What Is Neuropeptide S? Definition and What Research Reports

Neuropeptide S (NPS) is an endogenous neuropeptide — a small, gene-encoded signalling molecule made and released by neurons — that is conventionally described as a 20-amino-acid sequence whose first residue is a serine, which is the origin of its name. It is cleaved from a larger precursor protein and acts at a single identified G-protein-coupled receptor, neuropeptide S receptor 1 (NPSR1, also catalogued in older literature as GPR154). In research writing, "neuropeptide S" is used in three overlapping ways: as the name of the endogenous peptide, as the name of the gene and precursor, and as the name of the synthetic peptide used as a receptor agonist in laboratory experiments. NPS is not an approved medicine in any major jurisdiction, and the studies below are animal, cell-culture or observational human work.

This page is for educational purposes only and is not medical advice; consult a licensed physician about any health question, symptom or treatment decision.

What Class of Molecule Is It, and Where Does It Come From?

NPS belongs to the broad class of neuropeptides: peptide transmitters that are synthesised as precursors, packaged into dense-core vesicles, and released to act on G-protein-coupled receptors rather than on ion channels. Unlike classical neurotransmitters, neuropeptides typically act over slower timescales and at lower concentrations, and they often modulate the output of a circuit rather than carrying its fast signal.

The peptide is expressed by a small number of neurons concentrated in the brainstem, and its receptor is found much more widely — including outside the brain. A 2023 Current Biology report characterised a defined cluster of neuropeptide S neurons and reported that this population regulated breathing and arousal, illustrating how a numerically small cell group can be mapped onto specific physiological outputs (PMID 38056461). The system is not restricted to mammals: researchers who cloned NPS and NPSR1 in chickens described their tissue expression and carried out functional analysis of the receptor, indicating conservation of the ligand–receptor pair across vertebrate lineages (PMID 34634709).

How the Term Is Used in Peptide Research

In practice, papers use "neuropeptide S" in a handful of recognisable contexts:

• As an endogenous signal. Studies measure NPS gene or peptide expression to ask whether a manipulation changes the system's activity — for example, a 2025 study examined how psilocybin and ketamine affected the expression of novel neuropeptide genes in the rat hypothalamus (PMID 40243003).
• As an exogenous agonist in animal models. Synthetic NPS is administered to rodents, usually centrally, to probe what activating NPSR1 does to behaviour or physiology.
• As a receptor target. Much of the translational interest sits on NPSR1 rather than the peptide, including medicinal-chemistry programmes that design receptor antagonists.
• As a biomarker. Human studies measure circulating NPS concentrations and compare groups; a 2018 study in Nordic Journal of Psychiatry investigated the relationship between plasma neuropeptide-S levels and clinical depression (PMID 29488437).

A useful framing point: neuropeptide genes are themselves objects of evolutionary study. A 2024 Nature paper reported that circadian plasticity evolved through regulatory changes in a neuropeptide gene, a reminder that where and when a neuropeptide is expressed can matter as much as the peptide sequence itself (PMID 39415010).

What the Published Literature Reports

Arousal, breathing and sleep

The best-known characterisation of NPS is as an arousal-associated signal. The 2023 Current Biology study reported that a cluster of neuropeptide S neurons regulated both breathing and arousal, linking the peptide's cell population to respiratory and state control (PMID 38056461). In a separate rodent model, researchers reported that neuropeptide S counteracted paradoxical sleep deprivation-induced anxiety-like behaviour and sleep disturbances (PMID 29559896). That pairing — heightened wakefulness alongside reduced anxiety-like behaviour — is the profile most often cited as distinguishing NPS from sedating anxiolytics in preclinical descriptions.

Anxiety-like behaviour and alcohol-related models

A 2016 Psychopharmacology study reported that neuropeptide S differently modulated alcohol-related behaviours in alcohol-preferring versus non-preferring rat lines, indicating that genetic background shaped the response (PMID 27235017). A 2025 Neuropharmacology report extended this by describing a sex-dependent role of neuropeptide S on anxiety, fear conditioning and alcohol seeking in alcohol-preferring rats (PMID 40712753). Taken together, the study findings in this area are conditional rather than uniform: direction and magnitude depended on the strain and sex of the animals tested.

Peripheral and non-brain roles

NPSR1 is expressed outside the central nervous system, and several reports concern peripheral tissue. In a rat model, researchers reported that neuropeptide-S prevented 6-OHDA-induced gastric dysmotility (PMID 33753063). On the airway side, a 2025 Respiratory Research paper reported that neuropeptide S and its receptor aggravated asthma via TFEB-dependent autophagy in bronchial epithelial cells (PMID 39930427). The receptor has also been examined in oncology: a 2026 Cancer Immunology Research study reported that neuromedin B derived from NMB+CXCL13+CD4+ T cells promoted senescence and malignancy in NPSR1-positive malignant cells (PMID 42029557).

Snapshot of reported research areas

Adverse and Unfavourable Findings: What Studies Report

Published work on NPS is not uniformly favourable, and the receptor has been described as a driver of unwanted processes in some tissues. The 2025 Respiratory Research study reported that NPS and NPSR1 aggravated asthma through TFEB-dependent autophagy in bronchial epithelial cells, a finding consistent with long-standing genetic interest in NPSR1 as an asthma-associated locus (PMID 39930427). In the tumour setting, researchers reported that NPSR1-positive malignant cells underwent senescence and increased malignancy in response to neuromedin B from a defined CD4+ T cell population (PMID 42029557). Reflecting this, at least one 2025 medicinal-chemistry paper reported the design of a peripherally biased NPSR1 antagonist intended to address neuropeptide S-induced inflammation while limiting central exposure (PMID 40752839). No controlled human safety or dosing data for administered NPS appear in the sources cited on this page.

Limitations to Keep in Mind

• Species and route. Most behavioural findings come from rodents, often with central administration, which does not translate directly to human physiology.
• Conditional effects. Responses varied with strain and sex in alcohol-related models (PMID 40712753).
• Direction depends on tissue. The same receptor was reported as protective in a gastric motility model (PMID 33753063) and as aggravating in an airway model (PMID 39930427).
• Human data are observational. Biomarker comparisons such as plasma NPS and depression describe associations, not causation (PMID 29488437).

As a glossary entry, this page defines the term and summarises what the cited literature reported; it does not describe protocols, quantities or applications in people.

References

• A cluster of neuropeptide S neurons regulates breathing and arousal (Current Biology, 2023)
• Circadian plasticity evolves through regulatory changes in a neuropeptide gene (Nature, 2024)
• Neuropeptide S differently modulates alcohol-related behaviors in alcohol-preferring and non-preferring rats (Psychopharmacology, 2016)
• Sex-dependent role of Neuropeptide-S on anxiety, fear conditioning, and alcohol seeking in alcohol preferring rats (Neuropharmacology, 2025)
• Psilocybin and ketamine affect novel neuropeptides gene expression in the rat hypothalamus (Journal of Psychopharmacology, 2025)
• Neuropeptide S and its receptor aggravated asthma via TFEB dependent autophagy in bronchial epithelial cells (Respiratory Research, 2025)
• NMB+CXCL13+CD4+ T Cell-Derived Neuromedin B Promotes Neuropeptide S Receptor 1-Positive Malignant Cell Senescence and Malignancy (Cancer Immunology Research, 2026)
• Neuropeptide S Counteracts Paradoxical Sleep Deprivation-Induced Anxiety-Like Behavior and Sleep Disturbances (Frontiers in Cellular Neuroscience, 2018)
• Investigating the relationship between plasma neuropeptide-S levels and clinical depression (Nordic Journal of Psychiatry, 2018)
• Design of a peripherally biased NPSR1 antagonist for neuropeptide S induced inflammation (Bioorganic & Medicinal Chemistry Letters, 2025)
• Neuropeptide-S prevents 6-OHDA-induced gastric dysmotility in rats (Brain Research, 2021)
• Neuropeptide S (NPS) and its receptor (NPSR1) in chickens: cloning, tissue expression, and functional analysis (Poultry Science, 2021)