FIGURE 1.

Methods for the analysis of the effects of maternal isolation during infancy and environmental enrichment during adolescence on ethanol intake in adolescent Wistar rats. (A) From postnatal day (PD) 1 to PD21, the rats were reared under animal facility rearing conditions or were given daily episodes of maternal isolation (180 min). Between PD21 and PD42 they were given standard housing or environmental enrichment. The tests conducted on Experiments 1, 2, and 3 began on or after PD42. (B) The rats (males and females) were assessed for ethanol intake (Experiment 1) during 4 weeks, from PD46 to PD72. During each week animals were given three every other day, two-bottle choice tests (ethanol vs. plain water), followed by two rest days. Ethanol concentration was 3% (week 1, intake sessions 1–3), 4% (week 2, intake sessions 4–6), 5% (weeks 3 and 4, intake sessions 7–11) or 7.5% (session 12). (C) The rats, males only, were tested in an elevated plus-maze test at PD42. Taste conditioning, employing ethanol (2.5 g/kg, i.p.) as the unconditional stimulus, was acquired on PD47 and tested on PD49. Animals were given 4.0 g/kg ethanol (i.p.) and tested for ethanol-induced loss of righting reflex, sleep time and blood ethanol levels at PD52. (D) In Experiment 3, male rats exposed or not to MS during infancy and reared under EE or controls conditions during adolescence were tested on PD42, in a modified version of the concentric square field (CSF).