Studies on muscarinic binding sites in human brain identified with [3H]pirenzepine

S. C. Lin, K. C. Olson, H. Okazaki, E. Richelson

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Pirenzepine, a potent antimuscarinic agent with apparent selectivity for a subtype (M1) of muscarinic receptors, was used in tritiated form to characterize its binding to human brain tissue. Specific [3H]pirenzepine binding showed rapid association and dissociation. From kinetic and competitive binding experiments, its K(D) was 5.5 nM and 9 nM, respectively. Regional distribution of [3H]pirenzepine binding determined in parallel with [3H]quinuclidinyl benzilate binding, a nonselective muscarinic antagonist, indicated a significant correlation for the maximum number of binding sites for the two radio-ligands in 13 brain regions, with the highest amount of binding for each in the putamen and the least in the cerebellum. Binding for [3H]pirenzepine averaged 57% of that for [3H]quinuclidinyl benzilate, with a range of 20% (cerebellum) to 77% (frontal cortex). Most antidepressants and neuroleptics tested had affinities for [3H]pirenzepine binding sites that were not significantly different from their previously reported values obtained with the use of [3H]quinuclidinyl benzilate.

Original languageEnglish (US)
Pages (from-to)274-279
Number of pages6
JournalJournal of Neurochemistry
Volume46
Issue number1
StatePublished - 1986

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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    Lin, S. C., Olson, K. C., Okazaki, H., & Richelson, E. (1986). Studies on muscarinic binding sites in human brain identified with [3H]pirenzepine. Journal of Neurochemistry, 46(1), 274-279.