Septal Oxytocin Administration Impairs Peer Affiliation via V1a Receptors in Female Meadow Voles

The peptide hormone oxytocin (OT) plays an important role in social behaviors, including social bond formation. In different contexts, however, OT is also associated with aggression, social selectivity, and reduced affiliation. Female meadow voles form social preferences for familiar same-sex peers under short, winter-like day lengths in the laboratory, and provide a means of studying affiliation outside the context of reproductive pair bonds. Multiple lines of evidence suggest that the actions of OT in the lateral septum (LS) may decrease affiliative behavior, including greater density of OT receptors in the LS of meadow voles that huddle less. We infused OT into the LS of female meadow voles immediately prior to cohabitation with a social partner to determine its effects on partner preference formation. OT prevented the formation of preferences for the partner female. Co-administration of OT with a specific OT receptor antagonist did not reverse the effect, but co-administration of OT with a specific vasopressin 1a receptor (V1aR) antagonist did, indicating that OT in the LS likely acted through V1aRs to decrease partner preference. Receptor autoradiography revealed dense V1aR binding in the LS of female meadow voles. These results suggest that the LS is a brain region that may be responsible for inhibitory effects of OT administration on affiliation, which will be important to consider in therapeutic administrations of OT

Oxytocin administration in the lateral septum prevents same-sex partner preference via vasopressin 1a receptors

<p>Note: this poster abstract has been superseded by the published article at the link below.</p><p><br></p><p>Poster abstract P.1.19, Society for Behavioral Neuroendocrinology. Alisomar, CA. June 2015.</p> <p>The neuropeptide oxytocin (OT) plays a central role in the development of social affiliations. Female meadow voles form social preferences for other females under certain environmental conditions, and centrally-administered OT, acting via the OT receptor (OTR), enhances the preference for a specific social partner. However, the effects of OT may differ by neural circuit, and prior research suggests OTR density in the lateral septum correlates with low social huddling. We tested how OT in the septum would affect partner preferences. Adult female meadow voles received microinjections into the septum of one of 4 treatments: OT (1ng), OT+OTR antagonist (1ng+30ng), OT+vasopressin 1a receptor (AVPR1a) antagonist (1ng+30ng), or vehicle (artificial cerebrospinal fluid; aCSF). Immediately following treatment, subjects were paired with a novel adult female partner for 24h. A 3h partner preference test followed to assess the amount of time the subject spent huddling with the pa! rtner or a stranger. OT infused into the septum significantly reduced the fraction of huddling time spent with the partner, relative to the aCSF controls. Co-administration of OTR antagonist with OT did not block this effect. However, co-administration of AVPR1a antagonist did block the effect, indicating that the exogenous OT was acting through the AVPR1a to decrease partner preference. The promiscuity of oxytocin and vasopressin for each others’ receptors is well-documented, explaining the observed effects. These findings indicate that the effects of oxytocin are brain region-specific, and it will be important to study the role of the lateral septum and vasopressin in same-sex social affiliations.</p> <p> </p

Septal oxytocin administration impairs peer affiliation via V1a receptors in female meadow voles

The peptide hormone oxytocin (OT) plays an important role in social behaviors, including social bond formation. In different contexts, however, OT is also associated with aggression, social selectivity, and reduced affiliation. Female meadow voles form social preferences for familiar same-sex peers under short, winter-like day lengths in the laboratory, and provide a means of studying affiliation outside the context of reproductive pair bonds. Multiple lines of evidence suggest that the actions of OT in the lateral septum (LS) may decrease affiliative behavior, including greater density of OT receptors in the LS of meadow voles that huddle less. We infused OT into the LS of female meadow voles immediately prior to cohabitation with a social partner to determine its effects on partner preference formation. OT prevented the formation of preferences for the partner female. Co-administration of OT with a specific OT receptor antagonist did not reverse the effect, but co-administration of OT with a specific vasopressin 1a receptor (V1aR) antagonist did, indicating that OT in the LS likely acted through V1aRs to decrease partner preference. Receptor autoradiography revealed dense V1aR binding in the LS of female meadow voles. These results suggest that the LS is a brain region that may be responsible for inhibitory effects of OT administration on affiliation, which will be important to consider in therapeutic administrations of OT