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The effects of vascular smooth muscle caldesmon on force production by ‘desensitised’ skeletal muscle fibres
Author(s) -
Taggart Michael J.,
Marston Steven B.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81009-3
Subject(s) - caldesmon , isometric exercise , skeletal muscle , contractility , actin , chemistry , biophysics , vascular smooth muscle , microbiology and biotechnology , smooth muscle , anatomy , medicine , biochemistry , biology , endocrinology , calmodulin , enzyme
Smooth muscle caldesmon inhibits actomyosin MgATPase in the absence of Ca 2+ and is the key regulatory component of Ca 2+ ‐regulated thin filaments. We now show that caldesmon can affect contractility as well. Glycerinated skeletal muscle fibres were treated so as to produce substantial contractions without Ca 2+ as an activator. Addition of caldesmon caused reductions in force in a concentration‐ and time‐dependent manner. Perfusion with caldesmon concentrations for < 5 min gave up to 48% reduction in isometric tension with a half‐maximal effect at 1.5 μm caldesmon. Perfusion with 15 μM caldesmon for 30 min gave an irreversible tension drop.