ArticleAnnals of the rheumatic diseases2007
Beta-endorphin, Met-enkephalin and corresponding opioid receptors within synovium of patients with joint trauma, osteoarthritis and rheumatoid arthritis.
Article in Annals of the rheumatic diseases, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 42 papers.
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Who cites it
42 citing papers in PubMed, 115 citations in OpenAlex.
- No short term pain benefit of adding corticosteroids to periarticular analgesia after total knee arthroplasty: a prospective, double-blind, randomized controlled trial.Journal of orthopaedic surgery and research · 2026Trial
- Periarticular multimodal drug injection is better than single anesthetic drug in controlling pain after total knee arthroplasty.European journal of orthopaedic surgery & traumatology : orthopedie traumatologie · 2018Trial
- Which analgesic mixture is appropriate for periarticular injection after total knee arthroplasty? Prospective, randomized, double-blind study.Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA · 2015Trial
- Blockade of intra-articular adrenergic receptors increases analgesic demands for pain relief after knee surgery.Rheumatology international · 2011Trial
- Perineural morphine in patients with chronic ischemic lower extremity pain: efficacy and long-term results.Journal of anesthesia · 2009Trial
- Mechanisms of chronic abdominal pain in inflammatory bowel disease and implications for treatment.Nature reviews. Gastroenterology & hepatology · 2026Review
- Article
- Enkephalins and Pain Modulation: Mechanisms of Action and Therapeutic Perspectives.Biomolecules · 2024Review
- Interactions Between Endogenous Opioids and the Immune System.Advances in neurobiology · 2024Review
- A Closer Look at Opioid-Induced Adrenal Insufficiency: A Narrative Review.International journal of molecular sciences · 2023Review
- The Interplay between Chronic Pain, Opioids, and the Immune System.The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry · 2022Review
- Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation.International journal of molecular sciences · 2022Review
- Osteoarthritis-Induced Metabolic Alterations of Human Hip Chondrocytes.Biomedicines · 2022Article
- Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis.Journal of personalized medicine · 2022Article
- The role of intra-articular neuronal CCR2 receptors in knee joint pain associated with experimental osteoarthritis in mice.Arthritis research & therapy · 2021Article
- Peripherally Acting Opioids in Orofacial Pain.Frontiers in neuroscience · 2021Review
- On the Role of Peripheral Sensory and Gut Mu Opioid Receptors: Peripheral Analgesia and Tolerance.Molecules (Basel, Switzerland) · 2020Review
- Opioid Receptors in Immune and Glial Cells-Implications for Pain Control.Frontiers in immunology · 2020Review
- Prostanoid Receptor Subtypes and Its Endogenous Ligands with Processing Enzymes within Various Types of Inflammatory Joint Diseases.Mediators of inflammation · 2020Article
- [Pain inhibition by opioids-new concepts].Schmerz (Berlin, Germany) · 2019Review
Corrections and comments
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Authors and funding
4 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveIntra-articularly applied opioid agonists or antagonists modulate pain after knee surgery and in chronic arthritis. Therefore, the expression of beta-endorphin (END), Met-enkephalin (ENK), and mu and delta opioid receptors (ORs) within synovium of patients with joint trauma (JT), osteoarthritis (OA) and rheumatoid arthritis (RA) were examined.
methodsSynovial samples were subjected to double immunohistochemical analysis of opioid peptides with immune cell markers, and of ORs with the neuronal markers calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH).
resultsEND and ENK were expressed by macrophage-like (CD68(+)) and fibroblast-like (CD68(-)) cells within synovial lining layers of all disorders. In the sublining layers, END and ENK were mostly expressed by granulocytes in patients with JT, and by macrophages/monocytes, lymphocytes and plasma cells in those with OA and RA. Overall, END- and ENK-immunoreactive (IR) cells were more abundant in patients with RA than in those with OA and JT. ORs were found on nerve fibres and immune cells in all patients. OR-IR nerve fibres were significantly more abundant in patients with RA than in those with OA and JT. muORs and deltaORs were coexpressed with CGRP but not with TH.
conclusionsParallel to the severity of inflammation, END and ENK in immune cells and their receptors on sensory nerve terminals are more abundant in patients with RA than in those with JT and OA. These findings are consistent with the notion that, with prolonged and enhanced inflammation, the immune and peripheral nervous systems upregulate sensory nerves expressing ORs and their ligands to counterbalance pain and inflammation.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.