Characteristics of agonist displacement of [3H]ketanserin binding to platelet 5-HT(2A) receptors: Implications for psychiatric research

George N M Gurguis, Stephanie P. Phan, Jaishri E. Blakeley

Research output: Contribution to journalArticle

4 Scopus citations


Brain 5-HT(2A) receptors exist in two agonist affinity states as a function of their coupling to G(q) protein. This has not yet been shown in platelets. We examined [3H]ketanserin's saturable binding to platelet 5- HT(2A) receptors and characteristics of agonist displacement curves of [3H]ketanserin binding in healthy control subjects. [3H]ketanserin saturation curves showed a trend for a two-site model, reflecting two independent binding sites. At low [3H]ketanserin concentrations, agonist displacement curves were flat and best fit a two-site model, indicating the existence of two agonist affinity states. Guanylyl 5'-imidotriphosphate [Gpp(NH)p] induced a significant rightward shift in agonist displacement curves to fit a one-site model. Platelet membrane 5-HT(2A) receptors exist in two agonist affinity states that are regulated by G(q) protein. Platelet 5- HT(2A) receptors provide an accessible model for examining possible dysregulation in the agonist affinity or coupling efficiency to the phosphoinositide system in psychiatric disorders and their modulation by psychotropic medications.

Original languageEnglish (US)
Pages (from-to)227-238
Number of pages12
JournalPsychiatry research
Issue number3
StatePublished - Sep 21 1998



  • 5-HT(2A) receptors
  • Agonist affinity
  • Coupling efficiency
  • G(q) protein
  • Human platelets
  • [H]ketanserin

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry

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