Molecular basis of opioid dependence: role of signal regulation by G-proteins

Clin Exp Pharmacol Physiol. May-Jun 2003;30(5-6):307-16. doi: 10.1046/j.1440-1681.2003.03835.x.


1. Morphine and opiate narcotics are potent analgesics that have a high propensity to induce tolerance and physical dependence following their repeated administration. 2. The molecular basis of opiate dependence has not been completely elucidated, although the participation of opioid receptors is a prerequisite. Cellular dependence on opioids is believed to result from the chronic stimulation of opioid-regulated signalling networks. 3. As G-protein-coupled receptors, the opioid receptors must rely on heterotrimeric G-proteins for signal transduction. Recent advances in our understanding of G-protein signalling have unveiled novel signalling molecules and mechanisms, some of which may be intricately involved in the manifestation of opiate dependence. 4. In the present review, we will attempt to trace chronic opioid signals along elaborate G-protein-regulated pathways.

Publication types

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

MeSH terms

  • Animals
  • GTP-Binding Proteins / chemistry
  • GTP-Binding Proteins / metabolism*
  • Humans
  • Opioid-Related Disorders / metabolism*
  • Receptors, Opioid / metabolism
  • Signal Transduction / physiology*


  • Receptors, Opioid
  • GTP-Binding Proteins