Nociceptin/Orphanin FQ Opioid Peptide-Receptor Expression in the Endometriosis-Associated Nerve Fibers—Possible Treatment Option?

Qihui Guan, Renata Voltolini Velho, Alice Jordan, Sabrina Pommer, Irene Radde, Jalid Sehouli, Sylvia Mechsner
Cells · 2023 · vol. 12(10) , pp. 1395 · doi:10.3390/cells12101395 · PMID:37408230 · W4376645263
article OA: gold CC0 ⤵ 2 in-corpus citations
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⚙ AI-generated summary by claude@2026-06, 2026-06-08 ⓘ

This study found increased nociceptin/orphanin FQ peptide receptor expression in endometriosis-associated nerve fibers, suggesting a potential target for treating chronic pelvic pain.

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Abstract

Endometriosis (EM) is a chronic inflammatory disease affecting millions of women worldwide. Chronic pelvic pain is one of the main problems of this condition, leading to quality-of-life impairment. Currently, available treatment options are not able to treat these women accurately. A better understanding of the pain mechanisms would be beneficial to integrate additional therapeutic management strategies, especially specific analgesic options. To understand pain in more detail, nociceptin/orphanin FQ peptide (NOP) receptor expression was analyzed in EM-associated nerve fibers (NFs) for the first time. Laparoscopically excised peritoneal samples from 94 symptomatic women (73 with EM and 21 controls) were immunohistochemically stained for NOP, protein gene product 9.5 (PGP9.5), substance P (SP), calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP). Peritoneal NFs of EM patients and healthy controls were positive for NOP and often colocalized with SP-, CGRP-, TH-, and VIP-positive nerve fibers, suggesting that NOP is expressed in sensory and autonomic nerve fibers. In addition, NOP expression was increased in EM associate NF. Our findings highlight the potential of NOP agonists, particularly in chronic EM-associated pain syndromes and deserve further study, as the efficacy of NOP-selective agonists in clinical trials.

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Condition tags

mesh:D004715endometriosischronic_pelvic_pain

MeSH descriptors

Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain Chronic Pain

Citation neighborhood

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. [ expand to 2 hops ] — adds papers reached through this work's immediate citers/citees. Heavier; up to 60 extra dots.

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