[3H]SCH 23390 labels a novel 5-hydroxytryptamine binding site in human blood platelet membranes

Jacques De Keyser, H. Walraevens, Guy Ebinger, G. Vauquelin, A. Convents

Research output: Contribution to journalArticle

24 Citations (Scopus)


In human blood platelet membranes, 5-HT displaced the binding of the putative selective D-1 dopamine receptor antagonist [3H]SCH 23390 in a competitive manner with a Ki value of 5.7 +/- 0.8 nM, which was about 1000-fold lower than the Ki value for dopamine (Ki = 4400 +/- 150 nM). Thus the 'D-1 dopamine-like' site in human blood platelet membranes described previously corresponds to a 5-HT1-type site. [3H]SCH 23390 competition experiments with a number of serotonergic drugs disclosed a pharmacological profile that was distinct from the four 5-HT1 site subtypes reported previously. We therefore propose that this novel 5-HT site be designated the 5-HT1E site. Binding of [3H]SCH 23390 to 5-HT1-type sites could not be detected in several regions of the human brain. In some regions, however, 5-HT displaced part of the [3H]SCH 23390 binding with a K1 value of 320-380 nM. These sites correspond to 5-HT2 receptors.
Original languageEnglish
Pages (from-to)437-445
Number of pages9
JournalEuropean Journal of Pharmacology
Publication statusPublished - Mar 1989


  • Antipsychotic Agents/*pharmacology
  • Benzazepines/*pharmacology
  • Binding
  • Competitive/drug effects
  • Blood Platelets/drug effects/*metabolism
  • Cell Membrane/drug effects/metabolism
  • Cerebral Cortex/drug effects/metabolism
  • Human
  • In Vitro
  • Mianserin/pharmacology
  • Radioligand Assay
  • Receptors
  • Serotonin/drug effects/*metabolism
  • Spiperone/pharmacology


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