Opiorphin pentapeptide originates from the N-terminal region of the protein PROL1 (proline-rich, lacrimal 1).[3] Opiorphin inhibits three proteases: neutral ecto-endopeptidase (MME), ecto-aminopeptidase N (ANPEP)[3]
and perhaps also a dipeptidyl peptidase DPP3.[8]
Such action extends the duration of enkephalin effect where the natural pain killers are released physiologically in response to specific potentially painful stimuli, in contrast with administration of narcotics, which floods the entire body and causes many undesirable adverse reactions, including addiction liability and constipation.[11][12]
In addition, opiorphin may exert anti-depressive[13][14] and antipanic action.[15]
Therapeutic application of opiorphin in humans would require modifying the molecule to avoid its rapid degradation in the intestine and its poor penetration of the blood–brain barrier.[11][12] This modification is done in the body by transformation of N-terminal glutamine into pyroglutamate. This form preserves the analgesic properties of opiorphin but with increased pharmaceutical stability.[16]
^Rougeot C, Robert F, Menz L, Bisson JF, Messaoudi M (August 2010). "Systemically active human opiorphin is a potent yet non-addictive analgesic without drug tolerance effects". J. Physiol. Pharmacol. 61 (4): 483–490. PMID20814077.
^ abcDickinson DP, Thiesse M (April 1996). "cDNA cloning of an abundant human lacrimal gland mRNA encoding a novel tear protein". Curr. Eye Res. 15 (4): 377–386. doi:10.3109/02713689608995828. PMID8670737.
^Stanović S, Boranić M, Petrovecki M, et al. (2000). "Thiorphan, an inhibitor of neutral endopeptidase/enkephalinase (CD10/CALLA) enhances cell proliferation in bone marrow cultures of patients with acute leukemia in remission". Haematologia (Budap). 30 (1): 1–10. doi:10.1163/15685590051129814. PMID10841318.
^ abThanawala V, Kadam VJ, Ghosh R (October 2008). "Enkephalinase inhibitors: potential agents for the management of pain". Curr Drug Targets. 9 (10): 887–894. doi:10.2174/138945008785909356. PMID18855623.
^Tian XZ, Chen J, Xiong W, He T, Chen Q (July 2009). "Effects and underlying mechanisms of human opiorphin on colonic motility and nociception in mice". Peptides. 30 (7): 1348–1354. doi:10.1016/j.peptides.2009.04.002. PMID19442408. S2CID32291165.
^Yang QZ, Lu SS, Tian XZ, Yang AM, Ge WW, Chen Q (February 2011). "The antidepressant-like effect of human opiorphin via opioid-dependent pathways in mice". Neurosci. Lett. 489 (2): 131–135. doi:10.1016/j.neulet.2010.12.002. PMID21145938. S2CID22544303.
^Maraschin, Jhonatan Christian; Rangel, Marcel Pereira; Bonfim, Antonio Joaquim; Kitayama, Mariana; Graeff, Frederico Guilherme; Zangrossi Jr., Hélio; Audi, Elisabeth Aparecida (2016-02-01). "Opiorphin causes a panicolytic-like effect in rat panic models mediated by μ-opioid receptors in the dorsal periaqueductal gray". Neuropharmacology. 101: 264–270. doi:10.1016/j.neuropharm.2015.09.008. PMID26363194. S2CID34867419.
^Sitbon, Philippe; Van Elstraete, Alain; Hamdi, Leila; Juarez-Perez, Victor; Mazoit, Jean-Xavier; Benhamou, Dan; Rougeot, Catherine (2016-11-01). "STR-324, a Stable Analog of Opiorphin, Causes Analgesia in Postoperative Pain by Activating Endogenous Opioid Receptor-dependent Pathways". Anesthesiology. 125 (5): 1017–1029. doi:10.1097/ALN.0000000000001320. ISSN1528-1175. PMID27571257. S2CID36827893.