Neurotoxicologic evaluation of rats after 13 weeks of inhalation exposure to dichloromethane or carbon monoxide

• Published in: Pharmacology, biochemistry and behavior Vol. 36; no. 3; pp. 671 - 681
• Main Authors: Mattsson, J.L., Albee, R.R., Eisenbrandt, D.L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY Elsevier Inc 01.07.1990; Elsevier Science
• Subjects: Action Potentials - drug effects; Administration, Inhalation; Air Pollutants, Occupational - toxicity; Animals; Biological and medical sciences; Brain - drug effects; Brain - pathology; Brain - physiopathology; Carbon monoxide; Carbon Monoxide - toxicity; Caudal nerve action potentials; Chemical and industrial products toxicology. Toxic occupational diseases; Evoked Potentials - drug effects; Female; Flash-evoked potentials; Hydrocarbons, Chlorinated - toxicity; Male; Medical sciences; Methylene Chloride - toxicity; Neuropathology; Perfusion fixation; Rats; Rats, Inbred F344; Solvents; Somatosensory-evoked responses; Subchronic inhalation exposures; Tone-pip ABRs; Toxicology; Somatosensory-evoked responses; Neuropathology; Click auditory brainstem responses; Rats; Dichloromethane; Tone-pip ABRs; Carbon monoxide; Subchronic inhalation exposures; Flash-evoked potentials; Caudal nerve action potentials; Perfusion fixation; Nervous system diseases; Rat; Toxicity; Rodentia; Central nervous system; Functional deficit; Electrophysiology; Inhalation; Electrodiagnosis; Organic solvent; Vertebrata; Mammalia; Evoked potential; Animal
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/0091-3057(90)90273-K

Male and female Fischer 344 rats were exposed to dichloromethane (methylene chloride, DCM) or carbon monoxide (CO) for 6 hr/day, 5 days/week, for 13 weeks. Since oxidative metabolism of DCM to CO and CO 2 is a saturable process, DCM exposure concentrations were selected clearly below saturation (50 ppm), just below saturation (200 ppm), and well above saturation (2000 ppm). At saturation of metabolism, metabolic CO causes about 10% carboxyhemoglobinemia (COHb). Therefore, as a control for CO effects, a separate group of rats was exposed to 135 ppm CO to induce approximately 10% COHb. Postexposure functional tests included an observational battery, hindlimb grip strength, and a battery of evoked potentials (flash, auditory brainstem, somatosensory, caudal nerve). After functional tests were completed, rats from all groups were perfused with fixative and a comprehensive set of nervous tissues from the high DCM exposure group and from controls were examined by light microscopy. Although some miscellaneous functional and morphologic variations were recorded, none were related to treatment. Thus, subchronic exposures as high as 2000 ppm DCM or 135 ppm CO had no deleterious effects on any of the measures of this study.