Comparison of the effects of abstinence on MDMA and cocaine self-administration in rats.
Quenten Highgate, Susan Schenk
Psychopharmacology November 2018 DOI: 10.1007/s00213-018-5026-1 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Population | Rats self-administering MDMA or cocaine |
| Interventions | MDMA Cocaine |
| Dose | 350 mg/kg |
| Duration | 0- or 14-day abstinence, followed by 7 additional days of self-administration testing |
| Topics | MDMA Serotonin |
| Keywords | Abstinence Cocaine Self-administration |
| Key findings | Abstinence reduced subsequent MDMA self-administration but not cocaine self-administration. Cocaine was self-administered faster than MDMA, and MDMA responding was concentrated in the first hour of each session while cocaine responding was evenly distributed. The authors argue the selective reduction is consistent with MDMA-stimulated serotonin release being inhibitory to MDMA self-administration. |
Abstract
3,4-Methylenedioxymethamphetamine (MDMA) preferentially increases synaptic serotonin (5HT). This response was attenuated following repeated exposure but there was recovery as a result of abstinence. Effects of abstinence on self-administration of many drugs have been documented but the impact on MDMA self-administration is unknown. This study compared the effects of abstinence on MDMA and cocaine self-administration. Six-hour daily MDMA or cocaine sessions were conducted until a total of 350 mg/kg had been self-administered. Following this, rats were randomly assigned to either a 0- or 14-day abstinence group. Self-administration testing then continued for an additional 7 days. The latency to self-administer 350 mg/kg was shorter for rats that self-administered cocaine. The temporal distribution of responding within each test session also differed; MDMA self-administration was high during the first hour of each session, and decreased during subsequent hours, whereas cocaine self-administration was evenly distributed throughout each hour of the session. Abstinence decreased MDMA but not cocaine self-administration. The selective reduction of MDMA self-administration following abstinence is consistent with the idea that MDMA-stimulated 5-HT release is inhibitory to MDMA self-administration.