LONG-TERMACCESS TOETHANOLDURING ADOLESCENCE IN WISTAR RATS

PAUTASSI, RICARDO; WILLE-BILLE, ARANZA; BERARDO, LUCIANA; FABIO, MARÍA CAROLINA

Valencia

Simposio; ESBRA 2015; 2015

ESBRA

Wistar rats are notoriously reluctant to ingest ethanol and previousstudies have employed substantial liquid deprivation to promote ethanolintake. Our lab has employed an intermittent, every-other day,two-bottle choice access protocol to measure the modulatory role ofstress exposure or environmental enrichment on ethanol intake,throughout adolescence. Chronic restraint stress (5 daily sessions,120 min each; applied before the commencement of the ethanol intakeprotocol) significantly enhanced and decreased ethanol intake, in femaleand male rats, respectively. Contrary to our expectations, environmentalenrichment during postnatal days 21 to 42 significantlyincreased ethanol intake. The modulation of adolescent ethanol intakeby prenatal ethanol exposure (PEE; 2.0 g/kg, i.g., gestational days17-20) was also assessed. PEE adolescents drank twice as much ethanolthan control, un-exposed counterparts, nearing 6.0 g/kg ethanolingested per day and 60-80% ethanol preference, throughout adolescence.PEE was associated with heightened ethanol-inducedconditioned place preference and insensitivity to conditioned aversioninduced by high-dose ethanol or by the agonism of the kappa opioidsystem. PEE subjects exhibited heightened ethanol-induced cathecolaminergicactivity (i.e., measured via colocalization of C-fos and tiroxinehidroxilase) and increased μ (but not δ or κ) mRNA expression inthe ventral tegmental area (VTA), and required a larger dose of ethanolthan controls to show ethanol-induced FOS inmunoreactivity inthe nucleus accumbens shell. PEE decreased FOS inmunoreactivityat the VTA. These results pinpoint the promoting effect exerted by severalfactors (i.e., stress, enrichment of the standard rearing conditionand prenatal ethanol exposure) on ethanol intake during adolescence.