<prompt> Mechanism of action of aspirin as antiplatelet drug is its inhibitory action on?ProstacyclinsPGF 2 alphaThromboxane A2Phospholipase C  <response>: Ans. C Thromboxane A2Ref: KDT 8e p677By inhibiting cyclooxygenase enzyme, aspirin initially decreases the level of both prostacyclins in endothelium and TXA2 in platelets. However after some time prostacyclin synthesis resumes due to presence of nucleus in endothelium whereas TXA2 remain depressed because platelets are enucleated. Thus final effects of aspirin are due to decrease in TXA2 synthesis. 