title: Mechanisms of bronchoconstriction after allergen ingestion in sensitized guinea pigs.
abstract: We examined whether oral administration of allergen induced bronchoconstriction in sensitized guinea pigs and investigated the mechanisms of bronchoconstriction. The animals had been immunized intraperitoneally with a mixture of Ascaris suum extract and silica gel, and exposed to ozone. They were then challenged with an oral dose of A. suum extract (6 mg/kg), and respiratory resistance (Rrs) was measured up to 7 h. After oral administration of the allergen, an increase in Rrs was observed. The mean values at 1, 3, 5 and 7 h after oral allergen challenge were 150 +/- 21, 149 +/- 11, 151 +/- 12 and 134 +/- 10% of the baseline value, respectively. When saline instead of the allergen was orally administered, almost no significant increase in Rrs was observed up to 7 h. Moreover, in nonsensitized guinea pigs, oral administration of allergen produced no significant increase in Rrs for up to 7 h. When atropine was administered as an aerosol, the increase in Rrs induced by an oral allergen challenge was attenuated. Three of the five atropine-treated guinea pigs showed temporary increases in Rrs immediately after the oral allergen challenge. The mean values of Rrs in the atropine-treated animals challenged with oral allergen at 1, 3, 5 and 7 h were 106 +/- 3, 106 +/- 5, 115 +/- 5 and 102 +/- 4% of baseline value, respectively. In the animals which received oral allergen, the number of neutrophils in bronchoalveolar lavage fluid (BALF) significantly increased 2.0-fold (p < 0.05), while no significant increase in the number of eosinophils, macrophages, or lymphocytes in BALF was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamada
authors.forename: H
authors.initials: H
authors.lastname: Inoue
authors.forename: H
authors.initials: H
authors.lastname: Aratani
authors.forename: M
authors.initials: M
authors.lastname: Ichinose
authors.forename: T
authors.initials: T
authors.lastname: Takishima
mesh_terms: D000284:Administration, Oral; D000485:Allergens / Q000008:administration & dosage*; D000818:Animals; D017165:Ascaris suum / Q000276:immunology; D001285:Atropine / Q000494:pharmacology; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid; D016084:Bronchoconstriction / Q000187:drug effects; D005512:Food Hypersensitivity / Q000276:immunology; D006168:Guinea Pigs; D006967:Hypersensitivity / Q000503:physiopathology*; D007958:Leukocyte Count; D008297:Male
chemical_list: D000485:Allergens; D001285:Atropine