Frank A. Beach Award. Oxytocin and vasopressin receptors and species-typical social behaviors.

f c A m ( ( G s W Over the past 50 years, a great deal of behavioral ndocrinological research has established a central ole for gonadal steroid hormones in the control of exual behaviors in a wide range of vertebrate taxa. he underlying mechanisms controlling these behavors appear to be well conserved throughout evoluion. Both the neural structures regulating male and emale sexual behaviors and the distribution of sex teroid receptors within the brain are similar from eptiles to mammals (Meisel and Sachs, 1994; Pfaff and chwartz-Giblin, 1994). More recently, the roles of the europeptides oxytocin (OT) and vasopressin (AVP) n modulating reproductive and social behaviors have egun to be elucidated. Comparative studies focusing n these hormones suggest that unlike gonadal steoids, the specific behavioral roles of these neuropepides may be quite species specific. Here I review some f the behaviors associated with OT and AVP systems nd discuss the idea that OT and AVP receptor sysems are phylogenetically plastic, perhaps facilitating he evolution of species-typical social behavior paterns. Oxytocin and vasopressin are related nonapeptide ormones which differ in structure at only two amino cid positions (Gainer and Wray, 1994). Both peptides re synthesized in magnocellular neurons of the paraentricular (PVN) and supraoptic nuclei of the hypohalamus, which project to the neurohypophysis and re released into circulation where they modulate pe-