Characterization of muscarinic cholinergic receptor subtypes in human peripheral lung

J. W. Bloom, M. Halonen, H. I. Yamamura

Research output: Contribution to journalArticle

23 Scopus citations


The authors have characterized the muscarinic cholinergic receptor subtypes in human peripheral lung membranes using the selective muscarinic antagonist [3H]pirenzepine ([3H]PZ) and the classical muscarinic antagonist [3H](-)-quinuclidinyl benzilate. High-affinity binding with pharmacologic specificity was demonstrated for both radioligands. The high affinity K(d) for [3H]PZ binding determined from saturation isotherms was 5.6 nM, and the K(d) for [3H](-)-quinuclidinyl benzilate binding was 14.3 pM. Approximately 62% of the total muscarinic binding sites in human peripheral lung bind [3H]PZ with high affinity. There was no significant effect of the guanine nucleotide, guanyl-5'-yl imidodiphosphate, on the inhibition of [3H](-)-quinyclidinyl benzilate binding by the muscarinic agonist carbachol in peripheral lung membranes. If the muscarinic receptor with high affinity for PZ has an important role in bronchoconstriction, its characterization could result in the development of more selective bronchodilators.

Original languageEnglish (US)
Pages (from-to)625-632
Number of pages8
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number2
StatePublished - Jan 1 1988


ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this