ABSTRACT

The density of b-receptors varies within the lung, with high-expression levels found in the airway epithelium, alveoli, and submucosal glands (1).

Importantly, these receptors are also expressed on smooth muscle cells

(1,2), as well as inflammatory cells such as mast cells and lymphocytes

(3). The majority of pulmonary b-receptors are the b2-subtype, with a b2:b1 ratio of 3:1 (1).