Long-term opiate exposure leads to reduction of the alpha i-1 subunit of GTP-binding proteins

J Neurochem. 1989 Nov;53(5):1636-9. doi: 10.1111/j.1471-4159.1989.tb08562.x.


Desensitization or tolerance is a major consequence of long-term opiate exposure. The mechanism of opiate desensitization is only poorly understood. We report that exposure of rat spinal cord-dorsal root ganglion cocultured neurons to kappa-opiate agonist is accompanied by a 60-70% reduction in the level of the alpha i subunit of GTP-binding proteins. Using selective antibodies, which discriminate among the various alpha i subunit forms, it was found that the opiate treatment leads to a reduction in the amount of the alpha i-1 subunit. The levels of alpha s, alpha o, and beta subunits remain unchanged. This molecular event could underlie the development of tolerance and cross-tolerance to opiates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cells, Cultured
  • GTP-Binding Proteins / metabolism*
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / metabolism
  • Narcotics / pharmacology*
  • Neurons / metabolism
  • Spinal Cord / cytology
  • Spinal Cord / metabolism
  • Time Factors


  • Narcotics
  • GTP-Binding Proteins