An individual with asthma uses a beta-agonist inhaler during an attack. Which effect dominates as histamine binds to H1 receptors in the bronchial smooth muscle?

💡 Explanation

Histamine binding to H1 receptors triggers increased intracellular calcium, which enhances smooth muscle contraction; this leads to bronchoconstriction. Therefore, bronchiole constriction increases rather than dilation because the beta-agonist's effects are temporarily overwhelmed, and histamine's action dominates.

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