[3H]7-OH-DPAT is capable of labeling dopamine D2 as well as D3 receptors

Eur J Pharmacol. 1995 Jan 5;272(1):R1-3. doi: 10.1016/0014-2999(94)00738-s.

Abstract

The binding of [3H](+)-7-hydroxy-2-(N,N-di-n-propylamino)tetralin ([3H]7-OH-DPAT) to dopamine D2 and D3 receptors expressed in Chinese hamster ovary (CHO) cells was investigated and compared with [3H]methylspiperone. [3H]7-OH-DPAT labeled the D3 receptor in the CHO cells in a guanine nucleotide-insensitive fashion and exhibited a Kd of about 0.5 nM. In the presence of MgCl2. [3H]7-OH-DPAT was also found to label the D2 receptor in CHO cells with high affinity (3.6 nM). The binding of [3H]7-OH-DPAT to the D2 receptor was sensitive to guanine nucleotides suggesting occupancy of a high affinity G protein-coupled state of the receptor. These results suggest that caution should be exercised when using [3H]7-OH-DPAT to label the dopamine D3 receptor in brain tissues.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Binding, Competitive
  • Brain / drug effects
  • Brain / metabolism
  • CHO Cells / drug effects
  • CHO Cells / metabolism
  • Cricetinae
  • Cricetulus
  • Dopamine Agonists / metabolism
  • Dopamine Agonists / pharmacology*
  • Guanine Nucleotides / metabolism
  • Rats
  • Receptors, Dopamine / drug effects
  • Receptors, Dopamine / metabolism*
  • Receptors, Dopamine D2 / drug effects
  • Receptors, Dopamine D2 / metabolism*
  • Receptors, Dopamine D3
  • Spiperone / analogs & derivatives
  • Spiperone / metabolism
  • Spiperone / pharmacology
  • Tetrahydronaphthalenes / metabolism
  • Tetrahydronaphthalenes / pharmacology*

Substances

  • Dopamine Agonists
  • Drd3 protein, rat
  • Guanine Nucleotides
  • Receptors, Dopamine
  • Receptors, Dopamine D2
  • Receptors, Dopamine D3
  • Tetrahydronaphthalenes
  • Spiperone
  • 3-N-methylspiperone
  • 7-hydroxy-2-N,N-dipropylaminotetralin