This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenergic System, Subject name: Pharmacology
[{'content': 'Dopamine is preferred in treatment of shock because of: \nSelect and explain. \nA. Renal vasodilatory effect, B. Increased cardiac output, C. Peripheral vasoconstriction, D. Prolonged action', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (A) Renal vasodilatory effect(Ref: Katzung 11/e p137)Dopamine acts on D1 , b1 and a1 receptors. Stimulation of D1 receptors cause renal vasodilation, which is useful clinically to improve renal perfusion in shock with oligouria.', 'role': 'assistant'}]