Effects of m-cholinoceptor antagonists on the neuromuscular junction

E. Olmez, Y. Egilmez, M. O. Guc, M. Ilhan

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The effects of four m-cholinoceptor antagonists and d-tubocurarine on carbachol- or nicotine-induced contractions of frog rectus abdominis muscle were investigated. The n-cholinoceptor-mediated contractile responses of frog rectus abdominis muscle were inhibited competitively by d-tubocurarine whereas m-cholinoceptor antagonists inhibited them noncompetitively. Antagonistic potencies for m-cholinoceptor antagonists, assessed by PD'2 values, indicated a rank order of potency which was 4-DAMP > AF-DX 116 > atropine > pirenzepine. The antagonistic potencies of m-cholinoceptor antagonists on electrically induced twitch responses of rat phrenic nerve-diaphragm preparation were also examined. These responses were blocked by 4-DAMP, but pirenzepine had no effect. However, they were enhanced by AF-DX 116 or atropine. Inhibitory action of 4-DAMP in this preparation was suggested to be due to noncompetitive blockade of postjunctional n-cholinoceptors.

Original languageEnglish (US)
Pages (from-to)52-60
Number of pages9
JournalPharmacology
Volume49
Issue number1
DOIs
StatePublished - Jan 1 1994

Keywords

  • Neuromuscular junction
  • m-Cholinoceptor antagonists
  • n-Cholinoceptors

ASJC Scopus subject areas

  • Pharmacology

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