Excitation-contraction Coupling in the Heart and the Negative
... Ca2⫹ sparks as well as individual spark amplitude. Ca2⫹ Transport Systems The increase in cytosolic [Ca2⫹] and the accompanying force development after electrical activation is transient because Ca2⫹ is rapidly removed from the cytosol after release. There are four main Ca2⫹ transport systems that r ...
... Ca2⫹ sparks as well as individual spark amplitude. Ca2⫹ Transport Systems The increase in cytosolic [Ca2⫹] and the accompanying force development after electrical activation is transient because Ca2⫹ is rapidly removed from the cytosol after release. There are four main Ca2⫹ transport systems that r ...
Myelin and White Matter
... are asymmetrically distributed across the membrane bilayer and the protein composition on the inside is different from that on the outside of the bilayer. On electron microscopic examination, a plasma membrane is shown as a three-layered structure and consists of two dark lines separated by a lighte ...
... are asymmetrically distributed across the membrane bilayer and the protein composition on the inside is different from that on the outside of the bilayer. On electron microscopic examination, a plasma membrane is shown as a three-layered structure and consists of two dark lines separated by a lighte ...
Dynamic Equilibrium of Neurotransmitter Transporters: Not Just for
... volves coupled translocation of two Na⫹ ions, one Cl⫺ ion and one uncharged GABA molecule (Fig. 1B) (Kanner and Schuldiner 1987). Thus GABA is carried up its concentration gradient using the energy from the inward Na⫹ gradient and the flow of one positive charge down the electrical gradient. There i ...
... volves coupled translocation of two Na⫹ ions, one Cl⫺ ion and one uncharged GABA molecule (Fig. 1B) (Kanner and Schuldiner 1987). Thus GABA is carried up its concentration gradient using the energy from the inward Na⫹ gradient and the flow of one positive charge down the electrical gradient. There i ...
Highwire Regulates Guidance of Sister Axons in the
... powerful model system to investigate such axonal behaviors (Heisenberg, 1998; Davis, 2005; Fahrbach, 2006). The MB is composed of three neuronal subtypes—␥, ␣⬘/⬘, and ␣/ neurons—that can be distinguished by their birth order and the location of their axonal projections (Lee et al., 1999). Cell bod ...
... powerful model system to investigate such axonal behaviors (Heisenberg, 1998; Davis, 2005; Fahrbach, 2006). The MB is composed of three neuronal subtypes—␥, ␣⬘/⬘, and ␣/ neurons—that can be distinguished by their birth order and the location of their axonal projections (Lee et al., 1999). Cell bod ...
Muscle
... When force generation produces shortening of a skeletal muscle fiber, the overlapping thick and thin fi laments in each sarcomere move past each other, propelled by movements of the cross-bridges. During this shortening of the sarcomeres, there is no change in the lengths of either the thick or thin ...
... When force generation produces shortening of a skeletal muscle fiber, the overlapping thick and thin fi laments in each sarcomere move past each other, propelled by movements of the cross-bridges. During this shortening of the sarcomeres, there is no change in the lengths of either the thick or thin ...
Mechanisms of axon degeneration: From development to disease
... highlighted how this is an active process of controlled axon self-destruction similar in many ways to the active selfdestruction of cells during apoptosis (Coleman, 2005; Low and Cheng, 2005; Luo and O’Leary, 2005; Raff et al., 2002). Although the molecular mechanisms involved are different (but see ...
... highlighted how this is an active process of controlled axon self-destruction similar in many ways to the active selfdestruction of cells during apoptosis (Coleman, 2005; Low and Cheng, 2005; Luo and O’Leary, 2005; Raff et al., 2002). Although the molecular mechanisms involved are different (but see ...
Slow Ventricular Conduction in Mice Heterozygous for a
... express multiple connexins (3–5), members of a family of proteins that form gap junction channels (6). Different cardiac tissues that exhibit distinct conduction properties express different combinations of three cardiac connexins: connexin43 (Cx43), connexin45 (Cx45), and connexin40 (Cx40) (4, 5). ...
... express multiple connexins (3–5), members of a family of proteins that form gap junction channels (6). Different cardiac tissues that exhibit distinct conduction properties express different combinations of three cardiac connexins: connexin43 (Cx43), connexin45 (Cx45), and connexin40 (Cx40) (4, 5). ...
Microtubule Reconfiguration during Axonal Retraction Induced by
... The prevailing view is that cytoskeletal elements depolymerize extensively during physiological axonal retraction (Song and Poo, 1999). This view is largely based on pharmacological studies showing that wholesale microtubule depolymerization can indeed cause axons to retract (Yamada et al., 1970; Da ...
... The prevailing view is that cytoskeletal elements depolymerize extensively during physiological axonal retraction (Song and Poo, 1999). This view is largely based on pharmacological studies showing that wholesale microtubule depolymerization can indeed cause axons to retract (Yamada et al., 1970; Da ...
Neocortical Very Fast Oscillations (Ripples, 80–200 Hz) During
... Downloaded from http://jn.physiology.org/ by 10.220.32.247 on June 12, 2017 ...
... Downloaded from http://jn.physiology.org/ by 10.220.32.247 on June 12, 2017 ...
Cellular Physiology of Skeletal, Cardiac, and Smooth Muscle
... many smooth muscle cells are capableof initiating spontaneouselectricalactivity. In some cells, this spontaneous activity results from pacemakercurrents. These currents result from time- and voltage-dependentpropertiesof ion currents that produce either a spontaneousincrease in inward, or depolarizi ...
... many smooth muscle cells are capableof initiating spontaneouselectricalactivity. In some cells, this spontaneous activity results from pacemakercurrents. These currents result from time- and voltage-dependentpropertiesof ion currents that produce either a spontaneousincrease in inward, or depolarizi ...
CONTRIBUTION OF DYSFERLIN-CONTAINING
... “proximodistal” presentation [22]. In some instances divergent phenotypes can result from identical mutations within the dysferlin gene, which may result from modifier genes or environmental factors such as activity level [19, 23]. Mild cardiac involvement can occasionally be detected in dysferlinop ...
... “proximodistal” presentation [22]. In some instances divergent phenotypes can result from identical mutations within the dysferlin gene, which may result from modifier genes or environmental factors such as activity level [19, 23]. Mild cardiac involvement can occasionally be detected in dysferlinop ...
Down - 서울대 Biointelligence lab
... intervals (ISIs). (A) data from recordings of one cortical cell (Brodmann’s area 46) that fired without task-relevant characteristics with an average firing rate of about 15 spikes/s. The coefficient of variation of the spike trains is Cv ≈ 1.09. (B) Simulated data from a Poisson distributed spike t ...
... intervals (ISIs). (A) data from recordings of one cortical cell (Brodmann’s area 46) that fired without task-relevant characteristics with an average firing rate of about 15 spikes/s. The coefficient of variation of the spike trains is Cv ≈ 1.09. (B) Simulated data from a Poisson distributed spike t ...
Axon Initial Segment Cytoskeleton: Architecture, Development, and
... Figure 1: Architecture of the axon initial segment (AIS) and its key protein components. ((a), top) Neuron polarity. Polarized neurons receive synaptic inputs in the somatodendritic domain (green), which transmits the signals through the axon hillock to the axon initial segment (red). The AIS integr ...
... Figure 1: Architecture of the axon initial segment (AIS) and its key protein components. ((a), top) Neuron polarity. Polarized neurons receive synaptic inputs in the somatodendritic domain (green), which transmits the signals through the axon hillock to the axon initial segment (red). The AIS integr ...
Essential Roles for GSK-3s and GSK-3
... animals maintained for 6 days and stained with antibodies to tau to reveal axons and MAP2 to reveal dendrites, virtually all neurons in GSK-3b null mice exhibited a single long tau+ process (Figures 1B and 1C). Both GSK-3a and b Are Expressed throughout the Embryonic Nervous System Phospho-GSK-3a an ...
... animals maintained for 6 days and stained with antibodies to tau to reveal axons and MAP2 to reveal dendrites, virtually all neurons in GSK-3b null mice exhibited a single long tau+ process (Figures 1B and 1C). Both GSK-3a and b Are Expressed throughout the Embryonic Nervous System Phospho-GSK-3a an ...
Dendritic Calcium Spikes in Layer 5 Pyramidal Neurons Amplify and
... Oakley, J. C., P. C. Schwindt, and W. E. Crill. Dendritic calcium spikes in layer 5 pyramidal neurons amplify and limit transmission of ligand-gated dendritic current to soma. J Neurophysiol 86: 514 –527, 2001. Long-lasting, dendritic, Ca2⫹-dependent action potentials (plateaus) were investigated in ...
... Oakley, J. C., P. C. Schwindt, and W. E. Crill. Dendritic calcium spikes in layer 5 pyramidal neurons amplify and limit transmission of ligand-gated dendritic current to soma. J Neurophysiol 86: 514 –527, 2001. Long-lasting, dendritic, Ca2⫹-dependent action potentials (plateaus) were investigated in ...
Review Article Bifurcation theory and cardiac arrhythmias
... how cardiac cellular instability caused by the period doubling bifurcation scenario leads to temporal beat-to-beat action potential duration (APD) alternans of cardiac myocytes and then discuss the factors at the whole heart level that modulate the transition from spatially concordant form of APD al ...
... how cardiac cellular instability caused by the period doubling bifurcation scenario leads to temporal beat-to-beat action potential duration (APD) alternans of cardiac myocytes and then discuss the factors at the whole heart level that modulate the transition from spatially concordant form of APD al ...
Outputs of Radula Mechanoafferent Neurons in Aplysia are
... The transmission of sensory information from the periphery to the nervous system is modulated both at the level of primary sensory afferents (Brooke et al. 1997; Gu and MacDermott 1997; Hill et al. 1997; Passaglia et al. 1998; Pasztor and Macmillan 1990) and at various stages of processing in the CN ...
... The transmission of sensory information from the periphery to the nervous system is modulated both at the level of primary sensory afferents (Brooke et al. 1997; Gu and MacDermott 1997; Hill et al. 1997; Passaglia et al. 1998; Pasztor and Macmillan 1990) and at various stages of processing in the CN ...
KATP channels and preconditioning - Philipps
... blockers (cariporide and ethylisopropyl amiloride) [16]. In most cases, PPC produces a similar degree of protection against subsequent ischemic injury as IPC. It is generally assumed that preconditioning activates endogenous intracellular defense mechanisms that increase the tolerance to injury [3,6 ...
... blockers (cariporide and ethylisopropyl amiloride) [16]. In most cases, PPC produces a similar degree of protection against subsequent ischemic injury as IPC. It is generally assumed that preconditioning activates endogenous intracellular defense mechanisms that increase the tolerance to injury [3,6 ...
Intracellular control of developmental and regenerative axon growth
... Figure 2. Regulation of the axon cytoskeleton by PI3K signalling. Small GTPases, including Rac, Cdc42 and Rho, are major downstream mediators of PI3K signalling that regulate the cytoskeleton. Both Rac and Cdc42 are activated by neurotrophin signalling downstream of PI3K. Activated Rac can activate ...
... Figure 2. Regulation of the axon cytoskeleton by PI3K signalling. Small GTPases, including Rac, Cdc42 and Rho, are major downstream mediators of PI3K signalling that regulate the cytoskeleton. Both Rac and Cdc42 are activated by neurotrophin signalling downstream of PI3K. Activated Rac can activate ...
Differential Excitability Modulation of Striatal Medium Neuron
... entry in PD models. However, it is far from clear whether spikes initiated in the axon initial segment back-propagate any significant distance into the dendritic trees of MSNs that normally reside very near the K ⫹ equilibrium potential (approximately ⫺80 mV), far from spike threshold (Wilson and Ka ...
... entry in PD models. However, it is far from clear whether spikes initiated in the axon initial segment back-propagate any significant distance into the dendritic trees of MSNs that normally reside very near the K ⫹ equilibrium potential (approximately ⫺80 mV), far from spike threshold (Wilson and Ka ...
Axon Response to Guidance Cues Is Stimulated by
... should have a deficiency of extracellular acetylcholine. We found that mutations of cha-1, unc-17, and unc-104 that cause a reduction of function have AVM ventral axon guidance defects (Figure 2B). CHA-1 is a choline acetyltransferase and is expressed in ventral nerve cord cholinergic neurons (Alfons ...
... should have a deficiency of extracellular acetylcholine. We found that mutations of cha-1, unc-17, and unc-104 that cause a reduction of function have AVM ventral axon guidance defects (Figure 2B). CHA-1 is a choline acetyltransferase and is expressed in ventral nerve cord cholinergic neurons (Alfons ...
the resonate-and-fire neuron: time dependent and frequency
... Let us begin by considering the morphology of a typical nerve cell, along with the general approach utilized to model the various electrophysiological aspects of neurons. Panel (A) in figure 1.1 depicts the various specialized cellular processes that characterizes nerve cells, and panel (B) represen ...
... Let us begin by considering the morphology of a typical nerve cell, along with the general approach utilized to model the various electrophysiological aspects of neurons. Panel (A) in figure 1.1 depicts the various specialized cellular processes that characterizes nerve cells, and panel (B) represen ...
Characterization of Nifedipine Block of the Human Heart Delayed
... addition of nifedipine, the rate of current decay increased in a concentration-dependent manner (fig. 2, A and B) and could be well fitted with a double exponential function. The nifedipine-induced fast time constant, t2, was used as an index of the rate of block of hKv1.5. Figure 4A shows the effec ...
... addition of nifedipine, the rate of current decay increased in a concentration-dependent manner (fig. 2, A and B) and could be well fitted with a double exponential function. The nifedipine-induced fast time constant, t2, was used as an index of the rate of block of hKv1.5. Figure 4A shows the effec ...
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and endocrine cells, as well as in some plant cells. In neurons, they play a central role in cell-to-cell communication. In other types of cells, their main function is to activate intracellular processes. In muscle cells, for example, an action potential is the first step in the chain of events leading to contraction. In beta cells of the pancreas, they provoke release of insulin. Action potentials in neurons are also known as ""nerve impulses"" or ""spikes"", and the temporal sequence of action potentials generated by a neuron is called its ""spike train"". A neuron that emits an action potential is often said to ""fire"".Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane. These channels are shut when the membrane potential is near the resting potential of the cell, but they rapidly begin to open if the membrane potential increases to a precisely defined threshold value. When the channels open (in response to depolarization in transmembrane voltage), they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. This then causes more channels to open, producing a greater electric current across the cell membrane, and so on. The process proceeds explosively until all of the available ion channels are open, resulting in a large upswing in the membrane potential. The rapid influx of sodium ions causes the polarity of the plasma membrane to reverse, and the ion channels then rapidly inactivate. As the sodium channels close, sodium ions can no longer enter the neuron, and then they are actively transported back out of the plasma membrane. Potassium channels are then activated, and there is an outward current of potassium ions, returning the electrochemical gradient to the resting state. After an action potential has occurred, there is a transient negative shift, called the afterhyperpolarization or refractory period, due to additional potassium currents. This mechanism prevents an action potential from traveling back the way it just came.In animal cells, there are two primary types of action potentials. One type is generated by voltage-gated sodium channels, the other by voltage-gated calcium channels. Sodium-based action potentials usually last for under one millisecond, whereas calcium-based action potentials may last for 100 milliseconds or longer. In some types of neurons, slow calcium spikes provide the driving force for a long burst of rapidly emitted sodium spikes. In cardiac muscle cells, on the other hand, an initial fast sodium spike provides a ""primer"" to provoke the rapid onset of a calcium spike, which then produces muscle contraction.