Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Variations in onset of action potential broadening: effects on calcium current studied in chick ciliary ganglion neurones.
Pattillo JM
,
Artim DE
,
Simples JE
,
Meriney SD
.
???displayArticle.abstract???
1. The voltage dependence and kinetic properties of stage 40 ciliary ganglion calcium currents were determined using short (10 ms) voltage steps. These properties aided the interpretation of the action potential-evoked calcium current described below, and the comparison of our data with those observed in other preparations. 2. Three different natural action potential waveforms were modelled by a series of ramps to generate voltage clamp commands. Calcium currents evoked by these model action potentials were compared before and after alterations in the repolarization phase of each action potential. 3. Abrupt step repolarizations from various time points were used to estimate the time course of calcium current activation during each action potential. Calcium current evoked by fast action potentials (duration at half-amplitude, 0.5 or 1.0 ms) did not reach maximal activation until the action potential had repolarized by 40-50 %. In contrast, calcium current evoked by a slow action potential (duration at half-amplitude, 2.2 ms) was maximally activated near the peak of the action potential. 4. Slowing the rate of repolarization of the action potential (broadening) from different times was used to examine effects on peak and total calcium influx. With all three waveforms tested, broadening consistently increased total calcium influx (integral). However, peak calcium current was either increased or decreased depending on the duration of the control action potential tested and the specific timing of the initiation of broadening the repolarization phase. 5. The opposite effects on peak calcium current observed with action potential broadening beginning at different time points in repolarization may provide a mechanism for the variable effects of potassium channel blockers on transmitter release magnitude.
Adams,
Intracellular Ca2+ activates a fast voltage-sensitive K+ current in vertebrate sympathetic neurones.
1982, Pubmed
Adams,
Intracellular Ca2+ activates a fast voltage-sensitive K+ current in vertebrate sympathetic neurones.
1982,
Pubmed
Augustine,
The calcium signal for transmitter secretion from presynaptic nerve terminals.
1991,
Pubmed
Augustine,
Regulation of transmitter release at the squid giant synapse by presynaptic delayed rectifier potassium current.
1990,
Pubmed
Bertram,
Single-domain/bound calcium hypothesis of transmitter release and facilitation.
1996,
Pubmed
Borst,
Calcium current during a single action potential in a large presynaptic terminal of the rat brainstem.
1998,
Pubmed
Borst,
Pre- and postsynaptic whole-cell recordings in the medial nucleus of the trapezoid body of the rat.
1995,
Pubmed
Brody,
Bursts of action potential waveforms relieve G-protein inhibition of recombinant P/Q-type Ca2+ channels in HEK 293 cells.
1997,
Pubmed
Chad,
Calcium domains associated with individual channels can account for anomalous voltage relations of CA-dependent responses.
1984,
Pubmed
Coates,
Synaptic plasticity in the molluscan peripheral nervous system: physiology and role for peptides.
1985,
Pubmed
Davies,
Sources of Ca2+ for different Ca(2+)-activated K+ conductances in neurones of the rat superior cervical ganglion.
1996,
Pubmed
Fogelson,
Presynaptic calcium diffusion from various arrays of single channels. Implications for transmitter release and synaptic facilitation.
1985,
Pubmed
Gainer,
Action potentials and frequency-dependent secretion in the mouse neurohypophysis.
1986,
Pubmed
HAMBURGER,
A series of normal stages in the development of the chick embryo.
1951,
Pubmed
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
HODGKIN,
A quantitative description of membrane current and its application to conduction and excitation in nerve.
1952,
Pubmed
Klein,
Mechanism of calcium current modulation underlying presynaptic facilitation and behavioral sensitization in Aplysia.
1980,
Pubmed
Lancaster,
Calcium activates two types of potassium channels in rat hippocampal neurons in culture.
1991,
Pubmed
Lindgren,
Identification of ionic currents at presynaptic nerve endings of the lizard.
1989,
Pubmed
Llinás,
Relationship between presynaptic calcium current and postsynaptic potential in squid giant synapse.
1981,
Pubmed
Llinás,
Presynaptic calcium currents in squid giant synapse.
1981,
Pubmed
Naraghi,
Linearized buffered Ca2+ diffusion in microdomains and its implications for calculation of [Ca2+] at the mouth of a calcium channel.
1997,
Pubmed
Pumplin,
Are the presynaptic membrane particles the calcium channels?
1981,
Pubmed
Roberts,
Colocalization of ion channels involved in frequency selectivity and synaptic transmission at presynaptic active zones of hair cells.
1990,
Pubmed
Robitaille,
Presynaptic calcium signals and transmitter release are modulated by calcium-activated potassium channels.
1992,
Pubmed
Robitaille,
Functional colocalization of calcium and calcium-gated potassium channels in control of transmitter release.
1993,
Pubmed
Sabatini,
Control of neurotransmitter release by presynaptic waveform at the granule cell to Purkinje cell synapse.
1997,
Pubmed
Sabatini,
Timing of neurotransmission at fast synapses in the mammalian brain.
1996,
Pubmed
Sah,
Potassium currents contributing to action potential repolarization and the afterhyperpolarization in rat vagal motoneurons.
1992,
Pubmed
Simon,
Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.
1985,
Pubmed
Solaro,
Inactivating and noninactivating Ca(2+)- and voltage-dependent K+ current in rat adrenal chromaffin cells.
1995,
Pubmed
Spencer,
Presynaptic spike broadening reduces junctional potential amplitude.
1989,
Pubmed
Storm,
Action potential repolarization and a fast after-hyperpolarization in rat hippocampal pyramidal cells.
1987,
Pubmed
Toth,
Calcium and sodium currents evoked by action potential waveforms in rat sympathetic neurones.
1995,
Pubmed
Warbington,
Reduced transmitter release conferred by mutations in the slowpoke-encoded Ca2(+)-activated K+ channel gene of Drosophila.
1996,
Pubmed
Wheeler,
Changes in action potential duration alter reliance of excitatory synaptic transmission on multiple types of Ca2+ channels in rat hippocampus.
1996,
Pubmed
White,
Developmental changes in calcium current pharmacology and somatostatin inhibition in chick parasympathetic neurons.
1997,
Pubmed
Wisgirda,
Functional dependence of Ca(2+)-activated K+ current on L- and N-type Ca2+ channels: differences between chicken sympathetic and parasympathetic neurons suggest different regulatory mechanisms.
1994,
Pubmed
Yazejian,
Direct measurements of presynaptic calcium and calcium-activated potassium currents regulating neurotransmitter release at cultured Xenopus nerve-muscle synapses.
1997,
Pubmed
,
Xenbase
Zhang,
Potassium conductances underlying repolarization and after-hyperpolarization in rat CA1 hippocampal interneurones.
1995,
Pubmed
