title: Pre-treatment with high doses of cocaine decreases the reinforcing effects of cocaine in the conditioned place preference paradigm.
abstract: The aim of the present study was to determine if pre-exposure to high doses of cocaine can subsequently alter the rewarding effects of this drug. Adult male mice received a pretreatment of physiological saline, or 12.5 or 25 mg/kg of cocaine (one injection a day for five days). After an interval of six days without injections, the rewarding effects of low doses of cocaine (0.5, 1 or 1.5 mg/kg) were evaluated in the conditioned place preference (CPP) paradigm. Doses of 1 and 1.5 mg/kg induced a clear CPP in animals pre-treated with saline but were ineffective in those pre-treated with 25 mg/kg of cocaine. Only the dose of 1.5 mg/kg induced CPP in mice pre-treated with 12.5 mg/kg of cocaine. Our results, which reveal a decrease in the conditioned rewarding effects of threshold doses of cocaine, demonstrate that exposure to high doses of this drug can alter the reward system.
authors.affiliation: Unidad de Investigación Psicobiología de las Drogodependencias, Departamento de Psicobiología, Facultad de Psicología, Universitat de València, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Manzanedo
authors.forename: María P
authors.initials: MP
authors.lastname: García-Pardo
authors.forename: Marta
authors.initials: M
authors.lastname: Rodríguez-Arias
authors.forename: José
authors.initials: J
authors.lastname: Miñarro
authors.forename: María A
authors.initials: MA
authors.lastname: Aguilar
mesh_terms: D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D003214:Conditioning, Classical / Q000187:drug effects* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004361:Drug Tolerance; D008297:Male; D051379:Mice
chemical_list: D003042:Cocaine