The role of oxytocin and vasopressin in conditioned mate guarding behavior in the female rat Amanda Holley ⁎, Shannon Bellevue, Daniel Vosberg, Kerstin Wenzel, Sieger Roorda Jr., James G. Pfaus Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC H4B 1R6 Canada HIGHLIGHTS • Female rats can display mate guarding behavior. • Experience with sexual reward shifts sexual strategies in the female rat. • Female rats that display mate guarding show enhanced activation of OT and AVP neurons. • Injection of OT or AVP facilitates different aspects of mate guarding behavior. abstract article info Article history: Received 12 January 2015 Received in revised form 7 February 2015 Accepted 23 February 2015 Available online 24 February 2015 Keywords: Sexual behavior Oxytocin Vasopressin Pavlovian conditioning Bonding We have shown previously that female rats given their first copulatory experiences with the same male rat dis- play mate guarding behavior in the presence of that male provided a female competitor is also present. Females given access to the familiar male show more Fos induction within regions of the brain that contain oxytocin (OT) and vasopressin (AVP) cell bodies, notably the supraoptic (SON) and paraventricular nuclei (PVN) relative to females given sexual experience with different males. The present experiments examined whether the Fos induction we previously observed within the SON and PVN occurred within OT and/or AVP neurons, and whether exogenous administration of OT or AVP prior to female rats first sexual experience could potentiate the acquisi- tion of mate guarding behavior. Female rats that display conditioned mate guarding had significantly more double-labeled Fos/OT neurons in both SON and PVN, and significantly more Fos/AVP neurons in the PVN. Periph- eral administration of OT or AVP prior to their first sexual experience with the familiar male facilitated different aspects of mate guarding: OT augmented affiliative behaviors and presenting responses whereas AVP augmented interference behavior. These results indicate that female rats' first experiences with sexual reward when paired with the same male induce changes to bonding networks in the brain. Moreover peripheral administration of OT or AVP during their first sexual experience can augment different aspects of mate guarding behavior. © 2015 Elsevier Inc. All rights reserved. 1. Introduction Socially monogamous animals form enduring associations with one another that are characterized by selective affiliation, contact, and pref- erential copulation with their partners relative to strangers. These part- nerships are called pair bonds [1]. In rodents, the hallmark example of social monogamy is displayed by the prairie vole (Microtus ochrogaster), and this rich literature has provided the scientific community with ground breaking and in depth analyses that have laid the groundwork for other studies looking into monogamy, bonding, and mate guarding. Prairie voles inhabit a very harsh environment, with limited food, water, and mate access. It is thought that they adapted a socially monogamous mating strategy in order to increase the likelihood of their survival and reproductive success [2,3]. For example, if a prairie vole happens to come across a potential mate, it would make sense to bond with this mate, since there is not a large likelihood of encountering another one. Bonding would allow for access to a mate, reproduction, would allow for biparental care of the young, and ultimately enable the couple to defend territory and gather resources more efficiently. However, the in- fluence of the environment on bonding behavior in prairie voles can is most clearly observed during the winter months, when voles cluster together to form communal groups [4]. When living in communal groups, more extra pair copulations occur among pair bonded voles than in spring and summer months when the vole population is more widely dispersed, demonstrating that population density and mate ac- cess can create shifts toward promiscuity within the mating strategy of the prairie vole [4]. In the laboratory, pair bonding is determined when male prairie voles display a preference to spend more time with the first female they copulated with relative to a novel female [5], or Physiology & Behavior 144 (2015) 7–14 ⁎ Corresponding author at: Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, 7141 Sherbrooke W., Montréal, QC H4B 1R6 Canada. E-mail address: Amholley11@gmail.com (A. Holley). http://dx.doi.org/10.1016/j.physbeh.2015.02.039 0031-9384/© 2015 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Physiology & Behavior journal homepage: www.elsevier.com/locate/phb