Effects of duration and timing of environmental enrichment on voluntary ethanol intake in rats

The effects of exposure to five environmental rearing conditions on subsequent voluntary ethanol intake was examined. Male weanling rats were reared for 60 days in either an enriched environment, individually, or in a smaller enriched environment (quasienriched). The quasienriched environment was employed to allow for a group measurement of ethanol intake. Following the initial 60-day environmental exposure period, the three initial groups (Enriched, Isolation, Quasienriched) were randomly subdivided into five groups (Enriched/Isolation, Isolation, Isolation/Quasienriched, Quasienriched, Quasienriched/Isolation) and exposed to increasing concentrations of ethanol (3-9% v/v) in a free choice with water. Results indicated that exposure to an enriched environment for 60 days does not alter ethanol intake. In contrast, rats exposed to the quasienriched environment while having access to ethanol demonstrated a significant increase in voluntary ethanol intake as compared to all other groups. Exposure to different environmental conditions while having access to ethanol was not by itself sufficient to alter ethanol intake. These data are discussed in terms of the amount and timing of exposure to an enriched environment necessary to alter voluntary ethanol intake.