Adolescent binge-like ethanol intake increases voluntary ethanol consumption in adulthood regardless of subsequent ethanol exposure

Adolescent binge drinking is associated with later alcohol-related problems. It is, however, still unknown whether it holds a causal role with the emergence of problematic drinking or how it interacts with alcohol exposure in early adulthood. We assessed whether binge-like ethanol self-administration during adolescence, coupled or not with an intensive ethanol exposure in early adulthood, increases voluntary ethanol consumption in later adulthood. Thirty-seven male Wistar rats were exposed or not to nine 2-h binge-like ethanol self-administration sessions (8-10%; postnatal day 27-45, PD27-45). At PD61-65, they received intragastric ethanol (0.0 or 1.5 g/kg, three times daily). Ethanol intake was subsequently measured across six 24-h two-bottle choice tests (8% ethanol vs. water; PD75-87). Adolescent binge exposure increased adult ethanol intake (4.5-6.5 vs. ~2 g/kg/day in controls; F1,32=32.77, p<.001, η²=.51) and ethanol preference (F1,32=31.16, p<.001, η²=.49). Adult ethanol exposure enhanced intake across sessions (adult exposure × session: F5,160=2.88, p<.05, η²=.08), but did not significantly interact with adolescent binge exposure. These results indicate that binge-like ethanol drinking during adolescence produces a robust increase in voluntary ethanol consumption in adulthood that is independent of intensive ethanol exposure in early adulthood.