Pharmacological analysis of a dopamine D(2Short):G(alphao) fusion protein expressed in Sf9 cells

FEBS Lett. 2003 Jun 19;545(2-3):155-60. doi: 10.1016/s0014-5793(03)00520-9.

Abstract

A dopamine D(2Short) receptor:G(alphao) fusion protein was expressed in Sf9 cells using the baculovirus expression system. [(3)H]Spiperone bound to D(2Short):G(alphao) with a pK(d) approximately 10. Dopamine stimulated the binding of [(35)S]guanosine-5'-O-(3-thio)triphosphate (GTPgammaS) to D(2Short):G(alphao) expressed with Gbeta(1)gamma(2) (E(max)>460%; pEC(50) 5.43+/-0.06). Most of the putative D(2) antagonists behaved as inverse agonists (suppressing basal [(35)S]GTPgammaS binding) at D(2Short):G(alphao)/Gbeta(1)gamma(2) although (-)-sulpiride and ziprasidone were neutral antagonists. Competition of [(3)H]spiperone binding by dopamine and 10,11-dihydroxy-N-n-propylnorapomorphine revealed two binding sites of different affinities, even in the presence of GTP (100 micro M). The D(2Short):G(alphao) fusion protein is therefore a good model for characterising D(2) receptors.

Publication types

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

MeSH terms

  • Animals
  • Apomorphine / analogs & derivatives*
  • Apomorphine / pharmacology
  • Baculoviridae
  • Binding Sites
  • Binding, Competitive
  • Cell Line
  • Dopamine Agonists / pharmacology
  • Dopamine Antagonists / pharmacology
  • Drug Interactions
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Humans
  • Ligands
  • Receptors, Dopamine D2 / analysis
  • Receptors, Dopamine D2 / metabolism*
  • Recombinant Fusion Proteins / drug effects
  • Recombinant Fusion Proteins / metabolism*
  • Spiperone / pharmacology
  • Spodoptera

Substances

  • 10,11-dihydroxy-N-n-propylnorapomorphine
  • Dopamine Agonists
  • Dopamine Antagonists
  • Ligands
  • Receptors, Dopamine D2
  • Recombinant Fusion Proteins
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Spiperone
  • GTP-Binding Proteins
  • Apomorphine