Local analgesic effect of endogenous opioid peptides

Title

Local analgesic effect of endogenous opioid peptides

Creator

Stein C; Hassan AH; Lehrberger K; Giefing J; Yassouridis A

Publisher

Lancet

Date

1993

Subject

Humans; Pain; Adult; Aged; Middle Aged; Double-Blind Method; Biomarkers of Pain; Injections; Intravenous; Receptors; Opioid/drug effects; Immunohistochemistry; Enkephalin; Arthroscopy; beta-Endorphin/analysis/physiology; Dynorphins/analysis/physiology; Endorphins/analysis/physiology; Intra-Articular; Knee Joint/surgery; Methionine/analysis/physiology; Naloxone/administration & dosage/pharmacology; Postoperative/etiology; Synovial Membrane/chemistry; Synovitis/metabolism

Description

Opioids produce analgesia by interacting with local opioid receptors in peripheral inflamed tissue. This study investigated whether endogenous ligands of these receptors are present in synovia and whether such opioid peptides can inhibit pain by activation of intra-articular opioid receptors. Samples of synovium from 8 patients undergoing arthroscopic knee surgery were examined by immunohistochemistry for the presence of beta-endorphin, met-enkephalin, and dynorphin. All tissue samples showed synovitis. Inflammatory cells stained strongly for beta-endorphin and met-enkephalin but not for dynorphin. To find out whether blockade of intra-articular opioid receptors affected pain, we randomly assigned 22 patients undergoing arthroscopic knee surgery to receive naloxone (0.04 mg) intra-articularly (n = 10) or intravenously (n = 12); each patient received a placebo injection into the other site. Postoperative pain was assessed by visual analogue scale, a numerical rating scale, the McGill pain questionnaire, and supplementary analgesic consumption during the next 24 h. All pain scores were higher in the intra-articular naloxone group than in the intravenous naloxone group. The differences were significant (p < 0.05) during the first 4 h. Supplementary analgesic consumption was significantly higher in the intra-articular group (52.5 [14.0] vs 15.6 [8.0] mg diclofenac, p < 0.05). Opioid peptides are present in inflamed synovial tissue and can inhibit pain after knee surgery through an action specific to intra-articular opioid receptors. These findings expand the gate control theory of pain and suggest new approaches such as the development of peripherally acting opioid analgesics without central side-effects.
1993

Rights

Article information provided for research and reference use only. PedPalASCNET does not hold any rights over the resource listed here. All rights are retained by the journal listed under publisher and/or the creator(s).

Type

Journal Article

Citation List Month

Backlog

Pages

321-324

Issue

8867

Volume

342

Citation

Stein C; Hassan AH; Lehrberger K; Giefing J; Yassouridis A, “Local analgesic effect of endogenous opioid peptides,” Pediatric Palliative Care Library, accessed October 24, 2021, https://pedpalascnetlibrary.omeka.net/items/show/12302.

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