* To whom correspondence should be addressed.
Received September 15, 1999; Revision received November 9, 1999
The influence of an amide of prostaglandin E1 and ethanolamine plasmalogen platelet-activating factor analog 1-O-alk-1´-enyl-2-acetyl-sn-glycero-3-phospho-(N-11alpha,15alpha-dioxy-9-keto-13-prostenoyl)ethanolamine (PGE1-PPAF) on platelet-activating factor (PAF)-, ADP-, and thrombin-induced human platelet aggregation has been studied. It was found that PGE1-PPAF inhibits the PAF-, ADP-, and thrombin-induced platelet aggregation in platelet-rich plasma. 1-O-alk-1´-enyl-2-acetyl-sn-glycero-3-phosphoethanolamine inhibited PAF-induced aggregation up to 50% but had no influence on platelet aggregation induced by ADP or thrombin. The ethanolamine plasmalogen analog of PAF 1-O-alk-1´-enyl-2-acetyl-sn-glycero-3-phospho-(N-palmitoyl)ethanolamine, having a palmitoyl residue instead of PGE1, did not inhibit platelet aggregation induced by PAF, ADP, or thrombin. We propose that inhibition of human platelet aggregation by PGE1-PPAF is mediated by its action on platelet PAF-receptors and the adenylate cyclase system.
KEY WORDS: platelet-activating factor, amide of prostaglandin E1 and a PAF analog, prostaglandin E1, platelets