How do beta-2 agonists function to promote bronchodilation?

Beta-2 agonists function by stimulating beta-2 adrenergic receptors located in the smooth muscle of the airways. When these receptors are activated, there is an increase in cyclic adenosine monophosphate (cAMP) levels within the cells. Elevated cAMP leads to various downstream effects that result in relaxation of bronchial smooth muscle, which promotes bronchodilation. This mechanism is crucial for relieving symptoms in conditions like asthma and chronic obstructive pulmonary disease (COPD), where airway constriction is a major concern.

Additionally, increased levels of cAMP also inhibit the release of inflammatory mediators, thus contributing to the overall improvement in airway function. This makes beta-2 agonists an essential component of bronchodilator therapy in pulmonary disorders. The other choices pertain to different mechanisms not directly associated with the action of beta-2 agonists in promoting bronchodilation.