| A study on early post-denervation changes of non-quantal and quantal acetylcholine release in the rat diaphragm. | |
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MedLine Citation:
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PMID: 3627968 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The d-tubocurarine (dTC) induced hyperpolarization of antiesterase-treated muscles at the endplate zone, miniature endplate potentials (mepps), resting membrane potentials (RMPs) and the input resistances of single muscle fibres (Rin) were measured in rat diaphragm at various times after denervation. The dTC-induced hyperpolarization decreased in two phases: 2 h after denervation it decreased transiently to 25%, after 4 h it had partially recovered to 60% and from 6 h it progressively decreased up to 12 h after which time it changed to depolarization. The initial fall and recovery were also present in muscles from sham-operated animals. The frequency of mepps decreased by 25% and the amplitude diminished by 10% within the first 2-4 h. After 10 h the frequency had decreased by 35% and the amplitude by 65%. After 12 h no mepps were present. The RMP was not significantly changed during the first 16 h after denervation. From 16 to 24 h the membrane became depolarized at a rate of about 1 mV/h. The input resistance of a single muscle fibre was constant for 12 h after denervation and from 12 to 24 h it increased by 25%. It is concluded that the early decrease in the dTC-induced hyperpolarization is probably due to the desensitization of acetylcholine (ACh) receptors caused by stress-activated non-quantal ACh release. The later decrease of dTC-hyperpolarization reflects a fall in the non-quantal ACh release. The depolarization of the resting membrane after denervation is related to the decrease in passive membrane permeability which is a secondary consequence of transmission failure.(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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H Zemková; F Vyskocil; C Edwards |
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Publication Detail:
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Type: In Vitro; Journal Article |
Journal Detail:
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Title: Pflügers Archiv : European journal of physiology Volume: 409 ISSN: 0031-6768 ISO Abbreviation: Pflugers Arch. Publication Date: 1987 Aug |
Date Detail:
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Created Date: 1987-10-13 Completed Date: 1987-10-13 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0154720 Medline TA: Pflugers Arch Country: GERMANY, WEST |
Other Details:
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Languages: eng Pagination: 540-6 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acetylcholine
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secretion* Animals Diaphragm / physiology Female Membrane Potentials / drug effects Microelectrodes Motor Endplate / drug effects, physiology* Muscle Denervation* Muscles / physiology* Neuromuscular Junction / physiology* Rats Rats, Inbred Strains Time Factors Tubocurarine / pharmacology |
| Chemical | |
Reg. No./Substance:
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51-84-3/Acetylcholine; 57-95-4/Tubocurarine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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