Activation of which receptor by albuterol leads to bronchodilation in the airways?

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Multiple Choice

Activation of which receptor by albuterol leads to bronchodilation in the airways?

Explanation:
Albuterol bronchodilates by activating beta-2 adrenergic receptors on bronchial smooth muscle. This receptor is Gs-coupled, so its stimulation triggers adenylyl cyclase to raise intracellular cAMP. Increased cAMP activates protein kinase A, which lowers intracellular calcium and promotes smooth muscle relaxation, widening the airways. Beta-2 activation is the key for rapid relief in asthma or COPD. Activation of beta-1 receptors would mainly affect the heart, not the airways, while muscarinic M3 activation promotes constriction, and alpha-1 causes vasoconstriction elsewhere, not bronchodilation.

Albuterol bronchodilates by activating beta-2 adrenergic receptors on bronchial smooth muscle. This receptor is Gs-coupled, so its stimulation triggers adenylyl cyclase to raise intracellular cAMP. Increased cAMP activates protein kinase A, which lowers intracellular calcium and promotes smooth muscle relaxation, widening the airways. Beta-2 activation is the key for rapid relief in asthma or COPD. Activation of beta-1 receptors would mainly affect the heart, not the airways, while muscarinic M3 activation promotes constriction, and alpha-1 causes vasoconstriction elsewhere, not bronchodilation.

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