Induction of G protein-coupled receptor kinases 2 and 3 contributes to the cross-talk between mu and ORL1 receptors following prolonged agonist exposure

Neuropharmacology. 2002 Nov;43(6):979-90. doi: 10.1016/s0028-3908(02)00145-4.


The molecular mechanism(s) underlying cross-tolerance between mu and opioid receptor-like 1 (ORL1) receptor agonists were investigated using two human neuroblastoma cell lines endogenously expressing these receptors and G protein-coupled receptor kinases (GRKs). Prolonged (24 h) activation of the mu receptor desensitized both mu and ORL1 receptor-mediated inhibition of forskolin-stimulated cAMP accumulation and upregulated GRK2 levels in SH-SY5Y and BE(2)-C cells. Prolonged ORL1 activation increased GRK2 levels and desensitized both receptors in SH-SY5Y cells. Upregulation of GRK2 correlated with increases in levels of transcription factors Sp1 or AP-2. PD98059, an upstream inhibitor of extracellular signal-regulated kinases 1 and 2 (ERK1/2), reversed all these events. Pretreatment with orphanin FQ/nociceptin (OFQ/N) also upregulated GRK3 levels in both cell lines, and desensitized both receptors in BE(2)-C cells. Protein kinase C (PKC), but not ERK1/2, inhibition blocked OFQ/N-mediated GRK3 induction and mu and ORL1 receptor desensitization in BE(2)-C cells. Antisense DNA treatment confirmed the involvement of GRK2/3 in mu and ORL1 desensitization. Here, we demonstrate for the first time a role for ERK1/2-mediated GRK2 induction in the development of tolerance to mu agonists, as well as cross-tolerance to OFQ/N. We also demonstrate that chronic OFQ/N-mediated desensitization of ORL1 and mu receptors occurs via cell-specific pathways, involving ERK1/2-dependent GRK2, or PKC-dependent and ERK1/2-independent GRK3 induction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analysis of Variance
  • Cell Membrane / metabolism
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / biosynthesis*
  • Cyclic AMP-Dependent Protein Kinases / physiology
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Flavonoids / pharmacology
  • G-Protein-Coupled Receptor Kinase 3
  • Humans
  • Mitogen-Activated Protein Kinases / physiology
  • Morphine / agonists
  • Morphine / pharmacology
  • Neuroblastoma
  • Oligodeoxyribonucleotides, Antisense / pharmacology
  • Opioid Peptides / pharmacology
  • Protein-Serine-Threonine Kinases / biosynthesis*
  • Protein-Serine-Threonine Kinases / physiology
  • Receptor Cross-Talk / physiology*
  • Receptors, Opioid / agonists
  • Receptors, Opioid / physiology*
  • Receptors, Opioid, mu / agonists
  • Receptors, Opioid, mu / physiology*
  • Transcription Factors / drug effects
  • Transcription Factors / metabolism
  • Tumor Cells, Cultured
  • beta-Adrenergic Receptor Kinases


  • Enzyme Inhibitors
  • Flavonoids
  • Oligodeoxyribonucleotides, Antisense
  • Opioid Peptides
  • Receptors, Opioid
  • Receptors, Opioid, mu
  • Transcription Factors
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Morphine
  • nociceptin
  • nociceptin receptor
  • Cyclic AMP
  • Protein-Serine-Threonine Kinases
  • Cyclic AMP-Dependent Protein Kinases
  • G-Protein-Coupled Receptor Kinase 3
  • GRK3 protein, human
  • beta-Adrenergic Receptor Kinases
  • Mitogen-Activated Protein Kinases
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one