| Quantal currents evoked by graded intracellular depolarization of crayfish motor axon terminals. | |
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MedLine Citation:
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PMID: 2888878 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. Quantal transmitter release was examined at nerve terminals of the excitatory motor axon of the crayfish opener muscle. The magnitude of synaptic currents, recorded with macro-patch electrodes at a nerve terminal, served as a measure of quantal size. Transmitter release was initiated by pulses of depolarizing current applied intracellularly to the axonal terminals after application of tetrodotoxin. Quantal release was altered by a variety of methods and the resulting quantal output and quantal size were measured. 2. Amplitude distributions of quantal events were obtained during experimental manipulations which altered the rate of quantal release by up to 25-fold. These manipulations consisted of: varying pulse amplitude or pulse duration; facilitating the release by prolonged depolarization; and application of a potassium channel blocker, 4-aminopyridine. 3. The amplitude of quantal events is impervious to marked changes in presynaptic depolarization and is not affected by experimental procedures which promote accumulation of calcium ions in the terminals. The vesicular mechanism of release, in which transmitter substance is prepackaged in vesicles which individually undergo exocytosis at a release zone, could account for the observed results. |
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Authors:
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H L Atwood; H Parnas; I Parnas; J M Wojtowicz |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of physiology Volume: 383 ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 1987 Feb |
Date Detail:
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Created Date: 1987-11-16 Completed Date: 1987-11-16 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 587-99 Citation Subset: IM |
Affiliation:
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Department of Physiology, Faculty of Medicine, University of Toronto, Ontario, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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4-Aminopyridine Action Potentials / drug effects Aminopyridines / pharmacology Animals Astacoidea / physiology* Axons / physiology Electric Stimulation Membrane Potentials / drug effects Motor Neurons / physiology* Neuromuscular Junction / physiology Neurotransmitter Agents / secretion* Tetrodotoxin / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Aminopyridines; 0/Neurotransmitter Agents; 4368-28-9/Tetrodotoxin; 504-24-5/4-Aminopyridine |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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