This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Dopamine is preferred in treatment of shock because of 
Select and explain. 
A. Renal vasodilatory effect, B. increased cardiac output, C. Peripheral vasoconstruction, D. Prolonged action
A: Renal vasodilatory effect
Answer: A: Renal vasodilatory effect 
Explanation: ref; KD Tripathi 6th edition pharmacology (page no;134) Dopamine (DA) is a dopaminergic (D1 and D2) as well as adrenergic alps 1 &b 1 (but not b2 ) agonist. The D1 receptors in renal and mesenteric blood vessels are the most sensitive: i.v. infusion of a low dose of DA dilates these vessels (by raising intracellular cAMP). This increases GFR and Na+ excretion.