The role of the parasympathetic nervous system in the maintenance of chronic airway obstruction in asthmatic children.
To evaluate the role of the parasympathetic nervous system in the mediation and maintenance of reversible airway obstruction in perennially asthmatic children, we measured pulmonary function in 18 patients before and after the administration of atropine sulfate aerosol. The bronchodilatory effects of atropine were compared with those of isoproterenol hydrochloride and placebo aerosols. Placebo aerosol did not change any of the pulmonary functions tested. Atropine and isoproterenol aerosols improved forced expiratory flows, airway resistance, and specific airway conductance significantly and to the same degree. Hyperinflation was significantly lessened by atropine, but not by isoproterenol. Because atropine is not a direct smooth muscle relaxant, but rather a selective blocker of cholinergically induced smooth muscle tone, any significant improvement in the lung function of chronically asthmatic children by atropine suggests that at least some of their reversible airway obstruction is induced and maintained by parasympathetically mediated bronchial smooth muscle constriction.
D000402:Airway Obstruction / Q000503:physiopathology*; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D001285:Atropine / Q000494:pharmacology* / Q000627:therapeutic use; D001986:Bronchial Spasm / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009130:Muscle, Smooth / Q000503:physiopathology; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D012138:Respiratory Therapy
D001285:Atropine; D007545:Isoproterenol