dextro- and levo-morphine attenuate opioid δ and κ receptor agonist produced analgesia in μ-opioid receptor knockout mice

Hsiang En Wu, Han Sen Sun, Maia Terashivili, Emma Schwasinger, Ichiro Sora, F. Scott Hall, George R. Uhl, Leon F. Tseng

Research output: Contribution to journalArticle

Abstract

We have demonstrated that the antianalgesia induced by dextro-morphine and levo-morphine is not mediated by the stimulation of μ-opioid receptors in male CD-1 mice. We now report that the dextro-morphine and levo-morphine attenuated antinociception produced by δ-opioid receptor agonist deltorphin II and κ-opioid receptor agonist U50,488H given spinally in the male μ-opioid receptor knockout mice. The tail-flick response was used for the antinociceptive test. Intrathecal injection of levo-morphine (3 nmol) markedly inhibited the tail-flick response in wild type, partially in heterozygous, but not in homozygous μ-opioid receptor knockout mice. Intrathecal pretreatment with dextro-morphine (33 fmol) or levo-morphine (0.3 nmol) for 45 min also attenuated levo-morphine-produced antinociception in wide type mice. Intrathecal pretreatment with dextro-morphine (33 fmol) or levo-morphine (0.3 nmol) for 45 min attenuated the tail-flick inhibition produced by deltorphin II (12.8 nmol) and U50,488H (123.3 nmol) in wide type, heterozygous and homozygous μ-opioid receptor knockout mice. The findings provide additional evidence that μ-opioid receptors are not involved in the antianalgesia induced by dextro-morphine and levo-morphine.

Original languageEnglish (US)
Pages (from-to)103-107
Number of pages5
JournalEuropean Journal of Pharmacology
Volume531
Issue number1-3
DOIs
StatePublished - Feb 15 2006
Externally publishedYes

Keywords

  • Analgesia
  • Antianalgesia
  • Knockout mice
  • Opioid
  • Spinal cord

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Pharmacology

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  • Cite this

    Wu, H. E., Sun, H. S., Terashivili, M., Schwasinger, E., Sora, I., Scott Hall, F., Uhl, G. R., & Tseng, L. F. (2006). dextro- and levo-morphine attenuate opioid δ and κ receptor agonist produced analgesia in μ-opioid receptor knockout mice. European Journal of Pharmacology, 531(1-3), 103-107. https://doi.org/10.1016/j.ejphar.2005.12.012