[Correlation between inhibition of stimulatory membrane repolarization and positive inotropic response caused by ouabain in rat heart].
During a stimulus train, the diastolic membrane potential of rat atria exhibits a depolarization phase followed by a slower repolarization phase which has been attributed to the activation of an electrogenic sodium pump (ATPase Na+, K+). This pump seems to be all the more active as stimulation frequency is higher. The parallel evolution of the sodium pump inhibition and a positive inotropic effect in response to ouabain perfusion, suggests that the enzymatic inhibition is directly involved in the development of the cardiotonic effect of digitalis.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D004071:Digitalis Glycosides / Q000494:pharmacology; D004558:Electric Stimulation; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology*; D051381:Rats; D012964:Sodium / Q000378:metabolism
D004071:Digitalis Glycosides; D010042:Ouabain; D012964:Sodium
Corrélation entre l'inhibition de la repolarisation membranaire stimulative et la réponse inotrope positive provoquées par l'ouabaïne sur le myocarde de rat.