Which receptors are antagonized by the medication Timolol? (Choose 2)

Timolol is a non-selective beta-adrenergic antagonist, which means it blocks both beta-1 and beta-2 adrenergic receptors. The beta-1 receptors are primarily located in the heart, where their activation typically increases heart rate and contractility. By antagonizing these receptors, Timolol reduces heart rate and the force of cardiac contraction, making it useful in treating conditions like hypertension and glaucoma.

On the other hand, beta-2 receptors are found primarily in the smooth muscle of the airways and blood vessels. They mediate relaxation and dilation. Timolol’s antagonistic action here leads to bronchoconstriction and vasoconstriction, which can be a consideration in patients with respiratory issues.

The choice that identifies both beta-1 and beta-2 receptors as being blocked by Timolol is correct because it accurately reflects the pharmacological action of this medication.