Repeated toluene exposure and changes of response latency in shock avoidance learning

Behavioral effects of repeated exposure to toluene were investigated. After 1, 3, and 6 weeks exposure to toluene at 1000 and 2000 ppm, all rats received shock avoidance training. Toluene-exposed rats could acquire shock avoidance learning and there was no significant difference between exposed rats and control rats. Analyzing response latencies (RLs) of avoidance responses, control rats shifted them to a longer RL and at last they learned to perform avoidance responses with specific RLs (3-4 sec). However, rats exposed to 1000 ppm toluene for 1 week and to 2000 ppm toluene for 1 week and 3 weeks, did not learn to respond with specific RLs. Rats exposed to 1000 ppm and 2000 ppm toluene for 6 weeks did not shift to longer RLs. It was suggested that repeated exposure to toluene vapor ranging up to 2000 ppm had no influence on the acquisition of shock avoidance learning, but caused some functional impairments of higher nervous functions.