Electronic Theses and Dissertations

Date

2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Psychology

Committee Chair

Melloni N Cook

Committee Member

Deranda B Lester

Committee Member

Helen Sable

Committee Member

Meghan McDevitt-Murphy

Abstract

Anxiety disorders are the most prevalent psychological diagnoses in the U.S. Current pharmacological treatments for anxiety disorders have high non-response rates highlighting the necessity for novel therapeutic treatments. Oxytocin, a neuropeptide, is a potential candidate. The current study aimed to examine the effects of oxytocin on anxiety- and fear-related behaviors through (1) a battery of behavioral tests and (2) a fear extinction test in males and females from two strains of mice, C57BL/6J (B6) and DBA/2J (D2) which differ in the aforementioned behaviors and in dopaminergic circuitry. A second aim was to investigate the effects of oxytocin administration on mesolimbic dopamine activity via in vivo (3) fixed potential amperometry recordings in the nucleus accumbens (NAc). Mice received 8 intraperitoneal injections of oxytocin (1mg/kg) or saline over 16 days before being placed in one of three experiments. Results indicated no oxytocin effect in anxiety-or fear-related behaviors in any of the behavioral tests except for habituation of distance traveled and rears. Oxytocin-treated males and saline-treated females had significant habituation of distance traveled in the open field. Oxytocin-treated B6 males showed greatest habituation of distance traveled. Oxytocin reduced baseline dopamine half-life in D2 mice. Nomifensine-induced dopamine release was greater in B6 males than B6 females but higher in D2 females than D2 males. A strain difference was observed with D2 having a higher increased dopamine half-life following nomifensine than B6 mice. Nomifensine-induced dopaminergic responses were attenuated by oxytocin pretreatments for all groups except D2 females which showed a higher increase than saline-treated females. The results indicate that oxytocin effects are sex- and test-dependent relating to anxiety and reward. More research is needed on the clinical utility of oxytocin.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest

Notes

Open Access

Download

Share

COinS