Cardiac effects of prostaglandins E1 and F1α

Abstract

The effects of prostaglandin E1 (PGE1) and prostaglandin F1α (PGF1α) were studied on perfused rat hearts and isolated rat atria. Both PGE1 and PGF1α produced dose-dependent increases in right atrial rate but had no effect on left atrial tension development. PGE1 (10−4 M) increased right atrial cyclic AMP content without changing phosphorylase a activity. PGF1α (10−4 M) did not change right atrial cyclic AMP or cyclic GMP content. Both prostaglandins had no effect on left atrial cyclic nucleotide content. When infused at a rate of 1 μg/min, PGE1 produced a time-dependent increase in cyclic AMP content in the Langendorff perfused hearts but did not alter contractile force development or phosphorylase a activity. An infusion of PGF1α produced a dose-dependent increase in tension development which was secondary to a negative chronotropic effect. PGF1α (1 μg/min) did not produce any changes in cyclic nucleotide levels or phosphorylase a activity in the Langendorff perfused hearts. These results show that PGE1 can selectively increase myocardial cyclic AMP content without altering contractile force or phosphorylase activity and that PGF1α does not increase rat cardiac AMP levels.