Cellular neurophysiological actions of nociceptin/orphanin FQ

Peptides. 2000 Jul;21(7):969-76. doi: 10.1016/s0196-9781(00)00235-7.


Cellular actions of nociceptin/orphanin FQ (N/OFQ) resemble those of micro-, delta-, and kappa-opioids, i.e. activation of inwardly rectifying K(+) conductance, inhibition of high-voltage-activated Ca(2+) channel currents, and impediment of neurotransmitter release. Differences in ORL(1) and micro-receptor distribution lead to: 1) more widespread actions of N/OFQ on periaqueductal gray neurons than opioids and 2) differential effects of N/OFQ and opioids in the brainstem. Also, unlike opioids, N/OFQ inhibits T-type Ca(2+) channel current in sensory neurons. Opioids and N/OFQ may modulate glutamate responses in different ways, and certain actions of N/OFQ are potentiated following nerve injury whereas those of micro-opioids are attenuated. Agonists at ORL(1) receptors may therefore be of clinical interest in the management of neuropathic pain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Brain Stem / metabolism
  • Calcium / metabolism
  • Electrophysiology
  • Hippocampus / metabolism
  • Humans
  • Hypothalamus / metabolism
  • Narcotics / agonists
  • Neurons / metabolism
  • Neurotransmitter Agents / metabolism
  • Opioid Peptides / metabolism*
  • Opioid Peptides / physiology*
  • Potassium / metabolism
  • Spinal Cord / metabolism
  • Vasodilator Agents / metabolism
  • Xenopus


  • Narcotics
  • Neurotransmitter Agents
  • Opioid Peptides
  • Vasodilator Agents
  • nociceptin
  • Potassium
  • Calcium