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Calcium paradox in skeletal muscles: Physiologic and microscopic observations
Author(s) -
Soza Marco,
Karpati George,
Carpenter Stirling
Publication year - 1986
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.880090306
Subject(s) - sarcolemma , contracture , calcium , dantrolene sodium , chemistry , medicine , biophysics , endocrinology , anatomy , extensor digitorum muscle , extracellular , basal lamina , skeletal muscle , dantrolene , biochemistry , biology , ultrastructure , surgery , soleus muscle
Immersion of rat hemidiaphragms in Ca 2+ ‐free Krebs solution (KS) containing Ca 2+ chelator in vitro leads to separation of basal lamina from the plasma membrane, as well as transient contracture and rapid loss of twitch response [calcium paradox (CP) phase 1]. Subsequent immersion in regular KS results in necrosis of muscle fibers accompanied by slowly increasing contracture (CP phase 2). This contracture could be prevented or reduced by using either Ca 2+ ‐free KS or calcium channel blockers, but not by dantrolene sodium, implying that after drastic reduction of extracellular and sarcolemmal Ca 2+ during CP phase 1, the sarcolemma has lost its ability to control normal Ca 2+ fluxes. Contracture did not develop at 21°C. CP is a convenient model to study calciuminduced muscle cell death and the role of Ca 2+ in maintaining sarcolemmal integrity.