This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
[{'content': 'A 25 year drug addict is brought to hospital in an intoxicated state. History suggests cocaine misuse, what is the effect of cocaine on blood vessels? \nSelect and explain. \nA. Vasoconstrictor, B. Vasodilator, C. Vasoineffective, D. First constrict then dilates', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cocaine act as a vasoconstrictor by blocking re uptake of norepinephrine at sympathetic nerve endings.Coronary aery constriction causes myocardial infarction and with it the risk of cardioembolic stroke.Systemic aery constriction causes acute hypeension, predisposing to rupture of underlying vascular malformations or aneurysms.Cerebral aery constriction causes cerbral ischemia.', 'role': 'assistant'}]