Antagonism of the neuropeptide S receptor with RTI-118 decreases cocaine self-administration and cocaine-seeking behavior in rats

Neuropeptide S (NPS) is a neuromodulatory peptide, acting via a G-protein-coupled receptor to regulate sleep, anxiety and behavioral arousal. Recent research has found that intracerebroventricular NPS can increase cocaine and alcohol self-administration in rodents, suggesting a key role in reward-related neurocircuitry. It is hypothesized that antagonism of the NPS system might represent a novel strategy for the pharmacological treatment of cocaine abuse. To this end, a small-molecule NPSR antagonist (RTI-118) was developed and tested in animal models of cocaine seeking and cocaine taking. Male Wistar rats (n = 54) trained to self-administer cocaine and food under a concurrent alternating FR4 schedule exhibited specific dose-dependent decreases in cocaine intake when administered RTI-118. RTI-118 also decreased the reinstatement of extinguished cocaine-seeking behavior induced by conditioned cues, yohimbine and a priming dose of cocaine. These data support the hypothesis that antagonism of the neuropeptide S receptor may ultimately show efficacy in reducing cocaine use and relapse. (C) 2012 Elsevier Inc. All rights reserved