Effects of isolation rearing on locomotion, anxiety and responses to ethanol in Fawn Hooded and Wistar rats

Voluntary ethanol (EtOH) consumption is increased by isolation-rearing in several rat strains. The following experiments examined the effects of isolation-rearing on basal and ethanol-stimulated behavior in Fawn Hooded rats, an alcohol-preferring rat strain, compared to Wistar rats. Locomotor activity and anxiety were examined under both conditions. Basal locomotor activity was higher in isolated subjects of both strains in low light conditions, but under bright light conditions: this difference was only observed in Wistar rats. Locomotor stimulant effects of EtOH were only observed in isolation-reared rats. In the elevated plus maze, Fawn Hooded rats were more anxious than Wistar rats under low light conditions, but under bright light conditions, Wistar socials were less anxious than all of the other groups. Administration of 1.5 mg/kg EtOH produced an anxiolytic response in the elevated plus maze under bright light conditions in Fawn Hooded rats, but to a lesser degree Wistar rats, particularly Wistar isolates. In conclusion, although both strain and isolation-rearing had effects on locomotion and anxiety as well as the stimulatory and anxiolytic effects of EtOH, these effects appeared to be independent.