title: Role of peroxynitrite in airway microvascular hyperpermeability during late allergic phase in guinea pigs.
abstract: We investigated the role of peroxynitrite, which is formed by a rapid reaction between nitric oxide (NO) and superoxide anion (O(2)(-)), in the airway microvascular hyperpermeability during the late allergic response (LAR) in sensitized guinea pigs in vivo. The occurrence of LAR was assessed as a 100% increase in the transpulmonary pressure, which was monitored by the esophageal catheter technique. Airway microvascular permeability was assessed by Monastral blue dye trapping between the endothelium using an image analyzer. In the LAR phase (4 to 6 h after antigen inhalation), microvascular hyperpermeability and eosinophil infiltration within the airway wall were observed. NO production and xanthine oxidase (XO)/xanthine dehydrogenase activity, which are responsible for O(2)(-) production, were enhanced during the LAR. Peroxynitrite formation assessed by nitrotyrosine immunostaining was also exaggerated at that time. The microvascular hyperpermeability during the LAR was largely reduced by NO synthase inhibitor (L-NAME, 72.7% inhibition; p < 0.05), XO inhibitor (AHPP, 60.8% inhibition; p < 0. 05) and peroxynitrite scavenger (ebselen, 81.0% inhibition; p < 0. 05). L-NAME had a small but significant inhibitory effect on airway eosinophil accumulation, but AHPP and ebselen had no effect. These results suggest that excessive production of O(2)(-) and NO occurs in the LAR. These two molecules appear to cause airway microvascular hyperpermeability via peroxynitrite formation.
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sugiura
authors.forename: M
authors.initials: M
authors.lastname: Ichinose
authors.forename: T
authors.initials: T
authors.lastname: Oyake
authors.forename: Y
authors.initials: Y
authors.lastname: Mashito
authors.forename: Y
authors.initials: Y
authors.lastname: Ohuchi
authors.forename: N
authors.initials: N
authors.lastname: Endoh
authors.forename: M
authors.initials: M
authors.lastname: Miura
authors.forename: S
authors.initials: S
authors.lastname: Yamagata
authors.forename: A
authors.initials: A
authors.lastname: Koarai
authors.forename: T
authors.initials: T
authors.lastname: Akaike
authors.forename: H
authors.initials: H
authors.lastname: Maeda
authors.forename: K
authors.initials: K
authors.lastname: Shirato
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000276:immunology*; D005609:Free Radicals; D006168:Guinea Pigs; D007124:Immunoenzyme Techniques; D008297:Male; D008833:Microcirculation / Q000276:immunology; D009566:Nitrates / Q000502:physiology*; D012130:Respiratory Hypersensitivity / Q000276:immunology*; D014132:Trachea / Q000098:blood supply*; D014968:Xanthine Dehydrogenase / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D005609:Free Radicals; D009566:Nitrates; C039642:peroxynitric acid; D014968:Xanthine Dehydrogenase; D014969:Xanthine Oxidase