Disopyramide and quinidine bind with inverse selectivity to muscarinic receptors in cardiac and extracardiac rat tissues

Gabriel Schreiber, Adiel Barak, Mordechai Sokolovsky

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We investigated the interactions of disopyramide and quinidine with the muscarinic receptor in tissue homogenates from rat atrium, ventricle, cortex, submandibular gland, and urinary bladder by means of competition binding experiments, using the tritium-labeled antagonist N-methyl-4-piperidyl benzilate. The drugs displayed heterogeneous characteristics of binding to the muscarinic receptors in the different tissues. The binding affinity of quinidine to the muscarinic receptor in atrial tissue was five to 10 times greater than in the other tissues studied, whereas the affinity of disopyramide to the muscarinic receptor in the heart was five times lower than in the other tissues. This inverse selectivity shown by the two drugs in their binding to cardiac and to non-cardiac tissues may explain the extracardiac antimuscarinic side effects of treatment with disopyramide and their absence with quinidine.

Original languageEnglish
Pages (from-to)390-393
Number of pages4
JournalJournal of Cardiovascular Pharmacology
Volume7
Issue number2
DOIs
StatePublished - 1 Jan 1985
Externally publishedYes

Keywords

  • Disopyramide
  • Muscarinic receptors
  • Quinidine

ASJC Scopus subject areas

  • Pharmacology
  • Cardiology and Cardiovascular Medicine

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