Oxytocin and object preferences in the male prairie vole

The neuropeptide oxytocin has been previously associated with social attachment behaviors in various species. Studies in socially monogamous prairie voles (Microtus ochrogaster) and other species have implicated oxytocin in partner preferences and other social behaviors. In the present study male prairie voles were injected intraperitoneally with either oxytocin or the selective oxytocin antagonist, L-368,899, and were assessed for object preference (for small inanimate toys) 30-min after injection. Object preferences were assessed in animals tested alone or in the presence of their sibling cage mate. Saline-treated controls displayed preferences for the novel object, both when tested alone and in pairs, while oxytocin-treated voles did not demonstrate an object preference, regardless of whether tested alone or in pairs. Finally, oxytocin antagonist treated voles showed preference for the novel object, but only when tested in pairs. These data support a possible involvement of oxytocin and oxytocin receptors in object preference.