Document Detail

Catecholamine effects on intracellular sodium activity and tension in dog heart.
MedLine Citation:
PMID:  7137359     Owner:  NLM     Status:  MEDLINE    
Because catecholamines have been reported to stimulate the sodium pump and Na+-K+-ATPase in skeletal and cardiac muscle, we examined the effects of isoproterenol (0.2-1.0 X 10(-6) M) and norepinephrine (2-4 X 10(-7) M) on intracellular sodium activity (aiNa) and twitch tension in dog Purkinje strands and ventricular muscles, aiNa was measured with Na+-sensitive microelectrodes. During the initial rapid increase in tension induced by catecholamines in Purkinje strands, no changes in aiNa were found. After 5-10 min aiNa decreased by about 2 mM, coincident with a small decline in twitch tension. When the catecholamine was removed, tension declined rapidly to a level less than control. Recovery of tension to its control level less than control. Recovery of tension to its control level occurred simultaneously with recovery of aiNa. Comparable changes in aiNa occurred in ventricular muscle, but the biphasic effect of catecholamines on tension was not seen. These results are consistent with sodium pump stimulation in cardiac muscle. In Purkinje strands the resulting changes in aiNa may alter the direct positive inotropic effect of catecholamines, probably by influencing Na+-Ca2+ exchange.
J A Wasserstrom; D J Schwartz; H A Fozzard
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  243     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1982 Nov 
Date Detail:
Created Date:  1982-12-18     Completed Date:  1982-12-18     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H670-5     Citation Subset:  IM    
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MeSH Terms
Electric Conductivity
Heart / drug effects,  physiology*
Isoproterenol / pharmacology*
Myocardial Contraction / drug effects
Myocardium / metabolism
Norepinephrine / pharmacology*
Purkinje Fibers / drug effects,  physiology
Sodium / metabolism*
Grant Support
Reg. No./Substance:
51-41-2/Norepinephrine; 7440-23-5/Sodium; 7683-59-2/Isoproterenol

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

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