Atenolol is best described as which type of receptor blocker?

Atenolol is best described as which type of receptor blocker?

• A. Alpha-1 blocker
• B. Alpha-2 blocker
• C. Beta-1 selective blocker
• D. Beta-2 blocker

Answer: (C)

Atenolol acts as an adrenergic receptor blocker with specificity for beta-1 receptors located primarily in the heart. By blocking these receptors, it lowers heart rate, decreases contractility, and slows AV nodal conduction, which reduces blood pressure and myocardial oxygen demand. This cardioselectivity is what makes it a beta-1 selective blocker. Other blocker types target different receptors: alpha-1 blockers affect vascular smooth muscle causing vasodilation; alpha-2 blockers influence presynaptic regulation; beta-2 blockers would affect the lungs and metabolic tissues, potentially causing bronchoconstriction and other effects. Nonselective beta blockers hit both beta-1 and beta-2 receptors, so atenolol’s selective action fits best. Note that at very high doses, selectivity can lessen, but it is still characterized as beta-1 selective.

Atenolol acts as an adrenergic receptor blocker with specificity for beta-1 receptors located primarily in the heart. By blocking these receptors, it lowers heart rate, decreases contractility, and slows AV nodal conduction, which reduces blood pressure and myocardial oxygen demand. This cardioselectivity is what makes it a beta-1 selective blocker. Other blocker types target different receptors: alpha-1 blockers affect vascular smooth muscle causing vasodilation; alpha-2 blockers influence presynaptic regulation; beta-2 blockers would affect the lungs and metabolic tissues, potentially causing bronchoconstriction and other effects. Nonselective beta blockers hit both beta-1 and beta-2 receptors, so atenolol’s selective action fits best. Note that at very high doses, selectivity can lessen, but it is still characterized as beta-1 selective.