Evidence that N-terminal fragments of nociceptin modulate nociceptin-induced scratching, biting and licking in mice

Neurosci Lett. 2000 Jan 21;279(1):61-4. doi: 10.1016/s0304-3940(99)00958-1.


The intrathecal (i.t.) injection of 3.0 fmol nociceptin (orphanin FQ) elicited scratching, biting and licking responses in mice. N-terminal fragments of nociceptin, nociceptin (1-7), nociceptin (1-9) and nociceptin (1-13), induced no characteristic behavioral response. When these N-terminal fragments of nociceptin were injected simultaneously with nociceptin, the behavioral response induced by nociceptin was reduced dose-dependently. Nociceptin (1-13) was much more potent than nociceptin (1-7) and nociceptin (1-9) and antagonized nociceptin-induced response at equimolar doses. No significant effects of the N-terminal fragments were observed against the scratching, biting and licking response elicited by i.t. administration of substance P or N-methyl-D-aspartate. These results suggest that N-terminal fragments formed endogenously in the spinal cord may have an antagonistic effect on nociceptin-induced behavioral responses.

MeSH terms

  • Animals
  • Bites and Stings / chemically induced*
  • Bites and Stings / physiopathology
  • Grooming / drug effects*
  • Grooming / physiology
  • Male
  • Mice
  • Nociceptors / drug effects
  • Nociceptors / physiology
  • Opioid Peptides / chemistry
  • Opioid Peptides / pharmacology*
  • Opioid Peptides / physiology
  • Peptide Fragments / pharmacology*
  • Pruritus / chemically induced*
  • Pruritus / physiopathology
  • Spinal Cord / drug effects
  • Spinal Cord / physiology
  • Vasodilator Agents / chemistry
  • Vasodilator Agents / pharmacology


  • Opioid Peptides
  • Peptide Fragments
  • Vasodilator Agents
  • nociceptin