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 μg/1) produced a dose-dependent increase in action potential duration (APD) and the refractory period (RFP) in electrically driven Purkinie 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 μg/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. © 1979.