Characterization of the human dopamine D3 receptor expressed in transfected cell lines

Robert G. MacKenzie, Donald VanLeeuwen, Thomas A. Pugsley, Yu Hsin Shih, Steve Demattos, Lei Tang, Richard D. Todd, Karen L. O'Malley

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

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 or 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.

Original languageEnglish
Pages (from-to)79-85
Number of pages7
JournalEuropean Journal of Pharmacology: Molecular Pharmacology
Volume266
Issue number1
DOIs
StatePublished - Jan 1 1994

Keywords

  • Arachidonic acid release
  • Dopamine D receptor
  • Dopamine D receptor
  • Inositol phosphate
  • Receptor binding
  • cAMP accumulation

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