title: Vagal afferents contribute to exacerbated airway responses following ozone and allergen challenge.
abstract: Brown-Norway rats (n=113) sensitized and challenged with nDer f 1 allergen were used to examine the contribution of lung sensory nerves to ozone (O(3)) exacerbation of asthma. Prior to their third challenge rats inhaled 1.0ppm O(3) for 8h. There were three groups: (1) control; (2) vagus perineural capsaicin treatment (PCT) with or without hexamethonium; and (3) vagotomy. O(3) inhalation resulted in a significant increase in lung resistance (R(L)) and an exaggerated response to subsequent allergen challenge. PCT abolished the O(3)-induced increase in R(L) and significantly reduced the increase in R(L) induced by a subsequent allergen challenge, while hexamethonium treatment reestablished bronchoconstriction induced by allergen challenge. Vagotomy resulted in a significant increase in the bronchoconstriction induced by O(3) inhalation and subsequent challenge with allergen. In this model of O(3) exacerbation of asthma, vagal C-fibers initiate reflex bronchoconstriction, vagal myelinated fibers initiate reflex bronchodilation, and mediators released within the airway initiate bronchoconstriction.
authors.affiliation: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA. esschelegle@ucdavis.edu
authors.forename: Edward S
authors.initials: ES
authors.lastname: Schelegle
authors.forename: William F
authors.initials: WF
authors.lastname: Walby
mesh_terms: D000393:Air Pollutants / Q000494:pharmacology*; D000403:Airway Resistance; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000150:complications / Q000276:immunology / Q000503:physiopathology*; D016084:Bronchoconstriction / Q000187:drug effects* / Q000276:immunology; D002211:Capsaicin / Q000494:pharmacology; D005730:Ganglionic Blockers / Q000494:pharmacology; D018738:Hexamethonium / Q000494:pharmacology; D006967:Hypersensitivity / Q000150:complications / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000294:innervation; D008297:Male; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects / Q000502:physiology; D010126:Ozone / Q000494:pharmacology*; D051381:Rats; D011984:Sensory Receptor Cells / Q000187:drug effects*; D018689:Sensory System Agents / Q000494:pharmacology; D014628:Vagotomy
chemical_list: D000393:Air Pollutants; D000485:Allergens; D005730:Ganglionic Blockers; D018689:Sensory System Agents; D018738:Hexamethonium; D010126:Ozone; D002211:Capsaicin