Prevention of aspirin inhibition of platelet release reaction by the fatty acid precursor of platelet prostaglandins

Abstract

Preincubating human platelet-rich citrated plasma with eicosatetraenoic acid (E-tetra), the immediate precursor of PGE 2 and F 2α, prevents the inhibitory effect of aspirin on the release reaction induced by epinephrine, ADP, thrombin or collagen. The methyl ester of E-tetra as well as a saline solution of arachidonyl C1 had the same effect as the free acid. In striking contrast to E-tetra, E-tri or its methyl ester, E-penta, stearic, oleic, linoleic and γ-linolenic acid failed to prevent the inhibitory effect of aspirin. Although E-tetra alone induces the release reaction, this phenomenon does not explain the action of E-tetra in blocking effects of aspirin. Thus, we tentatively postulate that E-tetra's unique protection of the platelet against the untoward effect of aspirin, may be attributable to the role it plays in platelet prostaglandin synthesis.