Environmental enrichment during adolescence heightens ethanol intake in female, but not male, adolescent rats that are selectively bred for high and low ethanol intake during adolescence

摘要

Background Discriminating between adolescents who will eventually have ethanol use problems from those who do not is important. Environmental enrichment is a promising approach to reduce drug-related problems, but its impact on ethanol's effects and intake is being scrutinized.Objective: We tested the effects of environmental enrichment on ethanol intake, preference, and anxiety-like response as well as shelter seeking and risk-taking behaviors. Methods Experiment 1 examined ethanol intake, preference, and anxiety-like responses in 46 male and 54 female Wistar rats that were derived from a short-term breeding program that selected for high and low ethanol drinking during adolescence (ADHI(2)and ADLO(2)lines, respectively). Shelter-seeking and risk-taking behaviors were assessed (Experiment 2) in ADHI(2)and ADLO(2)rats (73 males, 76 females) reared under environmental enrichment or standard housing conditions and given doses of ethanol (2.5 g/kg, intraperitoneal) for 3 weeks. Environmental enrichment was applied on postnatal days 21-42. Ethanol intake was measured on postnatal days 42-68. Anxiety-like behavior and exploratory responses were assessed using the light-dark box and multivariate concentric square field test. Results In Experiment 1, environmental enrichment increased ethanol intake in female, but not male, ADHI(2)and ADLO(2)rats (p < 0.05). In the baseline measurement of Experiment 2, ADHI(2)rats exhibited reduced risk-taking and increased anxiety-like behavior (p < .05). After exposure to environmental enrichment the ADHI and ADLO rats, both males and females, exhibited increased risk-taking and exploratory behavior (p < 0.05). Conclusions Environmental enrichment appears to increase ethanol intake in female rats by promoting the exploration of new environments or stimuli. The findings indicate that environmental enrichment increased ethanol intake in female, but not male, rats. Clinical programs that treat alcohol use disorder by emphasizing environmental stimulation should be designed with caution.