title: Sensory and pulmonary irritation with exposure to methyl isocyanate.
abstract: Methyl isocyanate (MIC) was tested for its potency as a sensory irritant and as a pulmonary irritant in mice. To evaluate sensory irritation, animals were exposed to MIC at concentrations between 0.5 and 7.6 ppm for a period of 90 min. A characteristic reflex decrease in respiratory rate indicating sensory irritation was observed. The concentration evoking a 50% decrease in respiratory rate (RD50) was found to be 1.3 ppm. To evaluate pulmonary irritation, animals were first anesthetized and fitted with a tracheal cannula. Following recovery from anesthesia, they were exposed to MIC at concentrations between 0.4 and 7.3 ppm for a period of 90 min. A characteristic decrease in respiratory rate indicating pulmonary irritation in tracheally cannulated (TC) mice was observed. The concentration evoking a 50% decrease in respiratory rate (RD50TC) was found to be 1.9 ppm. Thus, MIC was found to be a potent sensory and pulmonary irritant.
mesh_terms: D000818:Animals; D001273:Atmosphere Exposure Chambers; D003485:Cyanates / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005740:Gases; D007442:Intubation, Intratracheal; D007509:Irritants; D017953:Isocyanates; D008297:Male; D051379:Mice; D012119:Respiration / Q000187:drug effects; D012137:Respiratory System / Q000187:drug effects*; D013997:Time Factors
chemical_list: D003485:Cyanates; D005740:Gases; D007509:Irritants; D017953:Isocyanates; C008461:methyl isocyanate