This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excretory System (Kidney, Bladder) Acid-Base Balance, Subject name: Physiology
The regional aerial resistance of the mesentery and kidney is reduced by- 
Select and explain. 
A. Dopamine, B. Nor adrenaline, C. Adrenaline, D. Isoprenaline
A: Dopamine
Answer: A: Dopamine 
Explanation: The D1 receptor in renal and mesenteric blood vessels are the most sensitive. I/V infusion of low dose of dopamine dilates these vessels (by raising intracellular cAMP). This increases GFR in addition dopamine exes natriuretic effect by D1 receptors on proximal tubules.