Social preference and maternal defeat-induced social avoidance in virgin female rats: Sex differences in involvement of brain oxytocin and vasopressin

• The social preference test for rats is suitable to monitor female social preference behavior, which was found to be independent of estrous cycle.
• The OXT and AVP systems are not involved in naturally-occurring social preference behavior in female rats.
• Exposure of virgin female rats to maternal defense results in specific social avoidance of the lactating defeater, which, however, cannot be reversed by icv infusion of OXT.

BackgroundResearch concerning non-reproductive sociability in rodents is mainly restricted to assessing the effects of oxytocin (OXT) and arginine-vasopressin (AVP) in male rats and mice. Comparable studies on natural social preference and social avoidance in females are substantially lacking.New methodHere, we adapted a behavioral paradigm for monitoring social preference of female rats consisting of two consecutive exposures to either non-social or social stimuli. Further, to induce stimulus-specific social avoidance, female rats were exposed to a single 10-min maternal defeat by a lactating dam.ResultsSocial preference towards same-sex conspecifics in female rats was shown to be independent of the estrous cycle and even more pronounced than in male rats. Intracerebroventricular (icv) application of OXT, AVP, or their selective receptor antagonists or agonists, did not alter naturally-occurring social preference in female rats. Stimulus-specific social avoidance could be induced by prior exposure to a lactating rat: an effect that could not be reversed/overcome by icv OXT.Comparison with existing method(s)The female social preference paradigm for rats established in this study detected subtle sex differences in social preference behavior of rats. Further, stimulus-specific social deficits could be induced in female rats using an acute exposure to social defeat – as previously observed in male rodents.ConclusionsFemale rats show strong social preference behavior, which can be prevented by social defeat, but does not seem to be regulated by the OXT or AVP systems. Accordingly, icv application of synthetic OXT does not reverse maternal defeat-induced social avoidance in female rats.