Delta-FosB induction in adolescent and adult rats after chronic ethanol self-administration

NIZHNIKOV ME; DE OLMOS, S; PAUTASSI R.M.; WILLE-BILLE, ARANZA; MARENGO, L

Berlín

Congreso; 2016 International Society for Biomedical Research on Alcoholism (ISBRA) World Congress and 16th Congress of the European Society for Biomedical Research on Alcoholism (ESBRA); 2016

International Society for Biomedical Research on Alcoholism

Studies with animal models have described age-related differences to ethanol?s motivational effects. For instance,adolescent rats are signi􀃖cantly more sensitive to the appetitive and less sensitive to the aversive effects of alcohol,when compared to adult counterparts. The characterization of age-related differences in neural consequences ofethanol self-administration is, however, less clear. ΔFosB is a transcription factor that accumulates after chronic drugexposure and may serve as a molecular marker of neural plasticity associated with the transition to addiction. Weanalyzed the impact of chronic (18 two-bottle choice intake sessions spread across 42 days, session length: 18 h)ethanol self-administration during adolescence and adulthood on the accumulation of ΔFosB in several brain areas,with a focus on the mesocorticolimbic pathway. Adolescent rats exhibited a progressive escalation of ethanol intakeand preference, whereas adult rats exhibited a stable pattern of ingestion, although the overall level of ingestion duringthe 􀃖rst weeks of testing was signi􀃖cantly higher in adult than in adolescent subjects. A signi􀃖cantly greater number ofethanol-induced ΔFosB positive cells was found in adolescent, compared to adult, rats at prelimbic cortex, dorsolateralstriatum, nucleus accumbens core and shell, and central amygdala nuclear capsular and bilateral amygdala, areasassociated with reward processing. Anxiety-like behavior and ethanol-induced locomotor activity were not affected by the chronic ethanol exposure, at either age. In conclusion, the relatively lower levels of ethanol ingestion found inadolescence, compared to those found at adulthood, resulted in signi􀃖cant ΔFosB induction. This may be yet anotherage-related difference that puts adolescents at risk for problematic ethanol use. The present results suggest thatsubjects that begin drinking during adolescence and continue doing so throughout that stage of development, asopposed to those that begin in adulthood, are more likely to exhibit brain changes in areas of the reward circuit.