[The importance of increased prostaglandins and prostacyclin for the effect of oxyfedrin in isolated guinea pig heart preparations]

Abstract

In isolated perfused heart preparations of guinea pigs coronary dilating and positive inotropic doses of oxyfedrine induce a significant increase of the release of prostaglandin-like substances (PLS) and prostacyclin (PGI2). Indometacin as an inhibitor of prostaglandin biosynthesis (140 mumol/l) enhances after a 10 min lasting perfusion contraction force and coronary flow of the hearts but inhibits PGI2-formation. Under these conditions oxyfedrine loses its positive influence on inotropism, coronary flow and PGI2-efflux. Indometacin (140 mumol/l) also completely abolishes the increase of cardiac performance of isolated auricle preparations by oxyfedrine (50 mumol/l). These findings agree with former results and indicate an involvement of the PLS- and PGI2-biosynthesis in the antianginal efficacy of oxyfedrine.