[Evaluation of toluene toxicity using Sidman avoidance behavior by lever pressing in rats (author's transl)]

Effects of single exposure to toluene on the operant behavior in rats were studied. The animals, in which the behavioral base line had been established, were exposed to 0, 1,000 and 3,000 ppm of toluene vapor for four hours, and the effects on the behavioral pattern of lever pressing were investigated for one hour after the end of exposure using Sidman avoidance test. 1) Exposure to 0 or 1,000 ppm of toluene did not affect the established operant behavior of the rats. 2) Exposure to 3,000 ppm produced increased responses, shortening of the inter-response-time, and no change in shock counts at the early stage of Sidman avoidance test when compared with those before exposure. 3) The behavioral change indicated here appears to be caused by a temporary breakdown of the established timing of lever pressing. 4) The effect of toluene on the operant behavior was strongest immediately after the aviodance test begun and the behavior recovered in about an hour. From the results of our experiment it can be said that the experimental methods used in this study is useful to evaluate the toxicity of toluene to the central nervous system of the animals.