The Physio-Pharmacological Role of the NPS/NPSR System in Psychiatric Disorders: A Translational Overview

In 2004, Neuropeptide S (NPS) was identified to be the cognate ligand of the previously discovered orphan receptor GPCR 154, now termed as NPS receptor (NPSR). Since, then a wealth of data has elucidated the unique behavioral profile of this peptidergic system in numerous physiological function such as being pro-arousal and anxiolytic at the same time. Besides, its robust anxiolytic profile, this peptide system has been found to activate HPA axis and concomitant release of ACTH and corticosterone. Additionally, the involvement of NPS in reinstatement of drug seeking behavior has also been reported. In recent years, accumulating data from various labs have demonstrated an A/T single-nucleotide polymorphism (SNP) resulting in (Asn107Ile) switch in the human NPSR gene as the risk factor for various psychiatric disorders such as panic disorder, post traumatic syndrome, alcohol use disorders and enhanced anxiety sensitivity, although, this is in stark contrast to the findings made in animal models which have consistently projected the anxiolytic nature of this peptide system. Therefore, in context of robust involvement of NPS system in various psychiatric disorders this review article considers the importance of NPS from translational point of view and appraises the need of therapies to be tailored around NPSR. In this respect, pharmacology of important NPSR ligands which have been recently developed has been discussed together with their possible side effects profile. Additionally, this review article encompasses all recent developments in the field of NPS system highlighting the role of this neuropeptide in all those biological functions which are modulated by this system. The role of this peptide has been discussed in detail in the perspective of sleep regulation, anxiety, fear expression and most importantly in drug addiction. Additionally, neuroimaging and genetic linkage studies addressing the functional impact of NPSR1 variants in the aforementioned psychiatric disorders have also been discussed.