title: Effect of dimethylthiourea, a hydroxyl radical scavenger, on cigarette smoke-induced bronchoconstriction in guinea pigs.
abstract: Cigarette smoke exposure causes bronchoconstriction in guinea pigs by stimulating cholinergic and excitatory nonadrenergic, noncholinergic (eNANC)-nerves in vagus system. The aim of this study is to elucidate the role of hydroxyl radical (OH(-)), contained in cigarette smoke, in bronchoconstriction. Anaesthetized animals were exposed to 80 puffs of smoke for 4 min. Pretreatment with dimethylthiourea, a OH(-) scavenger, significantly inhibited cigarette smoke-induced bronchoconstriction. To investigate its site of action, effects of dimethylthiourea were examined on vagally mediated bronchcoconstriction by electrical stimulation and on the bronchoconstriction by intravenous acetylcholine and neurokinin-A. Dimethylthiourea did not inhibit bronchoconstriction evoked by vagal stimulation, acetylcholine or neurokinin-A. These results suggest that dimethylthiourea inhibits cigarette smoke-induced bronchoconstriction by scavenging the smoke-derived OH(-), but not by inhibiting airway nerve function.
authors.affiliation: Research Institute for Diseases of the Chest, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Aizawa
authors.forename: H
authors.initials: H
authors.lastname: Inoue
authors.forename: H
authors.initials: H
authors.lastname: Koto
authors.forename: S
authors.initials: S
authors.lastname: Fukuyama
authors.forename: N
authors.initials: N
authors.lastname: Hara
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D016084:Bronchoconstriction / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006168:Guinea Pigs; D017665:Hydroxyl Radical / Q000378:metabolism; D007327:Insufflation; D008168:Lung / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D015288:Neurokinin A / Q000494:pharmacology; D011312:Pressure; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014630:Vagus Nerve / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D014028:Tobacco Smoke Pollution; D014665:Vasodilator Agents; D017665:Hydroxyl Radical; D001285:Atropine; D015288:Neurokinin A; C038983:1,3-dimethylthiourea; D013890:Thiourea; D000109:Acetylcholine