Background:There is controversy regarding bronchial responsiveness to b2-agonist drugs in asthma. Epithelial shedding in the airways is a pathological feature of asthma. Therefore, the present study focused on the effect of epithelial denudation of guinea pig tracheal chains in response to isoprenaline and b-adrenergic receptor blockade.Material/Methods:In control (group 1, n=10), epithelium-denuded (group 2, n=10), and epithelium-denuded + epithelial cell (group 3 n=6) we measured the responses of tracheal chains to cumulative concentrations of isoprenaline (I) in the absence and presence of 10 nM propranolol, and the value of EC50I was calculated. The propranolol blockade (CR-1) was calculated as the ratio of post propranolol EC50I to initial EC50I.Results:The tracheal responses to isoprenaline (EC50I) in groups 2 and 3 was significantly higher than in the controls (p

Keywords: Adrenergic beta-Agonists - pharmacology, Adrenergic beta-Antagonists - pharmacology, Asthma - chemically induced, Asthma - physiopathology, Dose-Response Relationship, Drug, Epithelium - drug effects, Epithelium - physiology, Guinea Pigs, Isoproterenol - pharmacology, Muscle Relaxation - drug effects, Muscle Relaxation - physiology, Propranolol - pharmacology, Regression Analysis, Trachea - drug effects, Trachea - physiology