Figure 3.

EPI induces MLC phosphorylation in HASM under β₂AR desensitizing conditions. As EPI (0.1–100 µM, 10 min) concentration increases, pMLC increases in β₂AR desensitized [Alb-PT (albuterol pretreated) 10 μM, 24 h] HASM but not in nondesensitized (basal). Carbachol (CCh; 20 µM, 10 min) was used as a positive control to elicit pMLC (values are mean ± SEM, n = 4 cell lines) (*P ≤ 0.05). β₂AR, β₂-adrenergic receptor; EPI, epinephrine; HASM, human airway smooth muscle; pMLC, myosin light chain phosphorylation.