Biophysical Properties and Responses to Neurotransmitters of
... from ⫺40 to ⫺78 mV, with a mean of ⫺59 ⫾ 8 mV. Input resistance ranged from 300 to 951 M⍀, with a mean of 542 ⫾ 147 M⍀. Membrane time constants, measured after a ⫺50 pA current was injected, averaged 34.5 ⫾ 10.2 ms. All the neurons recorded exhibited varying degrees of membrane rectification evident ...
... from ⫺40 to ⫺78 mV, with a mean of ⫺59 ⫾ 8 mV. Input resistance ranged from 300 to 951 M⍀, with a mean of 542 ⫾ 147 M⍀. Membrane time constants, measured after a ⫺50 pA current was injected, averaged 34.5 ⫾ 10.2 ms. All the neurons recorded exhibited varying degrees of membrane rectification evident ...
Mitochondria Buffer Physiological Calcium
... in HEPES-buffered Hank’s balanced salt solution (HHSS), pH 7.45, containing 0.5% bovine serum albumin. HHSS was composed of the following (in mM): HEPES, 20; NaCl, 137; CaCI,, 1.3; MgSO,, 0.4; MgCl, 0.5; KCI, 5.4; KH?PO,, 0.4; NaHPO,, 0.3; NaHCO,, 3.0; and glucose, 5.6. Loaded cells were mounted in ...
... in HEPES-buffered Hank’s balanced salt solution (HHSS), pH 7.45, containing 0.5% bovine serum albumin. HHSS was composed of the following (in mM): HEPES, 20; NaCl, 137; CaCI,, 1.3; MgSO,, 0.4; MgCl, 0.5; KCI, 5.4; KH?PO,, 0.4; NaHPO,, 0.3; NaHCO,, 3.0; and glucose, 5.6. Loaded cells were mounted in ...
Determinants of Action Potential Propagation in Cerebellar Purkinje
... accumulated to support the idea that under some circumstances axonal propagation may fail. Cerebellar Purkinje neurons fire highfrequency simple spikes, as well as bursts of spikes in response to climbing fiber activation (the “complex spike”). Here we have visualized the axon of individual Purkinje ...
... accumulated to support the idea that under some circumstances axonal propagation may fail. Cerebellar Purkinje neurons fire highfrequency simple spikes, as well as bursts of spikes in response to climbing fiber activation (the “complex spike”). Here we have visualized the axon of individual Purkinje ...
as PDF
... Durell et al. proposed a 3-D structural model of amyloid channels obtained from a computer simulation of the secondary structure of AβP(1–40) in membranes that showed the aggregation of 5- to 8-mers to form pore-like structures on the membranes (Durell et al., 1994). Jang et al. established a model ...
... Durell et al. proposed a 3-D structural model of amyloid channels obtained from a computer simulation of the secondary structure of AβP(1–40) in membranes that showed the aggregation of 5- to 8-mers to form pore-like structures on the membranes (Durell et al., 1994). Jang et al. established a model ...
Molecular Affinity and Permeability of Different Molecular Weight
... from the above process ranged from 30000 to 480000 Da, the DD ranged from 89.2 to 91.4% (Table 1). The MW of the chitosan sample were determined by using a GPC method with a Waters-1525 binary HPLC system, a Waters-2410 refractive index detector (Waters Corp., Miford, MA), and an SEC column (TSK Gel ...
... from the above process ranged from 30000 to 480000 Da, the DD ranged from 89.2 to 91.4% (Table 1). The MW of the chitosan sample were determined by using a GPC method with a Waters-1525 binary HPLC system, a Waters-2410 refractive index detector (Waters Corp., Miford, MA), and an SEC column (TSK Gel ...
Articles in PresS. J Neurophysiol (March 20, 2003). 10.1152/jn
... between these inputs that determines the membrane potential of the up state. The two K+ currents included in our model, Kir2 and Ksi (si, slowly inactivating), have been shown (Nisenbaum and Wilson 1995) to account for the characteristic nonlinear voltage dependence of the outward current measured i ...
... between these inputs that determines the membrane potential of the up state. The two K+ currents included in our model, Kir2 and Ksi (si, slowly inactivating), have been shown (Nisenbaum and Wilson 1995) to account for the characteristic nonlinear voltage dependence of the outward current measured i ...
AANEM Glossary of Terms in Neuromuscular
... end of the spike and the time when the membrane potential is restored to its resting value. The membrane during this period may be depolarized or hyperpolarized at different times. akinesia Lack or marked delay of intended movement, often observed in patients with Parkinson’s disease. Often used syn ...
... end of the spike and the time when the membrane potential is restored to its resting value. The membrane during this period may be depolarized or hyperpolarized at different times. akinesia Lack or marked delay of intended movement, often observed in patients with Parkinson’s disease. Often used syn ...
How proteins produce cellular membrane curvature
... physics and mathematics is to understand the evolutionary, developmental and functional rationale for these shapes, as well as the mechanisms that are used by cells to produce them. Each shape evolved for specific physiological reasons1–3. Cells without internal membranes, such as prokaryotic cells ...
... physics and mathematics is to understand the evolutionary, developmental and functional rationale for these shapes, as well as the mechanisms that are used by cells to produce them. Each shape evolved for specific physiological reasons1–3. Cells without internal membranes, such as prokaryotic cells ...
Aggregation of Sodium Channels during Development and
... membrane potential of the patch more negative than that of the cell. This “holding potential” was applied for several minutes before recording in order to remove slow inactivation of NaChs (Almers et al., 1983). Depolarizing pulses (4 msec) of different step sizes were then applied until the maximum ...
... membrane potential of the patch more negative than that of the cell. This “holding potential” was applied for several minutes before recording in order to remove slow inactivation of NaChs (Almers et al., 1983). Depolarizing pulses (4 msec) of different step sizes were then applied until the maximum ...
Dopamine – CNS Pathways and Neurophysiology
... neurons. Interestingly, DA neurons recorded from mesencephalic slices after severing of afferent processes continue to exhibit spontaneous activity that is derived from the active membrane properties of the neuron. One factor associated with spike generation in DA neurons is a large-amplitude (10–15 ...
... neurons. Interestingly, DA neurons recorded from mesencephalic slices after severing of afferent processes continue to exhibit spontaneous activity that is derived from the active membrane properties of the neuron. One factor associated with spike generation in DA neurons is a large-amplitude (10–15 ...
Mechanism of Irregular Firing of Suprachiasmatic Nucleus Neurons
... The mechanisms of irregular firing of spontaneous action potentials in neurons from the rat suprachiasmatic nucleus (SCN) were studied in hypothalamic slices using cell-attached and whole cell recording. The firing pattern of spontaneous action potentials could be divided into regular and irregular, ...
... The mechanisms of irregular firing of spontaneous action potentials in neurons from the rat suprachiasmatic nucleus (SCN) were studied in hypothalamic slices using cell-attached and whole cell recording. The firing pattern of spontaneous action potentials could be divided into regular and irregular, ...
Regulation of thalamocortical axon branching by BDNF and synaptic vesicle cycling
... have contributed equally to this work. ...
... have contributed equally to this work. ...
Cell-Type Specific Channelopathies in the Prefrontal Cortex of the
... provide evidence that the functional expression of h-channels (Ih) is down-regulated, whereas A-type K! channel function is up-regulated in pyramidal tract-projecting (PT) neurons in the fmr1-/y mouse PFC. This is the opposite pattern of results from published findings from hippocampus where Ih is u ...
... provide evidence that the functional expression of h-channels (Ih) is down-regulated, whereas A-type K! channel function is up-regulated in pyramidal tract-projecting (PT) neurons in the fmr1-/y mouse PFC. This is the opposite pattern of results from published findings from hippocampus where Ih is u ...
isolation and characterization of membranes from the cells of maize
... cytoplasmic vesicles (Northcote, 1971, 1974). Some of the components of the system are joined by structural connexions and they all have a functional continuity in the cytoplasm of eukaryotic cells (Morr6 & Ovtracht, 1977). It is now generally believed that the endomembrane system is present in a dy ...
... cytoplasmic vesicles (Northcote, 1971, 1974). Some of the components of the system are joined by structural connexions and they all have a functional continuity in the cytoplasm of eukaryotic cells (Morr6 & Ovtracht, 1977). It is now generally believed that the endomembrane system is present in a dy ...
Raven Ch
... d. repolarization The correct answer is a—temporal summation A. Answer a is correct. Temporal summation is the term used to describe a change in the timing of firing of the presynaptic cell. The correct answer is a— B. Answer b is incorrect. Spatial summation describes the effect of multiple presyna ...
... d. repolarization The correct answer is a—temporal summation A. Answer a is correct. Temporal summation is the term used to describe a change in the timing of firing of the presynaptic cell. The correct answer is a— B. Answer b is incorrect. Spatial summation describes the effect of multiple presyna ...
Neurons, Brain Chemistry, and Neurotransmission
... extend from the cell body. These processes usually branch out somewhat like tree branches and serve as the main apparatus for receiving input into the neuron from other nerve cells. The cell body also gives rise to the axon. Axons can be very long processes; in some cases, they may be up to 1 meter ...
... extend from the cell body. These processes usually branch out somewhat like tree branches and serve as the main apparatus for receiving input into the neuron from other nerve cells. The cell body also gives rise to the axon. Axons can be very long processes; in some cases, they may be up to 1 meter ...
Modulation of Jellyfish Potassium Channels by External Potassium
... modulatory effects might allow excitable cells to compensate for increases in [K1]out in intercellular space as a result of repetitive firing. Hounsgaard and Nicholson (1983) clearly demonstrated that an elevation of [K1]out by as little as 1 mM may alter the pattern of spontaneous activity in guine ...
... modulatory effects might allow excitable cells to compensate for increases in [K1]out in intercellular space as a result of repetitive firing. Hounsgaard and Nicholson (1983) clearly demonstrated that an elevation of [K1]out by as little as 1 mM may alter the pattern of spontaneous activity in guine ...
Selective Coupling of T-Type Calcium Channels to SK Potassium
... Dopaminergic midbrain (DA) neurons display two principal activity patterns in vivo, single-spike and burst firing, the latter coding for reward-related events. We have shown recently that the small-conductance calcium-activated potassium channel SK3 controls pacemaker frequency and precision in DA n ...
... Dopaminergic midbrain (DA) neurons display two principal activity patterns in vivo, single-spike and burst firing, the latter coding for reward-related events. We have shown recently that the small-conductance calcium-activated potassium channel SK3 controls pacemaker frequency and precision in DA n ...
Stimulation Within the Rostral Ventrolateral Medulla Can Evoke
... excitatory postsynaptic potentials (EPSPs) that were mediated by non-N-methyl-D-aspartate (NMDA) and NMDA receptors. These excitatory responses were the most prominent response in control artificial cerebrospinal fluid and have been studied previously. In 22 of the SPNs, RVLM stimulation also elicit ...
... excitatory postsynaptic potentials (EPSPs) that were mediated by non-N-methyl-D-aspartate (NMDA) and NMDA receptors. These excitatory responses were the most prominent response in control artificial cerebrospinal fluid and have been studied previously. In 22 of the SPNs, RVLM stimulation also elicit ...
Physical properties of lipid bilayer membranes: relevance to
... component factors, diffusion and concentration, is not necessary. For oxygen, important chemical reactions occurring within the membrane include lipid peroxidation as well as the formation of reactive oxygen species. In membranes, NO is protected against reactions with water soluble compounds, which ...
... component factors, diffusion and concentration, is not necessary. For oxygen, important chemical reactions occurring within the membrane include lipid peroxidation as well as the formation of reactive oxygen species. In membranes, NO is protected against reactions with water soluble compounds, which ...
Different Subthreshold Mechanisms Underlie Song Selectivity in
... hyperpolarization after the spike. Resting membrane potential was determined by subtracting any DC offset observed after electrode withdrawal from the membrane potential recorded during the 5–10 min before the end of the recording. All values are reported as the mean ⫾ SEM; statistics and tests for ...
... hyperpolarization after the spike. Resting membrane potential was determined by subtracting any DC offset observed after electrode withdrawal from the membrane potential recorded during the 5–10 min before the end of the recording. All values are reported as the mean ⫾ SEM; statistics and tests for ...
How do potentials derived from structural databases relate to true
... evolved to sequences having Z-scores between - 10 and - 15. At each step of the search process, two mutation sites were randomly chosen in a sequence, and the residues were swapped within the sequence. In this way, the amino acid composition remains the same during the search process. The compactnes ...
... evolved to sequences having Z-scores between - 10 and - 15. At each step of the search process, two mutation sites were randomly chosen in a sequence, and the residues were swapped within the sequence. In this way, the amino acid composition remains the same during the search process. The compactnes ...
A new look at sodium channel b subunits
... ions compared with that of sodium ions. This occurs in the presence of a high intracellular potassium ion concentration relative to the extracellular media, and a high extracellular to intracellular sodium ion concentration generated by sodium potassium ATPase activity. Under resting conditions, bot ...
... ions compared with that of sodium ions. This occurs in the presence of a high intracellular potassium ion concentration relative to the extracellular media, and a high extracellular to intracellular sodium ion concentration generated by sodium potassium ATPase activity. Under resting conditions, bot ...
compound action potential: nerve conduction
... through the completion of the response is measured, the complete cycle time for the impulse can be measured. The inverse of this period can be used to estimate the maximum frequency of stimulation in pulses per milliseconds (ppmsec) or pulses per second (pps). When an action potential is produced in ...
... through the completion of the response is measured, the complete cycle time for the impulse can be measured. The inverse of this period can be used to estimate the maximum frequency of stimulation in pulses per milliseconds (ppmsec) or pulses per second (pps). When an action potential is produced in ...
Ionic Channels in Biological Membranes
... include all the atoms of the water because the internal motions of water are calculated in present day simulations of molecular dynamics of proteins and solutions. There is no generally agreed upon way to avoid calculating the internal dynamics of the atoms of water and thereby replace the expensive ...
... include all the atoms of the water because the internal motions of water are calculated in present day simulations of molecular dynamics of proteins and solutions. There is no generally agreed upon way to avoid calculating the internal dynamics of the atoms of water and thereby replace the expensive ...
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.