Effects of taurine depletion on rat cardiac electrophysiology: in vivo and in vitro studies.
Electrocardiograms were monitored in unanesthetized rats during treatment with drinking water containing guanidinoethyl sulfonate (GES), an inhibitor of taurine transport, which depleted cardiac taurine content. Treatment led to a selective prolongation of the QT interval which was highly correlated with the degree of taurine depletion (r2 = 0.92, p less than .001). Compared to controls, the duration of ventricular muscle action potentials was significantly increased in GES-treated rats, and this accounted for the prolongation of QT intervals. Oral taurine supplements reversed GES-induced cardiac taurine depletion and the associated increased duration of action potentials and QT intervals. In vitro superfusion with 0.2-10 mM GES or taurine had no effect on action potentials of control or GES-treated rats. These data indicate that intracellular taurine may play a role in regulating myocardial action potential duration, particularly during repolarization.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000502:physiology; D004247:DNA / Q000032:analysis; D004562:Electrocardiography; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013654:Taurine / Q000031:analogs & derivatives / Q000032:analysis / Q000494:pharmacology / Q000502:physiology*; D013997:Time Factors
D013654:Taurine; C009558:taurocyamine; D004247:DNA; D002118:Calcium