SUMMARY Opioid dependence is a global public health issue for which more effective treatments are urgently needed. Opioid dependence is characterized by exacerbated brain stress signaling that drives an anxious, dysphoric, and irritable state that contributes to the intensity of opioid-seeking and opioid-taking in opioid use disorder (OUD). Neuropeptide S (NPS) administration, through interaction with its cognate receptor Neuropeptide S Receptor 1 (NPSR1), has an anxiolytic profile of action that is opposite to the anxious phenotype observed in withdrawal during OUD in both rodents and humans. The current proposal hypothesizes that agonism of the NPSR1 can alleviate the anxious phenotype observed during OUD and thereby ameliorate the intensified motivation to seek and consume opioids that is observed in OUD. A unique strength of this approach is that NPS agonism of NPSR1 is able to generate an anxiolytic profile of action without producing the sedative-hypnotic effects which are a common, major limitation of currently available anxiolytic compounds. We present novel data using a model of alcohol dependence demonstrating the potential for the anxiolytic action of NPS to curb the motivation to seek drugs of abuse. However, to date, NPS has not been evaluated for its ability to curb opioid self-administration. The few pieces of data available suggest that NPS and NPSR1 are implicated in opioid reward, and that brain levels of NPS and NPSR1 are dysregulated by repeated opioid exposure. Successful demonstration of the therapeutic potential of NPS-NPSR1 manipulations would fill this obvious gap in our collective scientific knowledge and provide strong justification for a future effort to develop a novel OUD medication based on manipulating NPS-NPSR1 interaction. The present R21 proposal seeks to identify a new neurobiological modulator in the context of opioid consumption, dependence, and relapse, and is therefore inherently high-risk in nature. Nevertheless, we propose a multi-faceted approach built on solid logic that has the potential to reveal a completely novel target in our collective efforts to develop effective OUD treatments. The proposed research team is ideally suited to completing this short-term research project, possessing all necessary expertise, equipment, and materials required to start the project. Specifically, we plan to leverage the best-available pharmacological tools for agonism and antagonism of the NPSR1 and use well validated preclinical models for testing therapeutic relevance for distinct features critical to the progression of OUD. By completing this short-term project, we will rapidly characterize the therapeutic potential of NPSR1 in the context of OUD, testing three compounds (each of which could potentially be leveraged in developing OUD treatments in the future) for their therapeutic efficacy against OUD in preclinical animal models. It is our firm belief that this project will be successful in these short- term goals. In the big picture, completion of this project will provide the necessary justification for a future R01- level application to support a large-scale, collaborative effort to develop novel NPSR1 ligands.

NARRATIVE Opioid use disorder (OUD) is the third leading cause of preventable death in the United States and negatively affects the quality of life of millions of people; we propose to test the best-available activators and inhibitors of the Neuropeptide S (NPS) receptor (NPSR1) for their therapeutic potential in rat models of distinct phases of OUD. More broadly, the experiments proposed will generate the preliminary data necessary to justify a large- scale, collaborative drug-development effort aimed at developing novel small molecule ligands of the NPSR1. Ultimately it is our hope that these efforts generate new and urgently needed treatment options for OUD.