Discriminative stimulus properties of toluene in the mouse

Little is known about the nature of the acute intoxication produced by exposure to high concentrations of toluene such as that which occurs with spills and in solvent abusers. The intoxication may be similar to that produced by classic central nervous system depressants such as the barbiturates. To investigate this hypothesis, drug discrimination procedures were used to compare the acute effects produced by toluene and pentobarbital (PB). Mice were trained to discriminate toluene (100 mg/kg, ip) from vehicle in a two-lever task in which responding was under the control of a fixed-ratio 20 (FR20) schedule of food presentation. Generalization tests were conducted after 20-min inhalation exposures to toluene (150-3600 ppm) and 20 min after injections with either PB (5-30 mg/kg) or morphine (3-20 mg/kg). Most mice generalized to inhaled toluene and to PB in a concentration- or dose-related fashion, but not to morphine. These results show that the effects of injected toluene can be established as a discriminative stimulus in mice, and that these stimulus effects are independent of route of administration. Shared discriminative stimulus properties with PB suggest that toluene produces an acute intoxication like that of other classic CNS depressants.