The Neuropeptide Oxytocin Facilitates Pro-Social Behavior and Prevents Social Avoidance in Rats and Mice

Michael Lukas, Iulia Toth, Stefan O Reber, David A Slattery, Alexa H Veenema, Inga D Neumann
2011 Neuropsychopharmacology  
Social avoidance and social phobia are core symptoms of various psychopathologies but their underlying etiology remains poorly understood. Therefore, this study aims to reveal pro-social effects of the neuropeptide oxytocin (OT), under both basal and stressinduced social avoidance conditions in rodents using a social preference paradigm. We initially show that intracerebroventricular (i.c.v.) application of an OT receptor antagonist (OTR-A) in naïve male rats (0.75 mg/5 ml), or mice (20 mg/2
more » ... , reduced social exploration of a novel con-specific indicative of attenuated social preference. Previous exposure of male rats to a single social defeat resulted in loss of their social preference and social avoidance, which could be restored by i.c.v. infusion of synthetic OT (0.1 mg/5 ml) 20 min before the social preference test. Although the amygdala has been implicated in both social and OT-mediated actions, bilateral OTR-A (0.1 mg/1 ml) or OT (0.01 mg/1 ml) administration into various subnuclei of the amygdala did not affect basal or stress-induced social preference behavior, respectively. Finally, we demonstrate the social specificity of these OT-mediated effects by showing that neither an arginine vasopressin V1a receptor antagonist (0.75 mg/5 ml, i.c.v.) nor the anxiogenic drug pentylenetetrazol (15 mg/kg, i.p.) altered social preference, with OTR-A not affecting non-social anxiety on the elevated plus-maze. Overall, the data indicate that the basal activity of the endogenous brain OT system is sufficient to promote natural occurring social preference in rodents while synthetic OT shows potential to reverse stress-induced social avoidance and might thus be of use for treating social phobia and social dysfunction in humans. Pro-social effects of oxytocin in rats and mice M Lukas et al 2160 Neuropsychopharmacology Figure 5 (a) Effects of i.c.v. infusion of an oxytocin receptor antagonist (OTR-A, 0.75 mg/5 ml) on non-social anxiety in the black-white box in rats and on the elevated plus-maze in mice, respectively. Non-social anxiety is reflected by the percentage of time spent in the white box of the black-white box and the percentage of time spent on the open arms in the elevated plus-maze. (b) Effects of PTZ (15 mg/kg, i.p.) on non-social anxiety and locomotion of male rats on the plus-maze. Data are means + SEM, *po0.05 vs vehicle, Students's t-test. (c) Effects of PTZ on social preference in rats reflected by the higher percentage of investigation time directed toward the social vs the object stimulus. Data are means + SEM, # po0.05 vs object stimulus, two-way ANOVA for repeated measures followed by Bonferroni post hoc test. Pro-social effects of oxytocin in rats and mice M Lukas et al
doi:10.1038/npp.2011.95 pmid:21677650 pmcid:PMC3176581 fatcat:2ksavcmnhjh5rdv4puii7cmzka