Honors Theses

Date of Award

Spring 5-5-2023

Document Type

Undergraduate Thesis



First Advisor

Alberto Del Arco

Second Advisor

Kristine Willett

Third Advisor

Paul Loprinzi

Relational Format



Studies that use Intermittent (episodic) Social Defeat (ISD) in rats demonstrate that ISD increases cocaine-self administration several weeks after the end of the adverse experience and suggest that a history of social stress makes individuals more vulnerable to substance abuse in the long term. The medial prefrontal cortex (mPFC) plays a key role in regulating drug-seeking behavior. The present study investigates whether ISD enhances the response of mPFC neurons to cocaine. Male Long Evans rats (3-4 months) were implanted with electrode arrays in the mPFC (prelimbic area) and divided into two groups (Control, n= 4; Stress, n= 4). They were then exposed to ISD or handling (control group) once every three days for ten days (four stress episodes in total). Three weeks after the last stress episode, control and stressed rats were injected with either cocaine or saline (10 mg/kg, i.e.) and the resultant effects on mPFC neuronal activity and locomotion were assessed. The results show that cocaine injections increase locomotion in both groups. However, cocaine-induced locomotion was stronger in stressed rats compared to controls (data not shown). Our results also show that mPFC neurons decrease their activity in response to cocaine injections in both stressed and control rats. These results suggest that ISD does not change the effects of cocaine in the mPFC and therefore do not support a role of this area of the brain in stress-induced behavioral sensitization to cocaine. Supported by NIGMS-NIH P30GM12273

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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.



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