Dopaminergic receptors are associated with which effect?

• A. Bronchodilation
• B. Renal and mesenteric vasodilation
• C. Increased water resorption in the nephrons
• D. Vasoconstriction of vascular smooth muscle

Answer: (B)

Dopaminergic receptors, especially the D1-like subtype, promote relaxation of vascular smooth muscle in certain beds, notably the renal and mesenteric arteries. Activating these receptors increases cAMP, leading to vasodilation and higher blood flow in the kidneys. In the kidney, this dopaminergic effect raises renal perfusion and tends to promote natriuresis and diuresis rather than fluid resorption. That’s why renal and mesenteric vasodilation is the best description of dopaminergic receptor effects.

Bronchodilation is primarily driven by beta-2 adrenergic receptors in the airways. Increased water resorption in nephrons isn’t a dopaminergic action (dopamine tends to promote natriuresis and diuresis). Vasoconstriction of vascular smooth muscle points to alpha-adrenergic receptors, not dopaminergic ones.