Why does increased histamine release in bronchial smooth muscle during an asthma attack cause airway constriction, despite beta-2 agonists typically providing relief?

💡 Explanation

Histamine release triggers bronchial constriction by directly stimulating H1 receptors on smooth muscle, causing contraction and mucus production. Therefore, even with beta-2 agonists promoting bronchodilation, the histamine-mediated constriction can override this effect, rather than receptor desensitization or vagal tone primarily affecting the response.

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