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
Action of dopamine in 1-2 mcg/kg/min dose is 
Select and explain. 
A. Vasoconstriction, B. Increases renal blood flow, C. Increases cardiac contractility, D. Increases blood pressure
B: Increases renal blood flow
Answer: B: Increases renal blood flow 
Explanation: Ans. (B) Increases renal blood flow(Ref: Goodman Gilman 12th/e p355; KDT 8th/e p146)Dopamine has dose dependent actionsLow dose (1-2 mcg/kg/min): It stimulates only D1 receptors leading to renal vasodilation and thus increase in renal blood flow.Medium dose (2-10 mcg/kg/min): It stimulates both D1 and beta 1 receptors means it will lead to inotropic action also.High dose (>10 mcg/kg/min): It stimulates Dl, beta 1 and alpha 1 receptors resulting in additional vasoconstriction.