Enhanced methamphetamine-induced conditioned place preference in risk-taking rats.

Patients with psychiatric disorders, such as gambling and substance use, tend to exhibit maladaptive decision-making. In this study, we assessed individual differences in risk-taking behaviors using a rat gambling task (GT) and investigated the relationship between risk-taking behaviors and vulnerability to drug dependence using methamphetamine (METH)-induced conditioned place preference (CPP). In the GT using a radial arm maze, male Long-Evans rats were trained to choose one of three choice arms (a low-risk/low reward (L-L), a high-risk/high reward (H-H), and an empty arm) in 16 trials per day for 14 days. METH-induced CPP consisted of 6 sessions: habituation, conditioning, preference test (Test I), extinction, extinction test (Test II), and reinstatement test (Test III). Results demonstrated that the percentage of choosing the H-H arm was significantly positively correlated with the percentage of time spent in the METH-paired compartment in the preference test, but not with the extinction and reinstatement tests, suggesting that risk-taking rats are more vulnerable to drug dependence.