Loss of antinociception induced by naloxone benzoylhydrazone in nociceptin receptor-knockout mice.

Abstract

Nociceptin and nociceptin receptor, which show structural similarities to opioid peptides and opioid receptors, respectively, have been recently found to constitute a novel neuromodulatory system. In the brain, however, the physiological role of the modulation via the nociceptin receptor is still unclear. Administered nociceptin produces hyperalgesia and hypolocomotion, whereas the nociceptin receptor-knockout mice show no significant abnormalities in nociceptive thresholds and locomotion. To clarify possible involvement of the nociceptin receptor in the regulation of nociception and locomotion, we made use of the knockout mice and naloxone benzoylhydrazone (NalBzoH) identified originally as a ligand for opioid receptors. Experiments on the cultured cells transfected with the nociceptin receptor cDNA showed that NalBzoH competed with [3H]nociceptin binding and attenuated the nociceptin-induced inhibition of cAMP accumulation. Furthermore, behavioral studies demonstrated that NalBzoH completely inhibited nociceptin-induced hyperalgesia and hypolocomotion. It is therefore likely that NalBzoH can act as a potent antagonist for the nociceptin receptor in vivo. In wild-type mice, NalBzoH induced antinociception but did not affect locomotor activity. In contrast, in the knockout mice, no significant changes in nociception and locomotion were induced by NalBzoH. These results clearly suggest that the nociceptin system takes part in the physiological regulation of nociceptive thresholds but not in the basal modulation of locomotion.

• Authors: Y Noda, T Mamiya, T Nabeshima, M Nishi, M Higashioka, H Takeshima
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 273 Issue 29 Pg. 18047-51 (Jul 17 1998) ISSN: 0021-9258 [Print] United States
• PMID: 9660760 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ligands
• Narcotic Antagonists
• Opioid Peptides
• Receptors, Opioid
• naloxone benzoylhydrazone
• Naloxone
• nociceptin
• Cyclic AMP
• Nociceptin Receptor

Topics

• Animals
• CHO Cells
• Cricetinae
• Cyclic AMP (metabolism)
• Ligands
• Locomotion (drug effects)
• Mice
• Mice, Knockout
• Naloxone (analogs & derivatives, pharmacology)
• Narcotic Antagonists (pharmacology)
• Opioid Peptides (physiology)
• Pain
• Rats
• Receptors, Opioid (physiology)
• Nociceptin Receptor