[3H]N-methylscopolamine dissociation from muscarine receptors affected by low concentrations of allosteric modulators

Arthur Christopoulos, Fred Mitchelson

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5 Citations (Scopus)


The ability of allosteric ligands to modulate the dissociation rate of [3H]N-methylscopolamine from atrial muscarinic receptors in the presence of varying concentrations of unlabelled N-methylscopolamine or atropine was evaluated. Gallamine, at a concentration approximating its KD value, slowed the dissociation of [3H] N-methylscopolamine in the presence of ca. 30× KD of both unlabelled NMS or atropine. This was less evident when concentrations of ca. 1000× KD of the unlabelled antagonists were employed. Similar findings were made with another allosteric modulator. These results indicate that gallamine can act allosterically at low concentrations.

Original languageEnglish
Pages (from-to)259-262
Number of pages4
JournalEuropean Journal of Pharmacology: Molecular Pharmacology
Issue number3
Publication statusPublished - 15 Aug 1995


  • Allosterism
  • Dissociation kinetics
  • Gallamine
  • [H]N-methylscopolamine

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