Prevention of the incubation of cocaine seeking by aerobic exercise in female rats.

Abstract

Recent research has demonstrated that aerobic exercise can attenuate craving for drugs of abuse and reduce escalation and reinstatement of drug-seeking behavior in animal models. The present study examined the effects of aerobic exercise on the development of the incubation of cocaine-seeking behavior or the progressive increase in cocaine seeking over a protracted withdrawal period from cocaine self-administration. Female rats were trained to self-administer cocaine (0.4mg/kg/inf) during daily 6-h sessions for 10days. Subsequently, access to cocaine and cocaine-paired cues was discontinued during a 3- or 30-day withdrawal period when rats had access to either a locked or unlocked running wheel. At the end of the withdrawal period, rats were reintroduced to the operant conditioning chamber and reexposed to cocaine-paired cues to examine cocaine-seeking behavior under extinction conditions. Rats with access to a locked running wheel during 30days of withdrawal had significantly greater cue-induced cocaine-seeking behavior than rats that had access to an unlocked running wheel for 30days. Further, there was robust incubation of cocaine seeking in rats with access to a locked running wheel as cocaine seeking was notably elevated at 30 vs. 3days of withdrawal. However, cocaine-seeking behavior did not differ between rats with access to an unlocked running wheel for 30 vs. 3days, indicating that incubation of cocaine seeking was suppressed following access to exercise for 30days. Aerobic exercise during extended withdrawal from cocaine self-administration decreased incubation of cue-induced cocaine-seeking behavior and may reduce vulnerability to relapse.