What is the primary mechanism of action (MOA) of leukotriene receptor antagonists?

Leukotriene receptor antagonists work primarily by binding to leukotriene receptors on smooth muscle and macrophages, thereby blocking the action of leukotrienes, which are inflammatory mediators that can contribute to bronchoconstriction and airway inflammation in asthma. By inhibiting these receptors, leukotriene receptor antagonists help to relax bronchial smooth muscles, reduce inflammation, and improve overall airway function, making them effective in preventing asthma attacks and easing symptoms in individuals with asthma.

The other options do not accurately describe the mechanism of action of leukotriene receptor antagonists. Increasing mucus production is more associated with asthma exacerbations rather than treatment. Reducing blood pressure does not relate to the action of leukotriene receptor antagonists as they do not have a significant effect on systemic blood pressure. Enhancing airway responsiveness would imply an increase in sensitivity to triggers, which contradicts the therapeutic goal of leukotriene receptor antagonists in stabilizing airway function and reducing reactivity.