title: Behavioral effects of sub-acute inhalation of toluene in adult rats.
abstract: Reports of behavioral effects of repeated inhalation of toluene in rats have yielded inconsistent findings. A recent study from this laboratory (Beasley et al., 2010) observed that after 13 weeks of inhaled toluene ("subchronic" exposure scenario), rats showed mild but persistent changes in behavior, primarily involving acquisition of an autoshaped lever-press response. The present experiment sought to systematically replicate these findings, using a 4-week "sub-acute" exposure scenario. Adult male Long-Evans rats inhaled toluene vapor (0, 10, 100, or 1000 ppm) for 6h/day, 5 days/week for 4 weeks. As in the subchronic study, toluene had no effect on motor activity, anxiety-related behavior in the elevated plus-maze, or acquisition of the visual discrimination. However, sub-acute toluene did not affect appetitively-motivated acquisition of the lever-press response, but did reduce accuracy of signal detection at the end of training. Analysis of the deficit in accuracy in the 1000 ppm group by means of manipulations of different task parameters suggested a greater influence of attentional impairment than visual or motor dysfunction as a source for the deficit. These results confirm a pattern of subtle and inconsistent long-term effects of repeated daily exposure to concentrations of toluene vapor of 1000 ppm and below, in contrast to robust and reliable effects of acute inhalation of the solvent at concentrations above 1000 ppm.
authors.affiliation: Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
authors.forename: Tracey E
authors.initials: TE
authors.lastname: Beasley
authors.forename: Paul A
authors.initials: PA
authors.lastname: Evansky
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Bushnell
mesh_terms: D000280:Administration, Inhalation; D000375:Aging / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D002908:Chronic Disease; D004195:Disease Models, Animal; D019570:Inhalation Exposure / Q000009:adverse effects*; D008297:Male; D001523:Mental Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D051381:Rats; D020318:Rats, Long-Evans; D012997:Solvents / Q000633:toxicity; D014050:Toluene / Q000633:toxicity*
chemical_list: D012997:Solvents; D014050:Toluene