Document Detail

Inhibition of connexin 43 in cardiac muscle during intense physical exercise.
MedLine Citation:
PMID:  23206241     Owner:  NLM     Status:  Publisher    
Endurance training is accompanied by important adaptations in both cardiovascular and autonomic nervous systems. Previous works have shown that the main component of gap junctions in the ventricular myocardium (connexin 43 (Cx43) can be regulated by adrenergic stimulus. On the other hand, training raises vagal and decreases sympathetic tone, while augmenting myocardial sensitivity to sympathetic stimulation during exercise. We therefore evaluated the regulation of Cx43 expression by sympathetic tone during exercise in trained and sedentary mice. Training induced an increase in the protein level of Cx43 by 45-70% under resting conditions. The expression of Cx43 was inhibited in trained but not in untrained mice in response to a 60 min exercise bout. Normal basal expression was restored after 60 min of resting. Cx43 reached a minimum that was not different from basal expression in untrained mice. In accordance, electrocardiography and action potential analysis did not reveal major electrophysiological implications for the drop in Cx43 abundance in trained-exercise mice. We prevented Cx43 inhibition using propranolol, and observed increased basal mRNA levels of β-adrenergic receptors without significant changes in the ratio β(1) to β(2) . In conclusion, we showed that Cx43 expression is transiently inhibited by β-adrenergic stimulus in trained mice during acute exercise.
G C Tiscornia; R Moretta; M A Argenziano; C E Amorena; E A Garcia Gras
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-4
Journal Detail:
Title:  Scandinavian journal of medicine & science in sports     Volume:  -     ISSN:  1600-0838     ISO Abbreviation:  Scand J Med Sci Sports     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-4     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9111504     Medline TA:  Scand J Med Sci Sports     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 John Wiley & Sons A/S.
CESyMA, ECyT, National University of San Martin, San Martin, Buenos Aires, Argentina.
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