Nociceptin (1 - 7) antagonizes nociceptin-induced hyperalgesia in mice

Br J Pharmacol. 1999 Nov;128(5):941-4. doi: 10.1038/sj.bjp.0702898.

Abstract

Nociceptin and its N-terminal fragment, nociceptin (1 7), were administered intrathecally (i.t.) into conscious mice. Nociceptin (3.0 fmol) produced a significant reduction in the nociceptive thermal threshold (hyperalgesia) measured as the tail-flick and paw-withdrawal responses. Nociceptin (1-7), injected i.t., at 150-1200 fmol had no significant effect. However, when nociceptin (1-7) (150 1200 fmol) was injected simultaneously with nociceptin (3.0 fmol), nociceptin-induced hyperalgesia was significantly reduced. Analgesia induced by a high dose (1200 pmol) of nociceptin was not antagonized by co-administration of nociceptin (1-7) (1200 fmol). These results suggest that N-terminal fragments of nociceptin formed endogenously could modulate the hyperalgesic action of nociceptin in the spinal cord.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Hyperalgesia / chemically induced
  • Hyperalgesia / prevention & control*
  • Injections, Intraventricular
  • Injections, Spinal
  • Male
  • Mice
  • Molecular Sequence Data
  • Opioid Peptides / antagonists & inhibitors*
  • Pain Measurement / drug effects
  • Peptide Fragments / administration & dosage
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / pharmacology*
  • Reaction Time / drug effects
  • Receptors, Opioid / metabolism
  • Spinal Cord / drug effects
  • Spinal Cord / metabolism

Substances

  • Opioid Peptides
  • Peptide Fragments
  • Receptors, Opioid
  • nociceptin
  • nociceptin receptor