1 Center for Studies in Behavioral Neurobiology, Department of Psychology,Concordia University, Montréal, QC H4B 1R6, Canada.
2 Center for Studies in Behavioral Neurobiology, Department of Psychology,Concordia University, Montréal, QC H4B 1R6, Canada; Pelvipharm Laboratories, University of Versailles, Saint-Quentin-en-Yvelines, Montigny le Bretonneux, France.
3 Center for Studies in Behavioral Neurobiology, Department of Psychology,Concordia University, Montréal, QC H4B 1R6, Canada; Instituto de Investigaciones Cerebrales, Universidad Veracruzana, Xalapa, VER 91193, Mexico.
4 Center for Studies in Behavioral Neurobiology, Department of Psychology,Concordia University, Montréal, QC H4B 1R6, Canada; Department of Psychology and Life Sciences, Faculty of Humanities, Charles University, 18200, Prague, Czech Republic; Laboratory of Sexual Neuroscience, Center for Sexual Health and Intervention, Czech National Institute of Mental Health, 25067 Klecan

Oxytocin (OT) and vasopressin (VP) are considered to be principal neurochemical substrates of bonding in monogamous species. We have reported previously that conditioning of a sexual partner preference in male rats resulted in conditioned activation of OT and VP neurons in hypothalamic paraventricular and supraoptc nuclei. Here we asked whether such conditioning would also alter OT or VP receptor densities. Sexually naïve male rats were assigned to one of three groups (n = 15/group). The Paired...