The effects of Mg2+ on submaximum Ca2+-activated tension in skinned fibers of frog skeletal muscle

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

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


This study evaluates the effects of free Mg2+ concentration on submaximum isometric tension generated by single skinned fibers from semitendinosus muscles of the frog. Increases in Mg2+ concentration are accompanied by decreases in the submaximum isometric tension generated in bathing solutions which have the same Ca2+ concentration and same ionic strength. The effects of changes in MgATP2- and ATP4- concentration were separated from those of Mg2+ and were found to be very small in comparison to those of Mg2+ concentration. The Mg2+ concentrations used in two sets of solutions were 0.3, 1, and 2 mM. In one set of solutions MgATP2- concentration changed from approximately 2 to 12 mM and in the other set of solutions ATP4- concentration changed from approximately 10-4 to 1.6×10-5 M. Ionic strength was found to have a significant inverse effect on submaximal isometric tension.

Original languageEnglish (US)
Pages (from-to)117-122
Number of pages6
JournalBBA - Bioenergetics
Issue number1
StatePublished - Jul 12 1972
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology


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