What is the mechanism of action of beta-agonists?

Beta-agonists function by stimulating beta receptors in the body, primarily the beta-2 adrenergic receptors located in the smooth muscle of the airways. When these receptors are activated, they relax the muscle surrounding the airways, leading to bronchodilation, which improves airflow and alleviates symptoms of bronchospasm commonly found in conditions like asthma and chronic obstructive pulmonary disease (COPD).

This mechanism is crucial in therapeutic settings where quick relief of bronchoconstriction is necessary. The use of beta-agonists can effectively reduce resistance in the respiratory airway and enhance respiratory function. Understanding this mechanism helps in recognizing how these medications alleviate symptoms and improve patients' quality of life in respiratory illnesses.

Other choices do not accurately describe the mechanism of beta-agonists, such as blocking receptors or decreasing heart rate, which pertain to different pharmacological effects not relevant to their primary action in bronchodilation.