This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Prostaglandins, Subject name: Pharmacology
[{'content': 'Aspirin is used for ischemic heart disease: \nSelect and explain. \nA. Inhibit TXA2 synthesis, B. Inhibit prostacyclin, C. Inhibit COX 2, D. Inhibit synthesis of endothelin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Inhibit TXA2 synthesisAspirin is irreversible COX inhibitor. At low dose 40-325mg they act as antiplatelet agent. They inhibit TXA2 synthesis which is platelet aggregator but also inhibit PGI2 which is platelet anti aggrator. But the net effect is TXA2 inhibition.', 'role': 'assistant'}]