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Receptor‐triggered polyphosphoinositide turnover produces less cytosolic free calcium in cultured dysgenic myotubes than in normal myotubes
Author(s) -
Tassin AnneMarie,
Häggblad Johan,
Heilbronn Edith
Publication year - 1990
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880130210
Subject(s) - myogenesis , calcium , cytosol , biology , endocrinology , medicine , ryanodine receptor , calcium metabolism , myocyte , inositol trisphosphate receptor , microbiology and biotechnology , receptor , inositol , biochemistry , enzyme
Myotubes prepared from mice with muscular dysgenesis (mdg) were used to further elucidate the putative role of inositol triphosphate (InsP 3 ) in excitation‐contraction (E‐C) coupling of skeletal muscle. The mdg mutation is characterized by an uncoupling of the E‐C coupling. InsP 3 production in normal and mdg / mdg myotube cultures and its relation to the levels of cytosolic free calcium were analyzed. Basal and ATP‐stimulated levels of InsP 3 were equal in normal and mdg / mdg myotube cultures. In contrast, the transient increases of cytosolic free calcium in mdg / mdg myotubes in culture were generally much lower than those in normal ones. This suggests that the defect in dysgenic myotubes does not rest on the InsP 3 formation but on the InsP 3 ‐triggered transduction of excitation and/or the induction of calcium release from internal stores.