Role of endogenous melatoninergic system in development of hyperalgesia and tolerance induced by chronic morphine administration in rats.

Abstract

Morphine is a widely used analgesic for various types of pain. However, its efficacy is impeded by development of hyperalgesia and tolerance. Melatonin has antinociceptive effect and is involved in morphine-induced hyperalgesia and tolerance but the mechanism of its involvement remains to be defined. In this study, we established a rat model of morphine-induced hyperalgesia and tolerance. We determined the serum level of melatonin and expression of μ-opioid receptor (MOR), melatonin receptor (MT1, MT2) and protein kinase C γ(PKCγ) in the spinal dorsal horn of the rats with morphine-induced hyperalgesia and tolerance. Comparing with control group (n=6), the group (n=6) of rats with morphine-induced hyperalgesia and tolerance exhibited a significant lower serum melatonin level, reduction in expression of the MT1, but up-regulation of the PKCγ in the spinal dorsal horn. These results may facilitate revealing the mechanism of opioid-induced hyperalgesia and tolerance and exploring new therapeutic remedy for pain management.

• Authors: Yuchao Fan, Xiao Liang, Rurong Wang, Li Song
• Journal: Brain research bulletin (Brain Res Bull) Vol. 135 Pg. 105-112 (Oct 2017) ISSN: 1873-2747 [Electronic] United States
• PMID: 28988976 (Publication Type: Journal Article)
• Copyright: Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical References

• Analgesics
• Analgesics, Opioid
• Receptors, Melatonin
• Receptors, Opioid, mu
• Morphine
• protein kinase C gamma
• Protein Kinase C
• Melatonin

Topics

• Analgesics (pharmacology)
• Analgesics, Opioid (pharmacology)
• Animals
• Disease Models, Animal
• Drug Tolerance (physiology)
• Hyperalgesia (drug therapy, metabolism, physiopathology)
• Male
• Melatonin (analysis, blood, metabolism, physiology)
• Morphine (metabolism, pharmacology)
• Pain (drug therapy)
• Pain Management
• Pain Measurement (drug effects)
• Protein Kinase C (metabolism)
• Rats
• Rats, Sprague-Dawley
• Receptors, Melatonin (metabolism)
• Receptors, Opioid, mu (metabolism)
• Spinal Cord (metabolism)
• Spinal Cord Dorsal Horn (metabolism)