Role of the endocannabinoid system in MDMA intracerebral self-administration in rats.
I.c.v. self-administration of MDMA (0.01-2 micro g per infusion), alone and in combination with CP 55,940 (0.4 micro g infusion(-1)), was studied on an operant responding procedure. On the basis of individual preference for one of two levers, developed during training, rats were allowed to self-administer vehicle from the preferred lever and MDMA from the other. Pressings on the MDMA associated-lever, except for the maximal unit dose, progressively increased. The combination of CP 55,940 with MDMA (1 micro g infusion(-1)) reduced the number of drug-associated lever pressings compared to the single drugs. Pre-treatment with SR 141716A (0.5 mg kg(-1) i.p.), 15 min before each daily session, significantly increased MDMA self-administration. These findings suggest that MDMA self-administration is under endogenous tonic control by the endocannabinoid system.
Braida
Daniela
D
Department of Pharmacology, Chemotherapy and medical Toxicology, University of Milan, Faculty of Mathematical, Physical and Natural Sciences, Via Vanvitelli 32, Italy.
Sala
Mariaelvina
M
D000818:Animals; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003216:Conditioning, Operant / Q000187:drug effects; D003511:Cyclohexanols / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D005231:Fatty Acids, Unsaturated / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006213:Hallucinogens / Q000008:administration & dosage / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology; D000077285:Rimonabant; D012646:Self Administration
D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids; D003511:Cyclohexanols; D063388:Endocannabinoids; D005231:Fatty Acids, Unsaturated; D006213:Hallucinogens; D010880:Piperidines; D011720:Pyrazoles; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D000077285:Rimonabant