Master of Science
The neuropeptide oxytocin alters the salience of rewards and is being investigated as a treatment for substance use disorder; however, the effects of oxytocin on reward-related neural circuits are not understood. The detection of rewarding stimuli is regulated in part by the mesolimbic dopamine system, with dopaminergic cell bodies in the ventral tegmental area (VTA) that project to the nucleus accumbens (NAc). The current study aimed to determine the effect of oxytocin receptor activation in the NAc on mesolimbic dopamine release. Fixed potential amperometry was used to measure stimulation-evoked dopamine release in the NAc of anesthetized C57BL/6J mice before and after an intra-NAc infusion of oxytocin (0.6 µg in 0.5 µl volume over a 1 min period). The hypothesis was that an infusion of oxytocin into the NAc would decrease dopamine release, increase DAR functioning, and have no effect on DAT functioning. Oxytocin infused into the NAc significantly reduced dopamine release (-24%) relative to the vehicle infusion of phosphate buffered saline (PBS, -4%); however, the oxytocin infusion did not significantly alter the synaptic half-life of dopamine (-2%) relative to PBS (-4%). Additionally, the oxytocin infusion did not significantly alter dopamine autoreceptor sensitivity as compared to PBS. No differences were observed between males and females. These results suggest that oxytocin receptor activation in the NAc inhibits dopamine release but does not alter reuptake rates (i.e., dopamine transporter functioning) or DAR functioning. Such findings aid in understanding the neural mechanisms of oxytocin on the reward system and further provide implications for the utility of targeting the oxytocin system in pharmaceutical treatments for substance use disorder.
Dissertation or thesis originally submitted to ProQuest.
Nalan, Patricia, "The Role of Oxytocin Receptor Activation in the Nucleus Accumbens on Dopamine Release" (2022). Electronic Theses and Dissertations. 3259.