Spinorphin Explained

Spinorphin is an endogenous, non-classical opioid peptide of the hemorphin family^[1] first isolated from the bovine spinal cord (hence the prefix spin-)^[2] and acts as a regulator of the enkephalinases, a class of enzymes that break down endogenous the enkephalin peptides.^[3] It does so by inhibiting the enzymes aminopeptidase N (APN), dipeptidyl peptidase III (DPP3), angiotensin-converting enzyme (ACE), and neutral endopeptidase (NEP). Spinorphin is a heptapeptide and has the amino acid sequence Leu-Val-Val-Tyr-Pro-Trp-Thr (LVVYPWT). It has been observed to possess antinociceptive,^[4] antiallodynic,^[4] and anti-inflammatory properties.^[1] The mechanism of action of spinorphin has not been fully elucidated (i.e., how it acts to inhibit the enkephalinases), but it has been found to act as an antagonist of the P2X₃ receptor,^[5] and as a weak partial agonist/antagonist of the FP₁ receptor.^[1]

See also

• Enkephalinase inhibitor

Notes and References

1. Liang TS, Gao JL, Fatemi O, Lavigne M, Leto TL, Murphy PM . The endogenous opioid spinorphin blocks fMet-Leu-Phe-induced neutrophil chemotaxis by acting as a specific antagonist at the N-formylpeptide receptor subtype FPR . Journal of Immunology . 167 . 11 . 6609–14 . December 2001 . 11714831 . 10.4049/jimmunol.167.11.6609. free .
2. Nishimura K, Hazato T . [Spinorphin, a new inhibitor of enkephalin-degrading enzymes derived from the bovine spinal cord] . ja . Masui. The Japanese Journal of Anesthesiology . 42 . 10 . 1497–503 . October 1993 . 8230703 .
3. Nishimura K, Hazato T . Isolation and identification of an endogenous inhibitor of enkephalin-degrading enzymes from bovine spinal cord . Biochemical and Biophysical Research Communications . 194 . 2 . 713–9 . July 1993 . 8343155 . 10.1006/bbrc.1993.1880 .
4. Honda M, Okutsu H, Matsuura T, etal . Spinorphin, an endogenous inhibitor of enkephalin-degrading enzymes, potentiates leu-enkephalin-induced anti-allodynic and antinociceptive effects in mice . Japanese Journal of Pharmacology . 87 . 4 . 261–7 . December 2001 . 11829145 . 10.1254/jjp.87.261. free .
5. Jung KY, Moon HD, Lee GE, Lim HH, Park CS, Kim YC . Structure-activity relationship studies of spinorphin as a potent and selective human P2X(3) receptor antagonist . Journal of Medicinal Chemistry . 50 . 18 . 4543–7 . September 2007 . 17676725 . 10.1021/jm070114m .