Beta blockers inhibit which adrenergic receptor subtypes?

Beta blockers inhibit which adrenergic receptor subtypes?

• A. Alpha-1 and Beta-1
• B. Beta-1 and Beta-2
• C. Alpha-2 and Beta-2
• D. Alpha-1 and Alpha-2

Answer: (B)

Beta blockers act as antagonists at beta-adrenergic receptors, preventing catecholamines from activating them. They primarily affect two subtypes: Beta-1, which are mainly in the heart and kidneys, and Beta-2, found in smooth muscle of the lungs and vasculature, as well as in liver and skeletal muscle. Because the drug class targets these beta receptors, it can inhibit both Beta-1 and Beta-2—though some agents are selective for Beta-1 only, while others are nonselective and block both. Alpha receptors (Alpha-1 and Alpha-2) are not targeted by beta blockers, which is why the relevant receptor subtypes are Beta-1 and Beta-2.

Beta blockers act as antagonists at beta-adrenergic receptors, preventing catecholamines from activating them. They primarily affect two subtypes: Beta-1, which are mainly in the heart and kidneys, and Beta-2, found in smooth muscle of the lungs and vasculature, as well as in liver and skeletal muscle. Because the drug class targets these beta receptors, it can inhibit both Beta-1 and Beta-2—though some agents are selective for Beta-1 only, while others are nonselective and block both. Alpha receptors (Alpha-1 and Alpha-2) are not targeted by beta blockers, which is why the relevant receptor subtypes are Beta-1 and Beta-2.