Alpha-1 blockers primarily block which receptor type?

Alpha-1 blockers primarily block which receptor type?

• A. Beta-1 receptors
• B. Alpha-2 receptors
• C. Alpha-1 adrenergic receptors
• D. Dopamine D2 receptors

Answer: (C)

Alpha-1 blockers work by antagonizing alpha-1 adrenergic receptors, which are located on vascular smooth muscle (and in the bladder neck). When norepinephrine binds these receptors, they trigger a pathway that causes smooth muscle contraction and vasoconstriction. Blocking these receptors prevents that contraction, leading to vasodilation, lower peripheral resistance, and often reduced blood pressure. In the bladder neck and prostate, alpha-1 blockade reduces smooth muscle tone to ease obstruction in benign prostatic hyperplasia. Other receptor types listed—beta-1 receptors, alpha-2 receptors, or dopamine D2 receptors—are not the primary targets of alpha-1 blockers, which is why the alpha-1 adrenergic receptor is the best match.

Alpha-1 blockers work by antagonizing alpha-1 adrenergic receptors, which are located on vascular smooth muscle (and in the bladder neck). When norepinephrine binds these receptors, they trigger a pathway that causes smooth muscle contraction and vasoconstriction. Blocking these receptors prevents that contraction, leading to vasodilation, lower peripheral resistance, and often reduced blood pressure. In the bladder neck and prostate, alpha-1 blockade reduces smooth muscle tone to ease obstruction in benign prostatic hyperplasia. Other receptor types listed—beta-1 receptors, alpha-2 receptors, or dopamine D2 receptors—are not the primary targets of alpha-1 blockers, which is why the alpha-1 adrenergic receptor is the best match.