What is the action of albuterol on the airways?

• A. Blocks beta-2 receptors causing bronchodilation
• B. Inhibits acetylcholine release
• C. Activates beta-2 receptors causing bronchodilation
• D. Causes bronchoconstriction

Answer: (C)

Albuterol works by activating beta-2 adrenergic receptors on bronchial smooth muscle. This receptor stimulation engages the Gs protein, increases cAMP, and leads to relaxation of the smooth muscle, producing rapid bronchodilation. This helps relieve acute bronchospasm and reduces airway resistance. It also has modest effects on decreasing mediator release from mast cells. So the best description is that it activates beta-2 receptors causing bronchodilation. It does not block beta-2 receptors (which would cause constriction), it does not inhibit acetylcholine release (that's an anticholinergic mechanism), and it does not cause bronchoconstriction.