• Energy Research
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• 11. Sustainability close
• Psychopharmacology close

The majority of preclinical studies assessing treatments for alcohol use disorder use singly housed animals. Because social factors affect ethanol intake, studies investigating such treatments in group-housed animals are needed.We investigated the effects of repeated oxytocin treatment on ethanol intake in socially housed male and female C57BL/6J mice.We used the novel "Herdsman" system implementing radiotracking technology to measure individual ethanol intake in group-housed animals. Mice were housed in same-sex groups of 4 per cage and exposed to 3 and 6% ethanol solutions. After baseline drinking was established, half of the animals in each cage received repeated intraperitoneal injections of 3 mg/kg oxytocin.During baseline, females consumed more ethanol than males partly due to greater number of ethanol drinks taken by females. We also observed a gradual development of two peaks of ethanol consumption during the dark phase of the circadian cycle. The effects of oxytocin treatment were short-acting and varied across treatment days. Oxytocin significantly decreased ethanol intake on three out the four treatment days. On the fourth treatment day, oxytocin decreased ethanol intake and water intake.The greater intake of ethanol in female mice is associated with the number of drinks taken. Oxytocin treatments not only cause an acute decrease in ethanol consumption, but can also change in efficacy over time. While the oxytocin system remains a promising therapeutic target for alcoholism, studies investigating longer periods of repeated oxytocin treatment and those using additional oxytocin receptor agonists are warranted.

Social environment influences alcohol consumption in humans; however, animal models have only begun to address biological underpinnings of these effects.We investigated whether social influences on alcohol drinking in the prairie vole are specific to the sex of the social partner.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.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.Social influences on alcohol self-administration in prairie voles differ based on the sex of a social partner, consistent with human drinking behavior.

Dominance hierarchies affect ethanol self-administration, with greater intake among subordinate animals compared to dominant animals. Excessive ethanol intake disrupts circadian rhythms. Diurnal rhythms of the hypothalamic-pituitary-adrenal axis have not been characterized in the context of ethanol self-administration with regard to social rank.This study aimed to determine whether diurnal pituitary-adrenal hormonal rhythms account for differences between social ranks in ethanol self-administration or are differentially affected by ethanol self-administration between social ranks.During alternating individual (n = 11-12) and social (n = 3 groups) housing of male cynomolgus monkeys (Macaca fascicularis), diurnal measures of cortisol and adrenocorticotropic hormone (ACTH) were obtained from plasma samples three times per week. Social rank was determined, ethanol (4 %, w/v) self-administration was induced, and then the monkeys were allowed a choice of water or ethanol for 22 h/day for 49 weeks.For all social ranks, plasma ACTH was elevated during social housing, but cortisol was stable, although greater among dominant monkeys. Ethanol self-administration blunted the effect of social housing, cortisol, and the diurnal rhythm for both hormones, regardless of daily ethanol intake (1.2-4.2 g/kg/day). Peak ACTH and cortisol were more likely to be observed in the morning during ethanol access. Ethanol, not vehicle, intake was lower during social housing across social ranks. Only dominant monkeys showed significantly lower blood-ethanol concentration during social housing.There was a low threshold for disruption of diurnal pituitary rhythms by ethanol drinking, but sustained adrenal corticosteroid rhythms. Protection against heavy drinking among dominant monkeys may have constrained ethanol intoxication, possibly to preserve dominance rank.