalis
neurons
Activation of IK(Ca)
channels;
modulation of AP
Stellate ganglion;
sympathetic neurons
Control of DAP
Supraoptic nucleus;
magnocellular
neurons
Control of DAP;
activation of
ICl(Ca)
Control of DAP
Superior cervical
ganglion; sympathetic
neurons
Nodose ganglion
Activation of ICl(Ca)
and nonselective
cation currents
Spontaneous
hyperpolarization
DRG
Spontaneous GABA
release from
presynaptic
terminals
CA3 hippocampal
neurons
Midbrain dopaminergic
neurons
Inhibition of CICR by ryanodine, dantrolene, or intracellular dialysis
with ruthenium red selectively inhibited K(Ca) channels
responsible for AHP.
Initiation of Ca2⫹ release by caffeine (20 mM) or IBMX (5 mM)
triggered outward K⫹ current; 0.5 mM IBMX triggered SMOCs. In
addition, IBMX inhibited M current in a Ca2⫹-release independent
manner.
Ryanodine (10 ␮M) almost completely blocked the activation of late
AHP component without affecting fast IAHP.
Ryanodine (20 ␮M) inhibited slow component of AHP.
262, 555
SMOC activation was potentiated by 2 mM caffeine and blocked by
CPA (10 ␮M) and ryanodine (10–100 ␮M).
Ryanodine (10 ␮M) inhibited slow component of AHP.
405
Ryanodine (10 ␮M) reduced amplitude of slow AHP by ⬃30%.
58, 572
Incubation of ganglia with ryanodine (10–20 ␮M) or caffeine (2–5
mM) inhibited both slow AHP and IAHP.
In voltage-clamped granule neurons, Ca2⫹ release events
potentiated by intracellularly applied cADPR and InsP3 controlled
STOCs and regulated neuronal excitability.
Frequency of SMOCs was reduced by ryanodine (10–100 ␮M) and
potentiated by caffeine (1 mM). ER inhibition by TG (100 nM) or
CPA (10 ␮M) blocked SMOCs.
Inhibition of CICR by ryanodine (20 ␮M) or TG (1 ␮M) decreased
the latency to AP generation in response to depolarizing current
ramps. It is suggested that CICR normally activates BK K(Ca)
channels, therefore limiting neuronal excitability. The effects of
CICR were potentiated following mitochondrial blockade, which
suggested some role of the mitochondria in rapid buffering of
Ca2⫹ released from the ER.
Inhibition of CICR by ryanodine (10 ␮M), dantrolene (10 ␮M),
ruthenium red (20 ␮M), or ER depletion with TG (3 ␮M) or CPA
(15 ␮M) suppressed DAP amplitudes by ⬃50%, shortened their
duration, and eliminated phasic patterns of firing. Application of
caffeine (5–10 mM, 5–10 min) increased DAP amplitudes and
increased firing rates. Heparin (2–4 mg/ml) either did not affect
or potentiated DAP (possible stimulation of RyRs?)
Ryanodine (20 ␮M) markedly (⬃75%) inhibited Ca2⫹-activated Cl⫺
current and associated afterdepolarization.
678
DAPs were recorded in neurons, isolated 4–6 days after vagotomy;
they were absent in control cells. Ryanodine (10 ␮M) reduced
DAP amplitudes by 37%.
Application of ryanodine (10 ␮M) activated Cl⫺ and nonselective
cation currents when holding the cell at resting potential.
Ryanodine also suppressed ICl evoked by depolarization.
Caffeine in a low (1 mM) concentration potentiated spontaneous
hyperpolarization; at high (10 mM) concentration, caffeine
transiently increased the frequency of hyperpolarization, followed
by its inhibition. Spontaneous hyperpolarization was reversibly
blocked by CPA (10 ␮M) and irreversibly by TG (10 ␮M).
328
660
711
114
227
579
13
30, 357
342
370
16
570
Regulation of neurotransmitter release
Slice incubation with Ca2⫹-free media did not significantly affect
mIPSPs; short (5 s) pulses of caffeine (10 mM) increased mIPSP
frequency, whereas long incubation with caffeine decreased
mIPSP amplitude and frequency. TG (10 ␮M) increased mIPSP
frequency, while ryanodine (30 ␮M) was without effect.
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
563
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Activation of IK(Ca)
Dorsal motor nucleus
of vagus; prevertebral
sympathetic neurons
DRG neurons
246
TABLE
ALEXEI VERKHRATSKY
9—Continued
Function
Experimental Evidence
Synaptic ACh
release
Cholinergic synapses in
Aplysia californica
buccal ganglion
Glutamate release
Rod photoreceptors
GABA release
Cerebellum; basket
cell–PN synapse
Synaptic ACh
release
Frog neuromuscular
junction
Synchronization of
EPSPs oscillations
Neocortex
Synaptic glutamate
release
Pyramidal neurons in
layer II of barrel
cortex
Spontaneous GABA
release from
presynaptic
terminals
Synaptic glutamate
release
Cerebellum; PN
CICR induced by intracellular injection of cADPR (10–1,000 ␮M)
potentiated ACh release. The injection of cADPR per se triggered
[Ca2⫹]i elevation. Effects of cADPR were prevented by
8-amino-cADPR and ryanodine.
Application of caffeine (10 mM) triggered transient [Ca2⫹]i elevation
followed by prominent undershoot. In the presence of caffeine the
glutamate release was depressed due to substantial (⬃50%)
inhibition of ICa. Ryanodine (20 ␮M) inhibited the effect of caffeine
on ICa but not on glutamate release.
High level of RyR expression was found in basket cell terminals on
PN. Treatment with high concentration of ryanodine (100 ␮M)
decreased the amplitude of depolarization-evoked [Ca2⫹]i transients
and significantly reduced amplitude and frequency of spontaneous
miniature IPSCs. Low ryanodine concentration (5–10 ␮M) enhanced
mIPSPC’s frequency, likely due to facilitating a multivesicular
GABA release.
TG (2 ␮M) prolonged presynaptic depolarization-induced [Ca2⫹]i
transients and induced a rapid rise in the amplitude of the EPP,
without affecting mEPPs. It appears as ER limits neurotransmitter
release by providing a Ca2⫹ clearance mechanism.
In acute slices of visual cortex, caffeine (4–6 mM) potentiated and
thapsigargin (20–80 ␮M) inhibited the appearance of oscillatory
synaptic potentials.
Frequency and amplitude of mEPSPs was inhibited by loading the
slice with BAPTA-AM, by blocking SERCA pumps with CPA (20
␮M), and by ryanodine (10 ␮M). Caffeine (10 mM) enhanced
mEPSPs; this enhancement was observed for up to 20-min
incubation with caffeine. Administration of 2-APB (14 ␮M) reduced
and activation of metabotropic receptors by DHPG (20 ␮M)
enhanced frequency and amplitude of mEPSPs.
Incubation with ryanodine (10 ␮M) and CPA (25 ␮M) affected
frequency of spontaneous mIPSPs in conditions of limited Ca2⫹
entry through VGCCs.
Hair cells
Synaptic GABA
release
Cerebellum; basket
cell–PN synapse
Regulation of
frequency and
amplitude of
spontaneous
mEPSPs
Hippocampus; CA3
neurons
Caffeine (1–10 mM) triggered [Ca2⫹]i elevation accompanied by an
increase of Cm (indicative of exocytosis) and potentiated
depolarization-evoked [Ca2⫹]i responses. Inhibition of CICR by
ryanodine (40 ␮M) depressed afferent transmission as judged from
a reduced frequency of mEPSPs.
Ryanodine (100 ␮M) induced ⬃70% inhibition of evoked
GABA-mediated IPSPs in basket cell–PN synapses studied in acute
rat slices. Low concentrations of ryanodine (5–10 ␮M) had a
biphasic effect: IPSPs were transiently enhanced, which was
followed by their depression.
In hippocampal slices CICR activated by Ca2⫹ entry following opening
of presynaptic NChRs potentiated frequency and increased
amplitude of mEPSPs. Inhibition of ER Ca2⫹ accumulation by TG (5
␮M) or blockade of CICR by ryanodine (100 ␮M) abolished effects
of nicotine; transient application of 20 mM caffeine mimicked
effects of nicotine.
Reference
Nos.
432
314
355
83
710
589
26
337
175
573
Presynaptic [Ca2⫹]i signaling and presynaptic plasticity
2⫹
[Ca ]i signaling in
presynaptic
terminal
MF terminals
[Ca2⫹]i signaling in
presynaptic
terminal;
short-term
plasticity
Frog motor nerve
terminals
[Ca2⫹]i elevation in synaptic terminals (“bulk” loaded with fura 2-AM;
microfluorimetric recordings from many terminals simultaneously),
triggered by electrical stimulation of MFs, was, in part, due to
CICR, as TG (10 ␮M), CPA (30 ␮M), ryanodine (20 ␮M), and
ruthenium red (100 ␮M) decreased [Ca2⫹]i signal in the terminal.
CICR contributed to ⬃50% of intraterminal [Ca2⫹]i elevation.
CICR contributes to intraterminal [Ca2⫹]i signals; CICR can be primed
by depolarization-induced Ca2⫹ influx and can participate in
regulated exocytosis of neurotransmitter and in short-term
presynaptic plasticity. Priming of CICR by conditioning stimulation
train can markedly increase neurotransmitter release.
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
344
449, 450
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Brain Region
CALCIUM STORE IN THE ER OF NEURONS
TABLE
247
9—Continued
Function
Brain Region
Experimental Evidence
Confocal recordings of [Ca2⫹]i in a single synaptic boutons of CA3
neurons in organotypic slices showed that inhibition of CICR by
30 ␮M ryanodine or emptying the ER with CPA (30 ␮M) or TG
(3.8 ␮M) reduced intraterminal [Ca2⫹]i transient and abolished
paired pulse facilitation. Ryanodine also obliterated spontaneous
mEPSPs, thus linking CICR to the release of neurotransmitter.
Application of caffeine triggered LTP of SC–CA1 pyramidal neuron
synapses, which was blocked by incubation of slice with
ryanodine (20 ␮M), but remained unaffected when ryanodine was
included into the patch pipette, suggesting presynaptic
mechanism.
Short-term synaptic
plasticity/synaptic
glutamate release
Hippocampus; CA3
neurons/
associationalcommissural (AC)
synapse
Presynaptic LTP
Hippocampus; CA1
neurons
LTD
Hippocampus/dentate
gyrus
Retina; ganglion cells
Reference
Nos.
139
369
Postsynaptic effects, including LTP and LTD
Hippocampus; CA1
neurons
Caffeine (10 mM) and intracellular dialysis of InsP3 (50 ␮M)
significantly inhibited GABAA-mediated currents. Effect of
caffeine was blocked by TG (10 ␮M) and ryanodine (20 ␮M)
Induction (but not maintenance) of LTD in SC–CA1 synapses was
blocked by slice superfusion with TG (1 ␮M), CPA (1 ␮M) or
ryanodine (10 ␮M).
Induction of LTD of GABAA-receptor mediated synaptic responses
was blocked by intracellularly applied ruthenium red (20 ␮M) but
not by heparin (2 mg/ml). The LTD was also blocked by bath
application of ryanodine (10 ␮M); intracellular administration of
ryanodine prevented LTD only when LTD induction protocol was
preceded by conditioning depolarizations (use dependence of
ryanodine?).
LTD in MF-CA3 synapses is expressed postsynaptically and is
controlled by Ca2⫹ influx through L-type VGCC and IICR/CICR
through InsP3Rs; inhibition of the InsP3Rs by heparin (0.2 mg/ml)
or emptying the ER by TG (10 ␮M) prevented LTD.
Homosynaptic potentiation produced by mild titanic stimulation
required IICR and CICR in both pre- and postsynaptic
compartments. This form of potentiation was blocked by TG (10
␮M), by 2-APB (10 ␮M), and by 8NH2-cADPR (20 ␮M) and
ryanodine (100 ␮M); low concentrations of ryanodine (1 ␮M)
facilitated this type of synaptic plastic response.
LTP of mossy fibers recorded in hippocampal slices were critically
dependent on CICR in presynaptic terminal; CICR was initiated
by Ca2⫹ entry through presynaptic Ca2⫹-permeable KA
receptors/L-type Ca2⫹ channels and CICR inhibition by ryanodine
(10 ␮M) inhibited LTP.
470
3
530
LTD
Hippocampus; CA3
neurons
71
LTD
Hippocampus; CA3
neurons
Homosynaptic
potentiation in
Aplysia
Sensory–motor neuron
synapses
Mossy fibers LTP
Hippocampus
Circadian rhythm
Suprachiasmatic
nucleus
Circadian rhythm
Suprachiasmatic
nucleus
In organotypic cultures of SCN, pharmacological manipulation with
ryanodine receptors/ER stores (caffeine, 1 mM; TG, 0.5 ␮M;
dantrolene, 20 ␮M; or ruthenium red, 10 mM) modulated clock
resetting mediated through iGluRs in the early night phase.
In SCN slice cultures, the circadian rhythms of [Ca2⫹]i, which
closely matched electrical circadian rhythms, were recorded
using chameleon probes transfected into SCN neurons. Inhibition
of CICR by ryanodine (up to 100 ␮M) dumped both electrical and
[Ca2⫹]i rhythms.
Tonic activity of
thalamocortical
neurons
Olfactory sensation/
propagating Ca2⫹
wave
BDNF release
Dorsolateral geniculate
nucleus
CICR triggered by plasmalemmal Ca2⫹ entry produced tonic activity
in talamocortical neurons associated with state of wakefulness.
Olfactory receptor
neurons
Odor-stimulating agents triggered Ca2⫹ waves propagating from
cilia towards dendrites and soma through activation of CICR.
722
Hippocampus; cultured
neurons
BDNF release from electrically stimulated rat neonatal cultured
hippocampal neurons was inhibited by TG (10 ␮M) and
dantrolene (50 ␮M). Caffeine (30 ␮M) induced BDNF release
even in the absence of electrical stimulation.
22
335
261
332
Circadian rhythms
126
244
Other effects
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
68
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Inhibition of
postsynaptic
GABAA currents
LTD
Dantrolene (50 ␮M) completely blocked LTD in rat dental gyrus.
248
TABLE
ALEXEI VERKHRATSKY
10. Neuronal functions regulated by InsP3-induced Ca2⫹ release
Function
Modulation of GABAB
receptors affinity
Regulation of locomotor
network activity
Brain Region
Retinal neurons
Motoneurons; spinal
cord preparation
Hippocampal neurons
Potentiation of
neurotransmitter release
Cholinergic synapses in
buccal ganglion
(Aplysia californica)
PF-PN synapses
LTD
Neuromuscular
junction
LTD
Visual cortex, layers
II/III
Synaptic potentiation
Hippocampus; SC-CA3
Glutamate-induced ER Ca2⫹ release reduced GABAB receptor affinity via
Ca2⫹-calmodulin system.
Activation of mGluR1/5 by DHPG (100 ␮M) produced [Ca2⫹]i oscillations
in primary cultured motoneurons from larval lampreys. These
oscillations were blocked by TG (1 ␮M, 45-min incubation), but not by
ryanodine (100 ␮M, 45 min), implying sole activation of InsP3Rs.
mGluRs are activated during locomotion as was ascertained in
experiments on spinal cord preparation, and [Ca2⫹]i oscillations are
believed to regulate locomotor activity. One of the pathways is
associated with stimulation of mGluR1/5 autoreceptors, which trigger
Ca2⫹ release, and the latter, in turn, enhances release of glutamate.
Activation of IICR following stimulation of SC in a conditions of
inhibited ionotropic receptors, or following application of mGluR
agonist trans-ACPD, resulted in potentiation of Ca2⫹-activated cation
selective channels (CAN).
Neurotrophin (NT-3) potentiated neurotransmitter release by
simultaneous activation of Trk-receptor/PLC-␥ mediated IICR and
stimulation of PI 3-kinase; both cascades were necessary for
potentiation of neurotransmitter release.
Intracellular injections of InsP3 and NAADP increased the amplitude of
IPSCs. Effects of InsP3, but not of NAADP, were blocked by heparin
(1 mM) and ryanodine (100 ␮M).
Local photorelease of InsP3 and subsequent IICR triggered LTD in PF to
PN synapse without requirement for climbing fiber input.
Cortical LTD required a simultaneous IICR in postsynaptic cell
(achieved by photorelease of caged InsP3 delivered to the neuron via
patch pipette) and tetanic stimulation of nearby cortex.
Synaptic potentiation induced by BDNF and NT-3 was blocked by
pretreatment with TG (5 ␮M, 30 min), suggesting the role for ER Ca2⫹
release (IICR?).
Reference
Nos.
576
280, 621
494
706
86
150
276
268
LTD, long-term depression; PLC, phospholipase C; PI, phosphatidylinosital; NAADP, nicotinic acid adenine dinucleotide phosphate; BDNF,
brain-derived neutrotrophic factor.
Refs. 50, 82, 203, 391; see also an excellent review by Ron
Bouchard et al. (59)], and moreover, ER structures are
located in close proximity (as near as 40 – 400 nm) to the
presynaptic active zone. As demonstrated already in 1986
by Westrum and Grey (693), the ER within the presynaptic terminal appears to be in close association with microtubules and synaptic vesicles and, moreover, ER portions impinge directly on the presynaptic membrane
forming “tubular-fibrillar” extensions. Such close apposition of the ER and the presynaptic membrane may perfectly well allow Ca2⫹ released from the store to participate in creation of [Ca2⫹]i microdomains relevant for
exocytosis. Yet the role of ER Ca2⫹ release in regulation
of neurotransmitter release remains controversial, with
arguments supporting (59) or denying (721) its importance.
Indeed, there are not many indications that ER Ca2⫹
release in the absence of plasmalemmal Ca2⫹ entry can
induce massive exocytosis in synaptic terminals, although
numerous data (see Tables 9 and 10) demonstrate that
both CICR and IICR may modulate/amplify neurotransmitter release from presynaptic compartments.
Probably the first to contemplate the importance of
presynaptic Ca2⫹ release in the regulation of neurotransPhysiol Rev • VOL
mission were Erulkar and Rahamimoff (141), who arrived
at this idea based on analysis of tetanic stimulation-induced changes in the frequency of the miniature end-plate
potentials at varying Ca2⫹ electrochemical gradients. Further experimentation, aimed at investigating the effects of
pharmacological manipulations with ER Ca2⫹ handling on
either spontaneous or evoked postsynaptic currents, demonstrated that both Ca2⫹ release from and Ca2⫹ uptake
into the ER may significantly modulate exocytosis of neurotransmitter in synaptic terminals. It appeared that spontaneous RyR-mediated presynaptic [Ca2⫹]i transients may
trigger neurotransmitter release in resting conditions.
This conclusion was based on experiments demonstrating
that the frequency or amplitude of miniature postsynaptic
currents (mIPSCs as well as mEPSCs) is sensitive to
inhibition of RyRs (by ryanodine) or SERCA pumps (by
TG and CPA). This phenomenon was observed in cerebellar neurons (26, 355) as well as in hippocampal pyramidal (139, 563) and cortical (589) neurons. In parallel,
Ca2⫹ imaging of presynaptic terminals indeed revealed
the spontaneous [Ca2⫹]i release events (139, 355). Moreover, in the presynaptic terminals of basket cells, the
amplitude of [Ca2⫹]i signals resulting from spontaneous
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Activation of
Ca2⫹-activated
cation-selective
channels
Potentiation of
neurotransmitter release
Experimental Evidence
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
CICR triggered in the presynaptic terminal by Ca2⫹ entry
through Ca2⫹-permeable NChRs was instrumental in the
action of nicotine on mEPSCs. Pharmacological inhibition
of presynaptic CICR completely abolished NChR-dependent modulation of mEPSCs (573). Most importantly,
CICR in the presynaptic terminal remodeled neurotransmitter release quite substantially, by a shift towards a
multiquantal mode, or else in synchronizing release
across several active zones, as judged by a dramatic (⬃3
times) increase in mean mEPSC amplitude and appearance of a relatively high number of extralarge mEPSCs
reaching ⬃200 pA (as compared with a mean mEPSC
amplitude of 20 pA in control conditions) upon activation
of NChRs. This remodeling has important functional consequences as nicotine-induced facilitation of neurotransmitter release was able to trigger a burst of action potentials in the postsynaptic cell, thus indicating the existence
of synaptic transmission without AP-induced depolarization of the presynaptic membrane (573). Local CICR in
response to Ca2⫹ entry through NChRs was also found in
nerve terminals in vas deferens; this CICR facilitated neurotransmitter release, which resulted in a 70% increase in
the amplitude of excitatory junction potentials (63).
Very much in line with the concept of Ca2⫹ store/sink
duality, the presynaptic ER may not only amplify, but also
limit neurotransmitter release, by buffering Ca2⫹ in the
terminal, thus reducing the lifetime of elevated [Ca2⫹]i
microdomains. This, for example, happens in the frog
neuromuscular junction, where inhibition of SERCAs facilitates synaptic transmission (83). In the rat neuromuscular junction, CICR also limits the transmission, albeit in
a completely different way, by limiting Ca2⫹ entry through
VGCC as a result of increased Ca2⫹-induced inactivation
of the latter (567).
However comprehensively the data discussed above
favor the role of presynaptic Ca2⫹ release in the regulation of neurotransmission, it may not be regarded as an
ubiquitous mechanism always present in all synapses. For
example, Carter et al. (80) while investigating transmission in the hippocampus (associational-commissural synapses and mossy fiber synapses in CA1 and CA3 neurons)
and cerebellum (parallel fiber-Purkinje neuron synapse)
did not observe any involvement of CICR in the regulation
of neurotransmitter release. Moreover, they failed to detect either caffeine-induced Ca2⫹ release or CICR in cerebellar parallel fibers. Likewise, a study of giant EPSCs
[which were quite similar to extralarge ACh-mediated
mEPSCs observed by Sharma and Vijayaraghavan (573)]
in the mossy fiber-CA3 synapse did not show dramatic
effects of either TG/CPA or ryanodine/caffeine on occurrence of giant EPSPs (215). Furthermore, the inhibition of
Ca2⫹ release affected the parameters of normal EPSPs
rather slightly, if at all (e.g., 10 ␮M ryanodine changed
EPSC frequency to 126 ⫾ 42% of the control; Ref. 215).
No significant CICR (as probed by 3 mM caffeine, 10
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Ca2⫹ release was comparable with [Ca2⫹]i rises produced
by single AP (105).
At the same time, CICR triggered by depolarizationinduced Ca2⫹ entry was detected in single presynaptic
terminals in intact bullfrog sympathetic ganglia, where it
accounted for ⬃46% of the total [Ca2⫹]i elevation induced
by electrical stimulation of the nerve (502) and in the
presynaptic mossy fiber terminals, where it contributed as
much as ⬃50% of the [Ca2⫹]i elevation induced by a train
of action potentials (344). In hair cells (which are presynaptic to primary afferent neurons), direct activation of
RyR-mediated Ca2⫹ release by caffeine induced a [Ca2⫹]i
elevation and an increase in membrane capacitance that
may indicate activation of exocytosis (337). Finally, pharmacological inhibition of ER reduced not only spontaneous but also evoked GABA-mediated IPSCs in basket
cell-Purkinje neuron synapses in the cerebellum (175),
whereas potentiation of CICR by intracellular addition of
cADPR augmented ACh release from terminals of Aplysia
buccal neurons (432). Likewise, CICR activated by Ca2⫹
entry via VGCC enhanced neurotransmitter release in the
frog neuromuscular junction (450). In this preparation, a
close apposition of RyRs and plasmalemmal Ca2⫹ channels was postulated, and it was also suggested that Ca2⫹
entry primes and activates CICR, which in turn contributes to neurotransmitter release (449).
The intimate mechanism of CICR-dependent potentiation of evoked neurotransmitter release may, however,
be more complicated than simple amplification of Ca2⫹
entry and therefore an increase in [Ca2⫹]i domains near
the active zone. The simplest hypothesis argues that CICR
events trigger neurotransmitter release and moreover favor the multiquantal release from the same active zone
(105, 355). However, analysis of ryanodine effects on the
amplitude and frequency of evoked IPSCs in basket cellPurkinje neuron synapse, led Galante and Marty (175) to
suggest that Ca2⫹ released by CICR arrives at the active
zone too late to affect exocytosis, but it does sensitize the
exocytotic machinery to a subsequent depolarization.
Sometimes the effective modulation of neurotransmitter release requires synergism between IICR and
CICR. When recording simultaneously from presynaptic
axons and postsynaptic motoneurons in a Lamprey spinal
cord preparation, Cochilla and Alford (102) observed potentiation of synaptic transmission by Ca2⫹ release from
the ER; both IICR and CICR were necessary as this potentiation could be blocked by pharmacological inhibition
of mGluRs as well as by 20 ␮M ryanodine.
Incidentally, the CICR responsible for spontaneous
neurotransmitter release may also be activated by Ca2⫹
entry through presynaptic Ca2⫹-permeable ionotropic receptors. The frequency and amplitude of spontaneous
mEPSCs in CA3 hippocampal neurons were greatly enhanced following activation of presynaptic nicotinic cholinoreceptors (NChRs). Subsequent analysis revealed that
249
250
ALEXEI VERKHRATSKY
C. Synaptic Plasticity
The living brain constantly remodels and modifies its
cellular networks. Throughout life, synapses weaken and
strengthen or else form and die. These processes underlie
the adaptation of the brain to the constantly changing
environment and represent what we know as learning and
memory. Modification of synaptic transmission efficacy is
an important part of this adaptation, which is manifested
in short- and long-term synaptic plasticity. The electrophysiological correlates of long-term synaptic plasticity
are long-term potentiation (LTP) or depression (LTD) of
synaptic potentials in response to either high-frequency
stimulation of single synaptic inputs or to simultaneous
activation of several distinct synaptic inputs.
LTP, discovered by Tim Bliss and Terje Lomo in
hippocampal neurons (53), was also the first form of
synaptic plasticity, which highlighted the importance of
cytoplasmic Ca2⫹ signals, as intracellular injection of the
Ca2⫹ chelator EGTA effectively obliterated the potentiation of synaptic strength (363). Very soon thereafter, the
importance of the cytoplasmic Ca2⫹ rise was also appreciated for cerebellar LTD (136, 301). More recent experiments also clearly demonstrate that the ER Ca2⫹ store
plays an important role in the generation of [Ca2⫹]i elevations relevant to the induction of synaptic plasticity
(154, 542, 552).
Physiol Rev • VOL
1. Short-term synaptic plasticity
Short-term synaptic plasticity is a form of presynaptic strengthening of neurotransmitter release, and as such,
it ultimately depends on presynaptic Ca2⫹ signaling as
discussed above. The involvement of CICR in a form of
short-term plasticity, known as paired-pulse facilitation
(PPF), was recently proposed for CA3 hippocampal neurons studied in organotypic slices (139). In contrast, a
detailed investigation of PPF in excitatory synapses in the
hippocampus and cerebellum failed to reveal any contribution of ER Ca2⫹ release to this phenomenon (80).
2. Long-term synaptic plasticity
Historically, LTP and LTD were mostly investigated
in the hippocampus and cerebellum, respectively. Incidentally, as far as ER Ca2⫹ release is concerned, the
mechanisms of hippocampal and cerebellar plasticity
clearly differ in that cerebellar LTD involves IICR,
whereas CICR is important for hippocampal LTP.
A) SYNAPTIC PLASTICITY IN THE HIPPOCAMPUS: A ROLE FOR CICR.
Much of our understanding of hippocampal synaptic plasticity comes from investigations of synapses formed by
CA3 neurons through Schaffer collaterals on CA1 pyramidal cells. A peculiarity of this synapse is that it possesses
both LTP and LTD depending on the stimulation protocol.
LTP is usually induced by high frequency (⬃100 Hz; 100
stimuli or so) stimulation, whereas LTD requires prolonged low-frequency stimulation of Schaffer collaterals
(many 100s of stimuli at 1–2 Hz) (154). Both LTP and LTD
critically require a [Ca2⫹]i increase. The precise mechanisms of differentiating between the different types of
synaptic input in favor of potentiation versus depression
are unclear, yet the signals arising from the ER may hold
the key to further understanding.
The first and foremost task in the elucidation of the
role of the ER in synaptic plasticity is to show that synaptic stimulation can result in Ca2⫹ release in dendritic
spines and proximal dendrites, i.e., where exactly do the
signaling events responsible for LTP/LTD occur. Hippocampal neurons have a rather peculiar distribution of
the ER and Ca2⫹ release channels. First, in vivo the ER is
not present in every spine. Only ⬃25–50% of the small
spines contain ER. In contrast, the latter is present in
⬃80 –90% of the big mushroom-like spines (604). Second,
hippocampal pyramidal neurons have a peculiar distribution of Ca2⫹ release channels (617). Only RyRs (particularly RyR3) are present in the spines, while both RyRs and
InsP3Rs reside in the dendritic ER [although prominent
species-dependent differences exist, i.e., RyR expression
in the rabbit hippocampus appears to be almost negligible
compared with the rat (558)].
Such a distribution of Ca2⫹ release channels suggests
strong CICR in those CA1 neuron spines, which possess a
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
␮M ryanodine, or 1 ␮M TG) was found during [Ca2⫹]i
recordings from the single synaptic boutons of rat sympathetic preganglionic terminals (347) and from sympathetic varicosities (as probed by 10 ␮M ryanodine; Ref.
62). CICR was also not found in presynaptic terminals of
goldfish retinal bipolar cells (296). Or was it? The same
group published results supporting the importance of intracellular Ca2⫹ release for amplification of intraterminal
[Ca2⫹]i transients and for facilitation of transmitter release from the same goldfish retinal bipolar cells (295);
these two contradictory papers are separated by exactly 6
wk and were published in the same journal. These discrepancies most likely reflect the complexity of the system responsible for synaptic transmission. In particular,
they may arise from differential expression of ER in various terminals, from differences in ER functional conditions (e.g., the degree of Ca2⫹ loading), and, naturally,
from the experimental difficulties, as all these measurements are technically quite demanding and are performed
at the very edge of the sensitivity of existing equipment.
One also has to consider that incubation of whole brain
slices with rather powerful pharmacological tools such as
TG or ryanodine may trigger obscure indirect effects, thus
complicating data interpretation.
CALCIUM STORE IN THE ER OF NEURONS
functional ER. Because the distribution/localization of the
latter may change depending on the experimental conditions (i.e., the animal’s age), conflicting results could be
anticipated safely, and, sure enough, the controversy did
not wait long to emerge. To begin with, a robust caffeineinduced Ca2⫹ release, sensitive to TG and ryanodine, and
CICR in response to glutamate application, were observed
in spines from cultured hippocampal neurons (303). This
observation was confirmed by [Ca2⫹]i imaging on hippocampal neurons in organotypic slices (138), which revealed that CICR is responsible for by far the largest
251
(⬃80 –90%) part of the [Ca2⫹]i elevation triggered by stimulation of NMDA receptors (Fig. 21A). Yet, when confocal
Ca2⫹ imaging was applied to hippocampal neurons in
acute slices, no signs of significant CICR following
NMDA-mediated Ca2⫹ influx were detected (312), and the
NMDA-induced Ca2⫹ flux was found to be almost solely
responsible for the [Ca2⫹]i elevation (Fig. 21B). All in all,
the question about functional CICR in spines remains
unresolved, which most likely reflects the complexity and
heterogeneity of the preparations. Yet, physiological data
support the notion of at least some involvement of CICR
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 21. CICR in spines of CA1 hippocampal neurons: evidence pro and contra. A: recordings of [Ca ]i in a single spine of hippocampal CA1
neuron filled with Oregon green BAPTA-1 through the tip of sharp microelectrode. Top row shows [Ca2⫹]i traces; the row on the bottom
demonstrates voltage recordings. In control conditions, synaptic stimulation triggers [Ca2⫹]i elevation and excitatory postsynaptic potentials
(EPSPs); incubation of slice with 15 ␮M CPA completely abolished [Ca2⫹]i increase without any apparent effects on EPSPs. One hour of washout
with normal saline restores the parameters of [Ca2⫹]i responses. B: similar recordings demonstrating a minor role played by CICR in synaptically
induced [Ca2⫹]i signals in hippocampal slices. a: EPSP-associated spine [Ca2⫹]i signal (color-coded image and top trace) was reduced by ⬃30% in
the presence of ryanodine (25 ␮M, bottom trace). b: Time course of the effect of ryanodine (indicated by the bar) on the peak amplitudes of [Ca2⫹]i
transients. Same experiment as in A. Single-shock stimuli were repeatedly delivered every 4 min; each data point represents a single trial. The dashed
lines represent the values during control conditions (1.0) and in the presence of ryanodine (0.72). The numbers point to the individual recordings
displayed in A. c: Application of CPA (30 ␮M, indicated by the bar) reduced the amplitude of synaptic Ca2⫹ signals in spines by ⬃36%. d: Bar graph
summarizing the effects of ryanodine (20 or 25 ␮M) and CPA (30 ␮M). Data points were normalized to control conditions. The first two bars
represent the effect on synaptically evoked [Ca2⫹]i signal in spines (n ⫽ 7 and 9 cells for ryanodine and CPA, respectively). The last two bars show
that both drugs effectively abolish dendritic [Ca2⫹]i responses evoked by local application of caffeine (20 – 40 mM, n ⫽ 5 for ryanodine and for CPA).
Data points were normalized to the mean control value. Experiments were done at 30°C. [A from Emptage et al. (138) copyright 1999 with permission
from Elsevier; B from Kovalchuk et al. (312) copyright 2000 by the Society for Neuroscience.]
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
252
ALEXEI VERKHRATSKY
Physiol Rev • VOL
or somatic depolarization may be replaced by an artificial
increase in [Ca2⫹]i due to photorelease of caged Ca2⫹
(338) (incidentally, stimulation of parallel fibers can be
fully substituted by NO generation, Ref. 338).
Genetic manipulation of components of the mGluRIICR signaling cascade evidently demonstrated the crucial
importance of this pathway for cerebellar LTD. Deletion
of mGluR1 resulted in the appearance of a clear cerebellar
phenotype, with ataxia, motor discoordination, and impaired LTD (1, 104). Both LTD and locomotive deficits can
be restored by expression of mGluR1 under the control of
a Purkinje neuron-specific promotor (243).
Almost simultaneously, the involvement of IICR in
cerebellar LTD was suggested by physiological experimentation. Direct activation of IICR by photorelease of
caged InsP3 in Purkinje neurons produced LTD when
coincident with somatic depolarization, thus fully substituting for the stimulation of parallel fibers (282). Furthermore, as shown by Finch and Augustine (150), local InsP3
uncaging and subsequent IICR were sufficient to induce
local LTD in synapses close to the uncaging foci.
It has to be noted, though, that IICR appeared not to
contribute to LTD in cultured or freshly isolated Purkinje
neurons, as no difference was found in [Ca2⫹]i transients
induced by depolarization and combination of depolarization and glutamate application. Moreover, LTD was insensitive to XeC, and diacylglycerol was able to substitute for
mGluR activation in the induction of LTD (448). Yet, these
results most likely reflect certain changes in signaling
pathways introduced by tissue culture conditions or the
isolation procedure.
Further evidence favoring the key role of IICR in
the generation of cerebellar LTD was obtained from
mice with genetically deleted InsP3R1s, in which LTD
completely vanished (Fig. 22A) (247). Interestingly,
InsP3R1⫺/⫺ animals never survived beyond the 23rd
day. The same authors also reported that a similar
disappearance of LTD can also be achieved by perfusing neurons with specific antibodies raised against
InsP3R1. Not only the expression but also the localization of InsP3R1s matters, as was demonstrated on animals mutated for myosin Va. This mutation causes the
ER not to enter PN spines, which therefore effectively
eliminates IICR specifically from this compartment.
The LTD in mutant mice and rats was completely lost
(Fig. 22B); nonetheless, it could be rescued by Ca2⫹
uncaging within the spine (421).
C) SYNAPTIC MODIFICATION. The most amazing results were
obtained when studying GABAergic synapses formed by
basket interneurons on CA1 hippocampal pyramidal cells.
When the CICR mechanism was primed by intracellular
cADPR, postsynaptic depolarization triggered a large
[Ca2⫹]i elevation that changed GABA-mediated IPSPs into
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
in LTP in SC-CA1 synapses, since emptying the ER with
TG (1 ␮M) or CPA (1 ␮M), or blocking CICR with 10 ␮M
ryanodine, inhibited the induction but did not affect the
maintenance of LTD in acute hippocampal slices (530).
The next step in investigating the role of ER Ca2⫹
release in LTP quite naturally involved genetic manipulation of Ca2⫹ release channels. The obvious candidate to
check was RyR3, because of its expression in CA1 neurons. In any case deletions of RyR1 and RyR2 are not
compatible with life. Genetic deletion of RyR3 led to
facilitated LTP and a complete disappearance of LTD in
CA1. Furthermore, RyR3-deficient mice demonstrated improved spatial learning on a Morris water maze task (173).
LTP in the RyR3 knockout mouse was, however, principally different from the wild type; it could not be blocked
by NMDA receptor inhibitors and was partially dependent
on Ca2⫹ influx through VGCC, and on metabotropic glutamate receptors. Another RyR3 knockout mouse, also
generated in Japan, displayed a smaller magnitude of LTP
and diminished synaptic AMPA responses, although this
was not due to downregulation of AMPAR expression
(578). Finally, a RyR3 knockout mouse generated in Italy
showed no changes in LTP induction, although depotentiation of LTP was impaired. In the water maze, the Italian
mice performed rather poorer than controls, and “in the
open-field, RyR3⫺/⫺ mice displayed a normal exploration
and habituation, but had an increased speed of locomotion and a mild tendency to circular running” (23). To add
to the degree of complexity, the genetic deletion of
InsP3R1 led to an increased magnitude of CA1 hippocampal LTP. Homosynaptic LTD remained unchanged,
whereas heterosynaptic LTD of nonassociated pathway
was blocked (168, 441). In summary, the role of ER Ca2⫹
release in synaptic plasticity in CA1 hippocampal neurons
remains obscure.
Some indications of the importance of CICR in generation of LTP/LTD are coming from other neurons (CA3
hippocampal cells, cortical neurons), although they often
involve both pre- and postsynaptic mechanisms (see Table 9). IICR seems to play a more important role in CA3
neurons, as deletion of InsP3Rs facilitated LTP and completely inhibited LTD in mossy fiber-CA3 neuron synapses
(254).
B) SYNAPTIC PLASTICITY IN THE CEREBELLUM: A ROLE FOR IICR. The
role for IICR in LTD generation in the cerebellum is rather
well established. The LTD of parallel fibers, which form
their synapses on dendrites of Purkinje neurons, occurs
as a result of simultaneous activation of parallel and
climbing fibers. Stimulation of climbing fibers can be fully
substituted by depolarization of the neuronal soma and
[Ca2⫹]i elevation (301). Whatever protocol of LTD induction is used, [Ca2⫹]i elevation in the PN is necessary for
LTD development. In fact, stimulation of climbing fibers
CALCIUM STORE IN THE ER OF NEURONS
253
excitatory postsynaptic potentials (612). The actual mechanism underlying such remodeling is not precisely understood, although it is sensitive to carbonic anhydrase inhibition. This may indicate certain changes in the GABAoperated Cl⫺ channel, resulting in the appearance of a
depolarizing HCO⫺
3 efflux.
D) MEMORY PROCESSES. Not much is known about the role
of Ca2⫹ release in consolidative memory processes. There
are some indications that synchronous oscillations of
membrane potential in the neocortex, which were suggested to be important for cognitive brain function (218),
are governed by CICR triggered by Ca2⫹ entering through
NMDA receptors (710). A certain importance of ER Ca2⫹
release may be also deduced from the observation that a
significant increase in RyR2 expression, at both the
mRNA and protein level, was found in the hippocampus
of rats subjected to intensive water maze training (716).
Physiol Rev • VOL
D. Gene Expression, ER Ca2ⴙ Waves, and ER
Ca2ⴙ Tunneling
The importance of cytoplasmic and nuclear Ca2⫹
signals in the regulation of gene expression is well established, and a variety of Ca2⫹-dependent cascades controlling transcription have been characterized (19, 91, 152,
183, 184, 692), which shall not be discussed here. However, the problem of how Ca2⫹ reaches the nucleus during
physiological activity of the geometrically complex and
highly polarized nerve cell remains unsolved. It is well
established that cytosolic Ca2⫹ buffering hampers Ca2⫹
diffusion from often distant entry sites towards the cell
interior. The ER can be instrumental in conveying Ca2⫹
over long distances and therefore providing nuclear systems with appropriate Ca2⫹ signals. Intracellular propagation of Ca2⫹ signals can be achieved by virtue of endo-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 22. InsP3-induced Ca
release is critical for cerebellar long-term depression (LTD). A: loss of LTD in InsP3R1⫺/⫺ Purkinje cells. a: Pairing
depolarization and PF stimulation (1 Hz, 240 times) induced long-lasting depression of the PF-EPSP amplitude in control experiments using a
wild-type (WT) InsP3R1⫹/⫹ cerebellar slice. b: LTD was lost in an InsP3R1⫺/⫺ cerebellar slice. Insets show an average of 10 consecutive sweeps
at time points indicated. c: Averaged time course of normalized EPSP amplitude. Results are presented as means ⫾ SE. B: LTD is absent in
dilute-opithotonus (dop) mutant rats (117), which lack ER Ca2⫹ stores in Purkinje cell dendritic spines. Top panel shows traces of PF-EPSPs
measured in control (left) and mutant (right) Purkinje cell before (pre) and 25 min after conjunctive PF and CF stimulation. Bottom panel shows
the time course of changes in EPSP amplitudes after PF-CF stimulation (incidence of stimulation is indicated on the graph) for control (left) and
mutant (right) rat. LTD is completely absent in mutant animal. [A from Inoue et al. (247) copyright 1998 by the Society for Neuroscience; B from
Miyata et al. (421) copyright 2000 with permission from Elsevier.]
254
ALEXEI VERKHRATSKY
Physiol Rev • VOL
ciated with substantial peripheral Ca2⫹ influx and
[Ca2⫹]i elevation in dendrites, which then had to be
conveyed to the nucleus to activate CREB. Bading and
co-workers (201) found that inhibition of ER Ca2⫹ accumulation by TG completely prevented the signal from
reaching the nucleus. In the described experimental
conditions, Ca2⫹ entry into the ER must occur in dendrites, precisely where [Ca2⫹]i is elevated, and therefore, the possibility of Ca2⫹ diffusing through the ER
lumen to the nucleus appears probable. Clearly many
more experiments are needed to test for ER Ca2⫹ tunneling in nerve cells.
E. Neuronal Growth and Morphological Plasticity
Neurite outgrowth is governed by [Ca2⫹]i fluctuations
within the growth cone, where both the level of [Ca2⫹]i
and patterns of [Ca2⫹]i fluctuations regulate the velocity
of cone extension (273). For example, complex [Ca2⫹]i
transients are produced in growth cones during their
migration in the embryonic spinal cord. The larger the
frequency and magnitude of these [Ca2⫹]i spikes, the
slower the outgrowth. Inhibition of [Ca2⫹]i elevation accelerates the rate of neurite extension, whereas artificial
increase of [Ca2⫹]i by Ca2⫹ photorelease inhibits axonal
extension (190).
The [Ca2⫹]i signals relevant for neurite outgrowth are
produced by both Ca2⫹ entry and Ca2⫹ release, and the
particular importance of CICR was appreciated quite
early (297, 330). Recent analysis of growth cone movements of Xenopus neurons treated with netrin-1, an established regulator of neurite outgrowth, has further substantiated the importance of CICR for growth cone extension (233). Focal administration of netrin-1 to the
neuronal culture created a local concentration gradient,
which, in turn, forced the neurites to turn towards the
source of netrin-1. This turning movement was modified
by pharmacological inhibition of either plasmalemmal
Ca2⫹ entry (by 50 ␮M Cd2⫹) or Ca2⫹ release from the ER
(by 10 ␮M BHQ or 1 ␮M TG). When the cultures were
treated with 100 ␮M ryanodine, however, the administration of netrin-1 produced repulsion of the cone. Most
interestingly, applications of low concentrations of ryanodine (⬃100 nM around the growth cone) caused a
[Ca2⫹]i elevation within the cone and turning of the latter
towards the source of the drug (233). Thus, by regulating
the pattern of local [Ca2⫹]i signaling in the growth cone,
CICR determines the direction and rate of axon extension/repulsion. A somewhat similar role of CICR was
observed in the embryonic chick retina, where local CICR
stabilized dendrite formation during development. Inhibition of this local Ca2⫹ release induced rapid retraction of
dendrites (358).
In contrast, in embryonic chick DRG neurons, the
regulation of growth cone motility seems to be regulated
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
membrane excitability. Either RyR-mediated CICR or
CICR-assisted Ca2⫹ release from InsP3Rs or their combination may create propagating Ca2⫹ waves transforming
near-plasmalemmal [Ca2⫹]i elevations into nuclear Ca2⫹
rises. Indeed, such propagating [Ca2⫹]i waves have been
observed experimentally. For instance, CICR maintains
spreading Ca2⫹ waves between the plasmalemma and the
nucleus of the frog sympathetic ganglion neurons. Moreover, the speed of this wave remains constant all the way
to the nucleus, suggestive of an active propagation,
whereas at the moment the Ca2⫹ signal reaches the nucleus, its spread becomes diffusion governed (112, 389).
Similarly, InsP3Rs-dependent propagating Ca2⫹ waves
have been described in a variety of central neurons (see
Ref. 25 for review). Most interestingly, the Ca2⫹ wave can
become amplified when approaching the center of the
cell. For example, pairing of muscarinic stimulation of
CA1 hippocampal neurons with trains of action potentials
resulted in a focal Ca2⫹ elevation, which triggered a propagating Ca2⫹ wave, and the [Ca2⫹]i increase resulting
from this wave was largest in the soma and the nuclear
region (518). This amplification critically depended on ER
Ca2⫹ release, as emptying the ER by caffeine completely
prevented wave propagation.
Yet, the ER may offer an alternative route for
long-range Ca2⫹ propagation, which relies on the much
faster Ca2⫹ diffusion within the ER lumen compared
with the cytoplasm. This pathway, known as the intraluminal Ca2⫹ tunnel, has been described in pancreatic acinar cells, where Ca2⫹ was shown to rapidly
equilibrate throughout the whole of the ER (491), and
moreover, intra-ER Ca2⫹ diffusion can effectively replenish the depleted store in conditions of highly localized Ca2⫹ entry (424). As discussed above, synaptic
stimulation can result in a very substantial accumulation of Ca2⫹ in the dendritic ER. This local increase of
luminal Ca2⫹ may, by Ca2⫹ tunneling, rapidly reach the
nucleus even from remote cellular processes. Because
the ER is connected with the nuclear envelope (or
rather the nuclear envelope is part of the ER), Ca2⫹ can
be released directly into the nucleus via Ca2⫹ release
channels residing in the envelope membrane (182, 642).
Furthermore, sustaining Ca2⫹ waves in the neuronal
soma would also require Ca2⫹ transport through the ER
lumen. As mentioned above, the ER in central neurons
may not be full in resting conditions, and therefore,
initial loading of the store is necessary for the maintenance of a propagating Ca2⫹ wave. The existence of
neuronal ER Ca2⫹ tunneling has not been demonstrated
directly, although recent experiments performed by
Hilmar Bading and co-workers (201) may provide some
evidence for such a pathway. They investigated CREBmediated gene expression in cultured hippocampal
neurons treated with bicuculline. This treatment facilitates spontaneous firing in peripheral dendrites asso-
CALCIUM STORE IN THE ER OF NEURONS
F. Neurohormone Release
An interesting hypothesis postulating that the ER
Ca2⫹ store may regulate dendritic (i.e., extraterminal)
release of oxytocin was developed as a result of in vivo
experiments, which measured oxytocin release in the supraoptic nucleus region of anesthetized rats in response
to local dialysis of ER-specific agents. TG, but not caffeine
or ryanodine, induced release of the neurohormone and
greatly potentiated depolarization-induced oxytocin secretion. Interestingly, this potentiation was not observed
shortly after (5 min) application of TG, but a large potentiation was detected 30 –90 min later (361). The authors
explained their results in terms of TG-induced sustained
Ca2⫹ release, which, in fact, does not seem a plausible
explanation. First, [Ca2⫹]i rises caused by SERCA inhibition are short-lived, and second, depletion of the ER store
renders additional Ca2⫹ release from this compartment
impossible. If anything, post-TG potentiation of depolarization-induced oxytocin release may be explained by
larger [Ca2⫹]i rises in the presence of TG due to exclusion
of ER Ca2⫹ buffering, or else due to activation of an
alternative Ca2⫹ entry pathway.
IICR triggered by stimulation of P2Y purinoreceptors
stimulated the release of a pain-related neuromodulator,
calcitonin gene-related peptide (CGRP), from small (presumed nociceptive) cultured DRG neurons (559).
Finally, the release of BDNF from electrically active
neurons required activation of Ca2⫹ influx through N-type
Ca2⫹ channels and CICR, as BDNF secretion was inhibited by ␻-conotoxin GVIA, TG, and dantrolene (22).
Physiol Rev • VOL
G. Circadian Rhythms
Ca2⫹ release via ryanodine receptors is intimately
involved in the control of circadian rhythms in the suprachiasmatic nucleus (SCN). Transfection of organotypic
SCN slices with cytosol- and nucleus-targeted chameleon
YC2.1 (422), by employing gene gun technology, allowed
long-term monitoring of intracellular Ca2⫹ in neurons that
maintain circadian rhythms (244). These long-lasting recordings revealed a circadian rhythm for cytosolic but not
nuclear [Ca2⫹], and the former was fully synchronized
with the electrical circadian rhythm measured by a multiple electrode array. Treatment with ryanodine (100 ␮M)
depressed both the [Ca2⫹]i and electrical rhythms, although TG (1 ␮M) was ineffective (244). Hence, the precise role played by the ER store remains to be investigated in much greater detail.
Most interestingly, the expression of RyR2 in SCN
neurons is also governed by the circadian rhythm, with
the maximal level in the second half of the day phase. This
rhythm of RyR2 expression was preserved even when the
animals were constantly kept in dim light, suggesting that
it has a fundamental importance in setting the circadian
clock (125). A role for InsP3Rs in regulation of circadian
rhythms has also been suggested, although the only evidence for this is the inhibitory action of 2-APB (199),
which may not be associated with suppression of IICR at
all due to the lack of specificity.
V. ENDOPLASMIC RETICULUM CALCIUM
HOMEOSTASIS AND NEURONAL
PATHOPHYSIOLOGY
A. ER Stress Response and Neurodegeneration
Since ER is responsible for transcription, posttranslational protein modification, and selective transport of
proteins to different destinies, it has developed a highly
sophisticated system for controlling the quality of the final
protein products. Any imbalance of protein handling triggers a specific reaction generally defined as the ER stress
response. This response is triggered either by accumulation of unfolded proteins (the “unfolded protein response,” UPR) or by overexpression of particular proteins
(“the ER overload response,” EOR). The ER stress results
in activation of several transcription factors (most notably IRE1 and its receptor PERK) that upregulate the expression of chaperones and reduce ER protein load by
inhibiting overall protein synthesis. In addition, the ER
triggers the activation of NF-␬B and the transcription
factor C/ERP-homologous protein, which in turn control
synthesis of proinflammatory and hemopoetic proteins
and act as inhibitors of growth as well as promoters of
apoptosis (see Refs. 12, 155, 364, 477, 478, 500). If the ER
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
by InsP3Rs. Growth cones of these neurons are particularly rich in InsP3R1. Depletion of the ER store with TG
(10 ␮m) arrested the extension of the cones, and inhibition of IICR with intracellularly injected heparin induced
neurite retraction (626).
ER Ca2⫹ release controls not only the extension of
growth cones, but also the extension of dendritic spines.
Caffeine-activated release of Ca2⫹ from the ER triggers
rapid elongation of spines in cultured embryonic hippocampal neurons. Spine elongation was already obvious
30 min after a short application of 5–10 mM caffeine, and
after 90 min, the spine length had increased by 0.35 ␮m
(⬃33%; Ref. 304). Short puffs of caffeine even triggered a
de novo formation of spines, although this was not very
frequent (new spines appeared in 4 of 22 preparations).
The effects of caffeine were a specific consequence of ER
Ca2⫹ release, as 10 ␮M ryanodine obliterated them completely (304).
In summary, ER Ca2⫹ release acts as a powerful
regulator of the motility of growth cones and dendrites,
most likely through interaction with enzymes controlling
polymerization/depolymerization of the cytoskeleton.
255
256
ALEXEI VERKHRATSKY
Physiol Rev • VOL
TG-induced [Ca2⫹]i increases, thus demonstrating that the
ER depletion, rather than [Ca2⫹]i disturbances, were responsible for neurotoxicity (455). Experiments on the
same cell line demonstrated that toxicity induced by oxygen-glucose deprivation is also mediated through Ca2⫹
depletion of the ER (684). In Caenorhabditis elegans,
necrotic neuronal death can be prevented by loss of function mutations in Ca2⫹ release channels; at the same time,
treatment with TG invariably exacerbated necrosis (e.g.,
Ref. 702).
The ER stress response may regulate neuronal death
through another pathway, which involves caspase-12.
This enzyme resides within the ER lumen and is activated
upon various insults initiating ER stress (577). Most notably, ER stress triggered by disruption of ER Ca2⫹ homeostasis also activated caspase-12 cascade (442). This
pathway is endowed with a degree of specificity as cortical neurons isolated from caspase-12-deficient mice were
resistant to apoptosis induced by amyloid-␤ proteins, but
not to apoptosis induced by staurosporine or trophic
factor deprivation (442). Caspase-induced cell death in
embryonic hippocampal neurons similarly depended on
ER Ca2⫹ signaling and required the activation of ryanodine receptors (239).
Overall, it is quite clear that nerve cells do develop
ER stress upon severe disruption of ER Ca2⫹ homeostasis. Yet, the maneuvers employed for damaging ER Ca2⫹
handling, such as the irreversible block of SERCA pumps
by TG, are rather brutal and are very far from the conditions that neurons may encounter even in a diseased
state. Clearly more experimentation is needed to precisely characterize the link between [Ca2⫹]L and ER
stress. Another very important point lies in the determination of harmful levels of [Ca2⫹]L. Indeed, it is evident
that dramatic falls in intra-ER free Ca2⫹ are detrimental
for the cell; however, increased [Ca2⫹]L can also be toxic
(147, 511). It seems that a certain normal “window” of
[Ca2⫹]L exists, and when ER Ca2⫹ rises or falls beyond a
particular limit, grave consequences follow. Lastly,
changes in ER Ca2⫹ concentration may cause severe fragmentation of the ER (610, 634), which may also have
pathological consequences.
B. ER Stores and Ischemia
As a rule, glucose/oxygen deprivation triggers a substantial elevation of [Ca2⫹]i in nerve cells (521, 630, 708),
part of which is due to ER Ca2⫹ release (569, 644). In
striatal slices exposed to hypoxic conditions, Ca2⫹ release from the ER (partially mediated by NO) was responsible for a large part of the 45Ca2⫹ liberation (394). When
cultured hippocampal neurons were subjected to an anoxic environment, mimicked by incubation with NaCN, a
large [Ca2⫹]i increase was induced. This [Ca2⫹]i elevation
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
stress persists, it may result in the release of necrotic
factors, which trigger cell death. As already discussed
above, the activity of many intra-ER enzymatic cascades
ultimately depends on the intraluminal Ca2⫹ concentration, and a strong link between ER Ca2⫹ homeostasis, ER
stress, and neurodegeneration therefore has been postulated (495– 498). This hypothesis is supported by several
lines of evidence, which show that 1) depletion of ER
stores induces upregulation of ER stress markers, 2) depletion of ER stores causes neuronal cell death, 3) exposure of neuronal cells to various insults upregulates ER
stress markers, and 4) inhibition of ER Ca2⫹ release
protects against neurotoxicity. Several examples of such
data are discussed below.
The depletion of ER Ca2⫹ stores in primary cultured
rat embryonic cortical neurons by incubation with TG (1
␮M), CPA (30 ␮M), or caffeine (10 mM) reduced protein
synthesis to 10 –70% of the control and caused complete
disaggregation of polysomes (129, 499). A significant decrease in protein synthesis was also observed in cultured
embryonic rat cortical neurons treated with 100 nM ryanodine, a concentration which depletes the ER store by
opening RyRs (5). At the same time, ER depletion following 30-min incubation with 1 ␮M TG led to an almost
200-fold increase in the expression of ER stress markers
grp78, grp94, gadd34, and gadd153 and in a 6-fold increase
of SERCA2b and BCl-2 (403). Therefore, severe disruption
of ER Ca2⫹ homeostasis triggers ER stress and has a clear
neurotoxic effect.
ER stress is also induced by exposure of nerve cells
to various neurotoxic conditions. For example, application of excitotoxic concentrations of glutamate as well as
oxidative insults elevated the level of grp78 in rat cultured
hippocampal neurons (713). This increase in grp78 expression was neuroprotective, as treatment of cultures
with grp78 antisense substantially increased neuronal cell
death. Hypoxia/reperfusion increased the expression of
another chaperon, grp94, in neuroblastoma cells. The increased level of grp94 was also cytoprotective, as treatment of neuroblastoma cells with grp94 antisense exacerbated cell death (24). Similarly, CA1 hippocampal neurons overexpressing grp94 were resistant to ischemic
damage in gerbils subjected to transient carotid artery
occlusion (24).
Finally, disturbances of ER Ca2⫹ handling cause neuronal death. Treatment of cultured cerebellar granule neurons with the neurotoxin mastoparan triggered massive
IICR, which in turn initiated apoptosis and cell death.
Inhibition of PLC (and hence InsP3 production) had a
neuroprotective effect (346). Depletion of Ca2⫹ stores
with TG (300 nM), CPA (300 ␮M), and BHQ (300 ␮M)
resulted in 50 – 60% neuroblastoma cell death within 48 h
and in an almost complete demise of the culture within
72 h (455). Interestingly, loading the cells with BAPTA-AM
did not protect against TG toxicity, although it prevented
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
ization) was not effective (473). Together, these findings
provide very important information on mechanisms of
ischemic damage of white matter, which seem to be different from those in gray matter. White matter damage is
accomplished by intracellular Ca2⫹ release, whereas injury of gray matter very much depends on plasmalemmal
Ca2⫹ entry.
The link between ischemia-induced changes in ER
Ca2⫹ homeostasis and intra-ER chaperone activity has
also been described recently, when the ischemia-induced
ER chaperone orp150 (oxygen-regulated protein of 150
kDa) was isolated and characterized. Orp150 is strongly
upregulated in astrocytes following ischemic stress,
which may explain their exceptional resistance to ischemic conditions. Overexpression of orp150 in cultured rat
cortical neurons protected them against ischemia, and
vice versa, inhibition of orp150 synthesis in cultured astrocytes increased their vulnerability to hypoxic shock
(627). Transgenic mice expressing orp150 under control
of a platelet-derived growth factor B-chin promoter displayed high levels of orp150 in the cortex, hippocampus,
and cerebellum and were much more resistant to global
cerebral ischemia compared with wild-type controls
(627). Interestingly, in cultured neurons with an increased
level of orp150, glutamate-induced [Ca2⫹]i loads were
substantially reduced, implying that this chaperone may
also stabilize cellular Ca2⫹ homeostasis, most likely by
limiting Ca2⫹ release from the ER, which accompanies
excessive glutamate stimulation (294).
C. ER Stores and Human Immunodeficiency Virus
The human immunodeficiency virus (HIV) envelope
glycoprotein GP120 was shown to induce large [Ca2⫹]i
increases in cultured hippocampal neurons and promote
their degeneration. Both the [Ca2⫹]i elevation and the
neurodegeneration can be prevented by the CICR blocker
dantrolene, or by ER depletion produced by preincubation of cells with caffeine, carbachol, or TG (393).
D. ER Stores and Diabetes
The involvement of the ER Ca2⫹ store in diabetic
peripheral neuropathies can be suggested on the basis of
a rather limited number of observations demonstrating a
reduction in the size of caffeine-induced Ca2⫹ release in
peripheral neurons isolated from animals with experimental (usually streptozotocin induced) diabetes type I.
Such a decrease was found in diabetic DRG neurons (242,
306, 316), and the reduced [Ca2⫹]i responses to caffeine
were especially prominent in cells isolated from lumbar
ganglia (242), which are the first to be affected by diabetic
neuropathies. A very substantial decrease in caffeine-induced [Ca2⫹]i transients (from 270 nM in control animals
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
was blocked by dantrolene and ruthenium red, therefore
implying an important role of CICR (132) The NaCNinduced [Ca2⫹]i increase considerably exceeded the
[Ca2⫹]i elevation in response to glutamate, although the
action of the latter was grossly amplified in conditions of
metabolic stress.
Similarly, energy deprivation (induced by perfusion
with an oxygen/glucose free solution) produced a large
[Ca2⫹]i elevation in hippocampal neurons in slices
([Ca2⫹]i increased up to 28 ␮M), and this increase was
invariably followed by cell edema and death. Similar massive (up to 30 ␮M) increases in [Ca2⫹]i following an
interruption in blood flow were observed in hippocampal
neurons impaled with ion-sensitive electrodes (588). Depletion of the ER stores by preincubation of hippocampal
slices from young Wistar rats with TG (1 ␮M, 30 min)
dramatically (⬃5 times) reduced the [Ca2⫹]i elevation
triggered by energy deprivation (192). Promotion of ER
Ca2⫹ release (by intracellular injection of InsP3 into gebril
hippocampal neurons) greatly facilitated the irreversible
depolarization induced by ischemia (288). Dantrolene significantly reduced neuronal death in the CA1 area of the
hippocampus in adult rats, subjected to global cerebral
ischemia, but this effect could be partly attributed to
reduced release of glutamate (447). Interestingly, however, the glutamate release was diminished to an equal
extent by dantrolene as well as by DMSO (used as a
solvent for dantrolene); DMSO alone also protected neurons against ischemia, yet dantrolene was twice as potent.
Inhibition of ER Ca2⫹ release also prevented the liberation of neurotoxic free fatty acids from the ischemic
cortex (510).
Ca2⫹ release from the ER also appears instrumental
in ischemic damage of white matter. Destruction of axons
upon ischemic stress is mediated through an increase in
cytosolic Ca2⫹. Experiments on rat dorsal columns
showed that this [Ca2⫹]i elevation persisted after removal
of Ca2⫹ from the perfusate; similarly, ischemic injury of
axons persisted in Ca2⫹-free conditions. At the same time,
the axonal [Ca2⫹]i increases were sensitive to ER depletion by TG or by inhibition of CICR by ryanodine (473).
Most intriguingly, the CICR in axons may be of the “skeletal muscle” variety, i.e., involving direct coupling between plasmalemmal Ca2⫹ channels and RyRs. This suggestion is based on the fact that blockage of the Ca2⫹
channel voltage sensor (by dihydropyridines), but not of
the Ca2⫹ channel pore (by Cd2⫹), was hugely protective
against ischemia. At the same time, simultaneous inhibition of RyRs (by ryanodine) and of Ca2⫹ channels by
nimodipine was not additive, thus favoring interdependence of two molecules. In concordance with this suggestion, replacement of extracellular Na⫹ with impermeable
cations, limiting depolarization, protected axons against
ischemia, whereas substitution of Na⫹ with Li⫹ (which is
carried through Na⫹ channels and hence allows depolar-
257
258
ALEXEI VERKHRATSKY
to 30 nM in diabetic ones) was also observed in dorsal
horn neurons from streptozotocin-induced diabetic rats
(316, 679). In in vivo experiments, ryanodine and TG
significantly modified the formalin-induced nociceptive
response in streptozotocin-diabetic mice (266) providing
further evidence that the ER Ca2⫹ store is involved in the
pathogenesis of diabetic neuropathies.
E. ER Stores and Gangliosidoses (Gaucher’s and
Sandhoff’s Disease)
F. ER Stores and Alzheimer’s Disease
Alzheimer’s disease (AD) is a form of senile dementia
characterized by the advent of plaques in the brain matter
(54, 153) and appearance of fibrillous structures within
the neuronal cytoplasm (11). It receives much attention
because of its social impact affecting the progressively
ageing mankind. The importance of cellular Ca2⫹ homeostasis in the pathogenesis of AD was perceived at the
beginning of 1980s, when Zaven Khachaturian promulgated his “Ca2⫹ hypothesis of AD and neuronal ageing”
(281). This hypothesis postulated that long-lasting subtle
changes in [Ca2⫹]i homeostasis would eventually result in
the neurodegeneration so characteristic of AD.
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Mutations of the human gene encoding glucocerebrosidase result in a reduction of activity of this enzyme and
accumulation of glycosylceramide, which, in turn, promotes neurodegeneration in the central nervous system.
Clinically this type of neurodegenerative disorder is
known as Gaucher’s disease (27). When the activity of
glucocerebrosidase in cultured hippocampal neurons was
blocked by incubation with conduritol-B-epoxide, accumulation of glycosylceramide occurred, thus mimicking
the pathological conditions associated with Gaucher’s
disease. This condition was accompanied by a significant
increase in ER tubular elements and by a great increase in
the release of Ca2⫹ from the ER in response to both
metabotropic stimulation and caffeine (302). Furthermore, hippocampal neurons with inhibited glucocerebrosidase were significantly more vulnerable to excitotoxic
shock (exposure to high glutamate concentrations), and
this increased vulnerability was blocked by ryanodine
(302). Therefore, remodeling of the ER Ca2⫹ homeostasis
which results in an increase of ER Ca2⫹ content may be
regarded as a key element of neurodegeneration associated with Gaucher’s disease.
Another type of gangliosidoses, when gangliosides
accumulate in cells due to a defect in lysosomal proteins
catalyzing their degradation, the GM2 gangliosidoses, or
Sandhoff’s disease, also affects the ER, as the rate of
SERCA-driven Ca2⫹ uptake was found to be considerably
lower in the Sandhoff mouse model (501).
Investigations in the last decade confirmed this early
reflection by clearly demonstrating that disruption of cellular Ca2⫹ homeostasis is a prominent feature of AD
pathophysiology. Furthermore, these investigations identified ER Ca2⫹ dysregulation as a key step in the development of AD.
As already mentioned, the histopathology of AD is
represented by plaques formed by aggregates of amyloid-␤ peptide (A␤) and by the appearance of intracellular
filamentous structures of a macrotubule-associated protein tau (378). This reflects several complex alterations of
enzymatic systems controlling the synthesis and processing of A␤. The familial form of AD (FAD) is caused by
mutations of genes encoding the A␤ precursor protein
(APP, chromosome 21) and presenilins 1 (PS1, chromosome 14) and 2 (PS2, chromosome 1). Mutations in PS1
are responsible for the majority of FAD cases. The central
question for the pathophysiology of AD is related to
events proximal to the malformation of A␤, as they could
represent potential therapeutic targets.
Disrupted Ca2⫹ homeostasis has been identified as a
feature of AD. Increased levels of free and bound Ca2⫹
have been detected in neurons containing neurofibrillary
tangles (439). Likewise, neurons possessing tangles
showed increased activity of various Ca2⫹-dependent proteases (461). Early studies on fibroblasts isolated from AD
patients also demonstrated impairment of Ca2⫹ mobilization in response to metabotropic stimulation (186, 252).
Direct administration of A␤ to nerve cells caused elevation in resting [Ca2⫹]i and greatly diminished the ability of
cells to cope with Ca2⫹ loads (207, 367, 379; see also Ref.
377 for review). Most importantly however, cellular Ca2⫹
dishomeostasis occurs at the initial stages of AD (142),
and studies on transgenic mice with APP or PS mutations
found that impaired Ca2⫹ handling occurs long before any
histopathological changes (195, 323). The mechanisms of
AD-related disruption of [Ca2⫹]i homeostasis can be multifacetous and involve plasmalemmal systems as well as
intracellular organelles. The effects of A␤ and its fragments, for instance, are reported to influence plasmalemmal Ca2⫹ transport by forming Ca2⫹-permeable pores
(47, 279), although acute application of A␤ additionally
augments intracellular Ca2⫹ release (207, 299). Several
recently conducted studies suggest that disrupted ER
Ca2⫹ homeostasis may be regarded as a specific feature of
the AD-related neuronal Ca2⫹ dysregulation (see Table 11
and Refs. 323, 378, 380, 608, 709).
Among molecules involved in the pathogenesis of
AD, presenilins are particularly relevant for disruption of
ER function. Presenilins are integral membrane proteins
that contain eight transmembrane domains and serve as
part of a multiprotein protease complex, the ␥-secretase,
which is responsible for the intramembranous cleavage of
the APP and the Notch receptors (124). Most importantly,
presenilins are involved in integrative neuronal functions,
CALCIUM STORE IN THE ER OF NEURONS
259
11. Involvement of ER Ca2⫹ homeostasis in neurodegenerative changes associated
with Alzheimer’s disease
TABLE
Effects
Preparation
Experimental Evidence
Reference
Nos.
Effects of A␤ peptide and its fragments
Applications of a secretory form of ␤-amyloid precursor protein APP695S
elevated InsP3 production and induced [Ca2⫹]i rise in Ca2⫹-free media.
299
Exposure of cultures to A␤ fragment A␤25–35 increased expression of
grp78.
713
Increased kainite (in vivo) and glutamate (in vitro) excitotoxicity
correlated with increased amplitude of glutamate-induced [Ca2⫹]i
elevation in PS1 mutant neurons. Dantrolene effectively prevented
excitotoxicity in culture.
In voltage-clamped neurons, application of A␤ fragment A␤25–35 increased
L- and T-type Ca2⫹ currents; in fura 2-AM-loaded cells, A␤25–35 induced
[Ca2⫹]i increase in Ca2⫹-free media.
195
207
Effect of presenilins
2⫹
Increased Ca
release
PC12 cells
In PC12 cells expressing mutant PS1 (L286V), carbachol, bradykinin, and 196, 197
TG induce larger [Ca2⫹]i responses compared with control. These cells
also show larger [Ca2⫹]i elevation and increased cell death upon
application of A␤; effects of A␤ can be inhibited by nifedipine and
dantrolene or expression of Bcl-2.
Upregulation of RyRs expression PC12, primary cultured In PC12 cells expressing mutant PS1 (L286V or M146V) and in
88
2⫹
and increased Ca release
hippocampal neurons
hippocampal neurons isolated from mutant PS1 (M146V) mice, the
greater levels of RyRs coincided with increased amplitude of
caffeine-induced Ca2⫹ release.
PS1 effects on SOC
SY5Y neuroblastoma,
In cultured neurons from PS1 knockout and SY5Y cells expressing
709
CHO cells, primary
inactive PS1 the SOC (determined as [Ca2⫹]i increase after depletion of
2⫹
cultured cortical
ER by CPA and Ca readmission) was potentiated. SY5Y cells
neurons
expressing PS1 mutant (M146L) or PS2 mutant (N141I) as well as
cortical neurons isolated from PS2 (N114I) mutant mice displayed
reduced SOC. In CHO cells with stable expression of PS1 mutant gene,
the ICRAC was severely inhibited.
Increased Ca2⫹ release and
SH-SY5Y
Expression of wild-type PS1 or mutant PS1 ⌬E9 increased the amplitude
596
inhibition of SOC
neuroblastoma cell
of muscarine-induced [Ca2⫹]i transients recorded in Ca2⫹-free media;
2⫹
2⫹
line
the SOC measured as [Ca ]i increase after readmission of Ca into
external solution was inhibited in cells expressing PS1 ⌬E9 only.
Increased sensitivity to oxidative PS1 knock-out mice;
Neuronal cultures prepared from PS-deficient mice exhibited much higher
443
stress
neocortical and
cell death in response to 24-h incubation with 100 ␮M H2O2 and to
hippocampal
100–1,000 ␮M glutamate.
embryonic primary
cultures
Increased LTP and vulnerability Transgenic mutant PS1 Depolarization (KCl 50 mM), glutamate (50 ␮M), TG (1 ␮M), and
564
to kainite excitotoxicity
mice; hippocampal
bradykinin produced higher [Ca2⫹]i elevation in PS1-derived cells
brain slices; primary
studied in both slices and culture. Mutant PS1 neurons were more
hippocampal cultures
vulnerable to kainite- (in vivo) and glutamate-induced excitotoxicity.
LTP in response to weak stimulation was facilitated in PS1 mutant
neurons.
2⫹
Various transgenics
The SOC was decreased in PS1 mutants, but not in APP-deficient animals
220
Increased ER Ca release and
increased SOC
containing mutant
(the SOC was measured as SKF-96365 sensitive component of [Ca2⫹]i
PS1, APP⫺/⫺ and
rise in response to readmission Ca2⫹ after the period of Ca2⫹-free
their combinations,
media with CPA). In mice deficient for PS1 and APP TG as well as in
hippocampal brain
PS1 mutant mice TG triggered much larger [Ca2⫹]i elevation compared
slices; primary
with wild-type animals.
hippocampal cultures
2⫹
Increased InsP3-mediated Ca
Cortical brain slices
The amplitude of InsP3-evoked (flash photolysis of caged InsP3) [Ca2⫹]i
608
release
transients was ⬃3 times larger in cortical neurons from mice
expressing mutant PS1 (M146V) as compared with wild-type
age-matched controls. Expression of mutant PS1 greatly increased
the number of neurons responding to caged InsP3 photolysis by [Ca2⫹]i
transient. The level of InsP3Rs was not affected by PS1 knock-in,
suggesting increased [Ca2⫹]L as a main reason for the differences
observed.
LTP, long-term potentiation; A␤, ␤-amyloid protein.
Physiol Rev • VOL
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
Increase of InsP3 production and Primary cultured
Ca2⫹ release
hippocampal
embryonic neurons
Increase of ER stress response
Primary cultured
marker grp78
hippocampal
embryonic neurons
Increased kainate and glutamate Mutant PS1 mice,
excitotoxicity
hippocampus and
primary hippocampal
cultures
Increase in VGCC and
Primary cultured DRG
stimulation of Ca2⫹ release
from the ER
260
ALEXEI VERKHRATSKY
Physiol Rev • VOL
production of A␤40 and A␤42 (561). Furthermore, neurons overexpressing the mutant (but not the wild-type)
form of PS1 were more susceptible to spontaneous
apoptosis and apoptosis induced by ER stress, through
decreased UPR (635).
An extremely important achievement in studying the
cellular mechanisms of AD occurred recently after several
genetic AD models were created. Conceptually these
models aimed at the insertion of various forms of APP,
which replicated A␤ deposition and plaque formation, or
inclusion of mutant PS genes, which produced numerous
AD-specific neuropathological changes. The recently discovered tau gene mutations (191), associated with frontotemporal dementia, have provided an additional tool for
genetic modeling. A big step forward was made by Frank
LaFerla, Mark Mattson, and co-workers who succeeded in
creating a triple transgenic mouse bearing presenilin 1
(PS1m146V), amyloid precursor protein (APPSwe), and
tau (tauP301L) transgenes (466). These animals possessed several hallmarks of AD such as progressively
developing plaques and tangles as well as deficiencies in
LTP, which preceded the appearance of the histological
markers of AD. The functional changes were clearly age
dependent, as both the amplitude of field-stimulation
evoked EPSPs and LTP were significantly impaired in
6-mo-old triple transgenic animals, whereas at 1 mo there
was no difference between the transgenic mice and wildtype controls (466). However, a detailed analysis of the
ER signaling changes associated with this model has yet
to be performed.
Although there is no doubt about the AD-related
impairment of ER Ca2⫹ homeostasis, the important question of whether ER changes precede A␤ formation or
conversely A␤ malsynthesis causes ER dysfunction remains open.
G. ER Stores and Ageing
The process of physiological ageing (646), which is
not associated with any prominent neuronal loss, yet is
accompanied by cognitive decline, involves changes in
neuronal Ca2⫹ homeostasis, which comprise alterations
of Ca2⫹ influx, mitochondrial and cytoplasmic Ca2⫹ buffering, and Ca2⫹ extrusion (108, 156, 289, 307, 329, 516,
639, 640, 647, 675, 700). The amplitudes of caffeine-induced [Ca2⫹]i responses are moderately decreased in
aged DRG, neocortical, and cerebellar granule cells (290,
291, 674) and in acutely dissociated rat basal forebrain
neurons (436). This may reflect the decreased [Ca2⫹]L,
and indeed, the studies mentioned above found a decreased Ca2⫹ sequestering capacity of the ER in aged
nerve cells. In contrast, old cultured hippocampal neurons (101) demonstrated prolonged CICR in response to
glutamate exposure, although the size of the caffeine-
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
as conditioning knockout of both PS1 and PS2 in the
forebrain of adult mice causes a remarkable impairment
of memory, LTP, NMDA responses, and CREB/CBP-mediated gene expression and promotes neurodegeneration
(562).
Presenilins are highly expressed in neurons and reside mostly in the ER membrane. Not much is known
about the involvement of presenilins in ER Ca2⫹ handling,
although it has been shown that PS1 can bind to RyRs (88)
and interact with sorcin (476), calsenilin (69), and calpain
(372), i.e., proteins known to regulate Ca2⫹ release channels. Nonetheless, every alteration of PS, be it in the form
of its genetic deletion or of expression of mutant (FAD
associated) PS, results in impairment of ER function. As a
rule, the latter is manifested as an increased amplitude of
the Ca2⫹ response to metabotropic agonists, caffeine, or
the SERCA inhibitors TG and CPA (see Table 11). This
increase in [Ca2⫹]i transients is generally regarded as a
consequence of an elevated [Ca2⫹]L. The changes in ER
Ca2⫹ content are not confined to neurons, but are also
observed in various peripheral cells such as, e.g., fibroblasts (336).
Manipulations of presenilin expression affect several
Ca2⫹-dependent functions as well as neuronal vulnerability to various types of insults. In transgenic mice expressing mutant PS1, neurons in hippocampal slices show an
increased sensitivity to kainate excitotoxicity and demonstrate facilitated LTP induction (564). Both effects are
attributable to an increased Ca2⫹ release from the ER.
Similarly, expression of mutant PS1 increased the size of
infarction following middle cerebral artery occlusion and
reperfusion in vivo and increased cell death in cortical
neurons in vitro, when exposed to hypoxia and glucose
deprivation (382). Likewise, cultured hippocampal neurons from the same animals displayed increased vulnerability to glutamate excitotoxic shock (195). Inhibition of
ER stores by dantrolene protected PS1 mutant-bearing
neurons (382). Higher susceptibility of PS1 mutant neurons to various insults correlated with failures of the Ca2⫹
homeostatic machinery. Recordings of [Ca2⫹]i in PS1 mutant neurons revealed larger [Ca2⫹]i elevations induced by
hypoxia, glutamate, and intracellular delivery of InsP3
(195, 382, 608). Modulation of PS functions by overexpressing calsenilin, a cytoplasmic protein interacting with
PS1 and PS2, enhanced apoptosis and increased the
amount of TG-released Ca2⫹, once more pointing to a
possible increase in [Ca2⫹]L (345).
The PS-mediated alterations of ER function were
accompanied by biochemical changes characteristic of
the ER stress response. Specifically, expression of mutant PS1 in hippocampal neurons was associated with
an abnormal activation of ER resident caspase-12 (87),
which, as has been mentioned previously, mediates ER
stress-related apoptosis. Expression of an aberrant
spliced form of PS2 (PS2V) altered UPR and increased
CALCIUM STORE IN THE ER OF NEURONS
releasable pool was similar in young and old cultures.
Experiments in hippocampal slices isolated from old
(22–24 mo) rats found that increased ER Ca2⫹ release
affects LTP induction in the aged hippocampus (321). All
in all, however, the age-dependent changes in ER Ca2⫹
homeostasis are rather mild when compared with the ER
alterations in AD. Moreover, no obvious increase in the
ER Ca2⫹ content has been discovered in old neurons,
which may reflect a fundamental difference between the
physiological processes of brain ageing and age-dependent neurodegeneration.
261
tion of the expression of numerous genes indicative of
UPR (550). Similarly, the ER stress response was evoked
by rotenone and 1-methyl-4-phenyl-pyridinium, other
agents used for cellular modeling of PD. Finally, the recently identified PD-related G protein-coupled receptor
protein, termed the Pael receptor, was found to accumulate in the ER and cause ER-related cell death (623).
Whether these biochemical changes become translated
into impairments of ER Ca2⫹ homeostasis remains totally
unexplored.
K. ER and Epileptiform Activity
Spinocerebellar ataxia type 1 (SCA1) is an autosomal
dominant neurological disorder characterized by loss of
Purkinje neurons and neurons in pontine nuclei, which is
clinically manifested as a malfunction of the brain stem
and ataxia. SCA1 is caused by the expansion of a CAG
trinucleotide repeat, which results in an expanded polyglutamine tract in its gene product, ataxin-1 (248). In
SCA1 transgenic mice, which carry the expanded allele, a
significant reduction in the expression of the InsP3R1 and
the SERCA2 pump was observed, although quantitatively
parameters of [Ca2⫹]i signaling and mGluR-mediated
Ca2⫹ release did not differ much from wild-type controls
(248).
I. ER and Neuronal Trauma
A direct link between neurotrauma and ER Ca2⫹
homeostasis has been demonstrated for cultured cortical
neurons subjected to mechanical deformation. It appeared that such a crude traumatization of neurons resulted in a remarkable decrease in the proportion of cells
able to produce ER-associated Ca2⫹ release. The percentage of cells responding to caffeine fell from 70% in control
to 30%, and the percentage of neurons producing IICR
from ⬃90% in normal cells to ⬃20% already 15 min after
the trauma (690). Three hours later the ER Ca2⫹ release
was normalized, although an increase in SOC was observed (689). SOC was determined as SKF96365-sensitive
component of the TG-induced [Ca2⫹]i elevation.
J. ER and Parkinson’s Disease
A possible role for the ER in the pathogenesis of
Parkinson’s disease (PD) has been suggested based on
investigations of a cellular model of PD, namely, exposure
of cells to 6-hydroxydopamine, an agent which causes a
type of neurodegeneration similar to that observed in PD
(659). When PC12 cells were exposed to 100 ␮M 6-hydroxydopamine for 8 h, they responded by an upregulaPhysiol Rev • VOL
There is some evidence indicating that incubation of
hippocampal slices with 1–5 ␮M TG or with 30 –100 ␮M
dantrolene suppresses epileptiform activity in CA3 hippocampal area (549). Similarly, TG is shown to inhibit
bicuculline-induced epileptiform activity in hippocampal
neuronal networks in culture (599). In a pilocarpine
model of epilepsy in hippocampal neuronal cultures, a
reduction of TG-sensitive Ca2⫹ uptake in “epileptic” neurons together with augmented CICR and altered IICR
were described (480). Whether these findings reflect any
involvement of the ER Ca2⫹ store in the pathogenesis of
epilepsy remains unknown.
L. ER and Huntington’s Disease
Huntington’s disease is a fatal autosomal dominant
neurodegenerative disorder, which is characterized by a
triad of motor (chorea), cognitive (progressive loss of
mental abilities), and psychiatric/behavioral disturbances.
This neuropathology is caused by mutations (polyglutamine expansion) of the protein huntingtin (85). The
mutant huntingtin sensitizes the InsP3R1 to InsP3, and
moreover, transfection of medium spiny striatal neurons
with this mutant protein facilitates [Ca2⫹]i responses to
mGluR1/5 activation (628).
VI. CONCLUDING REMARKS
The ER is deeply engaged in neuronal integration.
This integration involves coordinated activities of numerous molecular cascades that provide the ER with incoming signals, intra-ER information processing, and generation of output signals which control rapid neuronal signaling and long-lasting adaptive responses (Fig. 23). The
movements of Ca2⫹ across the ER membrane and within
the ER lumen are responsible for many of these duties.
Regulated Ca2⫹ release from the ER is implicated in rapid
neuronal responses to synaptic inputs and action potentials and is important for synaptic plasticity. Fluctuations
of the intra-ER Ca2⫹ concentration couple these rapid
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
H. Spinocerebellar Ataxia Type 1
262
ALEXEI VERKHRATSKY
signaling events to protein synthesis and modification.
Finally, disruptions of ER Ca2⫹ homeostasis may be intimately involved in numerous neuropathological processes.
Our understanding of the ER function in nerve cells is
clearly incomplete, and future investigations will undoubtedly result in many exciting discoveries in this field.
I am very grateful to Dr. Denis Burdakov for invaluable
help with the manuscript editing. I also thank Prof. Marina
Bentivoglio, Dr. Antony Galione, Dr. Olga Garaschuk, Dr. Paolo
Mazzarello, Prof. David Friel, Prof. Masanobu Kano, Prof. Arthur
Konnerth, Dr. Yuri Kovalchuk, Dr. David Ogden, Prof. Alexei
Tepikin, and Prof. William Ross for providing me with originals
of figures. I thank the reviewers for their meticulous revision of
the manuscript and for very constructive comments.
The author’s research was supported by The Wellcome
Trust, The Biotechnology and Biological Science Research
Council UK, Royal Society, North American Treaty Organization, and International Association of European Community.
Address for reprint requests and other correspondence: A.
Verkhratsky, Univ. of Manchester, Faculty of Life Sciences,
1.124 Stopford Building, Oxford Road, Manchester M13 9PT, UK
(E-mail: [email protected]).
Physiol Rev • VOL
REFERENCES
1. Aiba A, Kano M, Chen C, Stanton ME, Fox GD, Herrup K,
Zwingman TA, and Tonegawa S. Deficient cerebellar long-term
depression and impaired motor learning in mGluR1 mutant mice.
Cell 79: 377–388, 1994.
2. Akita T and Kuba K. Functional triads consisting of ryanodine
receptors, Ca2⫹ channels, and Ca2⫹-activated K⫹ channels in bullfrog sympathetic neurons. Plastic modulation of action potential.
J Gen Physiol 116: 697–720, 2000.
3. Akopian A, Gabriel R, and Witkovsky P. Calcium released from
intracellular stores inhibits GABAA-mediated currents in ganglion
cells of the turtle retina. J Neurophysiol 80: 1105–1115, 1998.
4. Albrecht MA, Colegrove SL, Hongpaisan J, Pivovarova NB,
Andrews SB, and Friel DD. Multiple modes of calcium-induced
calcium release in sympathetic neurons. I. Attenuation of endoplasmic reticulum Ca2⫹ accumulation at low [Ca2⫹]i during weak depolarization. J Gen Physiol 118: 83–100, 2001.
5. Alcazar A, Martin de la Vega C, Bazan E, Fando JL, and
Salinas M. Calcium mobilization by ryanodine promotes the phosphorylation of initiation factor 2␣ subunit and inhibits protein
synthesis in cultured neurons. J Neurochem 69: 1703–1708, 1997.
6. Alford S, Frenguelli BG, Schofield JG, and Collingridge GL.
Characterization of Ca2⫹ signals induced in hippocampal CA1 neurons by the synaptic activation of NMDA receptors. J Physiol 469:
693–716, 1993.
7. Alkon DL, Nelson TJ, Zhao W, and Cavallaro S. Time domains
of neuronal Ca2⫹ signaling and associative memory: steps through
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
2⫹
FIG. 23. ER calcium signaling and neuronal integration. The ER participates in rapid cytosolic signaling by releasing and accumulating Ca .
The diffusion of Ca2⫹ through intra-ER Ca2⫹ tunnel provides for spatial integration and supports propagating Ca2⫹ waves. Fluctuations of [Ca2⫹]L
regulate intra-ER chaperones, thus coordinating cellular Ca2⫹ fluxes with long-lasting adaptive responses.
CALCIUM STORE IN THE ER OF NEURONS
8.
9.
10.
11.
12.
13.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
Physiol Rev • VOL
30. Barstow KL, Locknar SA, Merriam LA, and Parsons RL. The
modulation of action potential generation by calcium-induced calcium release is enhanced by mitochondrial inhibitors in mudpuppy
parasympathetic neurons. Neuroscience 124: 327–339, 2004.
31. Basheer R, Arrigoni E, Thatte HS, Greene RW, Ambudkar IS,
and McCarley RW. Adenosine induces inositol 1,4,5-trisphosphate
receptor-mediated mobilization of intracellular calcium stores in
basal forebrain cholinergic neurons. J Neurosci 22: 7680 –7686,
2002.
32. Baumann O and Walz B. Endoplasmic reticulum of animal cells
and its organization into structural and functional domains. Int Rev
Cytol 205: 149 –214, 2001.
33. Beck A, Lohr C, and Deitmer JW. Calcium transients in subcompartments of the leech Retzius neuron as induced by single action
potentials. J Neurobiol 48: 1–18, 2001.
34. Benedeczky I, Molnar E, and Somogyi P. The cisternal organelle
as a Ca2⫹-storing compartment associated with GABAergic synapses in the axon initial segment of hippocampal pyramidal neurons. Exp Brain Res 101: 216 –230, 1994.
35. Benham CD, Gunthorpe MJ, and Davis JB. TRPV channels as
temperature sensors. Cell Calcium 33: 479 – 487, 2003.
36. Bennett MR. The concept of a calcium sensor in transmitter
release. Prog Neurobiol 59: 243–277, 1999.
37. Bentivoglio M. 1898: the Golgi apparatus emerges from nerve
cells. Trends Neurosci 21: 195–200, 1998.
38. Berridge M, Lipp P, and Bootman M. Calcium signalling. Curr
Biol 9: R157–R159, 1999.
39. Berridge MJ. Neuronal calcium signaling. Neuron 21: 13–26, 1998.
40. Berridge MJ. The endoplasmic reticulum: a multifunctional signaling organelle. Cell Calcium 32: 235–249, 2002.
41. Berridge MJ, Bootman MD, and Roderick HL. Calcium signalling: dynamics, homeostasis and remodelling. Nat Rev Mol Cell Biol
4: 517–529, 2003.
42. Berridge MJ, Lipp P, and Bootman MD. Signal transduction. The
calcium entry pas de deux. Science 287: 1604 –1605, 2000.
43. Bezprozvanny I and Ehrlich BE. ATP modulates the function of
inositol 1,4,5-trisphosphate-gated channels at two sites. Neuron 10:
1175–1184, 1993.
44. Bezprozvanny I and Ehrlich BE. The inositol 1,4,5-trisphosphate
(InsP3) receptor. J Membr Biol 145: 205–216, 1995.
45. Bezprozvanny I, Watras J, and Ehrlich BE. Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels
from endoplasmic reticulum of cerebellum. Nature 351: 751–754,
1991.
46. Bezprozvanny IB, Ondrias K, Kaftan E, Stoyanovsky DA, and
Ehrlich BE. Activation of the calcium release channel (ryanodine
receptor) by heparin and other polyanions is calcium dependent.
Mol Biol Cell 4: 347–352, 1993.
47. Bhatia R, Lin H, and Lal R. Fresh and globular amyloid beta
protein (1– 42) induces rapid cellular degeneration: evidence for
A␤P channel-mediated cellular toxicity. FASEB J 14: 1233–1243,
2000.
48. Bird MM. Presynaptic and postsynaptic organelles of synapses
formed in cultures of previously dissociated mouse spinal cord.
Cell Tissue Res 194: 503–511, 1978.
49. Birnbaumer L, Yildirim E, Abramowitz J, and Yidirim E. A
comparison of the genes coding for canonical TRP channels and
their M, V and P relatives. Cell Calcium 33: 419 – 432, 2003.
50. Blaustein MP, McGraw CF, Somlyo AV, and Schweitzer ES.
How is the cytoplasmic calcium concentration controlled in nerve
terminals? J Physiol 76: 459 – 470, 1980.
51. Blaustein MP, Ratzlaff RW, Kendrick NC, and Schweitzer ES.
Calcium buffering in presynaptic nerve terminals. I. Evidence for
involvement of a nonmitochondrial ATP-dependent sequestration
mechanism. J Gen Physiol 72: 15– 41, 1978.
52. Blaustein MP, Ratzlaff RW, and Schweitzer ES. Calcium buffering in presynaptic nerve terminals. II. Kinetic properties of the
nonmitochondrial Ca sequestration mechanism. J Gen Physiol 72:
43– 66, 1978.
53. Bliss TV and Lomo T. Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following
stimulation of the perforant path. J Physiol 232: 331–356, 1973.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
14.
a calexcitin, ryanodine receptor, K⫹ channel cascade. Trends Neurosci 21: 529 –537, 1998.
Alonso MT, Barrero MJ, Carnicero E, Montero M, GarciaSancho J, and Alvarez J. Functional measurements of [Ca2⫹] in
the endoplasmic reticulum using a herpes virus to deliver targeted
aequorin. Cell Calcium 24: 87–96, 1998.
Alonso MT, Barrero MJ, Michelena P, Carnicero E, Cuchillo I,
Garcia AG, Garcia-Sancho J, Montero M, and Alvarez J. Ca2⫹induced Ca2⫹ release in chromaffin cells seen from inside the ER
with targeted aequorin. J Cell Biol 144: 241–254, 1999.
Alvarez J and Montero M. Measuring [Ca2⫹] in the endoplasmic
reticulum with aequorin. Cell Calcium 32: 251–260, 2002.
Alzheimer A. über eine eigenartige Erkrankung der Hirnrinde. Allg
Z Psychiat Psych-Gericht Med 64: 146 –148, 1907.
Aridor M and Balch WE. Integration of endoplasmic reticulum
signaling in health and disease. Nat Med 5: 745–751, 1999.
Arima J, Matsumoto N, Kishimoto K, and Akaike N. Spontaneous miniature outward currents in mechanically dissociated rat
Meynert neurons. J Physiol 534: 99 –107, 2001.
Ascoli GA, Luu KX, Olds JL, Nelson TJ, Gusev PA, Bertucci C,
Bramanti E, Raffaelli A, Salvadori P, and Alkon DL. Secondary
structure and Ca2⫹-induced conformational change of calexcitin, a
learning-associated protein. J Biol Chem 272: 24771–24779, 1997.
Ashley CC and Ridgway EB. On the relationships between membrane potential, calcium transient and tension in single barnacle
muscle fibers. J Physiol 209: 105–130, 1970.
Ayar A and Scott RH. The actions of ryanodine on Ca2⫹-activated
conductances in rat cultured DRG neurons; evidence for Ca2⫹induced Ca2⫹ release. Naunyn-Schmiedebergs Arch Pharmacol
359: 81–91, 1999.
Baba A, Yasui T, Fujisawa S, Yamada RX, Yamada MK, Nishiyama N, Matsuki N, and Ikegaya Y. Activity-evoked capacitative
Ca2⫹ entry: implications in synaptic plasticity. J Neurosci 23: 7737–
7741, 2003.
Baba-Aissa F, Raeymaekers L, Wuytack F, De Greef C, Missiaen L, and Casteels R. Distribution of the organellar Ca2⫹
transport ATPase SERCA2 isoforms in the cat brain. Brain Res 743:
141–153, 1996.
Bading H. Transcription-dependent neuronal plasticity the nuclear
calcium hypothesis. Eur J Biochem 267: 5280 –5283, 2000.
Bak J, White P, Timar G, Missiaen L, Genazzani AA, and
Galione A. Nicotinic acid adenine dinucleotide phosphate triggers
Ca2⫹ release from brain microsomes. Curr Biol 9: 751–754, 1999.
Baker PF and Schlaepfer WW. Uptake and binding of calcium by
axoplasm isolated from giant axons of Loligo and Myxicola.
J Physiol 276: 103–125, 1978.
Balkowiec A and Katz DM. Cellular mechanisms regulating activity-dependent release of native brain-derived neurotrophic factor from hippocampal neurons. J Neurosci 22: 10399 –10407, 2002.
Balschun D, Wolfer DP, Bertocchini F, Barone V, Conti A,
Zuschratter W, Missiaen L, Lipp HP, Frey JU, and Sorrentino
V. Deletion of the ryanodine receptor type 3 (RyR3) impairs forms
of synaptic plasticity and spatial learning. EMBO J 18: 5264 –5273,
1999.
Bando Y, Katayama T, Kasai K, Taniguchi M, Tamatani M, and
Tohyama M. GRP94 (94 kDa glucose-regulated protein) suppresses ischemic neuronal cell death against ischemia/reperfusion
injury. Eur J Neurosci 18: 829 – 840, 2003.
Barbara JG. IP3-dependent calcium-induced calcium release mediates bidirectional calcium waves in neurons: functional implications for synaptic plasticity. Biochim Biophys Acta 1600: 12–18,
2002.
Bardo S, Robertson B, and Stephens GJ. Presynaptic internal
Ca2⫹ stores contribute to inhibitory neurotransmitter release onto
mouse cerebellar Purkinje cells. Br J Pharmacol 137: 529 –537,
2002.
Barranger JA and Ginns EI. Glucosylceramide Lipidoses: Gaucher Disease. New York: McGraw Hill, 1989.
Barrett PJ. Extasy and dantrolene. Br Med J 305: 1225, 1992.
Barry VA and Cheek TR. A caffeine- and ryanodine-sensitive
intracellular Ca2⫹ store can act as a Ca2⫹ source and a Ca2⫹ sink
in PC12 cells. Biochem J 300: 589 –597, 1994.
263
264
ALEXEI VERKHRATSKY
Physiol Rev • VOL
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
ated with inositol 1,4,5-trisphosphate receptor modulates calcium
flux. Proc Natl Acad Sci USA 92: 1784 –1788, 1995.
Cancela JM, Charpentier G, and Petersen OH. Co-ordination of
Ca2⫹ signalling in mammalian cells by the new Ca2⫹-releasing
messenger NAADP. Pflügers Arch 446: 322–327, 2003.
Cancela JM and Petersen OH. Regulation of intracellular Ca2⫹
stores by multiple Ca2⫹-releasing messengers. Diabetes 51 Suppl 3:
S349 –S357, 2002.
Cancela JM, Van Coppenolle F, Galione A, Tepikin AV, and
Petersen OH. Transformation of local Ca2⫹ spikes to global Ca2⫹
transients: the combinatorial roles of multiple Ca2⫹ releasing messengers. EMBO J 21: 909 –919, 2002.
Carey MB and Matsumoto SG. Calcium transient activity in
cultured murine neural crest cells is regulated at the IP3 receptor.
Brain Res 862: 201–210, 2000.
Carlson GC, Slawecki ML, Lancaster E, and Keller A. Distribution and activation of intracellular Ca2⫹ stores in cultured olfactory bulb neurons. J Neurophysiol 78: 2176 –2185, 1997.
Carter AG, Vogt KE, Foster KA, and Regehr WG. Assessing the
role of calcium-induced calcium release in short-term presynaptic
plasticity at excitatory central synapses. J Neurosci 22: 21–28, 2002.
Case RM and Clausen T. The relationship between calcium exchange and enzyme secretion in the isolated rat pancreas. J Physiol
235: 75–102, 1973.
Castejon OJ and Apkarian RP. Conventional and high resolution
scanning electron microscopy of outer and inner surface features
of cerebellar nerve cells. J Submicrosc Cytol Pathol 24: 549 –562,
1992.
Castonguay A and Robitaille R. Differential regulation of transmitter release by presynaptic and glial Ca2⫹ internal stores at the
neuromuscular synapse. J Neurosci 21: 1911–1922, 2001.
Castonguay A and Robitaille R. Xestospongin C is a potent
inhibitor of SERCA at a vertebrate synapse. Cell Calcium 32:
39 – 47, 2002.
Cattaneo E. Dysfunction of wild-type huntingtin in Huntington
disease. News Physiol Sci 18: 34 –37, 2003.
Chameau P, Van de Vrede Y, Fossier P, and Baux G. Ryanodine-, IP3- and NAADP-dependent calcium stores control acetylcholine release. Pflügers Arch 443: 289 –296, 2001.
Chan SL, Culmsee C, Haughey N, Klapper W, and Mattson
MP. Presenilin-1 mutations sensitize neurons to DNA damageinduced death by a mechanism involving perturbed calcium homeostasis and activation of calpains and caspase-12. Neurobiol Dis
11: 2–19, 2002.
Chan SL, Mayne M, Holden CP, Geiger JD, and Mattson MP.
Presenilin-1 mutations increase levels of ryanodine receptors and
calcium release in PC12 cells and cortical neurons. J Biol Chem
275: 18195–18200, 2000.
Chao MV. The p75 neurotrophin receptor. J Neurobiol 25: 1373–
1385, 1994.
Chavis P, Fagni L, Lansman JB, and Bockaert J. Functional
coupling between ryanodine receptors and L-type calcium channels in neurons. Nature 382: 719 –722, 1996.
Chawla S. Regulation of gene expression by Ca2⫹ signals in neuronal cells. Eur J Pharmacol 447: 131–140, 2002.
Cheek TR, Moreton RB, Berridge MJ, Stauderman KA, Murawsky MM, and Bootman MD. Quantal Ca2⫹ release from caffeine-sensitive stores in adrenal chromaffin cells. J Biol Chem 268:
27076 –27083, 1993.
Chen SR, Li X, Ebisawa K, and Zhang L. Functional characterization of the recombinant type 3 Ca2⫹ release channel (ryanodine
receptor) expressed in HEK293 cells. J Biol Chem 272: 24234 –
24246, 1997.
Cheng G and Kendig JJ. Enflurane decreases glutamate neurotransmission to spinal cord motor neurons by both pre and
postsynaptic actions. Anesth Analg 96: 1354 –1359, 2003.
Cheng G and Kendig JJ. Pre- and postsynaptic volatile anaesthetic actions on glycinergic transmission to spinal cord motor
neurons. Br J Pharmacol 136: 673– 684, 2002.
Churchill GC, Okada Y, Thomas JM, Genazzani AA, Patel S,
and Galione A. NAADP mobilizes Ca2⫹ from reserve granules,
lysosome-related organelles, in sea urchin eggs. Cell 111: 703–708,
2002.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
54. Blocq P and Marinesco G. Sur les lesions et la pathogenie de
l’epilepsie dite eesentielle. Semaine Med 12: 445– 446, 1892.
55. Bootman MD, Collins TJ, Mackenzie L, Roderick HL, Berridge MJ, and Peppiatt CM. 2-Aminoethoxydiphenyl borate
(2-APB) is a reliable blocker of store-operated Ca2⫹ entry but an
inconsistent inhibitor of InsP3-induced Ca2⫹ release. FASEB J 16:
1145–1150, 2002.
56. Bootman MD, Collins TJ, Peppiatt CM, Prothero LS, MacKenzie L, De Smet P, Travers M, Tovey SC, Seo JT, Berridge
MJ, Ciccolini F, and Lipp P. Calcium signalling: an overview.
Semin Cell Dev Biol 12: 3–10, 2001.
57. Bootman MD, Petersen OH, and Verkhratsky A. The endoplasmic reticulum is a focal point for co-ordination of cellular activity.
Cell Calcium 32: 231–234, 2002.
58. Borde M, Bonansco C, de Sevilla F, Le Ray D, and Buno W.
Voltage-clamp analysis of the potentiation of the slow Ca2⫹-activated K⫹ current in hippocampal pyramidal neurons. Hippocampus 10: 198 –206, 2000.
59. Bouchard R, Pattarini R, and Geiger JD. Presence and functional significance of presynaptic ryanodine receptors. Prog Neurobiol 69: 391– 418, 2003.
60. Bouron A. Activation of a capacitative Ca2⫹ entry pathway by
store depletion in cultured hippocampal neurons. FEBS Lett 470:
269 –272, 2000.
61. Bowden SE, Selyanko AA, and Robbins J. The role of ryanodine
receptors in the cyclic ADP ribose modulation of the M-like current
in rodent m1 muscarinic receptor-transformed NG108 –15 cells.
J Physiol 519: 23–34, 1999.
62. Brain KL and Bennett MR. Calcium in sympathetic varicosities of
mouse vas deferens during facilitation, augmentation and autoinhibition. J Physiol 502: 521–536, 1997.
63. Brain KL, Trout SJ, Jackson VM, Dass N, and Cunnane TC.
Nicotine induces calcium spikes in single nerve terminal varicosities: a role for intracellular calcium stores. Neuroscience 106: 395–
403, 2001.
64. Brinley FJ Jr, Tiffert T, and Scarpa A. Mitochondria and other
calcium buffers of squid axon studied in situ. J Gen Physiol 72:
101–127, 1978.
65. Brostrom MA and Brostrom CO. Calcium dynamics and endoplasmic reticular function in the regulation of protein synthesis:
implications for cell growth and adaptability. Cell Calcium 34:
345–363, 2003.
66. Brown GR, Sayers LG, Kirk CJ, Michell RH, and Michelangeli
F. The opening of the inositol 1,4,5-trisphosphate-sensitive Ca2⫹
channel in rat cerebellum is inhibited by caffeine. Biochem J 282:
309 –312, 1992.
67. Buck E, Zimanyi I, Abramson JJ, and Pessah IN. Ryanodine
stabilizes multiple conformational states of the skeletal muscle
calcium release channel. J Biol Chem 267: 23560 –23567, 1992.
68. Budde T, Sieg F, Braunewell KH, Gundelfinger ED, and Pape
HC. Ca2⫹-induced Ca2⫹ release supports the relay mode of activity
in thalamocortical cells. Neuron 26: 483– 492, 2000.
69. Buxbaum JD, Choi EK, Luo Y, Lilliehook C, Crowley AC,
Merriam DE, and Wasco W. Calsenilin: a calcium-binding protein
that interacts with the presenilins and regulates the levels of a
presenilin fragment. Nat Med 4: 1177–1181, 1998.
70. Cadiou H and Molle G. Adenophostin A and imipramine are two
activators of the olfactory inositol 1,4,5-trisphosphate-gated channel in fish olfatory cilia. Eur Biophys J 32: 106 –112, 2003.
71. Caillard O, Ben-Ari Y, and Gaiarsa JL. Activation of presynaptic
and postsynaptic ryanodine-sensitive calcium stores is required for
the induction of long-term depression at GABAergic synapses in
the neonatal rat hippocampus amphetamine. J Neurosci 20: 91–95,
2000.
72. Camello C, Lomax R, Petersen OH, and Tepikin AV. Calcium
leak from intracellular stores—the enigma of calcium signalling.
Cell Calcium 32: 355–361, 2002.
73. Cameron AM, Steiner JP, Roskams AJ, Ali SM, Ronnett GV,
and Snyder SH. Calcineurin associated with the inositol 1,4,5trisphosphate receptor-FKBP12 complex modulates Ca2⫹ flux. Cell
83: 463– 472, 1995.
74. Cameron AM, Steiner JP, Sabatini DM, Kaplin AI, Walensky
LD, and Snyder SH. Immunophilin FK506 binding protein associ-
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
118.
119.
120.
121.
122.
123.
124.
125.
126.
127.
128.
129.
130.
131.
132.
133.
134.
135.
136.
ulum is missing in dendritic spines of Purkinje cells of the ataxic
mutant rat. Brain Res 714: 226 –230, 1996.
Del Castillo J and Stark L. The effect of calcium ions on the
motor end-plate potentials. J Physiol 116: 507–515, 1952.
Del Rio E, McLaughlin M, Downes CP, and Nicholls DG. Differential coupling of G-protein-linked receptors to Ca2⫹ mobilization through inositol(1,4,5)trisphosphate or ryanodine receptors in
cerebellar granule cells in primary culture. Eur J Neurosci 11:
3015–3022, 1999.
Demaurex N and Frieden M. Measurements of the free luminal
ER Ca2⫹ concentration with targeted “cameleon” fluorescent proteins. Cell Calcium 34: 109 –119, 2003.
De Meis L. Ca2⫹-ATPases (SERCA): energy transduction and heat
production in transport ATPases. J Membr Biol 188: 1–9, 2002.
Dent MA, Raisman G, and Lai FA. Expression of type 1 inositol
1,4,5-trisphosphate receptor during axogenesis and synaptic contact in the central and peripheral nervous system of developing rat.
Development 122: 1029 –1039, 1996.
De Smet P, Parys JB, Callewaert G, Weidema AF, Hill E, De
Smedt H, Erneux C, Sorrentino V, and Missiaen L. Xestospongin C is an equally potent inhibitor of the inositol 1,4,5-trisphosphate receptor and the endoplasmic-reticulum Ca2⫹ pumps. Cell
Calcium 26: 9 –13, 1999.
De Strooper B, Annaert W, Cupers P, Saftig P, Craessaerts K,
Mumm JS, Schroeter EH, Schrijvers V, Wolfe MS, Ray WJ,
Goate A, and Kopan R. A presenilin-1-dependent gamma-secretase-like protease mediates release of Notch intracellular domain.
Nature 398: 518 –522, 1999.
Diaz-Munoz M, Dent MA, Granados-Fuentes D, Hall AC, Hernandez-Cruz A, Harrington ME, and Aguilar-Roblero R. Circadian modulation of the ryanodine receptor type 2 in the SCN of
rodents. Neuroreport 10: 481– 486, 1999.
Ding JM, Buchanan GF, Tischkau SA, Chen D, Kuriashkina L,
Faiman LE, Alster JM, McPherson PS, Campbell KP, and
Gillette MU. A neuronal ryanodine receptor mediates light-induced phase delays of the circadian clock. Nature 394: 381–384,
1998.
Donato R, Canepari M, Lape R, and Nistri A. Effects of caffeine
on the excitability and intracellular Ca2⫹ transients of neonatal rat
hypoglossal motoneurons in vitro. Neurosci Lett 346: 177–181,
2003.
Donoso P and Hidalgo C. pH-sensitive calcium release in triads
from frog skeletal muscle. Rapid filtration studies. J Biol Chem 268:
25432–25438, 1993.
Doutheil J, Gissel C, Oschlies U, Hossmann KA, and Paschen
W. Relation of neuronal endoplasmic reticulum calcium homeostasis to ribosomal aggregation and protein synthesis: implications for
stress-induced suppression of protein synthesis. Brain Res 775:
43–51, 1997.
Droz B, Koenig HL, Di Giamberardino L, Couraud JY, Chretien M, and Souyri F. The importance of axonal transport and
endoplasmic reticulum in the function of cholinergic synapse in
normal and pathological conditions. Prog Brain Res 49: 23– 44,
1979.
Droz B, Rambourg A, and Koenig HL. The smooth endoplasmic
reticulum: structure and role in the renewal of axonal membrane
and synaptic vesicles by fast axonal transport. Brain Res 93: 1–13,
1975.
Dubinsky JM and Rothman SM. Intracellular calcium concentrations during “chemical hypoxia” and excitotoxic neuronal injury.
J Neurosci 11: 2545–2551, 1991.
Dyer JL and Michelangeli F. Inositol 1,4,5-trisphosphate receptor
isoforms show similar Ca2⫹ release kinetics. Cell Calcium 30:
245–250, 2001.
East JM. Sarco(endo)plasmic reticulum calcium pumps: recent
advances in our understanding of structure/function and biology.
Mol Membr Biol 17: 189 –200, 2000.
Ehrlich BE, Kaftan E, Bezprozvannaya S, and Bezprozvanny
I. The pharmacology of intracellular Ca2⫹-release channels. Trends
Pharmacol Sci 15: 145–149, 1994.
Ekerot CF and Kano M. Long-term depression of parallel fibre
synapses following stimulation of climbing fibres. Brain Res 342:
357–360, 1985.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
97. Cibulsky SM and Sather WA. Block by ruthenium red of cloned
neuronal voltage-gated calcium channels. J Pharmacol Exp Ther
289: 1447–1453, 1999.
98. Cifuentes F, Gonzalez CE, Fiordelisio T, Guerrero G, Lai FA,
and Hernandez-Cruz A. A ryanodine fluorescent derivative reveals the presence of high-affinity ryanodine binding sites in the
Golgi complex of rat sympathetic neurons, with possible functional
roles in intracellular Ca2⫹ signaling. Cell Signal 13: 353–362, 2001.
99. Clapper DL, Walseth TF, Dargie PJ, and Lee HC. Pyridine
nucleotide metabolites stimulate calcium release from sea urchin
egg microsomes desensitized to inositol trisphosphate. J Biol
Chem 262: 9561–9568, 1987.
100. Clementi E, Riccio M, Sciorati C, Nistico G, and Meldolesi J.
The type 2 ryanodine receptor of neurosecretory PC12 cells is
activated by cyclic ADP-ribose. Role of the nitric oxide/cGMP
pathway. J Biol Chem 271: 17739 –17745, 1996.
101. Clodfelter GV, Porter NM, Landfield PW, and Thibault O.
Sustained Ca2⫹-induced Ca2⫹-release underlies the post-glutamate
lethal Ca2⫹ plateau in older cultured hippocampal neurons. Eur
J Pharmacol 447: 189 –200, 2002.
102. Cochilla AJ and Alford S. Metabotropic glutamate receptormediated control of neurotransmitter release. Neuron 20: 1007–
1016, 1998.
103. Cohen AS, Moore KA, Bangalore R, Jafri MS, Weinreich D,
and Kao JP. Ca2⫹-induced Ca2⫹ release mediates Ca2⫹ transients
evoked by single action potentials in rabbit vagal afferent neurones. J Physiol 499: 315–328, 1997.
104. Conquet F, Bashir ZI, Davies CH, Daniel H, Ferraguti F, Bordi
F, Franz-Bacon K, Reggiani A, Matarese V, and Conde F.
Motor deficit and impairment of synaptic plasticity in mice lacking
mGluR1. Nature 372: 237–243, 1994.
105. Conti R, Tan YP, and Llano I. Action potential-evoked and ryanodine-sensitive spontaneous Ca2⫹ transients at the presynaptic
terminal of a developing CNS inhibitory synapse. J Neurosci 24:
6946 – 6957, 2004.
106. Corbett EF and Michalak M. Calcium, a signaling molecule in the
endoplasmic reticulum? Trends Biochem Sci 25: 307–311, 2000.
107. Cordoba-Rodriguez R, Moore KA, Kao JP, and Weinreich D.
Calcium regulation of a slow post-spike hyperpolarization in vagal
afferent neurons. Proc Natl Acad Sci USA 96: 7650 –7657, 1999.
108. Corns RA, Boolaky UV, and Santer RM. Decreased calbindinD28k immunoreactivity in aged rat sympathetic pelvic ganglionic
neurons. Neurosci Lett 292: 91–94, 2000.
109. Crawford JH, Wootton JF, Seabrook GR, and Scott RH. Activation of Ca2⫹-dependent currents in dorsal root ganglion neurons
by metabotropic glutamate receptors and cyclic ADP-ribose precursors. J Neurophysiol 77: 2573–2584, 1997.
110. Cseresnyes Z, Bustamante AI, Klein MG, and Schneider MF.
Release-activated Ca2⫹ transport in neurons of frog sympathetic
ganglia. Neuron 19: 403– 419, 1997.
111. Cseresnyes Z, Bustamante AI, and Schneider MF. Caffeineinduced [Ca2⫹] oscillations in neurones of frog sympathetic ganglia. J Physiol 514: 83–99, 1999.
112. Cseresnyes Z and Schneider MF. Peripheral hot spots for local
Ca2⫹ release after single action potentials in sympathetic ganglion
neurons. Biophys J 86: 163–181, 2004.
113. Dargan SL, Lea EJ, and Dawson AP. Modulation of type-1
Ins(1,4,5)P3 receptor channels by the FK506-binding protein,
FKBP12. Biochem J 361: 401– 407, 2002.
114. Davies PJ, Ireland DR, and McLachlan EM. Sources of Ca2⫹ for
different Ca2⫹-activated K⫹ conductances in neurones of the rat
superior cervical ganglion. J Physiol 495: 353–366, 1996.
115. Dayel MJ, Hom EF, and Verkman AS. Diffusion of green fluorescent protein in the aqueous-phase lumen of endoplasmic reticulum. Biophys J 76: 2843–2851, 1999.
116. De Crescenzo V, ZhuGe R, Velazquez-Marrero C, Lifshitz LM,
Custer E, Carmichael J, Lai FA, Tuft RA, Fogarty KE, Lemos
JR, and Walsh JV Jr. Ca2⫹ syntillas, miniature Ca2⫹ release
events in terminals of hypothalamic neurons, are increased in
frequency by depolarization in the absence of Ca2⫹ influx. J Neurosci 24: 1226 –1235, 2004.
117. Dekker-Ohno K, Hayasaka S, Takagishi Y, Oda S, Wakasugi N,
Mikoshiba K, Inouye M, and Yamamura H. Endoplasmic retic-
265
266
ALEXEI VERKHRATSKY
Physiol Rev • VOL
161. Franzini-Armstrong C and Protasi F. Ryanodine receptors of
striated muscles: a complex channel capable of multiple interactions. Physiol Rev 77: 699 –729, 1997.
162. Freedman JE and Aghajanian GK. Role of phosphoinositide
metabolites in the prolongation of afterhyperpolarizations by alpha
1-adrenoceptors in rat dorsal raphe neurons. J Neurosci 7: 3897–
3906, 1987.
163. Frenguelli BG, Potier B, Slater NT, Alford S, and Collingridge
GL. Metabotropic glutamate receptors and calcium signalling in
dendrites of hippocampal CA1 neurones. Neuropharmacology 32:
1229 –1237, 1993.
164. Friel DD. Calcium oscillations in neurons. Ciba Found Symp 188:
210 –234, 1995.
165. Friel DD and Tsien RW. A caffeine- and ryanodine-sensitive Ca2⫹
store in bullfrog sympathetic neurones modulates effects of Ca2⫹
entry on [Ca2⫹]i. J Physiol 450: 217–246, 1992.
166. Friel DD and Tsien RW. Phase-dependent contributions from
Ca2⫹ entry and Ca2⫹ release to caffeine-induced [Ca2⫹]i oscillations in bullfrog sympathetic neurons. Neuron 8: 1109 –1125, 1992.
167. Fruen BR, Mickelson JR, and Louis CF. Dantrolene inhibition of
sarcoplasmic reticulum Ca2⫹ release by direct and specific action
at skeletal muscle ryanodine receptors. J Biol Chem 272: 26965–
26971, 1997.
168. Fujii S, Matsumoto M, Igarashi K, Kato H, and Mikoshiba K.
Synaptic plasticity in hippocampal CA1 neurons of mice lacking
type 1 inositol-1,4,5-trisphosphate receptors. Learn Mem 7: 312–
320, 2000.
169. Fujiwara A, Hirose K, Yamazawa T, and Iino M. Reduced IP3
sensitivity of IP3 receptor in Purkinje neurons. Neuroreport 12:
2647–2651, 2001.
170. Furuichi T, Furutama D, Hakamata Y, Nakai J, Takeshima H,
and Mikoshiba K. Multiple types of ryanodine receptor/Ca2⫹ release channels are differentially expressed in rabbit brain. J Neurosci 14: 4794 – 4805, 1994.
171. Furuichi T, Simon-Chazottes D, Fujino I, Yamada N, Hasegawa M, Miyawaki A, Yoshikawa S, Guenet JL, and Mikoshiba
K. Widespread expression of inositol 1,4,5-trisphosphate receptor
type 1 gene (Insp3r1) in the mouse central nervous system. Receptors Channels 1: 11–24, 1993.
172. Furuichi T, Yoshikawa S, Miyawaki A, Wada K, Maeda N, and
Mikoshiba K. Primary structure and functional expression of the
inositol 1,4,5-trisphosphate-binding protein P400. Nature 342: 32–
38, 1989.
173. Futatsugi A, Kato K, Ogura H, Li ST, Nagata E, Kuwajima G,
Tanaka K, Itohara S, and Mikoshiba K. Facilitation of NMDARindependent LTP and spatial learning in mutant mice lacking ryanodine receptor type 3. Neuron 24: 701–713, 1999.
174. Gafni J, Munsch JA, Lam TH, Catlin MC, Costa LG, Molinski
TF, and Pessah IN. Xestospongins: potent membrane permeable
blockers of the inositol 1,4,5-trisphosphate receptor. Neuron 19:
723–733, 1997.
175. Galante M and Marty A. Presynaptic ryanodine-sensitive calcium
stores contribute to evoked neurotransmitter release at the basket
cell-Purkinje cell synapse. J Neurosci 23: 11229 –11234, 2003.
176. Galione A. Cyclic ADP-ribose: a new way to control calcium.
Science 259: 325–326, 1993.
177. Galione A and Churchill GC. Interactions between calcium release pathways: multiple messengers and multiple stores. Cell Calcium 32: 343–354, 2002.
178. Galvani L and Aldini J. De viribus electricitatisin motu miscularicommentarius. Apud Societatem Typographicam. Translated
in Abhandlung über die Kräfte der Electricität bei der Muskelbewegung. Leipzig: Engelmann, 1894.
179. Garaschuk O, Yaari Y, and Konnerth A. Release and sequestration of calcium by ryanodine-sensitive stores in rat hippocampal
neurones. J Physiol 502: 13–30, 1997.
180. Gardiol A, Racca C, and Triller A. Dendritic and postsynaptic
protein synthetic machinery. J Neurosci 19: 168 –179, 1999.
181. Genazzani AA, Carafoli E, and Guerini D. Calcineurin controls
inositol 1,4,5-trisphosphate type 1 receptor expression in neurons.
Proc Natl Acad Sci USA 96: 5797–5801, 1999.
182. Gerasimenko JV, Maruyama Y, Yano K, Dolman NJ, Tepikin
AV, Petersen OH, and Gerasimenko OV. NAADP mobilizes Ca2⫹
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
137. Empson RM and Galione A. Cyclic ADP-ribose enhances coupling between voltage-gated Ca2⫹ entry and intracellular Ca2⫹ release. J Biol Chem 272: 20967–20970, 1997.
138. Emptage N, Bliss TV, and Fine A. Single synaptic events evoke
NMDA receptor-mediated release of calcium from internal stores in
hippocampal dendritic spines. Neuron 22: 115–124, 1999.
139. Emptage NJ, Reid CA, and Fine A. Calcium stores in hippocampal synaptic boutons mediate short-term plasticity, store-operated
Ca2⫹ entry, and spontaneous transmitter release. Neuron 29: 197–
208, 2001.
140. Endo M, Tanaka M, and Ogawa Y. Calcium induced release of
calcium from the sarcoplasmic reticulum of skinned skeletal muscle fibres. Nature 228: 34 –36, 1970.
141. Erulkar SD and Rahamimoff R. The role of calcium ions in
tetanic and post-tetanic increase of miniature end-plate potential
frequency. J Physiol 278: 501–511, 1978.
142. Etcheberrigaray R, Hirashima N, Nee L, Prince J, Govoni S,
Racchi M, Tanzi RE, and Alkon DL. Calcium responses in fibroblasts from asymptomatic members of Alzheimer’s disease families. Neurobiol Dis 5: 37– 45, 1998.
143. Eu JP, Xu L, Stamler JS, and Meissner G. Regulation of ryanodine receptors by reactive nitrogen species. Biochem Pharmacol
57: 1079 –1084, 1999.
144. Eun SY, Jung SJ, Park YK, Kwak J, Kim SJ, and Kim J. Effects
of capsaicin on Ca2⫹ release from the intracellular Ca2⫹ stores in
the dorsal root ganglion cells of adult rats. Biochem Biophys Res
Commun 285: 1114 –1120, 2001.
145. Fagni L, Chavis P, Ango F, and Bockaert J. Complex interactions between mGluRs, intracellular Ca2⫹ stores and ion channels
in neurons. Trends Neurosci 23: 80 – 88, 2000.
146. Fatt P and Katz B. Spontaneous subthreshold activity at motor
nerve endings. J Physiol 117: 109 –128, 1952.
147. Ferrari D, Pinton P, Szabadkai G, Chami M, Campanella M,
Pozzan T, and Rizzuto R. Endoplasmic reticulum, Bcl-2 and Ca2⫹
handling in apoptosis. Cell Calcium 32: 413– 420, 2002.
148. Fill M and Copello JA. Ryanodine receptor calcium release channels. Physiol Rev 82: 893–922, 2002.
149. Fill M, Zahradnikova A, Villalba-Galea CA, Zahradnik I, Escobar AL, and Gyorke S. Ryanodine receptor adaptation. J Gen
Physiol 116: 873– 882, 2000.
150. Finch EA and Augustine GJ. Local calcium signalling by inositol1,4,5-trisphosphate in Purkinje cell dendrites. Nature 396: 753–756,
1998.
151. Fink LA, Connor JA, and Kaczmarek LK. Inositol trisphosphate
releases intracellularly stored calcium and modulates ion channels
in molluscan neurons. J Neurosci 8: 2544 –2555, 1988.
152. Finkbeiner S and Greenberg ME. Spatial features of calciumregulated gene expression. Bioessays 19: 657– 660, 1997.
153. Fischer O. Miliäre Nekrosen mit drusigen Wucherungen der Neurofibrillen, eine regelmässige Veränderung der Hirnrinde bei seniler
Demenz. Monatschrift Psychiatr Neurol 22: 361–372, 1907.
154. Fitzjohn SM and Collingridge GL. Calcium stores and synaptic
plasticity. Cell Calcium 32: 405– 411, 2002.
155. Forman MS, Lee VM, and Trojanowski JQ. “Unfolding” pathways in neurodegenerative disease. Trends Neurosci 26: 407– 410,
2003.
156. Foster TC and Norris CM. Age-associated changes in Ca2⫹dependent processes: relationship to hippocampal synaptic plasticity. Hippocampus 7: 602– 612, 1997.
157. Franks JJ, Wamil AW, Janicki PK, Horn JL, Franks WT,
Janson VE, Vanaman TC, and Brandt PC. Anesthetic-induced
alteration of Ca2⫹ homeostasis in neural cells: a temperaturesensitive process that is enhanced by blockade of plasma membrane Ca2⫹-ATPase isoforms. Anesthesiology 89: 149 –164, 1998.
158. Franzini-Armstrong C. Pores in the sarcoplasmic reticulum.
J Cell Biol 19: 637– 641, 1963.
159. Franzini-Armstrong C. Annemarie Weber: Ca2⫹ and the regulation of muscle contraction. Trends Cell Biol 8: 251–253, 1998.
160. Franzini-Armstrong C and Jorgensen AO. Structure and development of E-C coupling units in skeletal muscle. Annu Rev Physiol
56: 509 –534, 1994.
CALCIUM STORE IN THE ER OF NEURONS
183.
184.
185.
186.
187.
189.
190.
191.
192.
193.
194.
195.
196.
197.
198.
199.
200.
201.
202.
203.
Physiol Rev • VOL
204. Hashii M, Minabe Y, and Higashida H. cADP-ribose potentiates
cytosolic Ca2⫹ elevation and Ca2⫹ entry via L-type voltage-activated Ca2⫹ channels in NG108 –15 neuronal cells. Biochem J 345:
207–215, 2000.
205. Hattori Y, Shibuya I, Tanaka K, Kabashima N, Ueta Y, and
Yamashita H. Ionotropic and metabotropic glutamate receptor
agonist-induced [Ca2⫹]i increase in isolated rat supraoptic neurons.
J Neuroendocrinol 10: 383–389, 1998.
206. Haynes LP, Tepikin AV, and Burgoyne RD. Calcium-binding
protein 1 is an inhibitor of agonist-evoked, inositol 1,4,5-trisphosphate-mediated calcium signaling. J Biol Chem 279: 547–555, 2004.
207. He LM, Chen LY, Lou XL, Qu AL, Zhou Z, and Xu T. Evaluation
of beta-amyloid peptide 25–35 on calcium homeostasis in cultured
rat dorsal root ganglion neurons. Brain Res 939: 65–75, 2002.
208. He X, Yang F, Xie Z, and Lu B. Intracellular Ca2⫹ and Ca2⫹/
calmodulin-dependent kinase II mediate acute potentiation of neurotransmitter release by neurotrophin-3. J Cell Biol 149: 783–792,
2000.
209. Hegde RS and Lingappa VR. Regulation of protein biogenesis at
the endoplasmic reticulum membrane. Trends Cell Biol 9: 132–137,
1999.
210. Heilbrunn LV. An Outline of General Physiology. Philadelphia,
PA: Saunders, 1943.
211. Heilbrunn LV and Wiercinsky FJ. Action of various cations on
muscle protoplasm. J Cell Comp Physiol 19: 15–32, 1947.
212. Henkart M. Identification and function of intracellular calcium
stores in axons and cell bodies of neurons. Federation Proc 39:
2783–2789, 1980.
213. Henkart M. Identification and function of intracellular calcium
stores in neurons. Federation Proc 39: 2776 –2777, 1980.
214. Henkart MP, Reese TS, and Brinley FJ Jr. Endoplasmic reticulum sequesters calcium in the squid giant axon. Science 202:
1300 –1303, 1978.
215. Henze DA, McMahon DB, Harris KM, and Barrionuevo G.
Giant miniature EPSCs at the hippocampal mossy fiber to CA3
pyramidal cell synapse are monoquantal. J Neurophysiol 87: 15–29,
2002.
216. Henzi V and MacDermott AB. Characteristics and function of
Ca2⫹- and inositol 1,4,5-trisphosphate-releasable stores of Ca2⫹ in
neurons. Neuroscience 46: 251–273, 1992.
217. Herbette L, Messineo FC, and Katz AM. The interaction of
drugs with the sarcoplasmic reticulum. Annu Rev Pharmacol Toxicol 22: 413– 434, 1982.
218. Herculano-Houzel S, Munk MH, Neuenschwander S, and
Singer W. Precisely synchronized oscillatory firing patterns require electroencephalographic activation. J Neurosci 19: 3992–
4010, 1999.
219. Hermann A and Hartung K. Ca2⫹ activated K⫹ conductance in
molluscan neurones. Cell Calcium 4: 387– 405, 1983.
220. Herms J, Schneider I, Dewachter I, Caluwaerts N,
Kretzschmar H, and Van Leuven F. Capacitive calcium entry is
directly attenuated by mutant presenilin-1, independent of the expression of the amyloid precursor protein. J Biol Chem 278: 2484 –
2489, 2003.
221. Hernandez-Cruz A, Diaz-Munoz M, Gomez-Chavarin M,
Canedo-Merino R, Protti DA, Escobar AL, Sierralta J, and
Suarez-Isla BA. Properties of the ryanodine-sensitive release
channels that underlie caffeine-induced Ca2⫹ mobilization from
intracellular stores in mammalian sympathetic neurons. Eur J Neurosci 7: 1684 –1699, 1995.
222. Hernandez-Cruz A, Escobar AL, and Jimenez N. Ca2⫹-induced
Ca2⫹ release phenomena in mammalian sympathetic neurons are
critically dependent on the rate of rise of trigger Ca2⫹. J Gen
Physiol 109: 147–167, 1997.
223. Higashida H and Brown DA. Membrane current responses to
intracellular injections of inositol 1,3,4,5-tetrakisphosphate and
inositol 1,3,4-trisphosphate in NG108 –15 hybrid cells. FEBS Lett
208: 283–286, 1986.
224. Higashida H, Hashii M, Yokoyama S, Hoshi N, Asai K, and
Kato T. Cyclic ADP-ribose as a potential second messenger for
neuronal Ca2⫹ signaling. J Neurochem 76: 321–331, 2001.
225. Higashida H, Yokoyama S, Hashii M, Taketo M, Higashida M,
Takayasu T, Ohshima T, Takasawa S, Okamoto H, and Noda
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
188.
from a thapsigargin-sensitive store in the nuclear envelope by
activating ryanodine receptors. J Cell Biol 163: 271–282, 2003.
Ghosh A, Ginty DD, Bading H, and Greenberg ME. Calcium
regulation of gene expression in neuronal cells. J Neurobiol 25:
294 –303, 1994.
Ghosh A and Greenberg ME. Calcium signaling in neurons: molecular mechanisms and cellular consequences. Science 268: 239 –
247, 1995.
Giannini G, Conti A, Mammarella S, Scrobogna M, and Sorrentino V. The ryanodine receptor/calcium channel genes are
widely and differentially expressed in murine brain and peripheral
tissues. J Cell Biol 128: 893–904, 1995.
Gibson GE, Zhang H, Toral-Barza L, Szolosi S, and TofelGrehl B. Calcium stores in cultured fibroblasts and their changes
with Alzheimer’s disease. Biochim Biophys Acta 1316: 71–77, 1996.
Golgi C. Intorno alla struttura della cellule nervose. Bollettino
della Societa medico-chirurgica di Pavia 13: 1–14, 1898.
Golgi C. Opera Omnia (Volumes I–III). Milano: Hoepli Editore,
1903.
Gomez RS, Guatimosim C, Barbosa J Jr, Massensini AR, Gomez MV, and Prado MA. Halothane-induced intracellular calcium
release in cholinergic cells. Brain Res 921: 106 –114, 2001.
Gomez TM and Spitzer NC. In vivo regulation of axon extension
and pathfinding by growth-cone calcium transients. Nature 397:
350 –355, 1999.
Gotz J. Tau and transgenic animal models. Brain Res 35: 266 –286,
2001.
Grondahl TO, Hablitz JJ, and Langmoen IA. Depletion of intracellular Ca2⫹ stores or lowering extracellular calcium alters
intracellular Ca2⫹ changes during cerebral energy deprivation.
Brain Res 796: 125–131, 1998.
Gruol DL, Netzeband JG, and Parsons KL. Ca2⫹ signaling pathways linked to glutamate receptor activation in the somatic and
dendritic regions of cultured cerebellar Purkinje neurons. J Neurophysiol 76: 3325–3340, 1996.
Guler AD, Lee H, Iida T, Shimizu I, Tominaga M, and Caterina
M. Heat-evoked activation of the ion channel, TRPV4. J Neurosci
22: 6408 – 6414, 2002.
Guo Q, Fu W, Sopher BL, Miller MW, Ware CB, Martin GM,
and Mattson MP. Increased vulnerability of hippocampal neurons
to excitotoxic necrosis in presenilin-1 mutant knock-in mice. Nat
Med 5: 101–106, 1999.
Guo Q, Furukawa K, Sopher BL, Pham DG, Xie J, Robinson N,
Martin GM, and Mattson MP. Alzheimer’s PS-1 mutation perturbs calcium homeostasis and sensitizes PC12 cells to death induced by amyloid beta-peptide. Neuroreport 8: 379 –383, 1996.
Guo Q, Sopher BL, Furukawa K, Pham DG, Robinson N, Martin GM, and Mattson MP. Alzheimer’s presenilin mutation sensitizes neural cells to apoptosis induced by trophic factor withdrawal
and amyloid beta-peptide: involvement of calcium and oxyradicals.
J Neurosci 17: 4212– 4222, 1997.
Hagar RE, Burgstahler AD, Nathanson MH, and Ehrlich BE.
Type III InsP3 receptor channel stays open in the presence of
increased calcium. Nature 396: 81– 84, 1998.
Hamada T, Liou SY, Fukushima T, Maruyama T, Watanabe S,
Mikoshiba K, and Ishida N. The role of inositol trisphosphateinduced Ca2⫹ release from IP3-receptor in the rat suprachiasmatic
nucleus on circadian entrainment mechanism. Neurosci Lett 263:
125–128, 1999.
Hamill OP, Marty A, Neher E, Sakmann B, and Sigworth FJ.
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflügers Arch
391: 85–100, 1981.
Hardingham GE, Arnold FJ, and Bading H. Nuclear calcium
signaling controls CREB-mediated gene expression triggered by
synaptic activity. Nat Neurosci 4: 261–267, 2001.
Hartmann J and Verkhratsky A. Relations between intracellular
Ca2⫹ stores and store-operated Ca2⫹ entry in primary cultured
human glioblastoma cells. J Physiol 513: 411– 424, 1998.
Hartter DE, Burton PR, and Laveri LA. Distribution and calcium-sequestering ability of smooth endoplasmic reticulum in olfactory axon terminals of frog brain. Neuroscience 23: 371–386, 1987.
267
268
226.
227.
228.
229.
230.
232.
233.
234.
235.
236.
237.
238.
239.
240.
241.
242.
243.
244.
M. Muscarinic receptor-mediated dual regulation of ADP-ribosyl
cyclase in NG108 –15 neuronal cell membranes. J Biol Chem 272:
31272–31277, 1997.
Higure Y and Nohmi M. Repetitive application of caffeine sensitizes caffeine-induced Ca2⫹ release in bullfrog sympathetic ganglion neurons. Brain Res 954: 141–150, 2002.
Hillsley K, Kenyon JL, and Smith TK. Ryanodine-sensitive
stores regulate the excitability of AH neurons in the myenteric
plexus of guinea-pig ileum. J Neurophysiol 84: 2777–2785, 2000.
Hirose K, Iino M, and Endo M. Caffeine inhibits Ca2⫹-mediated
potentiation of inositol 1,4,5-trisphosphate-induced Ca2⫹ release in
permeabilized vascular smooth muscle cells. Biochem Biophys Res
Commun 194: 726 –732, 1993.
Hoesch RE, Weinreich D, and Kao JP. A novel Ca2⫹ influx
pathway in mammalian primary sensory neurons is activated by
caffeine. J Neurophysiol 86: 190 –196, 2001.
Hoesch RE, Yienger K, Weinreich D, and Kao JP. Coexistence
of functional IP3 and ryanodine receptors in vagal sensory neurons
and their activation by ATP. J Neurophysiol 88: 1212–1219, 2002.
Hofer AM, Landolfi B, Debellis L, Pozzan T, and Curci S. Free
[Ca2⫹] dynamics measured in agonist-sensitive stores of single
living intact cells: a new look at the refilling process. EMBO J 17:
1986 –1995, 1998.
Hofer AM and Machen TE. Technique for in situ measurement of
calcium in intracellular inositol 1,4,5-trisphosphate-sensitive stores
using the fluorescent indicator mag-fura-2. Proc Natl Acad Sci USA
90: 2598 –2602, 1993.
Hong K, Nishiyama M, Henley J, Tessier-Lavigne M, and Poo
M. Calcium signalling in the guidance of nerve growth by netrin-1.
Nature 403: 93–98, 2000.
Hongpaisan J, Pivovarova NB, Colegrove SL, Leapman RD,
Friel DD, and Andrews SB. Multiple modes of calcium-induced
calcium release in sympathetic neurons. II. A [Ca2⫹]- and locationdependent transition from endoplasmic reticulum Ca accumulation
to net Ca release. J Gen Physiol 118: 101–112, 2001.
Honore B and Vorum H. The CREC family, a novel family of
multiple EF-hand, low-affinity Ca2⫹-binding proteins localised to
the secretory pathway of mammalian cells. FEBS Lett 466: 11–18,
2000.
Hoole S. The select works of Antony Van Leeuwenhoek, containing his microscopical discoveries in many of the works of nature.
In: On the Nature of Minute Fibres Which Compose the Fleshy
Parts of Several Animals, and Also of Fishes and Insects. London:
Henry Fry, 1798, vol. 2, p. 113–120.
Horton AC and Ehlers MD. Dual modes of endoplasmic reticulum-to-Golgi transport in dendrites revealed by live-cell imaging.
J Neurosci 23: 6188 – 6199, 2003.
Horton AC and Ehlers MD. Neuronal polarity and trafficking.
Neuron 40: 277–295, 2003.
Howard AS, Fitzpatrick R, Pessah I, Kostyniak P, and Lein
PJ. Polychlorinated biphenyls induce caspase-dependent cell
death in cultured embryonic rat hippocampal but not cortical neurons via activation of the ryanodine receptor. Toxicol Appl Pharmacol 190: 72– 86, 2003.
Hua SY, Nohmi M, and Kuba K. Characteristics of Ca2⫹ release
induced by Ca2⫹ influx in cultured bullfrog sympathetic neurones.
J Physiol 464: 245–272, 1993.
Hua SY, Tokimasa T, Takasawa S, Furuya Y, Nohmi M, Okamoto H, and Kuba K. Cyclic ADP-ribose modulates Ca2⫹ release
channels for activation by physiological Ca2⫹ entry in bullfrog
sympathetic neurons. Neuron 12: 1073–1079, 1994.
Huang TJ, Sayers NM, Fernyhough P, and Verkhratsky A.
Diabetes-induced alterations in calcium homeostasis in sensory
neurones of streptozotocin-diabetic rats are restricted to lumbar
ganglia and are prevented by neurotrophin-3. Diabetologia 45: 560 –
570, 2002.
Ichise T, Kano M, Hashimoto K, Yanagihara D, Nakao K,
Shigemoto R, Katsuki M, and Aiba A. mGluR1 in cerebellar
Purkinje cells essential for long-term depression, synapse elimination, and motor coordination. Science 288: 1832–1835, 2000.
Ikeda M, Sugiyama T, Wallace CS, Gompf HS, Yoshioka T,
Miyawaki A, and Allen CN. Circadian dynamics of cytosolic and
Physiol Rev • VOL
245.
246.
247.
248.
249.
250.
251.
252.
253.
254.
255.
256.
257.
258.
259.
260.
261.
262.
263.
264.
nuclear Ca2⫹ in single suprachiasmatic nucleus neurons. Neuron
38: 253–263, 2003.
Imanishi T, Yamanaka H, Rhee JS, and Akaike N. Interaction
between the intracellular Ca2⫹ stores in rat dissociated hippocampal neurones. Neuroreport 7: 1421–1426, 1996.
Inoue M, Sakamoto Y, Fujishiro N, Imanaga I, Ozaki S,
Prestwich GD, and Warashina A. Homogeneous Ca2⫹ stores in
rat adrenal chromaffin cells. Cell Calcium 33: 19 –26, 2003.
Inoue T, Kato K, Kohda K, and Mikoshiba K. Type 1 inositol
1,4,5-trisphosphate receptor is required for induction of long-term
depression in cerebellar Purkinje neurons. J Neurosci 18: 5366 –
5373, 1998.
Inoue T, Lin X, Kohlmeier KA, Orr HT, Zoghbi HY, and Ross
WN. Calcium dynamics and electrophysiological properties of cerebellar Purkinje cells in SCA1 transgenic mice. J Neurophysiol 85:
1750 –1760, 2001.
Irving AJ and Collingridge GL. A characterization of muscarinic
receptor-mediated intracellular Ca2⫹ mobilization in cultured rat
hippocampal neurones. J Physiol 511: 747–759, 1998.
Irving AJ, Collingridge GL, and Schofield JG. Interactions
between Ca2⫹ mobilizing mechanisms in cultured rat cerebellar
granule cells. J Physiol 456: 667– 680, 1992.
Ishizaka N, Noda M, Kimura Y, Hashii M, Fukuda K, Katayama
M, Brown DA, and Higashida H. Inositol 1,4,5-trisphosphate
formation and ryanodine-sensitive oscillations of cytosolic free
Ca2⫹ concentrations in neuroblastoma ⫻ fibroblast hybrid NL308
cells expressing m2 and m4 muscarinic acetylcholine receptor
subtypes. Pflügers Arch 429: 426 – 433, 1995.
Ito E, Oka K, Etcheberrigaray R, Nelson TJ, McPhie DL,
Tofel-Grehl B, Gibson GE, and Alkon DL. Internal Ca2⫹ mobilization is altered in fibroblasts from patients with Alzheimer disease. Proc Natl Acad Sci USA 91: 534 –538, 1994.
Ito K, Rome C, Bouleau Y, and Dulon D. Substance P mobilizes
intracellular calcium and activates a nonselective cation conductance in rat spiral ganglion neurons. Eur J Neurosci 16: 2095–2102,
2002.
Itoh S, Ito K, Fujii S, Kaneko K, Kato K, Mikoshiba K, and
Kato H. Neuronal plasticity in hippocampal mossy fiber-CA3 synapses of mice lacking the inositol-1,4,5-trisphosphate type 1 receptor. Brain Res 901: 237–246, 2001.
Ivanenko A, Baring MD, Airey JA, Sutko JL, and Kenyon JL.
A caffeine- and ryanodine-sensitive Ca2⫹ store in avian sensory
neurons. J Neurophysiol 70: 710 –722, 1993.
Jacobs JM and Meyer T. Control of action potential-induced
Ca2⫹ signaling in the soma of hippocampal neurons by Ca2⫹ release from intracellular stores. J Neurosci 17: 4129 – 4135, 1997.
Jarosch E, Geiss-Friedlander R, Meusser B, Walter J, and
Sommer T. Protein dislocation from the endoplasmic reticulum—
pulling out the suspect. Traffic 3: 530 –536, 2002.
Jayaraman T, Ondrias K, Ondriasova E, and Marks AR. Regulation of the inositol 1,4,5-trisphosphate receptor by tyrosine
phosphorylation. Science 272: 1492–1494, 1996.
Jenden DJ and Fairhurst AS. The pharmacology of ryanodine.
Pharmacol Rev 21: 1–25, 1969.
Jimenez N and Hernandez-Cruz A. Modifications of intracellular
Ca2⫹ signalling during nerve growth factor-induced neuronal differentiation of rat adrenal chromaffin cells. Eur J Neurosci 13:
1487–1500, 2001.
Jin I and Hawkins RD. Presynaptic and postsynaptic mechanisms
of a novel form of homosynaptic potentiation at aplysia sensorymotor neuron synapses. J Neurosci 23: 7288 –7297, 2003.
Jobling P, McLachlan EM, and Sah P. Calcium induced calcium
release is involved in the afterhyperpolarization in one class of
guinea pig sympathetic neurone. J Auton Nerv Syst 42: 251–257,
1993.
Jobsis FF and O’Connor MJ. Calcium release and reabsorption
in the sartorius muscle of the toad. Biochem Biophys Res Commun
25: 246 –252, 1966.
John LM, Lechleiter JD, and Camacho P. Differential modulation of SERCA2 isoforms by calreticulin. J Cell Biol 142: 963–973,
1998.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
231.
ALEXEI VERKHRATSKY
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
287.
288.
289.
290.
291.
292.
293.
294.
295.
296.
297.
298.
299.
300.
301.
302.
303.
304.
305.
306.
rons. Am J Physiol Gastrointest Liver Physiol 270: G594 –G603,
1996.
Kimball BC, Yule DI, and Mulholland MW. Extracellular ATP
mediates Ca2⫹ signaling in cultured myenteric neurons via a PLCdependent mechanism. Am J Physiol Gastrointest Liver Physiol
270: G587–G593, 1996.
Kirino T, Robinson HP, Miwa A, Tamura A, and Kawai N.
Disturbance of membrane function preceding ischemic delayed
neuronal death in the gerbil hippocampus. J Cereb Blood Flow
Metab 12: 408 – 417, 1992.
Kirischuk S, Pronchuk N, and Verkhratsky A. Measurements of
intracellular calcium in sensory neurons of adult and old rats.
Neuroscience 50: 947–951, 1992.
Kirischuk S and Verkhratsky A. Calcium homeostasis in aged
neurones. Life Sci 59: 451– 459, 1996.
Kirischuk S, Voitenko N, Kostyuk P, and Verkhratsky A. Ageassociated changes of cytoplasmic calcium homeostasis in cerebellar granule neurons in situ: investigation on thin cerebellar slices.
Exp Gerontol 31: 475– 487, 1996.
Kirischuk S, Voitenko N, Kostyuk P, and Verkhratsky A. Calcium signalling in granule neurones studied in cerebellar slices.
Cell Calcium 19: 59 –71, 1996.
Kitamura A, Marszalec W, Yeh JZ, and Narahashi T. Effects of
halothane and propofol on excitatory and inhibitory synaptic transmission in rat cortical neurons. J Pharmacol Exp Ther 304: 162–
171, 2003.
Kitao Y, Ozawa K, Miyazaki M, Tamatani M, Kobayashi T,
Yanagi H, Okabe M, Ikawa M, Yamashima T, Stern DM, Hori
O, and Ogawa S. Expression of the endoplasmic reticulum molecular chaperone (ORP150) rescues hippocampal neurons from glutamate toxicity. J Clin Invest 108: 1439 –1450, 2001.
Kobayashi K, Sakaba T, and Tachibana M. Potentiation of Ca2⫹
transients in the presynaptic terminals of goldfish retinal bipolar
cells. J Physiol 482: 7–13, 1995.
Kobayashi K and Tachibana M. Ca2⫹ regulation in the presynaptic terminals of goldfish retinal bipolar cells. J Physiol 483:
79 –94, 1995.
Kocsis JD, Rand MN, Lankford KL, and Waxman SG. Intracellular calcium mobilization and neurite outgrowth in mammalian
neurons. J Neurobiol 25: 252–264, 1994.
Koizumi S, Bootman MD, Bobanovic LK, Schell MJ, Berridge
MJ, and Lipp P. Characterization of elementary Ca2⫹ release
signals in NGF-differentiated PC12 cells and hippocampal neurons.
Neuron 22: 125–137, 1999.
Koizumi S, Ishiguro M, Ohsawa I, Morimoto T, Takamura C,
Inoue K, and Kohsaka S. The effect of a secreted form of betaamyloid-precursor protein on intracellular Ca2⫹ increase in rat
cultured hippocampal neurones. Br J Pharmacol 123: 1483–1489,
1998.
Koizumi S, Lipp P, Berridge MJ, and Bootman MD. Regulation
of ryanodine receptor opening by lumenal Ca2⫹ underlies quantal
Ca2⫹ release in PC12 cells. J Biol Chem 274: 33327–33333, 1999.
Konnerth A, Dreessen J, and Augustine GJ. Brief dendritic
calcium signals initiate long-lasting synaptic depression in cerebellar Purkinje cells. Proc Natl Acad Sci USA 89: 7051–7055, 1992.
Korkotian E, Schwarz A, Pelled D, Schwarzmann G, Segal M,
and Futerman AH. Elevation of intracellular glucosylceramide
levels results in an increase in endoplasmic reticulum density and
in functional calcium stores in cultured neurons. J Biol Chem 274:
21673–21678, 1999.
Korkotian E and Segal M. Fast confocal imaging of calcium
released from stores in dendritic spines. Eur J Neurosci 10: 2076 –
2084, 1998.
Korkotian E and Segal M. Release of calcium from stores alters
the morphology of dendritic spines in cultured hippocampal neurons. Proc Natl Acad Sci USA 96: 12068 –12072, 1999.
Kosaka T. The axon initial segment as a synaptic site: ultrastructure and synaptology of the initial segment of the pyramidal cell in
the rat hippocampus (CA3 region). J Neurocytol 9: 861– 882, 1980.
Kostyuk E, Voitenko N, Kruglikov I, Shmigol A, Shishkin V,
Efimov A, and Kostyuk P. Diabetes-induced changes in calcium
homeostasis and the effects of calcium channel blockers in rat and
mice nociceptive neurons. Diabetologia 44: 1302–1309, 2001.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
265. Kafitz KW, Rose CR, Thoenen H, and Konnerth A. Neurotrophin-evoked rapid excitation through TrkB receptors. Nature 401:
918 –921, 1999.
266. Kamei J, Taki K, Ohsawa M, and Hitosugi H. Modulation of the
formalin-induced nociceptive response by diabetes: possible involvement of intracellular calcium. Brain Res 862: 257–261, 2000.
267. Kanaseki T, Ikeuchi Y, and Tashiro Y. Rough surfaced smooth
endoplasmic reticulum in rat and mouse cerebellar Purkinje cells
visualized by quick-freezing techniques. Cell Struct Funct 23: 373–
387, 1998.
268. Kang H and Schuman EM. Intracellular Ca2⫹ signaling is required
for neurotrophin-induced potentiation in the adult rat hippocampus. Neurosci Lett 282: 141–144, 2000.
269. Kano M, Garaschuk O, Verkhratsky A, and Konnerth A. Ryanodine receptor-mediated intracellular calcium release in rat cerebellar Purkinje neurones. J Physiol 487: 1–16, 1995.
270. Kapur A, Yeckel M, and Johnston D. Hippocampal mossy fiber
activity evokes Ca2⫹ release in CA3 pyramidal neurons via a
metabotropic glutamate receptor pathway. Neuroscience 107: 59 –
69, 2001.
271. Karai L, Russell JT, Iadarola MJ, and Olah Z. Vanilloid receptor
1 regulates multiple calcium compartments and contributes to
Ca2⫹-induced Ca2⫹-release in sensory neurons. J Biol Chem 279:
16377–16387, 2004.
272. Kashiwayanagi M, Tatani K, Shuto S, and Matsuda A. Inositol
1,4,5-trisphosphate and adenophostin analogues induce responses
in turtle olfactory sensory neurons. Eur J Neurosci 12: 606 – 612,
2000.
273. Kater SB, Mattson MP, Cohan C, and Connor J. Calcium
regulation of the neuronal growth cone. Trends Neurosci 11: 315–
321, 1988.
274. Kato BM, Lachica EA, and Rubel EW. Glutamate modulates
intracellular Ca2⫹ stores in brain stem auditory neurons. J Neurophysiol 76: 646 – 650, 1996.
275. Kato BM and Rubel EW. Glutamate regulates IP3-type and CICR
stores in the avian cochlear nucleus. J Neurophysiol 81: 1587–1596,
1999.
276. Kato N, Isomura Y, and Tanaka T. Intracellular calcium releases
facilitate induction of long-term depression. Neuropharmacology
39: 1107–1110, 2000.
277. Kato N, Tanaka T, Yamamoto K, and Isomura Y. Distinct temporal profiles of activity-dependent calcium increase in pyramidal
neurons of the rat visual cortex. J Physiol 519: 467– 479, 1999.
278. Kato N, Tanaka T, Yamamoto K, and Isomura Y. Enhancement
of activity-dependent calcium increase by neurotrophin-4 in visual
cortex pyramidal neurons. Brain Res 832: 179 –183, 1999.
279. Kawahara M and Kuroda Y. Molecular mechanism of neurodegeneration induced by Alzheimer’s beta-amyloid protein: channel
formation and disruption of calcium homeostasis. Brain Res Bull
53: 389 –397, 2000.
280. Kettunen P, Krieger P, Hess D, and El Manira A. Signaling
mechanisms of metabotropic glutamate receptor 5 subtype and its
endogenous role in a locomotor network. J Neurosci 22: 1868 –
1873, 2002.
281. Khachaturian ZS. Hypothesis on the regulation of cytosol calcium
concentration and the aging brain. Neurobiol Aging 8: 345–346,
1987.
282. Khodakhah K and Armstrong CM. Induction of long-term depression and rebound potentiation by inositol trisphosphate in
cerebellar Purkinje neurons. Proc Natl Acad Sci USA 94: 14009 –
14014, 1997.
283. Khodakhah K and Armstrong CM. Inositol trisphosphate and
ryanodine receptors share a common functional Ca2⫹ pool in cerebellar Purkinje neurons. Biophys J 73: 3349 –3357, 1997.
284. Khodakhah K and Ogden D. Fast activation and inactivation of
inositol trisphosphate-evoked Ca2⫹ release in rat cerebellar Purkinje neurones. J Physiol 487: 343–358, 1995.
285. Khodakhah K and Ogden D. Functional heterogeneity of calcium
release by inositol trisphosphate in single Purkinje neurones, cultured cerebellar astrocytes, and peripheral tissues. Proc Natl Acad
Sci USA 90: 4976 – 4980, 1993.
286. Kimball BC, Yule DI, and Mulholland MW. Caffeine- and ryanodine-sensitive Ca2⫹ stores in cultured guinea pig myenteric neu-
269
270
ALEXEI VERKHRATSKY
Physiol Rev • VOL
331. Larkum ME, Watanabe S, Nakamura T, Lasser-Ross N, and
Ross WN. Synaptically activated Ca2⫹ waves in layer 2/3 and layer
5 rat neocortical pyramidal neurons. J Physiol 549: 471– 488, 2003.
332. Lauri SE, Bortolotto ZA, Nistico R, Bleakman D, Ornstein PL,
Lodge D, Isaac JT, and Collingridge GL. A role for Ca2⫹ stores
in kainate receptor-dependent synaptic facilitation and LTP at
mossy fiber synapses in the hippocampus. Neuron 39: 327–341,
2003.
333. Lee HC, Walseth TF, Bratt GT, Hayes RN, and Clapper DL.
Structural determination of a cyclic metabolite of NAD⫹ with
intracellular Ca2⫹-mobilizing activity. J Biol Chem 264: 1608 –1615,
1989.
334. Lehninger AL, Carafoli E, and Rossi CS. Energy-linked ion
movements in mitochondrial systems. Adv Enzymol Relat Areas
Mol Biol 29: 259 –320, 1967.
335. Lei S, Pelkey KA, Topolnik L, Congar P, Lacaille JC, and
McBain CJ. Depolarization-induced long-term depression at hippocampal mossy fiber-CA3 pyramidal neuron synapses. J Neurosci
23: 9786 –9795, 2003.
336. Leissring MA, Akbari Y, Fanger CM, Cahalan MD, Mattson
MP, and LaFerla FM. Capacitative calcium entry deficits and
elevated luminal calcium content in mutant presenilin-1 knockin
mice. J Cell Biol 149: 793–798, 2000.
337. Lelli A, Perin P, Martini M, Ciubotaru CD, Prigioni I, Valli P,
Rossi ML, and Mammano F. Presynaptic calcium stores modulate
afferent release in vestibular hair cells. J Neurosci 23: 6894 – 6903,
2003.
338. Lev-Ram V, Jiang T, Wood J, Lawrence DS, and Tsien RY.
Synergies and coincidence requirements between NO, cGMP, and
Ca2⫹ in the induction of cerebellar long-term depression. Neuron
18: 1025–1038, 1997.
339. Lezcano N and Bergson C. D1/D5 dopamine receptors stimulate
intracellular calcium release in primary cultures of neocortical and
hippocampal neurons. J Neurophysiol 87: 2167–2175, 2002.
340. Li HS, Xu XZ, and Montell C. Activation of a TRPC3-dependent
cation current through the neurotrophin BDNF. Neuron 24: 261–
273, 1999.
341. Li Y and Camacho P. Ca2⫹-dependent redox modulation of
SERCA 2b by ERp57. J Cell Biol 164: 35– 46, 2004.
342. Li Z and Hatton GI. Ca2⫹ release from internal stores: role in
generating depolarizing after-potentials in rat supraoptic neurones.
J Physiol 498: 339 –350, 1997.
343. Li Z, Miyata S, and Hatton GI. Inositol 1,4,5-trisphosphate-sensitive Ca2⫹ stores in rat supraoptic neurons: involvement in histamine-induced enhancement of depolarizing afterpotentials. Neuroscience 93: 667– 674, 1999.
344. Liang Y, Yuan LL, Johnston D, and Gray R. Calcium signaling at
single mossy fiber presynaptic terminals in the rat hippocampus.
J Neurophysiol 87: 1132–1137, 2002.
345. Lilliehook C, Chan S, Choi EK, Zaidi NF, Wasco W, Mattson
MP, and Buxbaum JD. Calsenilin enhances apoptosis by altering
endoplasmic reticulum calcium signaling. Mol Cell Neurosci 19:
552–559, 2002.
346. Lin SZ, Yan GM, Koch KE, Paul SM, and Irwin RP. Mastoparaninduced apoptosis of cultured cerebellar granule neurons is initiated by calcium release from intracellular stores. Brain Res 771:
184 –195, 1997.
347. Lin YQ, Brain KL, and Bennett MR. Calcium in sympathetic
boutons of rat superior cervical ganglion during facilitation, augmentation and potentiation. J Auton Nerv Syst 73: 26 –37, 1998.
348. Lipscombe D, Madison DV, Poenie M, Reuter H, Tsien RW,
and Tsien RY. Imaging of cytosolic Ca2⫹ transients arising from
Ca2⫹ stores and Ca2⫹ channels in sympathetic neurons. Neuron 1:
355–365, 1988.
349. Lipscombe D, Madison DV, Poenie M, Reuter H, Tsien RY, and
Tsien RW. Spatial distribution of calcium channels and cytosolic
calcium transients in growth cones and cell bodies of sympathetic
neurons. Proc Natl Acad Sci USA 85: 2398 –2402, 1988.
350. Liu DM, Katnik C, Stafford M, and Adams DJ. P2Y purinoceptor activation mobilizes intracellular Ca2⫹ and induces a membrane
current in rat intracardiac neurones. J Physiol 526: 287–298, 2000.
351. Liu LH, Paul RJ, Sutliff RL, Miller ML, Lorenz JN, Pun RY,
Duffy JJ, Doetschman T, Kimura Y, MacLennan DH, Hoying
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
307. Kostyuk P, Pronchuk N, Savchenko A, and Verkhratsky A.
Calcium currents in aged rat dorsal root ganglion neurones.
J Physiol 461: 467– 483, 1993.
308. Kostyuk P and Verkhratsky A. Calcium stores in neurons and
glia. Neuroscience 63: 381– 404, 1994.
309. Kostyuk P and Verkhratsky A. Calcium Signalling in the Nervous System. Chichester, UK: Wiley, 1995.
310. Kostyuk P and Verkhratsky A. Basic properties of calcium release channels in neural cells. In: Pharmacology of Ion Channels,
edited by Soria B. Oxford: OUP, 1998, p. 299 –320.
311. Kostyuk PG, Belan PV, and Tepikin AV. Free calcium transients
and oscillations in nerve cells. Exp Brain Res 83: 459 – 464, 1991.
312. Kovalchuk Y, Eilers J, Lisman J, and Konnerth A. NMDA
receptor-mediated subthreshold Ca2⫹ signals in spines of hippocampal neurons. J Neurosci 20: 1791–1799, 2000.
313. Krause T, Gerbershagen MU, Fiege M, Weisshorn R, and Wappler F. Dantrolene: a review of its pharmacology, therapeutic use
and new developments. Anaesthesia 59: 364 –373, 2004.
314. Krizaj D, Bao JX, Schmitz Y, Witkovsky P, and Copenhagen
DR. Caffeine-sensitive calcium stores regulate synaptic transmission from retinal rod photoreceptors. J Neurosci 19: 7249 –7261,
1999.
315. Krizaj D, Lai FA, and Copenhagen DR. Ryanodine stores and
calcium regulation in the inner segments of salamander rods and
cones. J Physiol 547: 761–774, 2003.
316. Kruglikov I, Gryshchenko O, Shutov L, Kostyuk E, Kostyuk P,
and Voitenko N. Diabetes-induced abnormalities in ER calcium
mobilization in primary and secondary nociceptive neurons.
Pflügers Arch 448: 395– 401, 2004.
317. Kuba K. Release of calcium ions linked to the activation of potassium conductance in a caffeine-treated sympathetic neurone.
J Physiol 298: 251–269, 1980.
318. Kuba K, Morita K, and Nohmi M. Origin of calcium ions involved
in the generation of a slow afterhyperpolarization in bullfrog sympathetic neurones. Pflügers Arch 399: 194 –202, 1983.
319. Kuba K and Nishi S. Rhythmic hyperpolarizations and depolarization of sympathetic ganglion cells induced by caffeine. J Neurophysiol 39: 547–563, 1976.
320. Kudo Y, Ogura A, and Iijima T. Stimulation of muscarinic receptor in hippocampal neuron induces characteristic increase in cytosolic free Ca2⫹ concentration. Neurosci Lett 85: 345–350, 1988.
321. Kumar A and Foster T. Enhanced long-term potentiation during
aging is masked by processes involving intracellular calcium
stores. J Neurophysiol 91: 2437–2444, 2004.
322. Ladewig T, Kloppenburg P, Lalley PM, Zipfel WR, Webb WW,
and Keller BU. Spatial profiles of store-dependent calcium release
in motoneurones of the nucleus hypoglossus from newborn mouse.
J Physiol 547: 775–787, 2003.
323. LaFerla FM. Calcium dyshomeostasis and intracellular signalling
in Alzheimer’s disease. Nat Rev Neurosci 3: 862– 872, 2002.
324. Lalo U and Kostyuk P. Developmental changes in purinergic
calcium signalling in rat neocortical neurones. Brain Res 111:
43–50, 1998.
325. Lalo U, Voitenko N, and Kostyuk P. Iono- and metabotropically
induced purinergic calcium signalling in rat neocortical neurons.
Brain Res 799: 285–291, 1998.
326. Lamb GD, Laver DR, and Stephenson DG. Questions about
adaptation in ryanodine receptors. J Gen Physiol 116: 883– 890,
2000.
327. Lamb K and Bielefeldt K. Rapid effects of neurotrophic factors
on calcium homeostasis in rat visceral afferent neurons. Neurosci
Lett 336: 9 –12, 2003.
328. Lancaster E, Oh EJ, Gover T, and Weinreich D. Calcium and
calcium-activated currents in vagotomized rat primary vagal afferent neurons. J Physiol 540: 543–556, 2002.
329. Landfield PW. Increased hippocampal Ca2⫹ channel activity in
brain aging and dementia. Hormonal and pharmacologic modulation. Ann NY Acad Sci 747: 351–364, 1994.
330. Lankford KL, Rand MN, Waxman SG, and Kocsis JD. Blocking
Ca2⫹ mobilization with thapsigargin reduces neurite initiation in
cultured adult rat DRG neurons. Brain Res 84: 151–163, 1995.
CALCIUM STORE IN THE ER OF NEURONS
352.
353.
354.
355.
356.
358.
359.
360.
361.
362.
363.
364.
365.
366.
367.
368.
369.
370.
371.
Physiol Rev • VOL
372. Maruyama K, Usami M, Kametani F, Tomita T, Iwatsubo T,
Saido TC, Mori H, and Ishiura S. Molecular interactions between
presenilin and calpain: inhibition of m-calpain protease activity by
presenilin-1, 2 and cleavage of presenilin-1 by m-, mu-calpain. Int J
Mol Med 5: 269 –273, 2000.
373. Maruyama T, Kanaji T, Nakade S, Kanno T, and Mikoshiba K.
2APB, 2-aminoethoxydiphenyl borate, a membrane-penetrable
modulator of Ins(1,4,5)P3-induced Ca2⫹ release. J Biochem 122:
498 –505, 1997.
374. Masgrau R, Churchill GC, Morgan AJ, Ashcroft SJ, and
Galione A. NAADP: a new second messenger for glucose-induced
Ca2⫹ responses in clonal pancreatic beta cells. Curr Biol 13: 247–
251, 2003.
375. Masgrau R, Servitja JM, Young KW, Pardo R, Sarri E, Nahorski SR, and Picatoste F. Characterization of the metabotropic
glutamate receptors mediating phospholipase C activation and calcium release in cerebellar granule cells: calcium-dependence of the
phospholipase C response. Eur J Neurosci 13: 248 –256, 2001.
376. Matifat F, Hague F, Brule G, and Collin T. Regulation of InsP3mediated Ca2⫹ release by CaMKII in Xenopus oocytes. Pflügers
Arch 441: 796 – 801, 2001.
377. Mattson MP. Cellular actions of beta-amyloid precursor protein
and its soluble and fibrillogenic derivatives. Physiol Rev 77: 1081–
1132, 1997.
378. Mattson MP and Chan SL. Neuronal and glial calcium signaling in
Alzheimer’s disease. Cell Calcium 34: 385–397, 2003.
379. Mattson MP, Cheng B, Davis D, Bryant K, Lieberburg I, and
Rydel RE. beta-Amyloid peptides destabilize calcium homeostasis
and render human cortical neurons vulnerable to excitotoxicity.
J Neurosci 12: 376 –389, 1992.
380. Mattson MP, Gary DS, Chan SL, and Duan W. Perturbed endoplasmic reticulum function, synaptic apoptosis and the pathogenesis of Alzheimer’s disease. Biochem Soc Symp: 151–162, 2001.
381. Mattson MP, LaFerla FM, Chan SL, Leissring MA, Shepel PN,
and Geiger JD. Calcium signaling in the ER: its role in neuronal
plasticity and neurodegenerative disorders. Trends Neurosci 23:
222–229, 2000.
382. Mattson MP, Zhu H, Yu J, and Kindy MS. Presenilin-1 mutation
increases neuronal vulnerability to focal ischemia in vivo and to
hypoxia and glucose deprivation in cell culture: involvement of
perturbed calcium homeostasis. J Neurosci 20: 1358 –1364, 2000.
383. Matyash M, Matyash V, Nolte C, Sorrentino V, and Kettenmann H. Requirement of functional ryanodine receptor type 3 for
astrocyte migration. FASEB J 16: 84 – 86, 2002.
384. Mazzarello P and Bentivoglio M. The centenarian Golgi apparatus. Nature 392: 543–544, 1998.
385. Mazzarello P, Calligaro A, Vannini V, and Muscatello U. The
sarcoplasmic reticulum: its discovery and rediscovery. Nat Rev Mol
Cell Biol 4: 69 –74, 2003.
386. McBurney RN and Neering IR. Neuronal calcium homeostasis.
Trends Neurosci 10: 164 –169, 1987.
387. McCarren M, Potter BV, and Miller RJ. A metabolically stable
analog of 1,4,5-inositol trisphosphate activates a novel K⫹ conductance in pyramidal cells of the rat hippocampal slice. Neuron 3:
461– 471, 1989.
388. McCracken AA and Brodsky JL. Evolving questions and paradigm shifts in endoplasmic-reticulum-associated degradation
(ERAD). Bioessays 25: 868 – 877, 2003.
389. McDonough SI, Cseresnyes Z, and Schneider MF. Origin sites
of calcium release and calcium oscillations in frog sympathetic
neurons. J Neurosci 20: 9059 –9070, 2000.
390. McGarry SJ and Williams AJ. Digoxin activates sarcoplasmic
reticulum Ca2⫹-release channels: a possible role in cardiac inotropy. Br J Pharmacol 108: 1043–1050, 1993.
391. McGraw CF, Somlyo AV, and Blaustein MP. Localization of
calcium in presynaptic nerve terminals. An ultrastructural and
electron microprobe analysis. J Cell Biol 85: 228 –241, 1980.
392. Meacock SL, Greenfield JJ, and High S. Protein targeting and
translocation at the endoplasmic reticulum membrane—through
the eye of a needle? Essays Biochem 36: 1–13, 2000.
393. Medina I, Ghose S, and Ben-Ari Y. Mobilization of intracellular
calcium stores participates in the rise of [Ca2⫹]i and the toxic
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
357.
JB, and Shull GE. Defective endothelium-dependent relaxation of
vascular smooth muscle and endothelial cell Ca2⫹ signaling in mice
lacking sarco(endo)plasmic reticulum Ca2⫹-ATPase isoform 3.
J Biol Chem 272: 30538 –30545, 1997.
Liu M, Liu MC, Magoulas C, Priestley JV, and Willmott NJ.
Versatile regulation of cytosolic Ca2⫹ by vanilloid receptor I in rat
dorsal root ganglion neurons. J Biol Chem 278: 5462–5472, 2003.
Llano I, DiPolo R, and Marty A. Calcium-induced calcium release in cerebellar Purkinje cells. Neuron 12: 663– 673, 1994.
Llano I, Dreessen J, Kano M, and Konnerth A. Intradendritic
release of calcium induced by glutamate in cerebellar Purkinje
cells. Neuron 7: 577–583, 1991.
Llano I, Gonzalez J, Caputo C, Lai FA, Blayney LM, Tan YP,
and Marty A. Presynaptic calcium stores underlie large-amplitude
miniature IPSCs and spontaneous calcium transients. Nat Neurosci
3: 1256 –1265, 2000.
Locke FS. Notiz uber den Einfluss physiologischer Kochsalzlosung
auf die elektrische Erregbarkeit von Muskel und Nerv. Zbl Physiol
8: 166 –167, 1894.
Locknar SA, Barstow KL, Tompkins JD, Merriam LA, and
Parsons RL. Calcium-induced calcium release regulates action
potential generation in guinea-pig sympathetic neurones. J Physiol
555: 627– 635, 2004.
Lohmann C, Myhr KL, and Wong RO. Transmitter-evoked local
calcium release stabilizes developing dendrites. Nature 418: 177–
181, 2002.
Lu B and Chow A. Neurotrophins and hippocampal synaptic
transmission and plasticity. J Neurosci Res 58: 76 – 87, 1999.
Lu YF and Hawkins RD. Ryanodine receptors contribute to
cGMP-induced late-phase LTP and CREB phosphorylation in the
hippocampus. J Neurophysiol 88: 1270 –1278, 2002.
Ludwig M, Sabatier N, Bull PM, Landgraf R, Dayanithi G, and
Leng G. Intracellular calcium stores regulate activity-dependent
neuropeptide release from dendrites. Nature 418: 85– 89, 2002.
Lupu VD, Kaznacheyeva E, Krishna UM, Falck JR, and Bezprozvanny I. Functional coupling of phosphatidylinositol 4,5bisphosphate to inositol 1,4,5-trisphosphate receptor. J Biol Chem
273: 14067–14070, 1998.
Lynch G, Larson J, Kelso S, Barrionuevo G, and Schottler F.
Intracellular injections of EGTA block induction of hippocampal
long-term potentiation. Nature 305: 719 –721, 1983.
Ma Y and Hendershot LM. The mammalian endoplasmic reticulum as a sensor for cellular stress. Cell Stress Chaperones 7:
222–229, 2002.
Majewska A, Brown E, Ross J, and Yuste R. Mechanisms of
calcium decay kinetics in hippocampal spines: role of spine calcium pumps and calcium diffusion through the spine neck in
biochemical compartmentalization. J Neurosci 20: 1722–1734,
2000.
Mammano F, Frolenkov GI, Lagostena L, Belyantseva IA,
Kurc M, Dodane V, Colavita A, and Kachar B. ATP-induced
Ca2⫹ release in cochlear outer hair cells: localization of an inositol
triphosphate-gated Ca2⫹ store to the base of the sensory hair
bundle. J Neurosci 19: 6918 – 6929, 1999.
Mark RJ, Hensley K, Butterfield DA, and Mattson MP. Amyloid beta-peptide impairs ion-motive ATPase activities: evidence
for a role in loss of neuronal Ca2⫹ homeostasis and cell death.
J Neurosci 15: 6239 – 6249, 1995.
Marrion NV and Adams PR. Release of intracellular calcium and
modulation of membrane currents by caffeine in bull-frog sympathetic neurones. J Physiol 445: 515–535, 1992.
Martin ED and Buno W. Caffeine-mediated presynaptic long-term
potentiation in hippocampal CA1 pyramidal neurons. J Neurophysiol 89: 3029 –3038, 2003.
Martinez-Pinna J, McLachlan EM, and Gallego R. Distinct
mechanisms for activation of Cl⫺ and K⫹ currents by Ca2⫹ from
different sources in mouse sympathetic neurones. J Physiol 527:
249 –264, 2000.
Martone ME, Zhang Y, Simpliciano VM, Carragher BO, and
Ellisman MH. Three-dimensional visualization of the smooth endoplasmic reticulum in Purkinje cell dendrites. J Neurosci 13:
4636 – 4646, 1993.
271
272
394.
395.
396.
397.
398.
400.
401.
402.
403.
404.
405.
406.
407.
408.
409.
410.
411.
412.
413.
414.
415.
416.
actions of the HIV coat protein GP120. Eur J Neurosci 11: 1167–
1178, 1999.
Meini A, Benocci A, Frosini M, Sgaragli GP, Garcia JB,
Pessina GP, Aldinucci C, and Palmi M. Potentiation of intracellular Ca2⫹ mobilization by hypoxia-induced NO generation in rat
brain striatal slices and human astrocytoma U-373 MG cells and its
involvement in tissue damage. Eur J Neurosci 17: 692–700, 2003.
Meissner G. Adenine nucleotide stimulation of Ca2⫹-induced Ca2⫹
release in sarcoplasmic reticulum. J Biol Chem 259: 2365–2374,
1984.
Meissner G. Regulation of mammalian ryanodine receptors. Front
Biosci 7: 2072–2080, 2002.
Mejia-Alvarez R, Kettlun C, Rios E, Stern M, and Fill M.
Unitary Ca2⫹ current through cardiac ryanodine receptor channels
under quasi-physiological ionic conditions. J Gen Physiol 113: 177–
186, 1999.
Melamed-Book N, Kachalsky SG, Kaiserman I, and Rahamimoff R. Neuronal calcium sparks and intracellular calcium “noise.”
Proc Natl Acad Sci USA 96: 15217–15221, 1999.
Meldolesi J. Rapidly exchanging Ca2⫹ stores in neurons: molecular, structural and functional properties. Prog Neurobiol 65: 309 –
338, 2001.
Meldolesi J. Rapidly exchanging Ca2⫹ stores: ubiquitous partners
of surface channels in neurons. News Physiol Sci 17: 144 –149,
2002.
Meldolesi J and Grohovaz F. Total calcium ultrastructure: advances in excitable cells. Cell Calcium 30: 1– 8, 2001.
Meldolesi J and Pozzan T. The endoplasmic reticulum Ca2⫹
store: a view from the lumen. Trends Biochem Sci 23: 10 –14, 1998.
Mengesdorf T, Althausen S, Oberndorfer I, and Paschen W.
Response of neurons to an irreversible inhibition of endoplasmic
reticulum Ca2⫹-ATPase: relationship between global protein synthesis and expression and translation of individual genes. Biochem
J 356: 805– 812, 2001.
Men’shikova EV, Ritov VB, and Kozlov Iu P. Release of Ca2⫹
ions from the sarcoplasmic reticulum of skeletal muscle induced
by heparin. Relation between the Ca2⫹ release caused by Ca2⫹ ions
and caffeine (in Russian). Biokhimiia 51: 1696 –1701, 1986.
Merriam LA, Scornik FS, and Parsons RL. Ca2⫹-induced Ca2⫹
release activates spontaneous miniature outward currents
(SMOCs) in parasympathetic cardiac neurons. J Neurophysiol 82:
540 –550, 1999.
Messutat S, Heine M, and Wicher D. Calcium-induced calcium
release in neurosecretory insect neurons: fast and slow responses.
Cell Calcium 30: 199 –211, 2001.
Meszaros LG and Volpe P. Caffeine- and ryanodine-sensitive
Ca2⫹ stores of canine cerebrum and cerebellum neurons. Am J
Physiol Cell Physiol 261: C1048 –C1054, 1991.
Mhyre TR, Maine DN, and Holliday J. Calcium-induced calcium
release from intracellular stores is developmentally regulated in
primary cultures of cerebellar granule neurons. J Neurobiol 42:
134 –147, 2000.
Michalak M, Robert Parker JM, and Opas M. Ca2⫹ signaling and
calcium binding chaperones of the endoplasmic reticulum. Cell
Calcium 32: 269 –278, 2002.
Michell RH. Inositol phospholipids and cell surface receptor function. Biochim Biophys Acta 415: 81–147, 1975.
Michikawa T, Miyawaki A, Furuichi T, and Mikoshiba K. Inositol 1,4,5-trisphosphate receptors and calcium signaling. Crit Rev
Neurobiol 10: 39 –55, 1996.
Mikoshiba K. The InsP3 receptor and intracellular Ca2⫹ signaling.
Curr Opin Neurobiol 7: 339 –345, 1997.
Mikoshiba K, Furuichi T, and Miyawaki A. Structure and function of IP3 receptors. Semin Cell Biol 5: 273–281, 1994.
Mikulec AA, Pittson S, Amagasu SM, Monroe FA, and MacIver MB. Halothane depresses action potential conduction in hippocampal axons. Brain Res 796: 231–238, 1998.
Miller LD, Petrozzino JJ, Golarai G, and Connor JA. Ca2⫹
release from intracellular stores induced by afferent stimulation of
CA3 pyramidal neurons in hippocampal slices. J Neurophysiol 76:
554 –562, 1996.
Miller RJ. The control of neuronal Ca2⫹ homeostasis. Prog Neurobiol 37: 255–285, 1991.
Physiol Rev • VOL
417. Mironov SL. Metabotropic ATP receptor in hippocampal and thalamic neurones: pharmacology and modulation of Ca2⫹ mobilizing
mechanisms. Neuropharmacology 33: 1–13, 1994.
418. Mironov SL, Usachev Yu M, and Lux HD. Spatial and temporal
control of intracellular free Ca2⫹ in chick sensory neurons.
Pflügers Arch 424: 183–191, 1993.
419. Missiaen L, De Smedt H, Droogmans G, and Casteels R. Luminal Ca2⫹ controls the activation of the inositol 1,4,5-trisphosphate receptor by cytosolic Ca2⫹. J Biol Chem 267: 22961–22966,
1992.
420. Miyakawa T, Mizushima A, Hirose K, Yamazawa T, Bezprozvanny I, Kurosaki T, and Iino M. Ca2⫹-sensor region of IP3
receptor controls intracellular Ca2⫹ signaling. EMBO J 20: 1674 –
1680, 2001.
421. Miyata M, Finch EA, Khiroug L, Hashimoto K, Hayasaka S,
Oda SI, Inouye M, Takagishi Y, Augustine GJ, and Kano M.
Local calcium release in dendritic spines required for long-term
synaptic depression. Neuron 28: 233–244, 2000.
422. Miyawaki A, Griesbeck O, Heim R, and Tsien RY. Dynamic and
quantitative Ca2⫹ measurements using improved cameleons. Proc
Natl Acad Sci USA 96: 2135–2140, 1999.
423. Mogami H, Gardner J, Gerasimenko OV, Camello P, Petersen
OH, and Tepikin AV. Calcium binding capacity of the cytosol and
endoplasmic reticulum of mouse pancreatic acinar cells. J Physiol
518: 463– 467, 1999.
424. Mogami H, Nakano K, Tepikin AV, and Petersen OH. Ca2⫹ flow
via tunnels in polarized cells: recharging of apical Ca2⫹ stores by
focal Ca2⫹ entry through basal membrane patch. Cell 88: 49 –55,
1997.
425. Mogami H, Tepikin AV, and Petersen OH. Termination of cytosolic Ca2⫹ signals: Ca2⫹ reuptake into intracellular stores is regulated by the free Ca2⫹ concentration in the store lumen. EMBO J
17: 435– 442, 1998.
426. Moore KA, Cohen AS, Kao JP, and Weinreich D. Ca2⫹-induced
Ca2⫹ release mediates a slow post-spike hyperpolarization in rabbit
vagal afferent neurons. J Neurophysiol 79: 688 – 694, 1998.
427. Mori F, Fukaya M, Abe H, Wakabayashi K, and Watanabe M.
Developmental changes in expression of the three ryanodine receptor mRNAs in the mouse brain. Neurosci Lett 285: 57– 60, 2000.
428. Morikawa H, Imani F, Khodakhah K, and Williams JT. Inositol
1,4,5-triphosphate-evoked responses in midbrain dopamine neurons. J Neurosci 20: RC103, 2000.
429. Morikawa H, Khodakhah K, and Williams JT. Two intracellular
pathways mediate metabotropic glutamate receptor-induced Ca2⫹
mobilization in dopamine neurons. J Neurosci 23: 149 –157, 2003.
430. Morita K, Kitayama S, and Dohi T. Stimulation of cyclic ADPribose synthesis by acetylcholine and its role in catecholamine
release in bovine adrenal chromaffin cells. J Biol Chem 272: 21002–
21009, 1997.
431. Morita K, North RA, and Tokimasa T. The calcium-activated
potassium conductance in guinea-pig myenteric neurones.
J Physiol 329: 341–354, 1982.
432. Mothet JP, Fossier P, Meunier FM, Stinnakre J, Tauc L, and
Baux G. Cyclic ADP-ribose and calcium-induced calcium release
regulate neurotransmitter release at a cholinergic synapse of Aplysia. J Physiol 507: 405– 414, 1998.
433. Mouton J, Marty I, Villaz M, Feltz A, and Maulet Y. Molecular
interaction of dihydropyridine receptors with type-1 ryanodine receptors in rat brain. Biochem J 354: 597– 603, 2001.
434. Murayama T and Ogawa Y. Properties of Ryr3 ryanodine receptor
isoform in mammalian brain. J Biol Chem 271: 5079 –5084, 1996.
435. Murayama T and Ogawa Y. Characterization of type 3 ryanodine
receptor (RyR3) of sarcoplasmic reticulum from rabbit skeletal
muscles. J Biol Chem 272: 24030 –24037, 1997.
436. Murchison D and Griffith WH. Age-related alterations in caffeine-sensitive calcium stores and mitochondrial buffering in rat
basal forebrain. Cell Calcium 25: 439 – 452, 1999.
437. Murphy SN and Miller RJ. A glutamate receptor regulates Ca2⫹
mobilization in hippocampal neurons. Proc Natl Acad Sci USA 85:
8737– 8741, 1988.
438. Murphy SN and Miller RJ. Two distinct quisqualate receptors
regulate Ca2⫹ homeostasis in hippocampal neurons in vitro. Mol
Pharmacol 35: 671– 680, 1989.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
399.
ALEXEI VERKHRATSKY
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
460.
461.
462.
463.
464.
465.
466.
467.
468.
469.
470.
471.
472.
473.
474.
475.
476.
477.
478.
479.
480.
cation currents through the epithelial Ca2⫹ channel ECaC1. Br J
Pharmacol 134: 453– 462, 2001.
Nishizaki T and Mori M. Diverse signal transduction pathways
mediated by endogenous P2 receptors in cultured rat cerebral
cortical neurons. J Neurophysiol 79: 2513–2521, 1998.
Nixon RA, Saito KI, Grynspan F, Griffin WR, Katayama S,
Honda T, Mohan PS, Shea TB, and Beermann M. Calciumactivated neutral proteinase (calpain) system in aging and Alzheimer’s disease. Ann NY Acad Sci 747: 77–91, 1994.
Nohmi M, Hua SY, and Kuba K. Basal Ca2⫹ and the oscillation of
Ca2⫹ in caffeine-treated bullfrog sympathetic neurones. J Physiol
450: 513–528, 1992.
Nucifora FC Jr, Li SH, Danoff S, Ullrich A, and Ross CA.
Molecular cloning of a cDNA for the human inositol 1,4,5-trisphosphate receptor type 1, and the identification of a third alternatively
spliced variant. Brain Res 32: 291–296, 1995.
Numakawa T, Nakayama H, Suzuki S, Kubo T, Nara F, Numakawa Y, Yokomaku D, Araki T, Ishimoto T, Ogura A, and
Taguchi T. Nerve growth factor-induced glutamate release is via
p75 receptor, ceramide, and Ca2⫹ from ryanodine receptor in developing cerebellar neurons. J Biol Chem 278: 41259 – 41269, 2003.
Nunn DL and Taylor CW. Luminal Ca2⫹ increases the sensitivity
of Ca2⫹ stores to inositol 1,4,5-trisphosphate. Mol Pharmacol 41:
115–119, 1992.
Oddo S, Caccamo A, Shepherd JD, Murphy MP, Golde TE,
Kayed R, Metherate R, Mattson MP, Akbari Y, and LaFerla
FM. Triple-transgenic model of Alzheimer’s disease with plaques
and tangles: intracellular Abeta and synaptic dysfunction. Neuron
39: 409 – 421, 2003.
Ogden D and Khodakhah K. Intracellular Ca2⫹ release by InsP3 in
cerebellar Purkinje neurones. Acta Physiol Scand 157: 381–394,
1996.
Ogura A, Myojo Y, and Higashida H. Bradykinin-evoked acetylcholine release via inositol trisphosphate-dependent elevation in
free calcium in neuroblastoma ⫻ glioma hybrid NG108 –15 cells.
J Biol Chem 265: 3577–3584, 1990.
Ohta T, Ito S, and Ohga A. Inhibitory action of dantrolene on
Ca-induced Ca2⫹ release from sarcoplasmic reticulum in guinea pig
skeletal muscle. Eur J Pharmacol 178: 11–19, 1990.
O’Mara SM, Rowan MJ, and Anwyl R. Dantrolene inhibits longterm depression and depotentiation of synaptic transmission in the
rat dentate gyrus. Neuroscience 68: 621– 624, 1995.
O’Neill SC, Donoso P, and Eisner DA. The role of [Ca2⫹]i and
[Ca2⫹] sensitization in the caffeine contracture of rat myocytes:
measurement of [Ca2⫹]i and [caffeine]i. J Physiol 425: 55–70, 1990.
Orkand RK and Thomas RC. Effects of low doses of caffeine on
[Ca2⫹]i in voltage-clamped snail (Helix aspersa) neurones.
J Physiol 489: 19 –28, 1995.
Ouardouz M, Nikolaeva MA, Coderre E, Zamponi GW, McRory
JE, Trapp BD, Yin X, Wang W, Woulfe J, and Stys PK. Depolarization-induced Ca2⫹ release in ischemic spinal cord white matter involves L-type Ca2⫹ channel activation of ryanodine receptors.
Neuron 40: 53– 63, 2003.
Ouyang Y, Deerinck TJ, Walton PD, Airey JA, Sutko JL, and
Ellisman MH. Distribution of ryanodine receptors in the chicken
central nervous system. Brain Res 620: 269 –280, 1993.
Ouyang Y, Martone ME, Deerinck TJ, Airey JA, Sutko JL, and
Ellisman MH. Differential distribution and subcellular localization
of ryanodine receptor isoforms in the chicken cerebellum during
development. Brain Res 775: 52– 62, 1997.
Pack-Chung E, Meyers MB, Pettingell WP, Moir RD, Brownawell AM, Cheng I, Tanzi RE, and Kim TW. Presenilin 2 interacts with sorcin, a modulator of the ryanodine receptor. J Biol
Chem 275: 14440 –14445, 2000.
Pahl HL. Signal transduction from the endoplasmic reticulum to
the cell nucleus. Physiol Rev 79: 683–701, 1999.
Pahl HL and Baeuerle PA. The ER-overload response: activation
of NF-␬B. Trends Biochem Sci 22: 63– 67, 1997.
Paiement J and Bergeron J. The shape of things to come: regulation of shape changes in endoplasmic reticulum. Biochem Cell
Biol 79: 587–592, 2001.
Pal S, Sun D, Limbrick D, Rafiq A, and DeLorenzo RJ. Epileptogenesis induces long-term alterations in intracellular calcium
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
439. Murray FE, Landsberg JP, Williams RJ, Esiri MM, and Watt F.
Elemental analysis of neurofibrillary tangles in Alzheimer’s disease
using proton-induced X-ray analysis. Ciba Found Symp 169: 201–
210, 1992.
440. Nagasaki K and Fleischer S. Ryanodine sensitivity of the calcium
release channel of sarcoplasmic reticulum. Cell Calcium 9: 1–7,
1988.
441. Nagase T, Ito KI, Kato K, Kaneko K, Kohda K, Matsumoto M,
Hoshino A, Inoue T, Fujii S, Kato H, and Mikoshiba K. Longterm potentiation and long-term depression in hippocampal CA1
neurons of mice lacking the IP3 type 1 receptor. Neuroscience 117:
821– 830, 2003.
442. Nakagawa T, Zhu H, Morishima N, Li E, Xu J, Yankner BA, and
Yuan J. Caspase-12 mediates endoplasmic-reticulum-specific apoptosis and cytotoxicity by amyloid-beta. Nature 403: 98 –103, 2000.
443. Nakajima M, Miura M, Aosaki T, and Shirasawa T. Deficiency
of presenilin-1 increases calcium-dependent vulnerability of neurons to oxidative stress in vitro. J Neurochem 78: 807– 814, 2001.
444. Nakamura T, Barbara JG, Nakamura K, and Ross WN. Synergistic release of Ca2⫹ from IP3-sensitive stores evoked by synaptic
activation of mGluRs paired with backpropagating action potentials. Neuron 24: 727–737, 1999.
445. Nakamura T, Lasser-Ross N, Nakamura K, and Ross WN.
Spatial segregation and interaction of calcium signalling mechanisms in rat hippocampal CA1 pyramidal neurons. J Physiol 543:
465– 480, 2002.
446. Nakamura T, Nakamura K, Lasser-Ross N, Barbara JG, Sandler VM, and Ross WN. Inositol 1,4,5-trisphosphate IP3-mediated
Ca2⫹ release evoked by metabotropic agonists and backpropagating action potentials in hippocampal CA1 pyramidal neurons.
J Neurosci 20: 8365– 8376, 2000.
447. Nakayama R, Yano T, Ushijima K, Abe E, and Terasaki H.
Effects of dantrolene on extracellular glutamate concentration and
neuronal death in the rat hippocampal CA1 region subjected to
transient ischemia. Anesthesiology 96: 705–710, 2002.
448. Narasimhan K, Pessah IN, and Linden DJ. Inositol-1,4,5trisphosphate receptor-mediated Ca mobilization is not required
for cerebellar long-term depression in reduced preparations. J Neurophysiol 80: 2963–2974, 1998.
449. Narita K, Akita T, Hachisuka J, Huang S, Ochi K, and Kuba K.
Functional coupling of Ca2⫹ channels to ryanodine receptors at
presynaptic terminals. Amplification of exocytosis and plasticity.
J Gen Physiol 115: 519 –532, 2000.
450. Narita K, Akita T, Osanai M, Shirasaki T, Kijima H, and Kuba
K. A Ca2⫹-induced Ca2⫹ release mechanism involved in asynchronous exocytosis at frog motor nerve terminals. J Gen Physiol 112:
593– 609, 1998.
451. Neary JT, Crow T, and Alkon DL. Change in a specific phosphoprotein band following associative learning in Hermissenda. Nature 293: 658 – 660, 1981.
452. Neering IR and McBurney RN. Role for microsomal Ca storage in
mammalian neurones? Nature 309: 158 –160, 1984.
453. Nelson TJ, Cavallaro S, Yi CL, McPhie D, Schreurs BG, Gusev
PA, Favit A, Zohar O, Kim J, Beushausen S, Ascoli G, Olds J,
Neve R, and Alkon DL. Calexcitin: a signaling protein that binds
calcium and GTP, inhibits potassium channels, and enhances membrane excitability. Proc Natl Acad Sci USA 93: 13808 –13813, 1996.
454. Nelson TJ, Zhao WQ, Yuan S, Favit A, Pozzo-Miller L, and
Alkon DL. Calexcitin interaction with neuronal ryanodine receptors. Biochem J 341: 423– 433, 1999.
455. Nguyen HN, Wang C, and Perry DC. Depletion of intracellular
calcium stores is toxic to SH-SY5Y neuronal cells. Brain Res 924:
159 –166, 2002.
456. Nicolson TA, Bevan S, and Richards CD. Characterisation of the
calcium responses to histamine in capsaicin-sensitive and capsaicin-insensitive sensory neurones. Neuroscience 110: 329 –338,
2002.
457. Nielsen SP and Petersen OH. Transport of calcium in the perfused submandibular gland of the cat. J Physiol 223: 685– 697, 1972.
458. Nilius B. From TRPs to SOCs, CCEs, and CRACs: consensus and
controversies. Cell Calcium 33: 293–298, 2003.
459. Nilius B, Prenen J, Vennekens R, Hoenderop JG, Bindels RJ,
and Droogmans G. Pharmacological modulation of monovalent
273
274
481.
482.
483.
484.
485.
487.
488.
489.
490.
491.
492.
493.
494.
495.
496.
497.
498.
499.
500.
501.
502.
release and sequestration mechanisms in the hippocampal neuronal culture model of epilepsy. Cell Calcium 30: 285–296, 2001.
Palade GE and Porter KR. Studies on the endoplasmic reticulum.
I. Its identification in cells in situ. J Exp Med 100: 641– 656, 1954.
Palade P, Dettbarn C, Alderson B, and Volpe P. Pharmacologic
differentiation between inositol-1,4,5-trisphosphate-induced Ca2⫹
release and Ca2⫹- or caffeine-induced Ca2⫹ release from intracellular membrane systems. Mol Pharmacol 36: 673– 680, 1989.
Palade P, Dettbarn C, Brunder D, Stein P, and Hals G. Pharmacology of calcium release from sarcoplasmic reticulum. J Bioenerg Biomembr 21: 295–320, 1989.
Palade P, Dettbarn C, Volpe P, Alderson B, and Otero AS.
Direct inhibition of inositol-1,4,5-trisphosphate-induced Ca2⫹ release from brain microsomes by K⫹ channel blockers. Mol Pharmacol 36: 664 – 672, 1989.
Palmi M and Meini A. Role of the nitric oxide/cyclic GMP/Ca2⫹
signaling pathway in the pyrogenic effect of interleukin-1beta. Mol
Neurobiol 25: 133–147, 2002.
Pan ZZ. Kappa-opioid receptor-mediated enhancement of the hyperpolarization-activated current (Ih) through mobilization of intracellular calcium in rat nucleus raphe magnus. J Physiol 548:
765–775, 2003.
Papp S, Dziak E, Michalak M, and Opas M. Is all of the endoplasmic reticulum created equal? The effects of the heterogeneous
distribution of endoplasmic reticulum Ca2⫹-handling proteins.
J Cell Biol 160: 475– 479, 2003.
Parekh AB. Store-operated Ca2⫹ entry: dynamic interplay between
endoplasmic reticulum, mitochondria and plasma membrane.
J Physiol 547: 333–348, 2003.
Parekh AB, Fleig A, and Penner R. The store-operated calcium
current ICRAC: nonlinear activation by InsP3 and dissociation from
calcium release. Cell 89: 973–980, 1997.
Parekh AB and Penner R. Store depletion and calcium influx.
Physiol Rev 77: 901–930, 1997.
Park MK, Petersen OH, and Tepikin AV. The endoplasmic
reticulum as one continuous Ca2⫹ pool: visualization of rapid Ca2⫹
movements and equilibration. EMBO J 19: 5729 –5739, 2000.
Park MK, Tepikin AV, and Petersen OH. What can we learn
about cell signalling by combining optical imaging and patch clamp
techniques? Pflügers Arch 444: 305–316, 2002.
Parker I and Ivorra I. Caffeine inhibits inositol trisphosphatemediated liberation of intracellular calcium in Xenopus oocytes.
J Physiol 433: 229 –240, 1991.
Partridge LD and Valenzuela CF. Ca2⫹ store-dependent potentiation of Ca2⫹-activated non-selective cation channels in rat hippocampal neurones in vitro. J Physiol 521: 617– 627, 1999.
Paschen W. Disturbances of calcium homeostasis within the endoplasmic reticulum may contribute to the development of ischemic-cell damage. Med Hypotheses 47: 283–288, 1996.
Paschen W. Dependence of vital cell function on endoplasmic
reticulum calcium levels: implications for the mechanisms underlying neuronal cell injury in different pathological states. Cell Calcium 29: 1–11, 2001.
Paschen W. Endoplasmic reticulum: a primary target in various
acute disorders and degenerative diseases of the brain. Cell Calcium 34: 365–383, 2003.
Paschen W. Mechanisms of neuronal cell death: diverse roles of
calcium in the various subcellular compartments. Cell Calcium 34:
305–310, 2003.
Paschen W, Doutheil J, Gissel C, and Treiman M. Depletion of
neuronal endoplasmic reticulum calcium stores by thapsigargin:
effect on protein synthesis. J Neurochem 67: 1735–1743, 1996.
Patil C and Walter P. Intracellular signaling from the endoplasmic reticulum to the nucleus: the unfolded protein response in
yeast and mammals. Curr Opin Cell Biol 13: 349 –355, 2001.
Pelled D, Lloyd-Evans E, Riebeling C, Jeyakumar M, Platt
FM, and Futerman AH. Inhibition of calcium uptake via the
sarco/endoplasmic reticulum Ca2⫹-ATPase in a mouse model of
Sandhoff disease and prevention by treatment with N-butyldeoxynojirimycin. J Biol Chem 278: 29496 –29501, 2003.
Peng Y. Ryanodine-sensitive component of calcium transients
evoked by nerve firing at presynaptic nerve terminals. J Neurosci
16: 6703– 6712, 1996.
Physiol Rev • VOL
503. Peppiatt CM, Collins TJ, Mackenzie L, Conway SJ, Holmes
AB, Bootman MD, Berridge MJ, Seo JT, and Roderick HL.
2-Aminoethoxydiphenyl borate (2-APB) antagonises inositol 1,4,5trisphosphate-induced calcium release, inhibits calcium pumps and
has a use-dependent and slowly reversible action on store-operated
calcium entry channels. Cell Calcium 34: 97–108, 2003.
504. Perez-Garcia MJ, Cena V, De Pablo Y, Llovera M, Comella JX,
and Soler RM. Glial cell line-derived neurotrophic factor increases
intracellular calcium concentration: role of calcium/calmodulin in
the activation of the phosphatidylinositol 3-kinase pathway. J Biol
Chem 279: 6132– 6142, 2004.
505. Pessah IN, Waterhouse AL, and Casida JE. The calcium-ryanodine receptor complex of skeletal and cardiac muscle. Biochem
Biophys Res Commun 128: 449 – 456, 1985.
506. Petersen OH, Burdakov D, and Tepikin AV. Polarity in intracellular calcium signaling. Bioessays 21: 851– 860, 1999.
507. Petersen OH, Gerasimenko OV, Gerasimenko JV, Mogami H,
and Tepikin AV. The calcium store in the nuclear envelope. Cell
Calcium 23: 87–90, 1998.
508. Petersen OH, Petersen CC, and Kasai H. Calcium and hormone
action. Annu Rev Physiol 56: 297–319, 1994.
509. Petersen OH, Tepikin A, and Park MK. The endoplasmic reticulum: one continuous or several separate Ca2⫹ stores? Trends
Neurosci 24: 271–276, 2001.
510. Phillis JW, Diaz FG, O’Regan MH, and Pilitsis JG. Effects of
immunosuppressants, calcineurin inhibition, and blockade of endoplasmic reticulum calcium channels on free fatty acid efflux
from the ischemic/reperfused rat cerebral cortex. Brain Res 957:
12–24, 2002.
511. Pinton P, Ferrari D, Rapizzi E, Di Virgilio F, Pozzan T, and
Rizzuto R. The Ca2⫹ concentration of the endoplasmic reticulum
is a key determinant of ceramide-induced apoptosis: significance
for the molecular mechanism of Bcl-2 action. EMBO J 20: 2690 –
2701, 2001.
512. Piriz J, Rosato Siri MD, Pagani R, and Uchitel OD. Nifedipinemediated mobilization of intracellular calcium stores increases
spontaneous neurotransmitter release at neonatal rat motor nerve
terminals. J Pharmacol Exp Ther 306: 658 – 663, 2003.
513. Pollack H. Micrurgical studies in cell physiology. VI. Calcium ions
in living protoplasm. J Gen Physiol 11: 539 –545, 1928.
514. Pollock J, Crawford JH, Wootton JF, Corrie JE, and Scott
RH. A comparison between the distinct inward currents activated
in rat cultured dorsal root ganglion neurones by intracellular flash
photolysis of two forms of caged cyclic guanosine monophosphate.
Neurosci Lett 338: 143–146, 2003.
515. Pollock J, McFarlane SM, Connell MC, Zehavi U, Vandenabeele P, MacEwan DJ, and Scott RH. TNF-alpha receptors simultaneously activate Ca2⫹ mobilisation and stress kinases in cultured sensory neurones. Neuropharmacology 42: 93–106, 2002.
516. Pottorf WJ, Duckles SP, and Buchholz JN. Aging and calcium
buffering in adrenergic neurons. Auton Neurosci 96: 2–7, 2002.
517. Poulsen JC, Caspersen C, Mathiasen D, East JM, Tunwell RE,
Lai FA, Maeda N, Mikoshiba K, and Treiman M. Thapsigarginsensitive Ca2⫹-ATPases account for Ca2⫹ uptake to inositol 1,4,5trisphosphate-sensitive and caffeine-sensitive Ca2⫹ stores in adrenal chromaffin cells. Biochem J 307: 749 –758, 1995.
518. Power JM and Sah P. Nuclear calcium signaling evoked by cholinergic stimulation in hippocampal CA1 pyramidal neurons. J Neurosci 22: 3454 –3462, 2002.
519. Pozzo-Miller LD, Connor JA, and Andrews SB. Microheterogeneity of calcium signalling in dendrites. J Physiol 525: 53– 61, 2000.
520. Pozzo-Miller LD, Pivovarova NB, Leapman RD, Buchanan RA,
Reese TS, and Andrews SB. Activity-dependent calcium sequestration in dendrites of hippocampal neurons in brain slices. J Neurosci 17: 8729 – 8738, 1997.
521. Pringle AK. In, out, shake it all about: elevation of [Ca2⫹]i during
acute cerebral ischaemia. Cell Calcium 36: 235–245, 2004.
522. Putney JW Jr. A model for receptor-regulated calcium entry. Cell
Calcium 7: 1–12, 1986.
523. Putney JW Jr. Capacitative calcium entry revisited. Cell Calcium
11: 611– 624, 1990.
524. Putney JW Jr. Capacitative calcium entry in the nervous system.
Cell Calcium 34: 339 –344, 2003.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
486.
ALEXEI VERKHRATSKY
CALCIUM STORE IN THE ER OF NEURONS
Physiol Rev • VOL
549.
550.
551.
552.
553.
554.
555.
556.
557.
558.
559.
560.
561.
562.
563.
564.
565.
566.
567.
568.
endoplasmic reticulum subcompartment rich in inositol 1,4,5trisphosphate receptors. J Neurocytol 22: 273–282, 1993.
Rutecki PA, Sayin U, Yang Y, and Hadar E. Determinants of ictal
epileptiform patterns in the hippocampal slice. Epilepsia 43 Suppl
5: 179 –183, 2002.
Ryu EJ, Harding HP, Angelastro JM, Vitolo OV, Ron D, and
Greene LA. Endoplasmic reticulum stress and the unfolded protein response in cellular models of Parkinson’s disease. J Neurosci
22: 10690 –10698, 2002.
Ryugo DK, Pongstaporn T, Wright DD, and Sharp AH. Inositol
1,4,5-trisphosphate receptors: immunocytochemical localization in
the dorsal cochlear nucleus. J Comp Neurol 358: 102–118, 1995.
Sabatini BL, Maravall M, and Svoboda K. Ca2⫹ signaling in
dendritic spines. Curr Opin Neurobiol 11: 349 –356, 2001.
Sacchetto R, Cliffer KD, Podini P, Villa A, Christensen BN,
and Volpe P. Intracellular Ca2⫹ stores in chick cerebellum Purkinje neurons: ontogenetic and functional studies. Am J Physiol
Cell Physiol 269: C1219 –C1227, 1995.
Sah P and Faber ES. Channels underlying neuronal calciumactivated potassium currents. Prog Neurobiol 66: 345–353, 2002.
Sah P and McLachlan EM. Ca2⫹-activated K⫹ currents underlying
the afterhyperpolarization in guinea pig vagal neurons: a role for
Ca2⫹-activated Ca2⫹ release. Neuron 7: 257–264, 1991.
Sakaki Y, Sugioka M, Fukuda Y, and Yamashita M. Capacitative
Ca2⫹ influx in the neural retina of chick embryo. J Neurobiol 32:
62– 68, 1997.
Salanki J, Budai D, and Vero M. Modification of bursting in a
Helix neuron by drugs influencing intracellular regulation of calcium level. Acta Physiol Hung 62: 213–224, 1983.
Salinska E, Ziembowicz A, Gordon-Krajcer W, SkangielKramska J, Jablonska B, Makarewicz D, Zieminska E, and
Lazarewicz JW. Differences between rats and rabbits in NMDA
receptor-mediated calcium signalling in hippocampal neurones.
Brain Res Bull 53: 813– 819, 2000.
Sanada M, Yasuda H, Omatsu-Kanbe M, Sango K, Isono T,
Matsuura H, and Kikkawa R. Increase in intracellular Ca2⫹ and
calcitonin gene-related peptide release through metabotropic P2Y
receptors in rat dorsal root ganglion neurons. Neuroscience 111:
413– 422, 2002.
Sandler VM and Barbara JG. Calcium-induced calcium release
contributes to action potential-evoked calcium transients in hippocampal CA1 pyramidal neurons. J Neurosci 19: 4325– 4336, 1999.
Sato N, Imaizumi K, Manabe T, Taniguchi M, Hitomi J, Katayama T, Yoneda T, Morihara T, Yasuda Y, Takagi T, Kudo T,
Tsuda T, Itoyama Y, Makifuchi T, Fraser PE, St GeorgeHyslop P, and Tohyama M. Increased production of beta-amyloid
and vulnerability to endoplasmic reticulum stress by an aberrant
spliced form of presenilin 2. J Biol Chem 276: 2108 –2114, 2001.
Saura CA, Choi SY, Beglopoulos V, Malkani S, Zhang D, Shankaranarayana Rao BS, Chattarji S, Kelleher RJ, Kandel ER,
Duff K, Kirkwood A, and Shen J. Loss of presenilin function
causes impairments of memory and synaptic plasticity followed by
age-dependent neurodegeneration. Neuron 42: 23–36, 2004.
Savic N and Sciancalepore M. Intracellular calcium stores modulate miniature GABA-mediated synaptic currents in neonatal rat
hippocampal neurons. Eur J Neurosci 10: 3379 –3386, 1998.
Schneider I, Reverse D, Dewachter I, Ris L, Caluwaerts N,
Kuiperi C, Gilis M, Geerts H, Kretzschmar H, Godaux E,
Moechars D, Van Leuven F, and Herms J. Mutant presenilins
disturb neuronal calcium homeostasis in the brain of transgenic
mice, decreasing the threshold for excitotoxicity and facilitating
long-term potentiation. J Biol Chem 276: 11539 –11544, 2001.
Schoppe J, Dierkes PW, Hochstrate P, and Schlue WR. NTP,
the photoproduct of nifedipine, activates caffeine-sensitive ion
channels in leech neurons. Cell Calcium 33: 207–221, 2003.
Schuman EM. Synapse specificity and long-term information storage. Neuron 18: 339 –342, 1997.
Schwartz AD, Whitacre CL, and Wilson DF. Do ryanodine receptors regulate transmitter release at the neuromuscular junction
of rat? Neurosci Lett 274: 163–166, 1999.
Sciancalepore M, Savic N, Gyori J, and Cherubini E. Facilitation of miniature GABAergic currents by ruthenium red in neonatal
rat hippocampal neurons. J Neurophysiol 80: 2316 –2322, 1998.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
525. Racca C, Gardiol A, and Triller A. Dendritic and postsynaptic
localizations of glycine receptor alpha subunit mRNAs. J Neurosci
17: 1691–1700, 1997.
526. Rae MG, Martin DJ, Collingridge GL, and Irving AJ. Role of
Ca2⫹ stores in metabotropic L-glutamate receptor-mediated supralinear Ca2⫹ signaling in rat hippocampal neurons. J Neurosci 20:
8628 – 8636, 2000.
527. Raiteri L, Giovedi S, Benfenati F, Raiteri M, and Bonanno G.
Cellular mechanisms of the acute increase of glutamate release
induced by nerve growth factor in rat cerebral cortex. Neuropharmacology 44: 390 – 402, 2003.
528. Reber BF, Stucki JW, and Reuter H. Unidirectional interaction
between two intracellular calcium stores in rat phaeochromocytoma (PC12) cells. J Physiol 468: 711–727, 1993.
529. Reiser MA, D’Souza T, and Dryer SE. Effects of caffeine and
3-isobutyl-1-methylxanthine on voltage-activated potassium currents in vertebrate neurones and secretory cells. Br J Pharmacol
118: 2145–2151, 1996.
530. Reyes M and Stanton PK. Induction of hippocampal long-term
depression requires release of Ca2⫹ from separate presynaptic and
postsynaptic intracellular stores. J Neurosci 16: 5951–5960, 1996.
531. Reyes-Harde M, Empson R, Potter BV, Galione A, and Stanton
PK. Evidence of a role for cyclic ADP-ribose in long-term synaptic
depression in hippocampus. Proc Natl Acad Sci USA 96: 4061–
4066, 1999.
532. Reznikoff P and Chambers R. Micrurgical studies in cell physiology. III. The action of CO2 and some salts of Na, Ca and K on the
protoplasm of Amoeba dubia. J Gen Physiol 10: 731–738, 1927.
533. Ridgway EB and Ashley CC. Calcium transients in single muscle
fibers. Biochem Biophys Res Commun 29: 229 –234, 1967.
534. Rigoni F and Deana R. Ruthenium red inhibits the mitochondrial
Ca2⫹ uptake in intact bovine spermatozoa and increases the cytosolic Ca2⫹ concentration. FEBS Lett 198: 103–108, 1986.
535. Ringer S. A further contribution regarding the influence of different constituents of the blood on the contractions of the heart.
J Physiol 4: 29 – 43, 1883.
536. Ringer S. Further experiments regarding the influence of small
quantituies of lime, potassium and other salts on musclular tissue.
J Physiol 7: 291–308, 1886.
537. Ringer S and Buxton LW. Concerning the action of calcium,
potassium and sodium salts upon the eel’s heart and upon skeletal
muscles of the frog. J Physiol 8: 15–19, 1887.
538. Ritov VB, Men’shikova EV, and Kozlov YP. Heparin induces
Ca2⫹ release from the terminal cisterns of skeletal muscle sarcoplasmic reticulum. FEBS Lett 188: 77– 80, 1985.
539. Rizzuto R and Pozzan T. When calcium goes wrong: genetic
alterations of a ubiquitous signaling route. Nat Genet 34: 135–141,
2003.
540. Rome C, Luo D, and Dulon D. Muscarinic receptor-mediated
calcium signaling in spiral ganglion neurons of the mammalian
cochlea. Brain Res 846: 196 –203, 1999.
541. Ronde P, Dougherty JJ, and Nichols RA. Functional IP3- and
ryanodine-sensitive calcium stores in presynaptic varicosities of
NG108 –15 (rodent neuroblastoma ⫻ glioma hybrid) cells. J Physiol
529: 307–319, 2000.
542. Rose CR and Konnerth A. Stores not just for storage. Intracellular calcium release and synaptic plasticity. Neuron 31: 519 –522,
2001.
543. Rosenbluth J. Subsurface cisterns and their relationship to the
neuronal plasma membrane. J Cell Biol 13: 405– 421, 1962.
544. Rossi CS, Carafoli E, and Lehninger AL. Active ion transport by
mitochondria. Protoplasma 63: 90 –94, 1967.
545. Rossi D and Sorrentino V. Molecular genetics of ryanodine receptors Ca2⫹-release channels. Cell Calcium 32: 307–319, 2002.
546. Rossier MF, Python CP, Burnay MM, Schlegel W, Vallotton
MB, and Capponi AM. Thapsigargin inhibits voltage-activated
calcium channels in adrenal glomerulosa cells. Biochem J 296:
309 –312, 1993.
547. Rousseau E and Meissner G. Single cardiac sarcoplasmic reticulum Ca2⫹-release channel: activation by caffeine. Am J Physiol
Heart Circ Physiol 256: H328 –H333, 1989.
548. Rusakov DA, Podini P, Villa A, and Meldolesi J. Tridimensional
organization of Purkinje neuron cisternal stacks, a specialized
275
276
ALEXEI VERKHRATSKY
Physiol Rev • VOL
591.
592.
593.
594.
595.
596.
597.
598.
599.
600.
601.
602.
603.
604.
605.
606.
607.
608.
609.
610.
611.
phate receptors and ryanodine receptors in cerebellar granule neurones. J Neurochem 67: 364 –373, 1996.
Sitia R and Braakman I. Quality control in the endoplasmic
reticulum protein factory. Nature 426: 891– 894, 2003.
Sitsapesan R, McGarry SJ, and Williams AJ. Cyclic ADP-ribose
competes with ATP for the adenine nucleotide binding site on the
cardiac ryanodine receptor Ca2⫹-release channel. Circ Res 75:
596 – 600, 1994.
Sitsapesan R and Williams AJ. Mechanisms of caffeine activation of single calcium-release channels of sheep cardiac sarcoplasmic reticulum. J Physiol 423: 425– 439, 1990.
Sitsapesan R and Williams AJ. Modification of the conductance
and gating properties of ryanodine receptors by suramin. J Membr
Biol 153: 93–103, 1996.
Sitsapesan R and Williams AJ. Do inactivation mechanisms
rather than adaptation hold the key to understanding ryanodine
receptor channel gating? J Gen Physiol 116: 867– 872, 2000.
Smith IF, Boyle JP, Vaughan PF, Pearson HA, Cowburn RF,
and Peers CS. Ca2⫹ stores and capacitative Ca2⫹ entry in human
neuroblastoma (SH-SY5Y) cells expressing a familial Alzheimer’s
disease presenilin-1 mutation. Brain Res 949: 105–111, 2002.
Smith SJ, MacDermott AB, and Weight FF. Detection of intracellular Ca2⫹ transients in sympathetic neurones using arsenazo III.
Nature 304: 350 –352, 1983.
Snyder HR Jr, Davis CS, Bickerton RK, and Halliday RP.
1-[(5-Arylfurfurylidene)amino]hydantoins. A new class of muscle
relaxants. J Med Chem 10: 807– 810, 1967.
Sokal DM, Mason R, and Parker TL. Multi-neuronal recordings
reveal a differential effect of thapsigargin on bicuculline- or gabazine-induced epileptiform excitability in rat hippocampal neuronal
networks. Neuropharmacology 39: 2408 –2417, 2000.
Solovyova N, Fernyhough P, Glazner G, and Verkhratsky A.
Xestospongin C empties the ER calcium store but does not inhibit
InsP3-induced Ca2⫹ release in cultured dorsal root ganglia neurones. Cell Calcium 32: 49 –52, 2002.
Solovyova N and Verkhratsky A. Monitoring of free calcium in
the neuronal endoplasmic reticulum: an overview of modern approaches. J Neurosci Methods 122: 1–12, 2002.
Solovyova N and Verkhratsky A. Neuronal endoplasmic reticulum acts as a single functional Ca2⫹ store shared by ryanodine and
inositol-1,4,5-trisphosphate receptors as revealed by intra-ER
[Ca2⫹] recordings in single rat sensory neurones. Pflügers Arch 446:
447– 454, 2003.
Solovyova N, Veselovsky N, Toescu EC, and Verkhratsky A.
Ca2⫹ dynamics in the lumen of the endoplasmic reticulum in
sensory neurons: direct visualization of Ca2⫹-induced Ca2⫹ release
triggered by physiological Ca2⫹ entry. EMBO J 21: 622– 630, 2002.
Spacek J and Harris KM. Three-dimensional organization of
smooth endoplasmic reticulum in hippocampal CA1 dendrites and
dendritic spines of the immature and mature rat. J Neurosci 17:
190 –203, 1997.
Spencer RJ, Jin W, Thayer SA, Chakrabarti S, Law PY, and
Loh HH. Mobilization of Ca2⫹ from intracellular stores in transfected neuro2a cells by activation of multiple opioid receptor subtypes. Biochem Pharmacol 54: 809 – 818, 1997.
Steward O. mRNA localization in neurons: a multipurpose mechanism? Neuron 18: 9 –12, 1997.
Streb H, Irvine RF, Berridge MJ, and Schulz I. Release of Ca2⫹
from a nonmitochondrial intracellular store in pancreatic acinar
cells by inositol-1,4,5-trisphosphate. Nature 306: 67– 69, 1983.
Stutzmann GE, Caccamo A, LaFerla FM, and Parker I. Dysregulated IP3 signaling in cortical neurons of knock-in mice expressing an Alzheimer’s-linked mutation in presenilin1 results in
exaggerated Ca2⫹ signals and altered membrane excitability.
J Neurosci 24: 508 –513, 2004.
Stutzmann GE, LaFerla FM, and Parker I. Ca2⫹ signaling in
mouse cortical neurons studied by two-photon imaging and photoreleased inositol triphosphate. J Neurosci 23: 758 –765, 2003.
Subramanian K and Meyer T. Calcium-induced restructuring of
nuclear envelope and endoplasmic reticulum calcium stores. Cell
89: 963–971, 1997.
Sukhareva M, Smith SV, Maric D, and Barker JL. Functional
properties of ryanodine receptors in hippocampal neurons change
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
569. Seta KA, Yuan Y, Spicer Z, Lu G, Bedard J, Ferguson TK,
Pathrose P, Cole-Strauss A, Kaufhold A, and Millhorn DE.
The role of calcium in hypoxia-induced signal transduction and
gene expression. Cell Calcium 36: 331–340, 2004.
570. Seutin V, Mkahli F, Massotte L, and Dresse A. Calcium release
from internal stores is required for the generation of spontaneous
hyperpolarizations in dopaminergic neurons of neonatal rats.
J Neurophysiol 83: 192–197, 2000.
571. Seymour-Laurent KJ and Barish ME. Inositol 1,4,5-trisphosphate and ryanodine receptor distributions and patterns of acetylcholine- and caffeine-induced calcium release in cultured mouse
hippocampal neurons. J Neurosci 15: 2592–2608, 1995.
572. Shah M and Haylett DG. Ca2⫹ channels involved in the generation of the slow afterhyperpolarization in cultured rat hippocampal
pyramidal neurons. J Neurophysiol 83: 2554 –2561, 2000.
573. Sharma G and Vijayaraghavan S. Modulation of presynaptic
store calcium induces release of glutamate and postsynaptic firing.
Neuron 38: 929 –939, 2003.
574. Sharp AH, McPherson PS, Dawson TM, Aoki C, Campbell KP,
and Snyder SH. Differential immunohistochemical localization of
inositol 1,4,5-trisphosphate- and ryanodine-sensitive Ca2⫹ release
channels in rat brain. J Neurosci 13: 3051–3063, 1993.
575. Sharp AH, Nucifora FC Jr, Blondel O, Sheppard CA, Zhang C,
Snyder SH, Russell JT, Ryugo DK, and Ross CA. Differential
cellular expression of isoforms of inositol 1,4,5-triphosphate receptors in neurons and glia in brain. J Comp Neurol 406: 207–220, 1999.
576. Shen W and Slaughter MM. Internal calcium modulates apparent
affinity of metabotropic GABA receptors. J Neurophysiol 82: 3298 –
3306, 1999.
577. Shibata M, Hattori H, Sasaki T, Gotoh J, Hamada J, and
Fukuuchi Y. Activation of caspase-12 by endoplasmic reticulum
stress induced by transient middle cerebral artery occlusion in
mice. Neuroscience 118: 491– 499, 2003.
578. Shimuta M, Yoshikawa M, Fukaya M, Watanabe M, Takeshima
H, and Manabe T. Postsynaptic modulation of AMPA receptormediated synaptic responses and LTP by the type 3 ryanodine
receptor. Mol Cell Neurosci 17: 921–930, 2001.
579. Shirasaki T, Houtani T, Sugimoto T, and Matsuda H. Spontaneous transient outward currents: modulation by nociceptin in
murine dentate gyrus granule cells. Brain Res 917: 191–205, 2001.
580. Shmigol A, Eisner D, and Verkhratsky A. Cyclic ADP ribose
enhances Ca2⫹-induced Ca2⫹ release in isolated mouse sensory
neurones. J Physiol 483: P63-P64, 1995.
581. Shmigol A, Kirischuk S, Kostyuk P, and Verkhratsky A. Different properties of caffeine-sensitive Ca2⫹ stores in peripheral and
central mammalian neurones. Pflügers Arch 426: 174 –176, 1994.
582. Shmigol A, Kostyuk P, and Verkhratsky A. Dual action of
thapsigargin on calcium mobilization in sensory neurons: inhibition
of Ca2⫹ uptake by caffeine-sensitive pools and blockade of plasmalemmal Ca2⫹ channels. Neuroscience 65: 1109 –1118, 1995.
583. Shmigol A, Kostyuk P, and Verkhratsky A. Role of caffeinesensitive Ca2⫹ stores in Ca2⫹ signal termination in adult mouse
DRG neurones. Neuroreport 5: 2073–2076, 1994.
584. Shmigol A, Svichar N, Kostyuk P, and Verkhratsky A. Gradual
caffeine-induced Ca2⫹ release in mouse dorsal root ganglion neurons is controlled by cytoplasmic and luminal Ca2⫹. Neuroscience
73: 1061–1067, 1996.
585. Shmigol A, Verkhratsky A, and Isenberg G. Calcium-induced
calcium release in rat sensory neurons. J Physiol 489: 627– 636,
1995.
586. Shoop RD, Chang KT, Ellisman MH, and Berg DK. Synaptically
driven calcium transients via nicotinic receptors on somatic spines.
J Neurosci 21: 771–781, 2001.
587. Shull GE. Gene knockout studies of Ca2⫹-transporting ATPases.
Eur J Biochem 267: 5284 –5290, 2000.
588. Silver IA and Erecinska M. Intracellular and extracellular
changes of [Ca2⫹] in hypoxia and ischemia in rat brain in vivo.
J Gen Physiol 95: 837– 866, 1990.
589. Simkus CR and Stricker C. The contribution of intracellular
calcium stores to mEPSCs recorded in layer II neurones of rat
barrel cortex. J Physiol 545: 521–535, 2002.
590. Simpson PB, Nahorski SR, and Challiss RA. Agonist-evoked
Ca2⫹ mobilization from stores expressing inositol 1,4,5-trisphos-
CALCIUM STORE IN THE ER OF NEURONS
612.
613.
614.
615.
616.
618.
619.
620.
621.
622.
623.
624.
625.
626.
627.
628.
629.
630.
631.
632.
633.
634.
Physiol Rev • VOL
635. Terro F, Czech C, Esclaire F, Elyaman W, Yardin C, Baclet
MC, Touchet N, Tremp G, Pradier L, and Hugon J. Neurons
overexpressing mutant presenilin-1 are more sensitive to apoptosis
induced by endoplasmic reticulum-Golgi stress. J Neurosci Res 69:
530 –539, 2002.
636. Thayer SA, Hirning LD, and Miller RJ. The role of caffeinesensitive calcium stores in the regulation of the intracellular free
calcium concentration in rat sympathetic neurons in vitro. Mol
Pharmacol 34: 664 – 673, 1988.
637. Thayer SA, Perney TM, and Miller RJ. Regulation of calcium
homeostasis in sensory neurons by bradykinin. J Neurosci 8: 4089 –
4097, 1988.
638. Thayer SA, Sturek M, and Miller RJ. Measurement of neuronal
Ca2⫹ transients using simultaneous microfluorimetry and electrophysiology. Pflügers Arch 412: 216 –223, 1988.
639. Thibault O and Landfield PW. Increase in single L-type calcium
channels in hippocampal neurons during aging. Science 272: 1017–
1020, 1996.
640. Thibault O, Porter NM, Chen KC, Blalock EM, Kaminker PG,
Clodfelter GV, Brewer LD, and Landfield PW. Calcium dysregulation in neuronal aging and Alzheimer’s disease: history and new
directions. Cell Calcium 24: 417– 433, 1998.
641. Thomas RC. The effects of HCl and CaCl2 injections on intracellular calcium and pH in voltage-clamped snail (Helix aspersa)
neurons. J Gen Physiol 120: 567–579, 2002.
642. Thorn P, Gerasimenko O, and Petersen OH. Cyclic ADP-ribose
regulation of ryanodine receptors involved in agonist evoked cytosolic Ca2⫹ oscillations in pancreatic acinar cells. EMBO J 13:
2038 –2043, 1994.
643. Thrower EC, Mobasheri H, Dargan S, Marius P, Lea EJ, and
Dawson AP. Interaction of luminal calcium and cytosolic ATP in
the control of type 1 inositol (1,4,5)-trisphosphate receptor channels. J Biol Chem 275: 36049 –36055, 2000.
644. Toescu EC. Hypoxia sensing and pathways of cytosolic Ca2⫹
increases. Cell Calcium 36: 187–199, 2004.
645. Toescu EC, O’Neill SC, Petersen OH, and Eisner DA. Caffeine
inhibits the agonist-evoked cytosolic Ca2⫹ signal in mouse pancreatic acinar cells by blocking inositol trisphosphate production.
J Biol Chem 267: 23467–23470, 1992.
646. Toescu EC and Verkhratsky A. Parameters of calcium homeostasis in normal neuronal ageing. J Anat 197: 563–569, 2000.
647. Toescu EC and Verkhratsky A. Neuronal ageing from an intraneuronal perspective: roles of endoplasmic reticulum and mitochondria. Cell Calcium 34: 311–323, 2003.
648. Tozzi A, Bengtson CP, Longone P, Carignani C, Fusco FR,
Bernardi G, and Mercuri NB. Involvement of transient receptor
potential-like channels in responses to mGluR-I activation in midbrain dopamine neurons. Eur J Neurosci 18: 2133–2145, 2003.
649. Trotta EE and de Meis L. ATP-dependent calcium accumulation
in brain microsomes. Enhancement by phosphate and oxalate.
Biochim Biophys Acta 394: 239 –247, 1975.
650. Tsai TD and Barish ME. Imaging of caffeine-inducible release of
intracellular calcium in cultured embryonic mouse telencephalic
neurons. J Neurobiol 27: 252–265, 1995.
651. Tse FW, Tse A, and Hille B. Cyclic Ca2⫹ changes in intracellular
stores of gonadotropes during gonadotropin-releasing hormonestimulated Ca2⫹ oscillations. Proc Natl Acad Sci USA 91: 9750 –
9754, 1994.
652. Tse FW, Tse A, Hille B, Horstmann H, and Almers W. Local
Ca2⫹ release from internal stores controls exocytosis in pituitary
gonadotrophs. Neuron 18: 121–132, 1997.
653. Tsien RY. A non-disruptive technique for loading calcium buffers
and indicators into cells. Nature 290: 527–528, 1981.
654. Tsien RY, Pozzan T, and Rink TJ. Calcium homeostasis in intact
lymphocytes: cytoplasmic free calcium monitored with a new,
intracellularly trapped fluorescent indicator. J Cell Biol 94: 325–
334, 1982.
655. Tsuneki H, Klink R, Lena C, Korn H, and Changeux JP. Calcium mobilization elicited by two types of nicotinic acetylcholine
receptors in mouse substantia nigra pars compacta. Eur J Neurosci
12: 2475–2485, 2000.
656. Tu JC, Xiao B, Yuan JP, Lanahan AA, Leoffert K, Li M, Linden
DJ, and Worley PF. Homer binds a novel proline-rich motif and
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
617.
during early differentiation in culture. J Neurophysiol 88: 1077–
1087, 2002.
Sun MK, Nelson TJ, and Alkon DL. Functional switching of
GABAergic synapses by ryanodine receptor activation. Proc Natl
Acad Sci USA 97: 12300 –12305, 2000.
Supattapone S, Worley PF, Baraban JM, and Snyder SH. Solubilization, purification, and characterization of an inositol
trisphosphate receptor. J Biol Chem 263: 1530 –1534, 1988.
Sutko JL, Airey JA, Welch W, and Ruest L. The pharmacology
of ryanodine and related compounds. Pharmacol Rev 49: 53–98,
1997.
Svichar N, Shmigol A, Verkhratsky A, and Kostyuk P. ATP
induces Ca2⫹ release from IP3-sensitive Ca2⫹ stores exclusively in
large DRG neurones. Neuroreport 8: 1555–1559, 1997.
Svichar N, Shmigol A, Verkhratsky A, and Kostyuk P. InsP3induced Ca2⫹ release in dorsal root ganglion neurones. Neurosci
Lett 227: 107–110, 1997.
Svoboda K and Mainen ZF. Synaptic [Ca2⫹]: intracellular stores
spill their guts. Neuron 22: 427– 430, 1999.
Sweadner KJ and Donnet C. Structural similarities of Na,KATPase and SERCA, the Ca2⫹-ATPase of the sarcoplasmic reticulum. Biochem J 356: 685–704, 2001.
Szent-Gyorgyi A. Chemistry of Muscular Contraction. New York:
Academic, 1945.
Takahashi K and Wood RL. Subsurface cisterns in the Purkinje
cells of cerebellum of Syrian hamster. Z Zellforsch Mikrosk Anat
110: 311–320, 1970.
Takahashi M and Alford S. The requirement of presynaptic
metabotropic glutamate receptors for the maintenance of locomotion. J Neurosci 22: 3692–3699, 2002.
Takahashi M, Tanzawa K, and Takahashi S. Adenophostins,
newly discovered metabolites of Penicillium brevicompactum, act
as potent agonists of the inositol 1,4,5-trisphosphate receptor.
J Biol Chem 269: 369 –372, 1994.
Takahashi R and Imai Y. Pael receptor, endoplasmic reticulum
stress, and Parkinson’s disease. J Neurol 250 Suppl 3: III-25–III-29,
2003.
Takechi H, Eilers J, and Konnerth A. A new class of synaptic
response involving calcium release in dendritic spines. Nature 396:
757–760, 1998.
Takei K, Mignery GA, Mugnaini E, Sudhof TC, and De Camilli
P. Inositol 1,4,5-trisphosphate receptor causes formation of ER
cisternal stacks in transfected fibroblasts and in cerebellar Purkinje cells. Neuron 12: 327–342, 1994.
Takei K, Shin RM, Inoue T, Kato K, and Mikoshiba K. Regulation of nerve growth mediated by inositol 1,4,5-trisphosphate
receptors in growth cones. Science 282: 1705–1708, 1998.
Tamatani M, Matsuyama T, Yamaguchi A, Mitsuda N, Tsukamoto Y, Taniguchi M, Che YH, Ozawa K, Hori O, Nishimura H,
Yamashita A, Okabe M, Yanagi H, Stern DM, Ogawa S, and
Tohyama M. ORP150 protects against hypoxia/ischemia-induced
neuronal death. Nat Med 7: 317–323, 2001.
Tang TS, Tu H, Chan EY, Maximov A, Wang Z, Wellington CL,
Hayden MR, and Bezprozvanny I. Huntingtin and huntingtinassociated protein 1 influence neuronal calcium signaling mediated
by inositol-(1,4,5) triphosphate receptor type 1. Neuron 39: 227–
239, 2003.
Tata AM, Tripiciano A, Filippini A, Biagioni S, and AugustiTocco G. Muscarinic receptors modulate intracellular calcium
level in chick sensory neurons. Brain Res 866: 65–72, 2000.
Tauskela JS and Morley P. On the role of Ca2⫹ in cerebral
ischemic preconditioning. Cell Calcium 36: 313–322, 2004.
Taylor CW and Laude AJ. IP3 receptors and their regulation by
calmodulin and cytosolic Ca2⫹. Cell Calcium 32: 321–334, 2002.
Terasaki M. Fluorescent labeling of endoplasmic reticulum. Methods Cell Biol 29: 125–135, 1990.
Terasaki M, Henson J, Begg D, Kaminer B, and Sardet C.
Characterization of sea urchin egg endoplasmic reticulum in cortical preparations. Dev Biol 148: 398 – 401, 1991.
Terasaki M, Slater NT, Fein A, Schmidek A, and Reese TS.
Continuous network of endoplasmic reticulum in cerebellar Purkinje neurons. Proc Natl Acad Sci USA 91: 7510 –7514, 1994.
277
278
657.
658.
659.
660.
661.
663.
664.
665.
666.
667.
668.
669.
670.
671.
672.
673.
674.
675.
676.
677.
678.
679.
links group 1 metabotropic glutamate receptors with IP3 receptors.
Neuron 21: 717–726, 1998.
Tully K and Treistman SN. Distinct intracellular calcium profiles
following influx through N vs. L type calcium channels: role of
Ca2⫹-induced Ca2⫹ release. J Neurophysiol 92: 135–143, 2004.
Uneyama H, Munakata M, and Akaike N. Caffeine response in
pyramidal neurons freshly dissociated from rat hippocampus.
Brain Res 604: 24 –31, 1993.
Ungerstedt U, Ljungberg T, and Steg G. Behavioral, physiological, and neurochemical changes after 6-hydroxydopamine-induced
degeneration of the nigro-striatal dopamine neurons. Adv Neurol 5:
421– 426, 1974.
Usachev Y, Kostyuk P, and Verkhratsky A. 3-Isobutyl-1-methylxanthine (IBMX) affects potassium permeability in rat sensory
neurones via pathways that are sensitive and insensitive to
[Ca2⫹]in. Pflügers Arch 430: 420 – 428, 1995.
Usachev Y, Shmigol A, Pronchuk N, Kostyuk P, and Verkhratsky A. Caffeine-induced calcium release from internal stores in
cultured rat sensory neurons. Neuroscience 57: 845– 859, 1993.
Usachev Y and Verkhratsky A. IBMX induces calcium release
from intracellular stores in rat sensory neurones. Cell Calcium 17:
197–206, 1995.
Usachev YM and Thayer SA. All-or-none Ca2⫹ release from intracellular stores triggered by Ca2⫹ influx through voltage-gated
Ca2⫹ channels in rat sensory neurons. J Neurosci 17: 7404 –7414,
1997.
Usachev YM and Thayer SA. Ca2⫹ influx in resting rat sensory
neurones that regulates and is regulated by ryanodine-sensitive
Ca2⫹ stores. J Physiol 519: 115–130, 1999.
Vanden Berghe P, Missiaen L, Janssens J, and Tack J. Calcium
signalling and removal mechanisms in myenteric neurones. Neurogastroenterol Motil 14: 63–73, 2002.
Vanden Berghe P, Tack J, Andrioli A, Missiaen L, and Janssens J. Receptor-induced Ca2⫹ signaling in cultured myenteric
neurons. Am J Physiol Gastrointest Liver Physiol 278: G905–G914,
2000.
Van Goor F, Krsmanovic LZ, Catt KJ, and Stojilkovic SS.
Coordinate regulation of gonadotropin-releasing hormone neuronal firing patterns by cytosolic calcium and store depletion. Proc
Natl Acad Sci USA 96: 4101– 4106, 1999.
Veratti E. Richerche sulle fine struttura della fibra muscolara
striata. Memorie Inst Lomb Cl Sci Mat e Nat 19: 87–133, 1902.
Veratti E. Investigations on the fine structure of striated muscle
fiber (translation of the original 1902 paper). J Biophys Biochem
Cytol 10: 3–59, 1961.
Verkhratsky A. The endoplasmic reticulum and neuronal calcium
signalling. Cell Calcium 32: 393– 404, 2002.
Verkhratsky A and Petersen OH. The endoplasmic reticulum as
an integrating signalling organelle: from neuronal signalling to
neuronal death. Eur J Pharmacol 447: 141–154, 2002.
Verkhratsky A and Petersen OH. Neuronal calcium stores. Cell
Calcium 24: 333–343, 1998.
Verkhratsky A and Shmigol A. Calcium-induced calcium release
in neurones. Cell Calcium 19: 1–14, 1996.
Verkhratsky A, Shmigol A, Kirischuk S, Pronchuk N, and
Kostyuk P. Age-dependent changes in calcium currents and calcium homeostasis in mammalian neurons. Ann NY Acad Sci 747:
365–381, 1994.
Verkhratsky A and Toescu EC. Calcium and neuronal ageing.
Trends Neurosci 21: 2–7, 1998.
Vites AM and Pappano AJ. Ruthenium red selectively prevents
Ins(1,4,5)P3-but not caffeine-gated calcium release in avian atrium.
Am J Physiol Heart Circ Physiol 262: H268 –H277, 1992.
Voeltz GK, Rolls MM, and Rapoport TA. Structural organization
of the endoplasmic reticulum. EMBO Rep 3: 944 –950, 2002.
Vogalis F, Furness JB, and Kunze WA. Afterhyperpolarization
current in myenteric neurons of the guinea pig duodenum. J Neurophysiol 85: 1941–1951, 2001.
Voitenko NV, Kostyuk EP, Kruglikov IA, and Kostyuk PG.
Changes in calcium signalling in dorsal horn neurons in rats with
streptozotocin-induced diabetes. Neuroscience 94: 887– 890, 1999.
Physiol Rev • VOL
680. Wakui M, Osipchuk YV, and Petersen OH. Receptor-activated
cytoplasmic Ca2⫹ spiking mediated by inositol trisphosphate is due
to Ca2⫹-induced Ca2⫹ release. Cell 63: 1025–1032, 1990.
681. Wakui M, Potter BV, and Petersen OH. Pulsatile intracellular
calcium release does not depend on fluctuations in inositol
trisphosphate concentration. Nature 339: 317–320, 1989.
682. Walz B. Ca2⫹-sequestering smooth endoplasmic reticulum in an
invertebrate photoreceptor. I. Intracellular topography as revealed
by OsFeCN staining and in situ Ca accumulation. J Cell Biol 93:
839 – 848, 1982.
683. Wamil AW, Franks JJ, Janicki PK, Horn JL, and Franks WT.
Halothane alters electrical activity and calcium dynamics in cultured mouse cortical, spinal cord, and dorsal root ganglion neurons. Neurosci Lett 216: 93–96, 1996.
684. Wang C, Nguyen HN, Maguire JL, and Perry DC. Role of
intracellular calcium stores in cell death from oxygen-glucose deprivation in a neuronal cell line. J Cereb Blood Flow Metab 22:
206 –214, 2002.
685. Wang CY, Yang F, He X, Chow A, Du J, Russell JT, and Lu B.
Ca2⫹ binding protein frequenin mediates GDNF-induced potentiation of Ca2⫹ channels and transmitter release. Neuron 32: 99 –112,
2001.
686. Watras J, Orlando R, and Moraru II. An endogenous sulfated
inhibitor of neuronal inositol trisphosphate receptors. Biochemistry 39: 3452–3460, 2000.
687. Watson WD, Facchina SL, Grimaldi M, and Verma A. Sarcoendoplasmic reticulum Ca2⫹ ATPase (SERCA) inhibitors identify a
novel calcium pool in the central nervous system. J Neurochem 87:
30 – 43, 2003.
688. Weber A. The mechanism of the action of caffeine on sarcoplasmic reticulum. J Gen Physiol 52: 760 –772, 1968.
689. Weber JT, Rzigalinski BA, and Ellis EF. Traumatic injury of
cortical neurons causes changes in intracellular calcium stores and
capacitative calcium influx. J Biol Chem 276: 1800 –1807, 2001.
690. Weber JT, Rzigalinski BA, and Ellis EF. Calcium responses to
caffeine and muscarinic receptor agonists are altered in traumatically injured neurons. J Neurotrauma 19: 1433–1443, 2002.
691. Weise E. Untersuchingen zur Frage der Verteilung und der Bindungsart des Calciums in Muskel. Naunun-Schmiedeberg’s Arch
Exp Pathol Pharm 176: 367–372, 1934.
692. West AE, Chen WG, Dalva MB, Dolmetsch RE, Kornhauser
JM, Shaywitz AJ, Takasu MA, Tao X, and Greenberg ME.
Calcium regulation of neuronal gene expression. Proc Natl Acad
Sci USA 98: 11024 –11031, 2001.
693. Westrum LE and Gray EG. New observations on the substructure
of the active zone of brain synapses and motor endplates. Proc R
Soc Lond B Biol Sci 229: 29 –38, 1986.
694. Wilcox RA, Primrose WU, Nahorski SR, and Challiss RA. New
developments in the molecular pharmacology of the myo-inositol
1,4,5-trisphosphate receptor. Trends Pharmacol Sci 19: 467– 475,
1998.
695. Williams AJ, West DJ, and Sitsapesan R. Light at the end of the
Ca2⫹-release channel tunnel: structures and mechanisms involved
in ion translocation in ryanodine receptor channels. Q Rev Biophys
34: 61–104, 2001.
696. Willoughby D, Thomas R, and Schwiening C. The effects of
intracellular pH changes on resting cytosolic calcium in voltageclamped snail neurones. J Physiol 530: 405– 416, 2001.
697. Womack MD, Walker JW, and Khodakhah K. Impaired calcium
release in cerebellar Purkinje neurons maintained in culture. J Gen
Physiol 115: 339 –346, 2000.
698. Woodward AA Jr. The release of radioactive 45Ca from muscle
during stimulation. Biol Bull 97: 264, 1949.
699. Wuytack F, Raeymaekers L, and Missiaen L. Molecular physiology of the SERCA and SPCA pumps. Cell Calcium 32: 279 –305,
2002.
700. Xiong J, Verkhratsky A, and Toescu EC. Changes in mitochondrial status associated with altered Ca2⫹ homeostasis in aged cerebellar granule neurons in brain slices. J Neurosci 22: 10761–10771,
2002.
701. Xu B, Gottschalk W, Chow A, Wilson RI, Schnell E, Zang K,
Wang D, Nicoll RA, Lu B, and Reichardt LF. The role of brainderived neurotrophic factor receptors in the mature hippocampus:
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
662.
ALEXEI VERKHRATSKY
CALCIUM STORE IN THE ER OF NEURONS
702.
703.
704.
705.
706.
708.
709.
710.
711.
712.
Physiol Rev • VOL
713. Yu Z, Luo H, Fu W, and Mattson MP. The endoplasmic reticulum
stress-responsive protein GRP78 protects neurons against excitotoxicity and apoptosis: suppression of oxidative stress and stabilization of calcium homeostasis. Exp Neurol 155: 302–314, 1999.
714. Zacchetti D, Clementi E, Fasolato C, Lorenzon P, Zottini M,
Grohovaz F, Fumagalli G, Pozzan T, and Meldolesi J. Intracellular Ca2⫹ pools in PC12 cells. A unique, rapidly exchanging pool is
sensitive to both inositol 1,4,5-trisphosphate and caffeine-ryanodine. J Biol Chem 266: 20152–20158, 1991.
715. Zhao FL, Lu SG, and Herness S. Dual actions of caffeine on
voltage-dependent currents and intracellular calcium in taste receptor cells. Am J Physiol Regul Integr Comp Physiol 283: R115–
R129, 2002.
716. Zhao W, Meiri N, Xu H, Cavallaro S, Quattrone A, Zhang L,
and Alkon DL. Spatial learning induced changes in expression of
the ryanodine type II receptor in the rat hippocampus. FASEB J 14:
290 –300, 2000.
717. Zho US and Ross WN. Threshold conditions for synaptically evoking Ca2⫹ waves in hippocampal pyramidal neurons. J Neurophysiol
87: 1799 –1804, 2002.
718. Zhou WL, Sugioka M, Sakaki Y, and Yamashita M. Regulation
of capacitative Ca2⫹ entry by tyrosine phosphorylation in the neural retina of chick embryo. Neurosci Lett 272: 123–126, 1999.
719. Zorzato F, Scutari E, Tegazzin V, Clementi E, and Treves S.
Chlorocresol: an activator of ryanodine receptor-mediated Ca2⫹
release. Mol Pharmacol 44: 1192–1201, 1993.
720. Zucchi R and Ronca-Testoni S. The sarcoplasmic reticulum Ca2⫹
channel/ryanodine receptor: modulation by endogenous effectors,
drugs and disease states. Pharmacol Rev 49: 1–51, 1997.
721. Zucker RS and Regehr WG. Short-term synaptic plasticity. Annu
Rev Physiol 64: 355– 405, 2002.
722. Zufall F, Leinders-Zufall T, and Greer CA. Amplification of
odor-induced Ca2⫹ transients by store-operated Ca2⫹ release and
its role in olfactory signal transduction. J Neurophysiol 83: 501–
512, 2000.
723. Zupanc GK, Airey JA, Maler L, Sutko JL, and Ellisman MH.
Immunohistochemical localization of ryanodine binding proteins in
the central nervous system of gymnotiform fish. J Comp Neurol
325: 135–151, 1992.
85 • JANUARY 2005 •
www.prv.org
Downloaded from http://physrev.physiology.org/ by 10.220.33.2 on May 10, 2017
707.
modulation of long-term potentiation through a presynaptic mechanism involving TrkB. J Neurosci 20: 6888 – 6897, 2000.
Xu K, Tavernarakis N, and Driscoll M. Necrotic cell death in C.
elegans requires the function of calreticulin and regulators of Ca2⫹
release from the endoplasmic reticulum. Neuron 31: 957–971, 2001.
Xu L, Tripathy A, Pasek DA, and Meissner G. Potential for
pharmacology of ryanodine receptor/calcium release channels.
Ann NY Acad Sci 853: 130 –148, 1998.
Yamamoto K, Hashimoto K, Isomura Y, Shimohama S, and
Kato N. An IP3-assisted form of Ca2⫹-induced Ca2⫹ release in
neocortical neurons. Neuroreport 11: 535–539, 2000.
Yamamoto K, Nakano M, Hashimoto K, Shimohama S, and
Kato N. Emergence of a functional coupling between inositol-1,4,5trisphosphate receptors and calcium channels in developing neocortical neurons. Neuroscience 109: 677– 685, 2002.
Yang F, He X, Feng L, Mizuno K, Liu XW, Russell J, Xiong WC,
and Lu B. PI-3 kinase and IP3 are both necessary and sufficient to
mediate NT3-induced synaptic potentiation. Nat Neurosci 4: 19 –28,
2001.
Yang J, McBride S, Mak DO, Vardi N, Palczewski K, Haeseleer
F, and Foskett JK. Identification of a family of calcium sensors as
protein ligands of inositol trisphosphate receptor Ca2⫹ release
channels. Proc Natl Acad Sci USA 99: 7711–7716, 2002.
Yao H and Haddad GG. Calcium and pH homeostasis in neurons
during hypoxia and ischemia. Cell Calcium 36: 247–255, 2004.
Yoo AS, Cheng I, Chung S, Grenfell TZ, Lee H, Pack-Chung E,
Handler M, Shen J, Xia W, Tesco G, Saunders AJ, Ding K,
Frosch MP, Tanzi RE, and Kim TW. Presenilin-mediated modulation of capacitative calcium entry. Neuron 27: 561–572, 2000.
Yoshimura H, Sugai T, Onoda N, Segami N, and Kato N.
Synchronized population oscillation of excitatory synaptic potentials dependent of calcium-induced calcium release in rat neocortex layer II/III neurons. Brain Res 915: 94 –100, 2001.
Yoshizaki K, Hoshino T, Sato M, Koyano H, Nohmi M, Hua SY,
and Kuba K. Ca2⫹-induced Ca2⫹ release and its activation in
response to a single action potential in rabbit otic ganglion cells.
J Physiol 486: 177–187, 1995.
Young KW and Nahorski SR. Sphingosine 1-phosphate: a Ca2⫹
release mediator in the balance. Cell Calcium 32: 335–341, 2002.
279