A possible role of a nonadrenergic inhibitory nervous system in airway hyperreactivity.
To investigate a possible role of a nonadrenergic inhibitory nervous system in airway hyperreactivity, we measured changes in RL and CL caused by electrical stimulation of cervical vagus nerve during the infusion of 5-HT, after treatment with atropine and propranolol in 18 cats. RL decreased to 56 +/- 3% (mean +/- SE) and CL increased to 186 +/- 13% of the prestimulated values, respectively, after stimulation. Hexamethonium diminished these responses significantly. Airway reactivity to 5-HT was reduced by continuous electrical stimulation of cervical vagus nerve in cats pretreated with atropine and propranolol. Hexamethonium potentiated airway reactivity to 5-HT. These results suggest that a nonadrenergic inhibitory nervous system could play an important role in the control of the bronchomotor tone and contribute to airway hyperreactivity.
D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002415:Cats; D004558:Electric Stimulation; D005260:Female; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D009420:Nervous System / Q000503:physiopathology*; D009433:Neural Inhibition; D011433:Propranolol / Q000494:pharmacology; D012130:Respiratory Hypersensitivity / Q000503:physiopathology*; D012137:Respiratory System / Q000294:innervation*; D012701:Serotonin / Q000494:pharmacology; D014630:Vagus Nerve / Q000503:physiopathology
D012701:Serotonin; D001285:Atropine; D011433:Propranolol