title: Intravenous self-administration of mephedrone, methylone and MDMA in female rats.
abstract: Male rats will intravenously self-administer (IVSA) the substituted cathinone stimulants ("bath salts") mephedrone (4-methylmethcathione) and methylone (3,4-methylenedioxymethcathinone) robustly, whereas the IVSA of 3,4-methylenedioxymethamphetamine (MDMA) is inconsistent in many rat models. There are no data available on the self-administration of these drugs in female rats, thus a study was undertaken to contrast them directly. Groups of female Wistar rats were trained to self-administer mephedrone, methylone or MDMA (0.5 mg/kg/inf) under a Fixed-Ratio (FR) 1 schedule of reinforcement for 14 sessions. Following the acquisition interval, animals were evaluated in FR (0.0, 0.125, 0.25, 0.5, 1.0, 2.5 mg/kg/inf) and PR (0.125, 1.0 mg/kg/inf) dose-substitution procedures. The results show that female rats acquired the self-administration of all three compounds with intakes in mephedrone-trained rats that were significantly higher than that of methylone-trained or MDMA-trained rats. In dose-substitution under either FR or PR contingencies, however, the potencies of all three drugs were similar within the original training groups. The mephedrone-trained animals exhibited higher intakes of all drugs during dose-substitution, indicating lasting consequences of the training drug. Abuse liability of these three compounds is therefore predicted to be similar in established stimulant users but may differ in liability if they are primary drugs of initiation.
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Creehan
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA.
authors.forename: Sophia A
authors.initials: SA
authors.lastname: Vandewater
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA. Electronic address: mtaffe@scripps.edu.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Taffe
mesh_terms: D061605:Administration, Intravenous; D000818:Animals; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects*; D004192:Discrimination, Psychological / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006213:Hallucinogens / Q000494:pharmacology*; D008694:Methamphetamine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule; D012646:Self Administration; D013997:Time Factors
chemical_list: D000697:Central Nervous System Stimulants; D006213:Hallucinogens; D008694:Methamphetamine; C548233:mephedrone; D018817:N-Methyl-3,4-methylenedioxyamphetamine; C400939:methylone
keywords: 3,4-methylenedioxymethamphetamine (PubChem CID:1615); 4-methylmethcathinone (PubChemCID: 45266826); Bath salts; Drug addiction; Ecstasy; Reward; Substance abuse; methylone (PubChem CID: 45789647)