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Presentation Time: 9:50-10:10
Home University: UNC-Chapel Hill
Research Mentor: Gregory Scherrer, Department of Cell Biology and Physiology
Program: SMART
Research Title: Investigating the role of μ opioid receptor in Chx10-expressing neurons

Mu opioid receptors (μ receptors) play a critical role in the effects of opioids, including analgesia, opioid-induced hyperalgesia (OIH), tolerance, withdrawal, and locomotor-related behaviors, but which populations of receptors are the primary mediators of these processes is yet to be determined. Neurons expressing Chx10, a molecular marker specifically expressed by V2a+ pre-motor neurons located in the regions of the ventral spinal cord and brainstem, also express μ receptors. By removing μ receptors in these neurons, we can determine their role in mediating various opioid effects. To this aim, we have quantified these effects using von Frey filaments, hot plate tests, naloxone-precipitated withdrawal, and video recordings of μ receptor-conditional knockout mice (cKO: Chx10Cre/+; Oprm1fl/fl) and wildtype littermates (control mice) after morphine administration. Altogether the data suggest that mechanical and thermal pain thresholds of cKO mice before and after morphine are very similar to those of control mice. However, we have found interesting differences in locomotor-related behaviors. Specifically, morphine-induced hyperlocomotion and straub tail, two very distinct behaviors occurring after morphine exposure, were completely absent in the cKO mice. Thus, the μ receptor/Chx10-expressing neurons likely play a role in hyperlocomotor activity and muscle rigidity caused by morphine. Future experiments will focus on these findings.