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Presentation Time: 3:35-3:55
Home University: Fayetteville State University
Research Mentor: Gregory Scherrer, Department of Cell Biology and Physiology
Program: SOLAR & SURE
Research Title: Development of Home Cage Self Administration and Conditioned Place Preference (CPP) Assays in Mice for Addiction Studies

Opioids are the most effective treatments for moderate to severe pain, but they can lead to addiction. The μ-opioid receptor (MOR) mediates various behaviors after morphine exposure including analgesia, hyperalgesia, weight decrease, hyperlocomotion, and addiction. Further investigation of morphine addiction is vital for identifying the specific neuronal populations across the nervous system responsible for addiction. In this study, we generated MOR conditional knockout mice (Chx10Cre/+ ;Oprm1fl/fl) where MOR was removed from the Chx10-expressing neurons, and tested these mice using traditional pain assays after morphine administration. We also established two new behavioral tests, the Conditioned Place Preference (CPP) and the Two Bottle Choice (TBC) assays, to measure addiction in mice. We found that MOR cKO mice showed similar analgesia and morphine withdrawal compared to control littermates, suggesting that the Chx10 expressing neurons may not mediate these effects. Using the CPP assay, mice developed a small preference for morphine after three days of conditioning, however the CPP requires further optimization for addiction testing. We successfully built TBC devices- the experiment is ongoing and we will use it to observe home cage self-administration of opioids in mice. We expect mice to self-administer opioids more than water, with time, during the 14-day experimental period. In the future, we intend to use different MOR cKO mice to elucidate which neurons are involved in the mediation of morphine addiction.