Opiorphin: an endogenous human peptide with intriguing application in diverse range of pathologies

Mammalian zinc ectopeptidases have significant functions in deactivating neurological and hormonal peptide signals on the cell surface. The identification of Opiorphin, a physiological inhibitor of zinc ectopeptidases that inactivate enkephalin, has revealed its strong analgesic effects in both chemical and mechanical pain models. Opiorphin achieves this by increasing the transmission of endogenous opioids, which are dependent on the body's own opioid system. The function of opiorphin is closely linked to the rat sialorphin peptide, which inhibits pain perception by enhancing the activity of naturally occurring enkephalinergic pathways that depend on μ- and δ-opioid receptors. Opiorphin is highly intriguing in terms of its physiological implications within the endogenous opioidergic pathways, particularly in its ability to regulate mood-related states and pain perception. Opiorphin can induce antidepressant-like effects by influencing the levels of naturally occurring enkephalin, which are released in response to specific physical and/or psychological stimuli. This effect is achieved through the modulation of delta-opioid receptor-dependent pathways. Furthermore, research has demonstrated that opiorphin's impact on the cardiovascular system is facilitated by the renin-angiotensin system (RAS), sympathetic ganglia, and adrenal medulla, rather than the opioid system. Hence, opiorphin shows great potential as a solitary candidate for the treatment of several illnesses such as neurodegeneration, pain, and mood disorders.