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
Dopamine given in acute CHF DOES NOT act on which of the following receptors? 
Select and explain. 
A. Receptors present on renal blood vessels, B. D1 receptors, C. Beta 1 receptors, D. Alpha 1 receptors
D: Alpha 1 receptors
Answer: D: Alpha 1 receptors 
Explanation: Ans. (D) Alpha 1 receptors(Ref: Katzung 13th/142, 144)Dopamine is used in CHF for its stimulatory effects on beta 1 receptors. It has dose dependent effects as followsReceptor stimulatedActionDose requiredD1Renal vasodilation1-2 mg/kg/minb1 Cardiac stimulation2-10 mg/kg/mina1 Vasoconstriction> 10 mg/kg/minTherefore, in CHF, it is used at a dose of 2-10 meg/kg/min. Thus, dopamine stimulates D1 and beta 1 receptors but not alpha 1 receptors.