Cholinergic Sites in Skeletal Muscle. II. Interaction of an Agonist and Two Antagonists with the Acetylcholine Site

Richard R. Almon, Stanley H. Appel

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

The equilibrium interactions of α-bungarotoxin, if-tubocurarine, and carbamylcholine with junctional and extrajunctional skeletal muscle acetylcholine receptors were examined. d-Tubocurarine is a competitive inhibitor of the bindings of α-bungarotoxin to the acetylcholine receptor. No substantive difference was observed in the association of d-tubocurarine with the junctional and extrajunctional receptors. In contrast, the carbamylcholine inhibition of toxin binding is not competitive. The data indicate that either the single set of α-bungarotoxin and d-tubocurarine binding sites contains two subsets of carbamylcholine sites or that the carbamylcholine binds in a cooperative manner to a single set of sites. In addition, the affinity of carbamylcholine for extrajunctional receptors may be higher than the affinity for junctional receptors.

Original languageEnglish (US)
Pages (from-to)3667-3671
Number of pages5
JournalBiochemistry
Volume15
Issue number17
DOIs
StatePublished - Aug 1 1976

ASJC Scopus subject areas

  • Biochemistry

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