Human OXT blocking peptide

Background: Research 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 method: Here, 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. Results: Social 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 (icy) 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 icy 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. Conclusions: Female 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, icy application of synthetic OXT does not reverse maternal defeat-induced social avoidance in female rats. (C) 2014 Elsevier B.V. All rights reserved.

Cooperation among individuals depends, in large part, on a sense of fairness. Many cooperating nonhuman primates show inequity aversion (i.e. negative responses to unequal outcomes), and these responses towards inequity probably evolved as a means to preserve the advantages of cooperative relationships. However, marmosets (Callithrix spp.) tend to show little or no inequity aversion, despite the high occurrence of prosociality and cooperative breeding in callitrichid monkeys. Oxytocin (OXT) has been implicated in a wide variety of social processes, but little is known about whether OXT modulates inequity aversion towards others. We used a tray-pulling task to evaluate whether marmosets would donate superior rewards to their long-term pair mate or an opposite-sex stranger following OXT, OXT antagonist and saline treatments. We found that marmosets show inequity aversion, and that this inequity aversion is socially and sex specific. Male marmosets showed inequity aversion towards their pair mates but not towards strangers, and female marmosets did not show inequity aversion. OXT treatments did not significantly influence inequity aversion in marmosets. While OXT may modulate prosocial preferences, the motivations underlying cooperative relationships, such as inequity aversion, are multifaceted. More research is needed to evaluate the evolutionary origins, biological processes and social contexts that influence complex phenotypes like inequity aversion. Inequity aversion can differ within species in important and distinct ways, including between individuals who do and do not share a cooperative relationship. Overall, these findings support the view that inequity aversion is an important behavioural strategy for the maintenance of cooperative relationships. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.