Neuromedin S

Where it comes from

Made in

The suprachiasmatic nucleus of the hypothalamus; spleen and testis

Sent out by

With the day-night rhythm

Acts on

• Suprachiasmatic nucleus
• Hypothalamic feeding circuits
• Smooth muscle

What it does

• Shifts circadian rhythm in animals: injected into the brain at the right hour it moves the whole behavioural clock ¹
• Reduces food intake when given into the brain, as neuromedin U does, through the same two receptors ¹
• Stimulates oxytocin and vasopressin release in rats, which neuromedin U does not do as strongly

In medicine

• None: no medicine, no clinical assay, and no disease traced to it
• Because it shares its active tail with neuromedin U, antibodies and receptor assays built for one read the other, and much older work cannot be assigned to either

Beyond the body’s own use

• Not in human trials, and no analogue has been made as a candidate medicine
• The open question is whether the two peptides divide the work or duplicate it. They bind the same receptors, yet neuromedin S is concentrated in the clock nucleus and neuromedin U is not, which is the strongest hint that the difference is one of place rather than of signal ¹