The comparative effects of [Ca2+] and [Mg2+] on tension generation in the fibers of skinned frog skeletal muscle and mechanically disrupted rat ventricular cardiac muscle

W. Glenn L. Kerrick, Sue K.Bolitho Donaldson

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The effects of intracellular Mg2+ on Ca2+-activated isometric tension generation in rat cardiac muscle fibers and frog skeletal muscle were compared. The membranous sarcolemmal barrier was removed from rat cardiac muscle fibers by mechanical disruption and from frog skeletal muscle by skinning. Tension was recorded in the fibers in bathing solutions of different Ca2+ concentrations and either 5×10-5 M or 1×10-3 M Mg2+ concentration (the same concentrations used in a previous study on single skinned frog skeletal muscle fibers [3]). The amount of Ca2+ required to activate the muscle increased with Mg2+ concentration for both rat ventricular muscle and frog skeletal muscle. These data indicate that intracellular Mg2+ concentration could strongly modulate Ca2+-activated tension in cardiac muscle and that very similar molecular mechanisms are responsible for Ca2+-activated tension in rat ventricular muscle and frog skeletal muscle. The possible sites of action of Mg2+ on Ca2+-activated tension are discussed.

Original languageEnglish (US)
Pages (from-to)195-201
Number of pages7
JournalPflügers Archiv European Journal of Physiology
Volume358
Issue number3
DOIs
StatePublished - Sep 1 1975
Externally publishedYes

Keywords

  • Ca Sensitivity
  • Ca-Activated Isometric Tension
  • Intracellular Ca
  • Intracellular Mg
  • Removal of Sarcolemma

ASJC Scopus subject areas

  • Physiology

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