Effect of ouabain on sodium movement in cardiac cells.
A computer simulation indicates that intracellular sodium concentration within a space near the inner surface of sarcolemma fluctuates during a cycle of myocardial function. The sodium transient (a transient increase in sodium ion concentration associated with membrane excitation) is enhanced by the inhibition of (Na+, K+)-ATPase by ouabain, but an accumulation of myocardial sodium does not occur until the inhibition exceeds a critical point. The critical magnitude of sodium pump inhibition that causes a progressive sodium accumulation is dependent on the heart rate.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D003201:Computers; D007700:Kinetics; D008954:Models, Biological; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology*; D012508:Sarcolemma / Q000187:drug effects / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*
D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases