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Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats
PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems u...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Yonsei University College of Medicine
2013
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635624/ https://www.ncbi.nlm.nih.gov/pubmed/23549827 http://dx.doi.org/10.3349/ymj.2013.54.3.763 |
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author | Lee, Heeseung |
author_facet | Lee, Heeseung |
author_sort | Lee, Heeseung |
collection | PubMed |
description | PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems using selective opioid receptor antagonists in rat formalin tests. MATERIALS AND METHODS: I.t. N/OFQ was injected in different doses (1-10 nmol) via a lumbar catheter prior to a 50 µL injection of 5% formalin into the right hindpaw of rats. Flinching responses were measured from 0-10 min (phase I, an initial acute state) and 11-60 min (phase II, a prolonged tonic state). To observe which opioid receptors are involved in the anti-nociceptive effect of i.t. N/OFQ in the rat-formalin tests, naltrindole (5-20 nmol), β-funaltrexamine (1-10 nmol), and norbinaltorphimine (10 nmol), selective δ-, µ- and κ-opioid receptor antagonists, respectively, were administered intrathecally 5 min after i.t. N/OFQ. RESULTS: I.t. N/OFQ attenuated the formalin-induced flinching responses in a dose-dependent manner in both phases I and II. I.t. administration of naltrindole and β-funaltrexamine dose-dependently reversed the N/OFQ-induced attenuation of flinching responses in both phases; however, norbinaltorphimine did not. CONCLUSION: I.t. N/OFQ exerted an antinociceptive effect in both phases of the rat-formalin test through the nociceptin opioid peptide receptor. In addition, the results suggested that δ- and µ-opioid receptors, but not κ-opioid receptors, are involved in the antinociceptive effects of N/OFQ in the spinal cord of rats. |
format | Online Article Text |
id | pubmed-3635624 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Yonsei University College of Medicine |
record_format | MEDLINE/PubMed |
spelling | pubmed-36356242013-05-02 Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats Lee, Heeseung Yonsei Med J Original Article PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems using selective opioid receptor antagonists in rat formalin tests. MATERIALS AND METHODS: I.t. N/OFQ was injected in different doses (1-10 nmol) via a lumbar catheter prior to a 50 µL injection of 5% formalin into the right hindpaw of rats. Flinching responses were measured from 0-10 min (phase I, an initial acute state) and 11-60 min (phase II, a prolonged tonic state). To observe which opioid receptors are involved in the anti-nociceptive effect of i.t. N/OFQ in the rat-formalin tests, naltrindole (5-20 nmol), β-funaltrexamine (1-10 nmol), and norbinaltorphimine (10 nmol), selective δ-, µ- and κ-opioid receptor antagonists, respectively, were administered intrathecally 5 min after i.t. N/OFQ. RESULTS: I.t. N/OFQ attenuated the formalin-induced flinching responses in a dose-dependent manner in both phases I and II. I.t. administration of naltrindole and β-funaltrexamine dose-dependently reversed the N/OFQ-induced attenuation of flinching responses in both phases; however, norbinaltorphimine did not. CONCLUSION: I.t. N/OFQ exerted an antinociceptive effect in both phases of the rat-formalin test through the nociceptin opioid peptide receptor. In addition, the results suggested that δ- and µ-opioid receptors, but not κ-opioid receptors, are involved in the antinociceptive effects of N/OFQ in the spinal cord of rats. Yonsei University College of Medicine 2013-05-01 2013-03-19 /pmc/articles/PMC3635624/ /pubmed/23549827 http://dx.doi.org/10.3349/ymj.2013.54.3.763 Text en © Copyright: Yonsei University College of Medicine 2013 http://creativecommons.org/licenses/by-nc/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Article Lee, Heeseung Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title | Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title_full | Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title_fullStr | Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title_full_unstemmed | Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title_short | Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats |
title_sort | effects of co-administration of intrathecal nociceptin/orphanin fq and opioid antagonists on formalin-induced pain in rats |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635624/ https://www.ncbi.nlm.nih.gov/pubmed/23549827 http://dx.doi.org/10.3349/ymj.2013.54.3.763 |
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