Escalation of intravenous self-administration of methylone and mephedrone under extended access conditions
| Autor: | Nguyen, Jacques D, Grant, Yanabel, Creehan, Kevin M, Vandewater, Sophia A, Taffe, Michael A |
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| Rok vydání: | 2017 |
| Předmět: |
Male
drug addiction Time Factors Wistar Self Administration bath salts Medical and Health Sciences Methamphetamine Operant Substance Misuse substance abuse Animals ecstasy reward Behavior Animal Psychology and Cognitive Sciences Neurosciences Rats Brain Disorders Good Health and Well Being Administration Central Nervous System Stimulants Intravenous Drug Abuse (NIDA only) Conditioning |
| Zdroj: | Addiction biology, vol 22, iss 5 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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