This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inflammation & Repair, Subject name: Pathology
[{'content': 'Which among the following is a vasoconstrictor? \nSelect and explain. \nA. Histamine, B. PGI2, C. Bradykinin, D. TXA2', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., TXA2 Important mediators* Vasodilatation Histamine, prostaglandins, prostacyclins, serotonin, Nitric oxide, bradykinin.* Vasoconstriction Leukotrienes (LTC4, D4, E4), Thromboxane A2.", 'role': 'assistant'}]