title: Neurochemical effects of extended exposure to white spirit vapour at three concentration levels.
abstract: Male Wistar rats were exposed to 575 (100 ppm), 2875 (500 ppm) or 5750 mg/m3 (1000 ppm) white spirit vapour for 4-17 weeks 5 days a week, 6 h daily. Perirenal fat solvent concentration corresponded in composition and concentration to those of the vapour at all times. The neurochemical effects included a dose-dependent decrease in the cerebellar succinate dehydrogenase activity for 8 weeks while creatine kinase activity increased after 12 weeks. The specific creatine kinase activity in the glial cell fraction, a marker for astroglia, did not increase suggesting proliferation of astroglial cells in the homogenate. The serum creatine kinase activity originating mainly from striated muscle was below the control range at the two higher concentrations after 12 weeks. Simultaneous analyses for isolated muscle membrane sialic acid and uronic acid residues showed decreased concentrations in proportion to lipid phosphorus or total membrane protein. Thus, the white spirit mixture has neurochemical effects possibly caused by paraffins and the same components may have caused the muscle cell membrane effects. The lowest exposure concentration represents a virtual 'no effect' level for rats in the 17-week exposure.
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D003402:Creatine Kinase / Q000378:metabolism; D005387:Finland; D005978:Glutathione / Q000378:metabolism; D006838:Hydrocarbons / Q000633:toxicity*; D008297:Male; D008566:Membranes / Q000187:drug effects; D009132:Muscles / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012997:Solvents / Q000633:toxicity*
chemical_list: D006838:Hydrocarbons; D012997:Solvents; C013089:ligroin; D003402:Creatine Kinase; D005978:Glutathione