Neurochemical and behavioural effects of long-term intermittent inhalation of xylene vapour and simultaneous ethanol intake.

Two-month-old male Wistar rats were exposed to 300 p.p.m. of xylene vapour with simultaneous ethanol ingestion for 5 to 18 weeks. Neurochemical effects of mere vapour inhalation included an increase in microsomal superoxide dismutase activity in brain at the end of the experiment. Concomitant ethanol ingestion added significantly to the xylene-induced effects by causing increased proteolysis at the 9th and 14th week of exposure whereas cerebral superoxide dismutase failed to increase in these animals. Preening frequency decreased transiently in ethanol and in xylene groups at 6 and 9 to 12 weeks, respectively, whereas increased ambulation occurred only in the xylene--ethanol group after 12 and 14 weeks of exposure. The behavioural effects were therefore different in the combined exposure, and our biochemical and behavioural observations may point at significant interaction of both solvents although the biochemical mechanisms remain largely unexplained.