Lack of interaction of heparin with ADP and prostacyclin on rat platelets

Abstract

It has recently been reported that heparin is able to counteract the ir hibitory effect of prostacyclin (PGI2) on human platelet aggregation (l-3). The mechanism of this interaction, however, still awaits clarification.There is growing evidence that heparin neutralizes the effect of prostanoid and non prostanoid inhibitors of human platelet aggregation by potentiating pletelet response to aggregating stimuli (3,4). If this is so, in a system where heparin does not potentiate platelet aggregation it should also fail to blunt the inhibitory effect of PG12. We report here evidence that in rat platelets the positive interacticn between ADP and heparin does not occur and heparin does not modify the inhibitory potency of PGI2.