Ionic mechanism of inotropic effect of prostaglandin E1 on frog atrial muscle

Prostaglandin E1 increases the amplitude and duration of cardiac action potential and exerts a positive inotropic effect on the frog heart. In voltage-clamp experiments, prostaglandin E1 increases both, the slow inward current and the delayed outward as well as the two components of the heart contraction. These results imply that calcium influx and the release of intracellular calcium are involved in the inotropic action of prostaglandin E1.