D-cycloserine facilitates extinction of cocaine self-administration in rats

Previous research has indicated that D-cycloserine [DCS; a N-methyl-D-aspartate (NMDA) partial agonist] facilitates the extinction of conditioned fear as well as the extinction of cocaine conditioned place preference. Sprague Dawley rats were first trained to self-administer cocaine and then we compared their extinction behavior (lever pressing) following treatment with vehicle; 15 mg/kg DCS; or 30 mg/kg DCS. We showed that 30 mg/kg DCS, but not 15 mg/kg significantly accelerated extinction of cocaine self-administration behavior when compared with saline by almost half (4 days vs. 9 days). At 2 weeks when all animals had extinguished, there were no longer differences between the groups. The present findings support of the potential of NMDA partial agonists as prospectively valuable in facilitating the extinction of cocaine-seeking behavior. More specifically, we demonstrate that 30 mg/kg DCS was effective at significantly accelerating the extinction of cocaine self-administration behavior in rats. These results provide further support for the potential of DCS as a treatment strategy for addiction.