Characterization of the Human Dopamine D3 Receptor Expressed in Transfected Cell Lines

Eur J Pharmacol. 1994 Jan 1;266(1):79-85. doi: 10.1016/0922-4106(94)90212-7.

Abstract

A full-length cDNA clone of the human dopamine D3 receptor was obtained by the polymerase chain reaction (PCR) using reverse-transcribed RNA from human brain as the template. The cDNA was inserted into an expression vector which was then stably transfected into either Chinese hamster ovary (CHO), SK-N-MC human epithelioma or mouse CCL1.3 fibroblast cell lines. Post-transfection, the Bmax for D3 receptor expression was 1.9, 1.1 and 0.4 pmol/mg protein in the CHO-K1, SK-N-MC and CCL1.3 cell lines, respectively. The D3 receptor expressed in CHO-K1 and CCL1.3 cells exhibited similar radioligand binding profiles, especially for the D3-selective compound, 7-hydroxy-2-(di-n-propylamino)tetralin (7-OH-DPAT). Radioligand-binding competition curves of presumed D3 agonists were shifted to the right by the addition of guanine nucleotides and Na+ to the assay buffer. Presumed D3-receptor agonists had no effect on cAMP accumulation in any of the D3-transfected cell lines although cAMP accumulation was inhibited by dopamine D2 receptor activation in D2-transfected CHO and CCL1.3 cells and by activation of the exogenously expressed neuropeptide Y receptor in SK-N-MC cells. Also, D3 receptor activation neither potentiated ATP-stimulated arachidonic acid release from CHO cells nor stimulated inositol phosphate production in CCL1.3-cells although both of these responses were elicited by D2 agonists in D2-transfected cells. We conclude that the signalling properties of the D3 receptor differ from those of its closest homolog, the D2 receptor.

MeSH terms

  • Animals
  • Arachidonic Acid / metabolism*
  • Binding, Competitive
  • CHO Cells
  • Cell Line
  • Cloning, Molecular
  • Cricetinae
  • Cricetulus
  • Cyclic AMP / metabolism*
  • Dopamine Agents / metabolism
  • Dopamine Agents / pharmacology*
  • Dopamine Antagonists
  • Dopamine D2 Receptor Antagonists
  • Humans
  • Inositol Phosphates / metabolism*
  • Mice
  • Radioligand Assay
  • Receptors, Dopamine / metabolism*
  • Receptors, Dopamine D2 / metabolism
  • Receptors, Dopamine D3
  • Tetrahydronaphthalenes / metabolism
  • Transfection

Substances

  • DRD3 protein, human
  • Dopamine Agents
  • Dopamine Antagonists
  • Dopamine D2 Receptor Antagonists
  • Drd3 protein, mouse
  • Inositol Phosphates
  • Receptors, Dopamine
  • Receptors, Dopamine D2
  • Receptors, Dopamine D3
  • Tetrahydronaphthalenes
  • Arachidonic Acid
  • Cyclic AMP
  • 7-hydroxy-2-N,N-dipropylaminotetralin