neuropeptidek

Neuropeptide K (NPK) is a neuropeptide derived from the neurotensin (NT) precursor protein in vertebrates. It is produced by proteolytic processing of prepro-neurotensin and is released together with neurotensin from NT-expressing neurons in the brain and gut. It is detected in various brain regions and peripheral tissues such as the gastrointestinal tract.

NPK acts as a signaling molecule by interacting with neurotensin receptors. It functions as a ligand within the neurotensinergic system, with activity related to the broader effects of neurotensin. The exact receptor affinities and signaling properties may differ from full-length neurotensin and can vary by tissue.

Physiological roles attributed to neuropeptide K include modulation of nociception, locomotor and behavioral responses, feeding and energy balance, thermoregulation, and gastrointestinal motility. It may contribute to dopaminergic signaling in reward pathways and to neuroendocrine regulation, although the specifics are still under investigation.

In research contexts, NPK is studied as part of the neurotensinergic system and as a potential biomarker in certain conditions. Quantification is performed using immunoassays or mass spectrometry in brain tissue, cerebrospinal fluid, or plasma. There are currently no approved clinical applications of neuropeptide K as a drug, and much of its biology remains to be clarified.