title: Different inhalation lethality between micron-sized and submicron-sized aerosols of organophosphorus insecticide, chlorfenvinphos, in rats.
abstract: This study was designed to evaluate that a difference in the route of absorption or the mode of lethality is responsible for the higher inhalation lethality of micron-sized organophosphorus insecticide, chlorfenvinphos (CVP), aerosols than the submicron-sized aerosols. Male Fischer 344 rats were exposed to the micron-sized (> 1 micron) or the submicron-sized aerosols (< 1 micron) for 4 h using the nose-only exposure system. LC50 of the micron-sized and the submicron-sized aerosols was 0.13 mg/l and 0.51 mg/l, respectively. Placing a drain cannula in the esophagus markedly increased LC50 of the micron-sized aerosols to 0.49 mg/l, but not that of the submicron-sized aerosols. There was no qualitative difference in lethal profile in cardiorespiration between 2 types of aerosols. The higher lethality of the micron-sized aerosols could be ascribed to swallowed CVP.
authors.affiliation: Institute of Environmental Toxicology, Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: N
authors.initials: N
authors.lastname: Murao
authors.forename: K
authors.initials: K
authors.lastname: Maita
mesh_terms: D000042:Absorption; D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects; D002709:Chlorfenvinphos / Q000493:pharmacokinetics / Q000633:toxicity*; D004569:Electroencephalography / Q000187:drug effects; D004947:Esophagus; D008297:Male; D010316:Particle Size; D051381:Rats; D011916:Rats, Inbred F344; D012119:Respiration / Q000187:drug effects; D013047:Specific Pathogen-Free Organisms
chemical_list: D000336:Aerosols; D002709:Chlorfenvinphos