Drug-induced up-regulation of dopamine D2 receptors on cultured cells

S. Starr, L. B. Kozell, Kim Neve

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Ligand-induced up-regulation of recombinant dopamine D2 receptors was assessed using C6 glioma cells stably expressing the shod (415-amino-acid; D2(s)) and long (444-amino-acid; D2(L)) forms of the receptor. Overnight treatment of C6-D2(L) cells with N-propylnor-apomorphine (NPA) caused a time- and concentration-dependent increase in the density of receptors, as assessed by the binding of radioligand to membranes prepared from the cells, with no change in the affinity of the receptors for the radioligand. The effect of 10 μM NPA was maximal after 10 h, at which time the density of D2(L) receptors was more than doubled. The agonists dopamine and quinpirole also increased the density of D2(L) receptors. The receptor up-regulation was not specific for agonists, because the antagonists epidepride, sulpiride, and domperidone caused smaller (30-60%) increases in receptor density. Prolonged treatment with 10 μM NPA desensitized D2(L) receptors, as evidenced by a reduced ability of dopamine to inhibit adenylyl cyclase, whereas treatment with sulpiride was associated with an enhanced responsiveness to dopamine. The magnitude of NPA-induced receptor up-regulation in each of four clonal lines of C6-D2(L) cells (mean increase, 80%) was greater than in all four lines of C6-D2(s) cells (33%). Inactivation of pertussis toxin-sensitive G proteins had no effect on the basal density of D2(L) receptors or on the NPA- induced receptor up-regulation. Treatment with 5 μg/ml of cycloheximide, on the other hand, decreased the basal density of receptors and attenuated, but did not prevent, the NPA-induced increase. Chimeric D1/D2 receptors were used to identify structural determinants of dopamine receptor regulation. Treatment with the D1/D2 agonist NPA decreased the density of D1 and chimeric CH4 and CH3 receptors. The latter two receptors have D1 sequence from the amino-terminus to the amino-terminal end of transmembrane region (TM) VII and VI, respectively. CH2, with D1 sequence up to the amino-terminal end of TM V, and thus the third cytoplasmic loop of the D2 receptor, was up-regulated by NPA or the D2-selective agonist quinpirole. Quinpirole treatment decreased the density of CH3 and had no effect on CH4 or D1 receptors. The different responses of CH2 and CH3 to agonist treatment suggest a role for TM V and the third cytoplasmic loop in the direction of receptor regulation.

Original languageEnglish (US)
Pages (from-to)569-577
Number of pages9
JournalJournal of Neurochemistry
Volume65
Issue number2
StatePublished - 1995

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Dopamine D2 Receptors
Apomorphine
Cultured Cells
Up-Regulation
Cells
Quinpirole
Pharmaceutical Preparations
Sulpiride
Dopamine
Domperidone
L Forms
Amino Acids
Dopamine Agonists
Pertussis Toxin
Dopamine Receptors
Cycloheximide
GTP-Binding Proteins
Adenylyl Cyclases
Glioma
Cell Membrane

Keywords

  • cDNA
  • Chimeric receptors
  • Dopamine
  • Dopamine D2 receptors

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Drug-induced up-regulation of dopamine D2 receptors on cultured cells. / Starr, S.; Kozell, L. B.; Neve, Kim.

In: Journal of Neurochemistry, Vol. 65, No. 2, 1995, p. 569-577.

Research output: Contribution to journalArticle

Starr, S. ; Kozell, L. B. ; Neve, Kim. / Drug-induced up-regulation of dopamine D2 receptors on cultured cells. In: Journal of Neurochemistry. 1995 ; Vol. 65, No. 2. pp. 569-577.
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