Skeletal muscle force and actomyosin ATPase activity reduced by nitric oxide donor

William J. Perkins, Young Soo Han, Gary C. Sieck

Research output: Contribution to journalArticle

104 Scopus citations

Abstract

Nitric oxide (NO) may exert direct effects on actin-myosin cross-bridge cycling by modulating critical thiols on the myosin head. In the present study, the effects of the NO donor sodium nitroprusside (SNP; 100 μM to 10 mM) on mechanical properties and actomyosin adenosinetriphosphatase (ATPase) activity of single permeabilized muscle fibers from the rabbit psoas muscle were determined: The effects of N-ethylmaleimide (NEM; 5-250 μM), a thiol- specific alkylating reagent, on mechanical properties of single fibers were also evaluated. Both NEM (≤25 μM) and SNP ≤1 mM) significantly inhibited isometric force and actomyosin ATPase activity. The unloaded shortening velocity of SNP-treated single fibers was decreased but to a lesser extent, suggesting that SNP effects on isometric force and actomyosin ATPase were largely due to decreased cross-bridge recruitment. The calcium sensitivity of SNP-treated single fibers was also decreased. The effects of SNP, but not NEM, on force and actomyosin ATPase activity were reversed by treatment with 10 mM DL-dithiothreitol, a thiol-reducing agent. We conclude that the NO donor SNP inhibits contractile function caused by reversible oxidation of contractile protein thiols.

Original languageEnglish (US)
Pages (from-to)1326-1332
Number of pages7
JournalJournal of applied physiology
Volume83
Issue number4
DOIs
StatePublished - Oct 1997

Keywords

  • Adenosinetriphosphatase
  • Dithiothreitol
  • Ethylmaleimide
  • Pharmacology
  • Rabbit psoas
  • Sodium nitroprusside
  • Sulfhydryl reagents

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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