Distribution of Vasopressin 1a and Oxytocin Receptor Binding in the Basal Forebrain and Midbrain of Male and Female Mongolian Gerbils

Abstract

The nonapeptide system modulates a diversity of social behaviors, including aggression, parental care, affiliation, sexual behavior, and pair bonding. Such social behaviors are regulated through oxytocin and vasopressin activation of the oxytocin receptor (OXTR) and vasopressin V1a receptor (AVPR1A) in the brain. Nonapeptide receptor distributions have been mapped for several species, however, studies have demonstrated that there is substantial variation across species. Mongolian gerbils (Meriones unguiculatus) are an excellent organism for studying family dynamics, social development, pair bonding, and territorial aggression. Although an increasing number of studies are examining the neural mechanisms of social behavior in Mongolian gerbils, nonapeptide receptor distributions have yet to be characterized for this species. Here we conducted receptor autoradiography to map distributions of OXTR and AVPR1A binding throughout the basal forebrain and midbrain of female and male Mongolian gerbils. Further, we assessed whether gonadal sex influenced binding densities in brain regions important for social behavior and reward, however, we observed no effects of sex on OXTR or AVPR1A binding densities. These findings provide mapping distributions of nonapeptide receptors in male and female Mongolian gerbils, laying a foundation for future studies that seek to manipulate the nonapeptide system to examine nonapeptide-mediated social behavior.