[125I]Thienylphencyclidine, a novel ligand for the NMDA receptor

Ian J. Reynolds, Kristi Rothermund, Sunita Rajdev, Abdul H. Fauq, Alan P. Kozikowski

Research output: Contribution to journalArticlepeer-review


We have monitored the binding of [125I]thienylphencyclidine ([125I]TCP), a novel high affinity radioiodinated ligand that specifically recognizes the NMDA (N-methyl-D-aspartate) receptor in rat brain membranes. [125I]TCP binds with an affinity of about 30 nM, and recognizes a similar number of binding sites to previously employed ligands for this receptor. [125I]TCP binding is characterized by slow association and dissociation rates, and the latter can be modified by the addition of Mg2+ or Zn2+, as previously described for [3H]dizocilpine ([3MK801). Other phencylidine-like ligands displaced [125I]TCP binding with the order of potency dizocilpine > thienylphencyclidine > ITCP > phencyclidine > ketamine. The binding of [125I]TCP was also increased by NMDA and glycine-site agonists and inhibited by antagonists of these sites. Surprisingly, however, the polyamines spermidine and spermine did not increase [125I]TCP, even though the polyamine antagonist arcaine was an effective inhibitor of binding. These results show that [125I]TCP is a useful ligand for the NMDA receptor complex that binds to the receptor in a manner that is qualitatively distinct from previously described ligands.

Original languageEnglish (US)
Pages (from-to)53-58
Number of pages6
JournalEuropean Journal of Pharmacology: Molecular Pharmacology
Issue number1
StatePublished - May 12 1992


  • NMDA receptor
  • Polyamines
  • [I]Thienylphencyclidinc

ASJC Scopus subject areas

  • Pharmacology


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