Reinforcing effects of oxytocin in female rats: Intracerebroventricular self-administration
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
BACKGROUND: The neuropeptide oxytocin (OT) is involved in reproduction, promoting milk-ejection and uterine contractions. In addition, the hormone also stimulates social affiliation such as pair bonding and maternal attachment. In non-social settings, OT has anxiolytic, antidepressant and stress-reducing effects. Since affiliative behaviors are rewarding, this suggests that OT may enhance reward and reinforcement in a non-social context. If so, rats should be willing to work to obtain it. AIM: Test the hypothesis that a physiological dose of OT is reinforcing in a non-social setting. Intracerebroventricular (ICV) self-administration in female rats was used as the experimental model. METHODS: Ovariectomized female Long-Evans rats with estrogen replacement were implanted with an ICV cannula. Self-administration of oxytocin [1 ng in 1 ?l] or vehicle was conducted 4 h/day for 5 days/week, for a total of 30 days. RESULTS: Unlike vehicle controls, OT-treated rats showed a significant preference for the active lever. However, by RM-ANOVA there was no effect of OT, a significant effect of lever (active over inactive) and the OT x Lever interaction just missed significance. CONCLUSION: These results indicate that OT may be reinforcing. Future studies will test reinforcing effects of OT across a range of doses, and in the presence of a social partner. Reinforcement may be a mechanism by which OT promotes social behaviors, such as sexual and parental behavior, that are risky for the individual, but necessary for the species. The pro-social aspects of OT also have pharmaceutical implications, with the hormone being a possible treatment for social-deficit disorders such as autism. Similarly, OT may be effective against diminished emotional abilities, which are often observed in drug addicts.
Place, publisher, year, edition, pages
2014. , 22 p.
Oxytocin, self-administration, Reinforcement, Intracerebroventricular
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-237767OAI: oai:DiVA.org:uu-237767DiVA: diva2:768834
Subject / course
Master of Science Programme in Pharmacy
Wood, Ruth, Professor
Hallberg, Mathias, Senior Lektor