title: Juvenile ethanol exposure increases rewarding properties of cocaine and morphine in adult DBA/2J mice.
abstract: Convergent data showed that ethanol exposure during adolescence can alter durably ethanol-related behaviour at adulthood. However, the consequences of juvenile ethanol exposure on the reinforcing effects of other drugs of abuse remain unclear. In the present work, we evaluated in adult male DBA/2J mice the effects of early ethanol exposure on the sensitivity to the incentive effects of cocaine and morphine, and on extracellular signal-regulated kinase (ERK) activation in response to cocaine. Juvenile male mice received intragastric administration of ethanol (2×2.5g/kg/day) or water for 5 days starting on postnatal day 28. When reaching adult age (10 week-old), animals were subjected to an unbiased procedure to assess conditioned place preference (CPP) to cocaine or morphine. In addition, activation of ERK in response to an acute injection of cocaine was investigated using immunoblotting in the striatum and the nucleus accumbens. Mice that have been subjected to early ethanol exposure developed CPP to doses of cocaine (5mg/kg) or morphine (10mg/kg) below the threshold doses to induce CPP in water pre-exposed mice. In addition, early ethanol administration significantly increased striatal ERK phosphorylation normally induced by acute cocaine (10 and 20mg/kg) in adult mice. These results show that, in DBA/2J mice, early exposure to ethanol enhanced the perception of the incentive effects of cocaine and morphine. Ethanol pre-exposure also induced a positive modulation of striatal ERK signalling, in line with the inference that juvenile ethanol intake may contribute to the development of addictive behaviour at adult age.
authors.affiliation: UMR-S 894, Inserm, Centre de Psychiatrie et Neuroscience, F-75013 Paris, France; Université Pierre et Marie Curie, F-75005 Paris, France.
authors.forename: Jenny
authors.initials: J
authors.lastname: Molet
authors.forename: Denis
authors.initials: D
authors.lastname: Hervé
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Thiébot
authors.forename: Michel
authors.initials: M
authors.lastname: Hamon
authors.forename: Laurence
authors.initials: L
authors.lastname: Lanfumey
mesh_terms: D000367:Age Factors; D000700:Analgesics / Q000008:administration & dosage*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D000431:Ethanol / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008124:Locomotion / Q000187:drug effects; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D009020:Morphine / Q000008:administration & dosage*; D012201:Reward
chemical_list: D000700:Analgesics; D002492:Central Nervous System Depressants; D000431:Ethanol; D009020:Morphine; D048049:Extracellular Signal-Regulated MAP Kinases; D003042:Cocaine
keywords: Adolescence; Conditioned place preference; Ethanol; Extracellular signal-regulated kinase; Locomotion; Mouse