Neuromedin S: brain clock and appetite-suppressing neuropeptide
A natural brain hormone made in the body's internal clock region that helps regulate daily rhythms, suppresses appetite, and controls body temperature; used only as a lab research tool.
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
What this is
Neuromedin S (NMS) is a brain neuropeptide discovered in 2005 that acts on the same receptors as its close relative neuromedin U. It is produced almost exclusively in the suprachiasmatic nucleus (SCN) — the brain's master circadian clock — and plays roles in synchronizing daily biological rhythms, suppressing appetite, regulating body temperature, and coordinating hormonal responses. NMS has not been approved for any clinical use and is currently a research tool peptide. The stored sequence (LPRLLHTDSRMATIDFPKKDPTTSLGRPFFLFRPRN) is the 36-residue rat form; the human variant (NMS33) is 33 residues. In both species the C-terminus carries an amide group (–NH₂) critical for receptor binding that is not represented in the stored 1-letter sequence.
History
NMS was identified by Mori and colleagues at the National Cardiovascular Center Research Institute in Osaka, Japan, and published in The EMBO Journal in January 2005 (Mori and colleagues 2005). The team was screening for endogenous ligands of two orphan G protein-coupled receptors — FM-3/GPR66 and FM-4/TGR-1 — that had earlier been deorphanized as neuromedin U receptors. Purification of rat brain extracts yielded a novel 36-amino-acid peptide whose C-terminal seven residues are identical to those of neuromedin U (NMU). Because mRNA expression was restricted to the suprachiasmatic nucleus of the hypothalamus, the peptide was named neuromedin S (for "suprachiasmatic"). The discovery paper immediately noted that central injection of NMS caused non-photic phase shifts in locomotor circadian rhythms in rats, establishing its circadian role from the outset. Subsequent years produced a series of functional studies: anorexigenic effects (Ida and colleagues 2005), antidiuretic action via vasopressin (Sakamoto and colleagues 2007), involvement in oxytocin-mediated milk ejection (Sakamoto and colleagues 2008), and modulation of luteinizing hormone secretion (Vigo and colleagues 2007). The first cryo-EM structures of both neuromedin U receptor subtypes in complex with NMS were reported by You and colleagues in Nature Communications in 2022, revealing the molecular basis of receptor activation and subtype selectivity.
What it does
NMS acts mainly in the brain, where it binds to two G protein-coupled receptors — NMUR1 and NMUR2 — and activates multiple physiological circuits simultaneously. Its most prominent central role is in the hypothalamus, where it suppresses food intake and reduces gastric emptying, an effect shown to depend on NMUR2 in gene-knockout mice (Kotera and colleagues 2009). NMS also modulates the body's internal clock by activating neurons in the SCN and inducing phase shifts in circadian locomotor rhythms (Mori and colleagues 2005). Additional effects documented in rodent studies include: raising body temperature by activating brown adipose tissue thermogenesis; stimulating corticosterone release through CRH and POMC pathways in the paraventricular nucleus; triggering vasopressin release to reduce urine output; stimulating oxytocin neurons involved in the milk ejection reflex; and modulating luteinizing hormone secretion in females in a cycle-dependent manner. The breadth of NMS actions reflects its position at the SCN, where it can influence the timing and amplitude of multiple hormonal axes.
Evidence
- Human: No clinical trials have been conducted with NMS. The human gene (NMS, chromosome 2q11.2) has been identified and NMS33 protein confirmed, but no human pharmacological data are published as of mid-2026.
- Animal: Rodent studies show NMUR2-dependent suppression of food intake and body weight in both lean and diet-induced-obese mice (Kotera and colleagues 2009). NMS elicited near-complete anorectic responses in wild-type mice that were absent in Nmur2-knockout animals, establishing receptor dependence. Thermogenic effects via UCP1 upregulation in brown adipose tissue were demonstrated in mice (Involvement of endogenous neuromedin U and neuromedin S in thermoregulation, 2016). NMS-knockout mice showed significantly lower body surface temperature during the active phase compared with wild-type controls, implicating endogenous NMS in basal thermoregulation. HPA axis activation (near 5-fold increase in plasma corticosterone after intracerebroventricular injection) was documented in rats (Malendowicz and Rucinski 2021, review).
- In vitro: Cryo-EM structural studies by You and colleagues (2022) resolved NMS–NMUR1–Gq and NMS–NMUR2–Gq complexes, revealing that NMS and NMU adopt distinct binding poses despite sharing the same C-terminal heptapeptide. NMUR2 shows significantly higher binding affinity for NMS than for NMU, a selectivity attributed to differences in the polar environment around receptor position 6.55.
Known effects
- Circadian phase shifting — Preclinical (rat): intracerebroventricular NMS induces non-photic type phase shifts in locomotor rhythm
- Appetite suppression — Preclinical (mouse): NMUR2-mediated reduction in food intake and body weight; absent in NMUR2-knockout animals
- Thermogenesis — Preclinical (mouse): raises core and surface body temperature via UCP1 upregulation in brown adipose tissue
- HPA axis activation — Preclinical (rat, bird): dose-dependent increase in plasma corticosterone; mediated via CRH/POMC pathways
- Antidiuresis — Preclinical (rat): vasopressin release from supraoptic nucleus reduces nocturnal urinary output
- Oxytocin stimulation — Preclinical (rat): activates oxytocinergic neurons in paraventricular and supraoptic nuclei; endogenous NMS supports milk ejection reflex
- LH modulation — Preclinical (rat): state-dependent effects on luteinizing hormone secretion, varying across the estrous cycle and in response to fasting
Mechanism
NMS signals through two class A GPCRs: NMUR1 (predominantly peripheral expression) and NMUR2 (predominantly central, highly expressed in the hypothalamus and cerebral cortex). Both receptors couple to Gq/11, activating phospholipase C and generating intracellular calcium signals; some Gi coupling has also been reported. The central anorectic and thermogenic effects of NMS are mediated almost exclusively through NMUR2, as demonstrated by knockout experiments. NMS preferentially binds NMUR2 over NMUR1 compared with NMU, a selectivity that has been linked to a more pronounced polar environment at the R4 position of the peptide's binding interface in NMUR2 (You and colleagues 2022). The C-terminal amidated heptapeptide (Phe-Leu-Phe-Arg-Pro-Arg-Asn–NH₂) is the pharmacophore shared with NMU; it drives the R6.55-triggered conformational switch that propagates through conserved receptor micro-switches to engage Gq. The N-terminal 29 (rat) or 26 (human) residues differ between NMS and NMU and contribute to receptor subtype selectivity. Despite NMS mRNA being confined to the SCN, the NMS peptide is detectable throughout the brainstem (midbrain, pons, and medulla), consistent with axonal projections from SCN neurons distributing the peptide to downstream circuits (Mori and colleagues 2012).
Safety signals
No human safety data exist for neuromedin S. All available information derives from rodent pharmacology studies using intracerebroventricular administration (a research route with no clinical equivalent). No regulatory filings or preclinical toxicology packages have been published for NMS itself. NMUR2-selective synthetic agonists are in early preclinical exploration for obesity, and some of that work has begun to characterize receptor-mediated side effects (including potential HPA axis activation), but those are distinct compounds from native NMS.
Regulatory status
- US (FDA): Not approved. No IND or clinical trial application on record.
- EU (EMA): Not approved.
- WADA: Not listed on the current Prohibited List; NMS is not known to be used in sport.
- Research use: Synthetic rat NMS and human NMS33 are available from commercial peptide suppliers as research-grade reagents.
Related peptides
- Neuromedin U (NMU) — the structural and functional sister peptide sharing the C-terminal heptapeptide pharmacophore; more widely expressed in peripheral tissues (gut, pituitary) than NMS; early-stage preclinical NMUR2 agonist drug discovery programs have used NMU as the template
Research directions for this peptide, selected from the current sources — hypotheses you can explore and model. None of it is proven yet; tap any one to see the full thinking.
Does neuromedin S actually engage the GLP-1 receptor, or is that a database labeling error?
GLP-1 receptor drugs are blockbuster obesity treatments. If NMS is incorrectly linked to GLP-1R, researchers designing NMS-based weight-loss compounds are starting from a false premise, wasting resources that could be redirected to the correct receptor pathway.
Does neuromedin S amplify the brain's internal clock by feeding back onto the same neurons that release it?
If this loop exists, drugs that mimic it could help reset disrupted circadian rhythms in shift workers or jet-lagged travelers, and might improve outcomes in sleep disorders without the side effects of current sedatives.
Could a clock-synchronized appetite signal like neuromedin S reduce overeating caused by shift work or irregular sleep?
Shift workers and people with disrupted sleep have much higher obesity rates, partly because their hunger signals fire at the wrong times. A treatment tied to the body clock could correct this mismatch, helping a large underserved population that current weight-loss drugs do not address well.
Could neuromedin S reduce stress-hormone overactivation in people whose circadian rhythms are disrupted?
Chronic stress and circadian disruption often co-occur in shift workers, trauma survivors, and people with burnout. A peptide that links the clock to the stress system could offer a fundamentally new way to treat anxiety conditions that current drugs address only partially.
Does the large N-terminal extension of neuromedin S make it hit only the brain receptor and not the gut/peripheral receptor?
If NMS targets only the brain receptor, an NMS-based drug could suppress appetite and reset the body clock without causing the gut cramps or blood pressure changes tied to activating the same receptor family in peripheral organs.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.6398810148239136 | boltz-2 |
| ranking score | 0.7018434405326843 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 1.029 | global PDE — lower = better |
| disorder | NaN | fraction disordered |
▸3-letter notation
▸recipeboltz-2 1.0
| parameter | value |
|---|---|
| model | boltz-2 1.0 |
| weights | — |
| hardware | nvidia_nim_api |
| mlx version | — |
| python | — |
| random seed | — |
| msa strategy | none |
| diffusion samples | 1 |
| runtime | — |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
▸citationbibtex
@peptide{pep10620,
sequence = {LPRLLHTDSRMATIDFPKKDPTTSLGRPFFLFRPRN},
target = {glp-1r},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}