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Direct measurements of presynaptic calcium and calcium-activated potassium currents regulating neurotransmitter release at cultured Xenopus nerve-muscle synapses.
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The understanding of neurotransmitter release at vertebrate synapses has been hampered by the paucity of preparations in which presynaptic ionic currents and postsynaptic responses can be monitored directly. We used cultured embryonic Xenopus neuromuscular junctions and simultaneous pre- and postsynaptic patch-clamp current-recording procedures to identify the major presynaptic conductances underlying the initiation of neurotransmitter release. Step depolarizations and action potential waveforms elicited Na and K currents along with Ca and Ca-activated K (KCa) currents. The onset of KCa current preceded the peak of the action potential. The predominantly omega-CgTX GVIA-sensitive Ca current occurred primarily during the falling phase, but there was also significant Ca2+ entry during the rising phase of the action potential. The postsynaptic current began a mean of 0.7 msec after the time of maximum rate of rise of the Ca current. omega-CgTX also blocked KCa currents and transmitter release during an action potential, suggesting that Ca and KCa channels are colocalized at presynaptic active zones. In double-ramp voltage-clamp experiments, KCa channel activation is enhanced during the second ramp. The 1 msec time constant of decay of enhancement with increasing interpulse interval may reflect the time course of either the deactivation of KCa channels or the diffusion/removal of Ca2+ from sites of neurotransmitter release after an action potential.
Anderson,
Effects of innervation on the distribution of acetylcholine receptors on cultured muscle cells.
1977, Pubmed,
Xenbase
Anderson,
Effects of innervation on the distribution of acetylcholine receptors on cultured muscle cells.
1977,
Pubmed
,
Xenbase
Artalejo,
Three types of Ca2+ channel trigger secretion with different efficacies in chromaffin cells.
1994,
Pubmed
Augustine,
Calcium entry into voltage-clamped presynaptic terminals of squid.
1985,
Pubmed
Augustine,
Calcium entry and transmitter release at voltage-clamped nerve terminals of squid.
1985,
Pubmed
Augustine,
Calcium action in synaptic transmitter release.
1987,
Pubmed
Augustine,
Calcium dependence of presynaptic calcium current and post-synaptic response at the squid giant synapse.
1986,
Pubmed
Augustine,
Regulation of transmitter release at the squid giant synapse by presynaptic delayed rectifier potassium current.
1990,
Pubmed
Barish,
Voltage-gated calcium currents in cultured embryonic Xenopus spinal neurones.
1991,
Pubmed
,
Xenbase
Blatz,
Ion conductance and selectivity of single calcium-activated potassium channels in cultured rat muscle.
1984,
Pubmed
Blundon,
Presynaptic calcium-activated potassium channels and calcium channels at a crayfish neuromuscular junction.
1995,
Pubmed
Borst,
Calcium influx and transmitter release in a fast CNS synapse.
1996,
Pubmed
Borst,
Pre- and postsynaptic whole-cell recordings in the medial nucleus of the trapezoid body of the rat.
1995,
Pubmed
Brehm,
Acetylcholine receptor channel properties during development of Xenopus muscle cells in culture.
1984,
Pubmed
,
Xenbase
Buchanan,
Studies of nerve-muscle interactions in Xenopus cell culture: fine structure of early functional contacts.
1989,
Pubmed
,
Xenbase
Candia,
Mode of action of iberiotoxin, a potent blocker of the large conductance Ca(2+)-activated K+ channel.
1992,
Pubmed
Charlton,
Role of presynaptic calcium ions and channels in synaptic facilitation and depression at the squid giant synapse.
1982,
Pubmed
Cohen,
Calcium and transmitter release.
1985,
Pubmed
Cohen,
Distribution of Ca2+ channels on frog motor nerve terminals revealed by fluorescent omega-conotoxin.
1991,
Pubmed
,
Xenbase
Cohen,
Localization of acetylcholine receptors and synaptic ultrastructure at nerve-muscle contacts in culture: dependence on nerve type.
1980,
Pubmed
,
Xenbase
Dodge,
Co-operative action a calcium ions in transmitter release at the neuromuscular junction.
1967,
Pubmed
Dunlap,
Identification of calcium channels that control neurosecretion.
1994,
Pubmed
Evers,
Studies of nerve-muscle interactions in Xenopus cell culture: analysis of early synaptic currents.
1989,
Pubmed
,
Xenbase
Fu,
L-type Ca2+ channel is involved in the regulation of spontaneous transmitter release at developing neuromuscular synapses.
1994,
Pubmed
,
Xenbase
Grinnell,
Dependence of spontaneous release at frog junctions on synaptic strength, external calcium and terminal length.
1989,
Pubmed
HODGKIN,
A quantitative description of membrane current and its application to conduction and excitation in nerve.
1952,
Pubmed
Heidelberger,
Calcium dependence of the rate of exocytosis in a synaptic terminal.
1994,
Pubmed
Horn,
Muscarinic activation of ionic currents measured by a new whole-cell recording method.
1988,
Pubmed
Hulsizer,
Calcium currents in presynaptic varicosities of embryonic motoneurons.
1991,
Pubmed
,
Xenbase
Jones,
Calcium currents in bullfrog sympathetic neurons. I. Activation kinetics and pharmacology.
1989,
Pubmed
Jones,
Dihydropyridine actions on calcium currents of frog sympathetic neurons.
1990,
Pubmed
KATZ,
THE MEASUREMENT OF SYNAPTIC DELAY, AND THE TIME COURSE OF ACETYLCHOLINE RELEASE AT THE NEUROMUSCULAR JUNCTION.
1965,
Pubmed
Katz,
A study of synaptic transmission in the absence of nerve impulses.
1967,
Pubmed
Katz,
Estimates of quantal content during 'chemical potentiation' of transmitter release.
1979,
Pubmed
Katz,
Further study of the role of calcium in synaptic transmission.
1970,
Pubmed
Katz,
Effects of Ca2+ channel blockers on transmitter release and presynaptic currents at the frog neuromuscular junction.
1995,
Pubmed
Kerr,
A venom peptide with a novel presynaptic blocking action.
,
Pubmed
Kidokoro,
Changes in synaptic potential properties during acetylcholine receptor accumulation and neurospecific interactions in Xenopus nerve-muscle cell culture.
1980,
Pubmed
,
Xenbase
Kidokoro,
Action potentials and sodium inward currents of developing neurons in Xenopus nerve-muscle cultures.
1989,
Pubmed
,
Xenbase
Kidokoro,
Initial synaptic transmission at the growth cone in Xenopus nerve-muscle cultures.
1982,
Pubmed
,
Xenbase
Koyano,
Effects of synthetic omega-conotoxin on synaptic transmission.
1987,
Pubmed
Kullberg,
Development of the myotomal neuromuscular junction in Xenopus laevis: an electrophysiological and fine-structural study.
1977,
Pubmed
,
Xenbase
Lancaster,
Properties of two calcium-activated hyperpolarizations in rat hippocampal neurones.
1987,
Pubmed
Lim,
Direct measurement of exocytosis and calcium currents in single vertebrate nerve terminals.
1990,
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,
Transmission by presynaptic spike-like depolarization in the squid giant synapse.
1982,
Pubmed
Luebke,
Multiple calcium channel types control glutamatergic synaptic transmission in the hippocampus.
1993,
Pubmed
MacKinnon,
Mechanism of charybdotoxin block of the high-conductance, Ca2+-activated K+ channel.
1988,
Pubmed
Marty,
Ca-dependent K channels with large unitary conductance in chromaffin cell membranes.
1981,
Pubmed
McCobb,
Action potential waveform voltage-clamp commands reveal striking differences in calcium entry via low and high voltage-activated calcium channels.
1991,
Pubmed
Miller,
Charybdotoxin, a protein inhibitor of single Ca2+-activated K+ channels from mammalian skeletal muscle.
,
Pubmed
Mintz,
P-type calcium channels blocked by the spider toxin omega-Aga-IVA.
1992,
Pubmed
Mintz,
Calcium control of transmitter release at a cerebellar synapse.
1995,
Pubmed
Pfrieger,
Pharmacological characterization of calcium currents and synaptic transmission between thalamic neurons in vitro.
1992,
Pubmed
Plummer,
Elementary properties and pharmacological sensitivities of calcium channels in mammalian peripheral neurons.
1989,
Pubmed
Rae,
Low access resistance perforated patch recordings using amphotericin B.
1991,
Pubmed
Reeve,
Calcium channel currents in undifferentiated human neuroblastoma (SH-SY5Y) cells: actions and possible interactions of dihydropyridines and omega-conotoxin.
1994,
Pubmed
Regehr,
Participation of multiple calcium channel types in transmission at single climbing fiber to Purkinje cell synapses.
1994,
Pubmed
Roberts,
Colocalization of ion channels involved in frequency selectivity and synaptic transmission at presynaptic active zones of hair cells.
1990,
Pubmed
Robitaille,
Functional colocalization of calcium and calcium-gated potassium channels in control of transmitter release.
1993,
Pubmed
Robitaille,
Presynaptic calcium signals and transmitter release are modulated by calcium-activated potassium channels.
1992,
Pubmed
Sabatini,
Timing of neurotransmission at fast synapses in the mammalian brain.
1996,
Pubmed
Scroggs,
Multiple Ca2+ currents elicited by action potential waveforms in acutely isolated adult rat dorsal root ganglion neurons.
1992,
Pubmed
Sivaramakrishnan,
Pharmacological characterization of presynaptic calcium currents underlying glutamatergic transmission in the avian auditory brainstem.
1995,
Pubmed
Spitzer,
The development of the action potential mechanism of amphibian neurons isolated in culture.
1976,
Pubmed
,
Xenbase
Stanley,
Single calcium channels and acetylcholine release at a presynaptic nerve terminal.
1993,
Pubmed
Stanley,
Characterization of a calcium current in a vertebrate cholinergic presynaptic nerve terminal.
1991,
Pubmed
Stanley,
Decline in calcium cooperativity as the basis of facilitation at the squid giant synapse.
1986,
Pubmed
Tabti,
Study on the induction of spontaneous transmitter release at early nerve-muscle contacts in Xenopus cultures.
1994,
Pubmed
,
Xenbase
Takahashi,
Presynaptic calcium current modulation by a metabotropic glutamate receptor.
1996,
Pubmed
Takahashi,
Structure and physiology of developing neuromuscular synapses in culture.
1987,
Pubmed
,
Xenbase
Wang,
Two types of high-threshold calcium currents inhibited by omega-conotoxin in nerve terminals of rat neurohypophysis.
1992,
Pubmed
Weldon,
Development of synaptic ultrastructure at neuromuscular contacts in an amphibian cell culture system.
1979,
Pubmed
,
Xenbase
Wheeler,
Changes in action potential duration alter reliance of excitatory synaptic transmission on multiple types of Ca2+ channels in rat hippocampus.
1996,
Pubmed
Yawo,
Re-evaluation of calcium currents in pre- and postsynaptic neurones of the chick ciliary ganglion.
1993,
Pubmed
Yawo,
Omega-conotoxin-sensitive and -resistant transmitter release from the chick ciliary presynaptic terminal.
1994,
Pubmed
