Effect of cardiotonic polypeptide anthopleurin-A on canine Purkinje and ventricular muscle fibers.
Effects of Anthopleurin-A (AP-A, polypeptide from sea anemone) were studied on electrophysiological properties of isolated canine Purkinje and ventricular muscle fibers. Ap-A (in concentrations above 20 micrograms/l) produced a dose-dependent increase in action potential duration (APD) and the refractory period (RFP) in electrically driven Purkinje fibers, but had no effect on other parameters. Similar but less prominent change in APD and RFP was observed in ventricular muscle fibers. AP-A in high concentrations (200 micrograms/l or higher) did alter the spontaneous firing rate of Purkinje fibers. Since AP-A in low concentrations will increase the refractory period of conducting fibers without affecting a conduction velocity, it may abolish some re-entrant arrhythmias.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001950:Bretylium Tosylate / Q000494:pharmacology; D004285:Dogs; D006329:Heart Conduction System / Q000187:drug effects*; D006352:Heart Ventricles / Q000187:drug effects; D066298:In Vitro Techniques; D009431:Neural Conduction / Q000187:drug effects; D010455:Peptides / Q000494:pharmacology*; D011690:Purkinje Fibers / Q000187:drug effects*; D012615:Sea Anemones
D010455:Peptides; D001950:Bretylium Tosylate