Escalation of intravenous self-administration of methylone and mephedrone under extended access conditions.
Jacques D. Nguyen, Yanabel Grant, Kevin M Creehan, Sophia A. Vandewater, Michael A. Taffe
Addiction Biology September 2017 DOI: 10.1111/adb.12398 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Population | Male Wistar rats |
| Interventions | Methylone Mephedrone Methamphetamine |
| Dose | 0.5 mg/kg/infusion for self-administration training; progressive-ratio dose-substitution ranges: methylone 0.125-2.5 mg/kg/infusion, mephedrone 0.125-2.5 mg/kg/infusion, methamphetamine 0.01-0.5 mg/kg/infusion |
| Duration | Short-access (2 h) and long-access (6 h) daily self-administration sessions |
| Topics | MDMA |
| Keywords | Bath salts Drug addiction Reward Substance abuse |
| Key findings | Long-access (6-hour) self-administration of mephedrone escalated intake and produced significantly higher progressive-ratio breakpoints for mephedrone and methamphetamine than short-access or methylone-trained groups, whereas long-access methylone self-administration showed only a rightward shift in peak effective dose without an overall efficacy change. The authors conclude mephedrone carries greater risk for dysregulated drug consumption. |
Abstract
The recreational use of substituted cathinones continues to grow as a public health concern in the United States. Studies have shown that extended access to intravenous (i.v.) self-administration of stimulants, such as cocaine and methamphetamine, results in escalation of drug intake relative to shorter access; however, little is known about the impact of extended access on self-administration of entactogen class stimulants such as methylone and 4-methylmethcathinone (mephedrone). Male Wistar rats were randomly assigned to short-access (ShA, 2- h) and long-access (LgA, 6- h) groups and trained to self-administer methylone or mephedrone (0.5 mg/kg/infusion) using a fixed-ratio 1 response contingency. The methylone-trained groups were evaluated on a progressive-ratio (PR) procedure incorporating dose-substitution of methylone (0.125-2.5 mg/kg/infusion), mephedrone (0.125-2.5 mg/kg/infusion) or methamphetamine (MA; 0.01-0.5 mg/kg/infusion). Mephedrone-trained rats were similarly evaluated on a PR with mephedrone and MA. Rats trained with LgA to methylone and mephedrone earned more infusions during acquisition compared with ShA groups. Mephedrone-trained LgA rats reached significantly higher breakpoints than all other groups in mephedrone and MA PR tests. Methylone-trained LgA rats exhibited a rightward shift of the peak effective dose but no overall efficacy change compared with methylone-trained ShA rats. These findings show that the self-administration of mephedrone escalates under LgA conditions in a manner similar to traditional stimulants whereas escalation of 6 h intakes of methylone is not accompanied by differences in PR performance. Thus mephedrone represents the greater risk for dysregulated drug consumption.
Comparable studies
Other preclinical and animal studies on MDMA, most cited first.
Citations in the library
Cited by 9
- Pharmacological effects of methylone and MDMA in humans Frontiers in Pharmacology February 17, 2023
- Self-Administration of Entactogen Psychostimulants Dysregulates Gamma-Aminobutyric Acid (GABA) and Kappa Opioid Receptor Signaling in the Central Nucleus of the Amygdala of Female Wistar Rats Frontiers in Behavioral Neuroscience December 16, 2021
- Lasting effects of repeated Δ9-tetrahydrocannabinol (THC) vapor inhalation during adolescence in male and female rats bioRxiv (Cold Spring Harbor Laboratory) September 25, 2018
- Locomotor and Reinforcing Effects of Pentedrone, Pentylone and Methylone in Rats bioRxiv Preprint Server July 21, 2017
- Methylenedioxymethamphetamine-like discriminative stimulus effects of seven cathinones in rats Behavioural Pharmacology June 1, 2020
and 4 more in the library
Cites 8
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- Intravenous self-administration of mephedrone, methylone and MDMA in female rats Neuropharmacology January 17, 2015
- The Reinforcing and Rewarding Effects of Methylone, a Synthetic Cathinone Commonly Found in “Bath Salts” Journal of Addiction Research & Therapy December 1, 2012
- Mephedrone, compared with MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and 5-HT levels in nucleus accumbens of awake rats British Journal of Pharmacology May 26, 2011
- Intravenous self-administration of entactogen-class stimulants in male rats. Neuropharmacology December 2015
and 3 more in the library