Social housing and alcohol drinking in male-female pairs of prairie voles (Microtus ochrogaster)

Rationale: Social environment influences alcohol consumption in humans; however, animal models have only begun to address biological underpinnings of these effects. Objectives: We investigated whether social influences on alcohol drinking in the prairie vole are specific to the sex of the social partner. Methods: In Experiment 1, control, sham, and gonadectomized voles were placed either in mesh-divided housing with a same-sex sibling or isolation with access to ethanol. In Experiment 2, animals were given an elevated plus maze test (EPM) and then females were paired with a castrated male followed by isolation or mesh-divided housing with access to ethanol. In Experiment 3, subjects categorized as low or high drinkers based on initial ethanol intake were placed in mesh-divided housing with an opposite-sex partner of the same or opposite drinking group and ethanol access. Subjects were then moved back to isolation for a final ethanol access period. Results: Same-sex pairs showed social facilitation of drinking similar to previous reports. Gonadectomy did not affect alcohol drinking. Opposite-sex paired animals in Experiment 2 did not differ in alcohol drinking based on social housing. EPM measures suggested a relationship between anxiety-like behaviors and drinking that depended on social environment. Experiment 3 identified moderate changes in alcohol preference based on social housing, but these effects were influenced by the animal's own drinking behavior and were independent of their partner's drinking. Conclusions: Social influences on alcohol self-administration in prairie voles differ based on the sex of a social partner, consistent with human drinking behavior.