title: Effect of calcium antagonist gallopamil on antigen-induced early and late bronchoconstrictor responses in allergic sheep.
abstract: Calcium channel blockers have been shown to modify acute antigen-induced bronchoconstriction in allergic animals and in some human subjects with bronchial asthma; however, the effects of calcium antagonists on late-phase bronchial responses are not known. In this investigation, we studied the effects of calcium antagonist gallopamil on antigen-induced early- and late-phase bronchial responses in sheep allergic to Ascaris suum antigen. In 11 unsedated sheep, specific lung resistance (SRL) was measured before, immediately after, and serially up to 8 h after inhalation challenge with A. suum antigen. On different experiment days, at least 3 wk apart, the sheep were pretreated with gallopamil, administered either as an aerosol (5 mg, n = 10; 10 mg, n = 9) or as an intravenous injection (20 micrograms/kg, n = 10), and the antigen challenge was repeated. For the control experiments (n = 11), mean +/- SE SRL increased immediately after antigen challenge (early response) to 533 +/- 72% of baseline and again 6 to 8 h after challenge (late response) to 304 +/- 31% of baseline (p less than 0.05). Neither intravenously administered nor aerosolized gallopamil had a significant effect on baseline SRL. Both aerosolized and intravenously administered gallopamil blunted the early response and completely blocked the late-phase bronchoconstrictor response (p less than 0.05). Mean SRL during early phase increased to 208 +/- 39% and 245 +/- 39% of baseline with 5 mg and 10 mg of aerosolized gallopamil and to 191 +/- 35% of baseline with intravenously administered gallopamil, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Pulmonary Disease, University of Miami School of Medicine, Mount Sinai Medical Center, Miami Beach, Florida.
authors.forename: J
authors.initials: J
authors.lastname: D'Brot
authors.forename: W M
authors.initials: WM
authors.lastname: Abraham
authors.forename: T
authors.initials: T
authors.lastname: Ahmed
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D001200:Ascaris / Q000276:immunology; D001986:Bronchial Spasm / Q000188:drug therapy* / Q000209:etiology; D005711:Gallopamil / Q000627:therapeutic use*; D012130:Respiratory Hypersensitivity / Q000188:drug therapy*; D012756:Sheep; D013997:Time Factors
chemical_list: D000947:Antigens, Helminth; D005711:Gallopamil