Endogenous opioid receptor-like receptor in human neuroblastoma SK-N-SH cells: activation of inhibitory G protein and homologous desensitization

Neuroreport. 1997 May 27;8(8):1913-8. doi: 10.1097/00001756-199705260-00024.


Endogenous expression of opioid receptor-like receptor (ORL1), in human neuroblastoma SK-N-SH cells was demonstrated by binding with nociceptin/ orphanin FQ (N/OFQ). Scatchard analysis of [3H]N/ OFQ saturation binding data gave Kd = 1.3 +/- 0.1 nM and Bmax = 1.58 +/- 2.5 fmol/mg protein. N/OFQ stimulation increased [35S]GTP gamma S binding to cell membranes and attenuated forskolin-induced cAMP accumulation in a concentration-dependent manner. The effects of N/OFQ were eliminated by the pretreatment of pertussis toxin (PTX) but not by the antagonists of opioid receptors, revealing mediation of N/OFQ signal transduction by ORL1 receptor and PTX sensitive G protein(s). The ability of N/OFQ to inhibit cAMP production was greatly reduced after prechallenging with N/OFQ, indicating that ORL1 undergoes homologous desensitization in neuronal cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Neoplasms / metabolism*
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Humans
  • Kinetics
  • Neuroblastoma / metabolism*
  • Opioid Peptides / pharmacology
  • Receptors, Opioid / agonists
  • Receptors, Opioid / biosynthesis
  • Receptors, Opioid / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Sulfur Radioisotopes
  • Tumor Cells, Cultured


  • Opioid Peptides
  • Receptors, Opioid
  • Sulfur Radioisotopes
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • nociceptin
  • nociceptin receptor
  • GTP-Binding Proteins