Cholic acid and the heart: in vitro studies of the effect on heart rate and myocardial contractility in the rat.
1. Cholic acid has a dose-dependent negative chronotropic effect on isolated atria of Wistar rats. 2. The positive inotropic effect of cholic acid is the result of a negative chronotropic effect and can be eliminated by electrical pacing. 3. Cholic acid does not appear to exert its negative chronotropic effect through cholinoceptors and alterations in bath concentrations of calcium and potassium does not influence this effect significantly. 4. Cholic acid is a functional antagonist of isoprenaline. 5. It is suggested that cholic acid exerts its negative chronotropic effect by forming a monolayer on the surface of the cell membrane, thereby mechanically interfering with membrane function.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002793:Cholic Acids / Q000494:pharmacology*; D003864:Depression, Chemical; D004558:Electric Stimulation; D004912:Erythrocytes / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000648:ultrastructure; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D002793:Cholic Acids; D011188:Potassium; D002118:Calcium