This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Which of the following drug is an example of psychological antagonism \nSelect and explain. \nA. Heparin-protamine, B. Prostacycline-thromboxane, C. Adrenaline-phenoxybenzamine, D. Physostigmine-acetylcholine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Physiological antagonism describes the behavior of a substance that produces effects counteracting those of another substance (a result similar to that produced by an antagonist blocking the action of an agonist at the same receptor) using a mechanism that does not involve binding to the same receptor. Prostacyclin (PGI(2)) is a potent endogenous inhibitor of platelet function and possesses a strong vasodilator effect. Fuhermore, prostacyclin is currently presented as the physiologic antagonist of thromboxane Ref-KDT 7/e p58', 'role': 'assistant'}]