In human brain two subtypes of D1 dopamine receptors can be distinguished on the basis of differences in guanine nucleotide effect on agonist binding

J Neurochem. 1989 Oct;53(4):1096-102. doi: 10.1111/j.1471-4159.1989.tb07401.x.


D1 dopamine receptors were identified in membranes of human nucleus caudatus, nucleus accumbens, amygdala, and globus pallidus, by the specific binding of [3H](+)-R-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-benzazepine-7 -ol [( 3H]SCH 23390). In these four brain regions, dopamine/[3H]SCH 23390 competition binding curves were computer-analyzed to a two-site model, distinguishing a high- (RH) and low- (RL) affinity site for dopamine. The ability of guanine nucleotides (0.4 mM GTP or 0.1 mM 5'-guanylylimidodiphosphate) to provoke a conversion of RH into RL was different between these brain regions. In amygdala, a complete conversion was seen, whereas there was no guanine nucleotide-effect on RH in globus pallidus. In nucleus caudatus and nucleus accumbens, guanine nucleotides provoked only a partial conversion of RH into RL, suggesting that these brain regions may contain guanine nucleotide-sensitive and -insensitive receptors. Heating of the membranes at 60 degrees C for 5 min had the same effect as guanine nucleotides. The pharmacological profiles of the guanine nucleotide-sensitive and -insensitive D1 receptors were similar, suggesting that D1 receptors in human brain are heterogeneous only with respect to their effector-coupling mechanism: guanine nucleotide-sensitive receptors, which are capable of undergoing functional coupling with Gs, and guanine nucleotide-insensitive receptors, which are not.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Amygdala / metabolism
  • Autoradiography
  • Benzazepines / metabolism
  • Brain / metabolism*
  • Caudate Nucleus / metabolism
  • Cerebral Infarction / metabolism*
  • Dopamine / pharmacology*
  • Dopamine Antagonists
  • Female
  • Globus Pallidus / metabolism
  • Guanosine Triphosphate / pharmacology*
  • Hot Temperature
  • Humans
  • Kinetics
  • Male
  • Middle Aged
  • Nucleus Accumbens / metabolism
  • Organ Specificity
  • Receptors, Dopamine / drug effects
  • Receptors, Dopamine / metabolism*
  • Receptors, Dopamine D1
  • Reference Values
  • Tritium


  • Benzazepines
  • Dopamine Antagonists
  • Receptors, Dopamine
  • Receptors, Dopamine D1
  • Tritium
  • Guanosine Triphosphate
  • Dopamine