(15) The effects of environmental enrichment and stress on ethanol preference in female mice

     Alcohol misuse and abuse is a major concern on college campuses. Converging evidence from animal and human studies suggests that an individual’s response to, and preference for, drugs and alcohol are influenced by... [ view full abstract ]

     Alcohol misuse and abuse is a major concern on college campuses. Converging evidence from animal and human studies suggests that an individual’s response to, and preference for, drugs and alcohol are influenced by his/her environment and exposure to stress. Specifically, mice living in enriched environments containing polysensory activities and stimuli (e.g., toys, burrows) prefer drugs less than mice living in standard cages, and drug-abstinent mice are more likely to return to drug use if stressed. However, the majority of existing literature has focused on males, and relatively little is known about drinking behavior in female rodents, whose regular fluctuations in reproductive hormones (i.e., estrus cycle) have been shown to alter the sensitivity of neural circuits involved in reward and motivation. We hypothesized that ethanol preference would be lower in females living in enriched homecage environments than females living in standard cages (a) following chronic ethanol exposure and (b) following a stressor presented after an ethanol abstinence period. In the present study, female mice were exposed chronically to ethanol for twelve days, followed by a three-day ethanol-free abstinence period. At the end of this abstinence period, mice performed a series of forced swim tests, which acted as a stressor and an indicator of despair-like behavior, and anxiety levels were measured on an elevated plus-maze. Ethanol preference was measured using a 2hr two-bottle choice test prior to ethanol exposure, after ethanol exposure and after the ethanol-abstinence period. Estrus cycle stage was identified via vaginal cytology on the days after the final two ethanol preference tests (see Gray et al., 2017). Mice’s body weight and volume of ethanol drank were monitored across the ethanol exposure period. Preliminary results suggest that ethanol consumption was impacted by environment but not stress. This study was designed and conducted by PSYC359 students in Spring 2017.