Generalization of a restraint-induced discriminative stimulus to cocaine in rats

The ability of the interoceptive cues produced following exposure to restraint stress to generalize to the discriminative stimulus effects of cocaine was investigated. Rats were trained to discriminate cocaine (10 mg/kg, IP, n=10; or 20 mg/kg, IP, n=6) from saline using a two-choice, food-reinforced, drug discrimination design. Substitution for the 10 mg/kg training dose of cocaine was observed subsequent to exposure to 15 min of restraint when administered immediately following an injection of saline. Restraint-induced generalization in the 20 mg/kg training group was substantial, but not statistically significant. These data suggest that a component of the subjective effects of cocaine may be associated with "anxiety".