Document Detail


Potassium balance and ouabain binding sites in intact porcine hearts during isoproterenol infusion.
MedLine Citation:
PMID:  3992054     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A pacing-induced tachycardia causes a net loss of K+ from the myocardium whereas adrenergic stimulation at constant heart rate will cause a net K+ accumulation. In the intact heart, isoproterenol (ISO) will, as expected, exert both effects, but the net result with regard to K+ balance is unknown. In the experiments on intact porcine hearts presented herein, a shunt from the coronary sinus to the right atrium allowed continuous monitoring of the myocardial K+ balance. ISO caused heart rate, dP/dt, and peak aortic flow to increase to a new steady state in less than 10 sec. There was an initial K+ loss lasting 1 min followed by a 10- to 15-times larger net uptake subsiding after 7 min. Overall, tissue K+ increased by 140.5 +/- 60.0 mumole/100 g, corresponding roughly to a 3 mM increase in intracellular concentration during ISO infusion. Ouabain binding sites determined in intact biopsies from the left ventricle remained unchanged. Thus, ISO has a biphasic effect on myocardial K+ balance, eventually causing a net increase of tissue K+ content probably unrelated to the inotropic effects. Direct stimulation of the Na+, K+-ATPase without changing the number of enzymes is possible.
Authors:
O M Sejersted; F R Andersen; A Ilebekk
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Advances in myocardiology     Volume:  6     ISSN:  0270-4056     ISO Abbreviation:  Adv Myocardiol     Publication Date:  1985  
Date Detail:
Created Date:  1985-06-14     Completed Date:  1985-06-14     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8000285     Medline TA:  Adv Myocardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  83-95     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Cardiac Pacing, Artificial
Female
Heart / drug effects*
Heart Ventricles / drug effects
Hemodynamics / drug effects
Isoproterenol / pharmacology*
Kinetics
Male
Myocardium / metabolism*
Ouabain / metabolism
Potassium / metabolism*
Receptors, Drug / drug effects*,  metabolism
Sodium / metabolism
Sodium-Potassium-Exchanging ATPase*
Swine
Chemical
Reg. No./Substance:
0/Receptors, Drug; 0/cardiac glycoside receptors; 630-60-4/Ouabain; 7440-09-7/Potassium; 7440-23-5/Sodium; 7683-59-2/Isoproterenol; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase

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


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