Voles and vasopressin: a review of molecular, cellular, and behavioral studies of pair bonding and paternal behaviors.

Several lines of evidence have implicated the neurohypophyseal peptide, vasopressin (VP), in the mediation of complex social behaviors including affiliation, aggression, juvenile recognition and parental behavior. Recent studies in microtine rodents using cellular, molecular and behavioral approaches provide additional evidence suggesting a role for VP in the formation of pair bonding and male parental care. Monogamous and promiscuous voles differ in social behaviors such as mating-induced pair bonding, selective aggression, and male parental care. Comparative studies have demonstrated that they also differ in dynamics of VP synthesis and release associated with reproduction, in the distribution pattern and regional quantity of VP receptors, and in the promoter sequence of the V1a receptor gene. In monogamous prairie voles, (Microtus ochrogaster), brain administration of VP induces pair bonding and male parental care whereas administration of the VP antagonist diminishes these behaviors. Together, these data suggest that VP is involved in the regulation of social behaviors in monogamous voles and differences in the brain VP system may underlie species differences in behavior and life strategy in voles.