The regional aerial resistance of the mesentery and kidney is reduced by-: (A) Dopamine, (B) Nor adrenaline, (C) Adrenaline, (D) Isoprenaline
Answer is A. 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.