408 In vivo calcium imaging in the medial prefrontal cortex reveals novel site of action for therapeutic effects of Neuromedin U

Abstract

OBJECTIVES/GOALS: The primary goals of this study are 1) expand our understanding of the neural circuitry influenced by the neuropeptide Neuromedin U (NMU) via its receptor Neuromedin U Receptor 2 (NMUR2), and 2) provide alternative top-down mechanisms for how NMU regulates high fat food intake and cocaine taking. METHODS/STUDY POPULATION: Immunohistochemistry (IHC) for NMUR2 and cell markers was performed on rat brain tissue containing the medial prefrontal cortex (mPFC). To identify the source of the presynaptic NMUR2, anterograde tracing from the paraventricular nucleus or dorsal raphe nucleus to the mPFC utilizing an AAV2- dsRed-synaptobrevin fusion protein were performed (n=3) and will be followed by IHC. Using in vivo calcium imaging technology (InScopix nVista), neuronal activity (calcium transients) was recorded from the mPFC of two awake, freely behaving rats. Each animal underwent a single session of 30 minutes baseline activity, intraperitoneal NMU administration, and 30 minutes of post-treatment activity. Activity was then processed and recorded as distinct events using the InScopix data acquisition software. RESULTS/ANTICIPATED RESULTS: Medial prefrontal cortex staining for NMUR2 revealed a characteristic “beads on a string” motif, consistent with presynaptic receptor expression. Furthermore, we expect the anterograde tracing experiment will show colocalization of the dsRed-synaptobrevin fusion protein with NMUR2 on synaptic inputs into the medial prefrontal cortex. Following quantification of pre- and post- treatment events using the InScopix data acquisition software, total events during the pre- and post-treatment time periods were calculated. In these studies, both animals demonstrated a clear increase in calcium transient activity between pre- and post- treatment evaluations, suggesting that NMU administration increases the neuronal activity of neurons in the prefrontal cortex. DISCUSSION/SIGNIFICANCE: This research provides a new site of action for the known therapeutic effects of NMU. We demonstrate the presence of presynaptic NMUR2 in the mPFC and show that systemic administration of NMU increases mPFC neuronal activity. This illustrates NMU may act as a top-down mediator for substance use disorders and binge eating behaviors.