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

Note: this poster abstract has been superseded by the published article at the link below.

Poster abstract P.1.19, Society for Behavioral Neuroendocrinology. Alisomar, CA. June 2015.

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.