A patient experiences an asthma exacerbation characterized by increased airway resistance. Which mechanism explains why inhaled beta-2 agonists rapidly alleviate bronchospasm following mast cell histamine release?

💡 Explanation

Beta-2 agonists stimulate adenylyl cyclase in smooth muscle cells, which then increases intracellular cAMP levels, causing smooth muscle relaxation and bronchodilation. This occurs because cAMP-dependent protein kinase activation decreases myosin light-chain kinase activity, therefore decreasing smooth muscle contraction, rather than blocking histamine release directly.

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