125I-spiperone: A novel ligand for D2 dopamine receptors

Andrew L. Gundlach, Brian L. Largent, Solomon H. Snyder

Research output: Contribution to journalArticlepeer-review

Abstract

125I-Spiperone binds with high affinity (KD 0.3 nM) to a single specific site (Bmax 34 pmol/g wet weight) in homogenates of rat corpus striatum. Specific binding is about 40-60 percent of total binding and is displaced stereo-specifically by butaclamol and clopenthixol. Neuroleptic drugs of various classes are potent inhibitors of 125I-spiperone binding (Ki's 1-10 nM). Selective dopamine antagonists such as sulpiride (Ki 50 nM) are dopamine agonists such as apomorphine (Ki 200 nM) are also potent inhibitors. The drug specificity of 125I-spiperone binding correlates well with that of 3H-spiperone binding, providing good evidence that 125I-spiperone labels D2 dopamine receptors in striatal membranes. 125I-Spiperone, with its high specific activity (2200 Ci/mmol) may prove to be a useful ligand in studies examining D2 dopamine receptors in soluble preparations and by autoradiography. Furthermore iodinated spiperone may be useful in radioreceptor assays of neuroleptic drug levels and, in a 123I-labeled form, for imaging of dopamine receptors, in vivo, using single photon tomography.

Original languageEnglish (US)
Pages (from-to)1981-1988
Number of pages8
JournalLife Sciences
Volume35
Issue number19
DOIs
StatePublished - Nov 5 1984

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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