Why does histamine release during an asthma attack cause airway constriction, rather than dilation, despite some histamine receptors promoting vasodilation elsewhere in the body?

💡 Explanation

During an asthma attack, the predominant histamine receptors in bronchial smooth muscle are H1 receptors. Activation of these receptors causes bronchoconstriction because they trigger intracellular calcium release and smooth muscle contraction; therefore, airway constriction occurs, rather than dilation mediated by H2 receptors in other tissues.

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