Bupropion differentially impacts acquisition of methamphetamine self-administration and sucrose-maintained behavior

Abstract

Bupropion reduces the subjective effects and cue-induced craving for methamphetamine in humans. Given these effects of bupropion on methamphetamine in humans and its widespread clinical use, a preclinical model of drug-taking was used to determine if pretreatment with bupropion would alter the acquisition of methamphetamine self-administration. During acquisition, rats were given saline or bupropion (30 or 60 mg/kg, IP) 5 min before a 60-min session. For the first 8 days, each response on the active lever produced an infusion of methamphetamine (0.025 mg/kg). Responding on the inactive lever had no programmed consequence. This FR1 schedule was then increased to an FR3 for 4 more days. In a parallel study, the identical procedures were used to test the impact of bupropion on sucrose-maintained responding. Bupropion pretreatment decreased the number of methamphetamine infusions and sucrose deliveries earned on an FR1 and FR3. However, bupropion pretreatment only delayed discrimination between the active and inactive levers in the methamphetamine self-administration rats. Discrimination between active and inactive levers was acquired in all groups in the sucrose experiment regardless of pretreatment condition. Combined, these results suggest that bupropion has a more general effect within the appetitive/reward system of the brain rather than having complete specificity for methamphetamine.