Oxytocin induces social communication by activating arginine-vasopressin V1a receptors and not oxytocin receptors

Arginine-vasopressin (AVP) and oxytocin (OT) and their receptors are very similar in structure. As a result, at least some of the effects of these peptides may be the result of crosstalk between their canonical receptors. The present study investigated this hypothesis by determining whether the induction of flank marking, a form of social communication in Syrian hamsters, by OT is mediated by the OT receptor or the AVP Via receptor. Intracerebroventricular (ICV) injections of OT or AVP induced flank marking in a dose-dependent manner although the effects of AVP were approximately 100 times greater than those of OT. Injections of highly selective Via receptor agonists but not OT receptor agonists induced flank marking, and Via receptor antagonists but not OT receptor antagonists significantly inhibited the ability of OT to induce flank marking. Lastly, injection of alpha-melanocyte-stimulating hormone (alpha-MSH), a peptide that stimulates OT but not AVP release, significantly increased odor-induced flank marking, and these effects were blocked by a Via receptor antagonist. These data demonstrate that OT induces flank marking by activating AVP Via and not OT receptors, suggesting that the Via receptor should be considered to be an OT receptor as well as an AVP receptor. (C) 2014 Elsevier Ltd. All rights reserved.