title: Transition from ethanol-induced sensitization to tolerance across early and late infancy in the rat.
abstract: Drugs of abuse, as cocaine or amphetamine, induce locomotor sensitization during infancy and adulthood of the rat. This effect during the preweanling period is observed only after a short interval of time between training and testing. We recently reported short-term locomotor sensitization induced by ethanol in pups chronically exposed to the drug during the second postnatal week of life. The present series of experiments was designed to explore the persistence of the sensitization effect across the preweanling period. Pups were chronically exposed to ethanol in five consecutive days during the second or the third postnatal weeks, and their locomotor activity was evaluated in an open field 3, 8 or 15days later. Our results showed that, contrarily to what has been observed with other drugs during infancy, sensitization to ethanol persisted at least 8days in rats exposed to the drug during the second postnatal week. Surprisingly, in older pups, the same procedure induced tolerance instead sensitization. This ontogenetic model offers a potentially interesting tool for studying within the same species, how tolerance and sensitization are interrelated, and how these effects affect ethanol-mediated reinforcement and ethanol intake during ontogeny.
authors.affiliation: Instituto de Investigación Médica M. y M. Ferreyra INIMEC-CONICET-UNC, Friuli 2434, Córdoba, Argentina.
authors.forename: Stefania
authors.initials: S
authors.lastname: Castello
authors.affiliation: Facultad de Psicología, Universidad Nacional de Córdoba (UNC), Av. Haya de la Torre s/n, Córdoba, Argentina.
authors.forename: Genesis
authors.initials: G
authors.lastname: D'Aloisio
authors.affiliation: Instituto de Investigación Médica M. y M. Ferreyra INIMEC-CONICET-UNC, Friuli 2434, Córdoba, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba (UNC), Av. Haya de la Torre s/n, Córdoba, Argentina. Electronic address: carias@immf.uncor.edu.
authors.forename: Carlos
authors.initials: C
authors.lastname: Arias
authors.affiliation: Instituto de Investigación Médica M. y M. Ferreyra INIMEC-CONICET-UNC, Friuli 2434, Córdoba, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba (UNC), Av. Haya de la Torre s/n, Córdoba, Argentina.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Molina
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D004361:Drug Tolerance; D000431:Ethanol / Q000494:pharmacology*; D005106:Exploratory Behavior; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000431:Ethanol
keywords: Ethanol; Infant rat; Locomotor activity; Sensitization; Tolerance