Document Detail


Habitual exercise enhances neuromuscular transmission efficacy of rat soleus muscle in situ.
MedLine Citation:
PMID:  11181618     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Rat motor nerve terminals and the endplates they interact with exhibit changes to varying patterns of use, as when exposed to increased activation in the form of endurance exercise training. The extent to which these changes affect neuromuscular transmission efficacy is uncertain. In this study, the effects of habitual exercise on the electrophysiological properties of neuromuscular transmission in rat soleus muscle were investigated using a novel in situ approach. Consistent with previous reports, miniature endplate potential frequency was enhanced by habitual exercise. Other passive properties, such as resting membrane potential, miniature endplate potential amplitude, and "giant" miniature endplate potential characteristics were unaltered by the training program. Full-size endplate potentials were obtained by blocking soleus muscle action potentials with mu-conotoxin GIIIb. Quantal content values were 91.5 and 119.9 for control and active groups, respectively (P < 0.01). We also measured the rate and extent of endplate potential amplitude rundown during 3-s trains of continuous stimulation at 25, 50, and 75 Hz; at 50 and 75 Hz, we found both the rate and extent of rundown to be significantly attenuated (10--20%) in a specific population of cells from active rats (P < 0.05). The results establish the degree of activity-dependent plasticity as it pertains to neuromuscular transmission in a mammalian slow-twitch muscle.
Authors:
P Desaulniers; P A Lavoie; P F Gardiner
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  90     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-02-22     Completed Date:  2001-05-10     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1041-8     Citation Subset:  IM; S    
Affiliation:
Département de Kinésiologie, Université de Montréal, Montréal, Québec, Canada H3C 3J7.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects
Animals
Conotoxins / pharmacology
Electric Stimulation
Female
Hindlimb
Membrane Potentials / physiology
Motor Endplate / physiology
Muscle, Skeletal / innervation,  physiology*
Neuromuscular Junction / physiology*
Physical Conditioning, Animal / physiology*
Physical Exertion / physiology
Rats
Rats, Sprague-Dawley
Sodium Channels / drug effects
Synaptic Transmission / physiology*
Chemical
Reg. No./Substance:
0/Conotoxins; 0/Sodium Channels; 101484-15-5/conotoxin GIII

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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