Neuropeptide B-23

Where it comes from

Made in

Hippocampus, hypothalamus and the adrenal, with its transcript in the spinal cord

Sent out by

Pain and stress

Acts on

• Pain circuits of the spinal cord
• Hypothalamus (feeding, stress hormones)
• Amygdala

What it does

• Reduces inflammatory pain when given spinally ²
• Takes part in feeding and the stress response ³
• Mice without it gain weight in adulthood and feel inflammatory pain more keenly; the bromine is not needed for activity, and what adds it is unknown ¹²

In medicine

• No medicine copies it or blocks it, and it is not measured in people
• It is the only mammalian peptide known to carry a bromine atom, which makes it a curiosity rather than a target: no enzyme that puts the bromine on has been found ¹

Beyond the body’s own use

• Nothing containing it is in trials, approved or obtainable outside the laboratory
• Mice that cannot make it feel inflammatory pain more keenly and gain weight in adulthood, so the peptide appears to restrain both; the bromine is needed for neither effect, since the plain peptide is as active in the assays used ¹²
• What is unknown is what the bromine is for. It is the one chemical feature that sets this peptide apart from every other mammalian neuropeptide, and nothing explains why a brain would spend a halogen on it ¹