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Ca +2 ‐accumulating components in developing skeletal muscle
Author(s) -
Smalls Charley M.,
Goode Dennis
Publication year - 1977
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051510204
Subject(s) - myofibril , biology , endoplasmic reticulum , calcium , myogenesis , skeletal muscle , microbiology and biotechnology , sarcomere , myocyte , sarcoplasm , anatomy , biochemistry , ultrastructure , vesicle , biophysics , medicine , membrane
This ultrastructural study on the localization of Ca +2 in developing skeletal muscle indicates that the formation of calcium‐accumulating components begins during embryonic development. Both oxalate and pyroantimonate techniques are used to localize Ca +2 in distinct cellular components of chick pectoral and sartorius muscles. Two major sites for Ca +2 accumulation are present in ultrathin sections of embryonic and post‐embryonic muscles: the terminal cisternae of the sarcoplasmic reticulum and specific lines in the I‐bands. Calcium oxalate‐accumulating vesicles are present in the smallest recognizable myotubes at the twelfth day of incubation, but calcium‐accumulating components are not seen at myofibrillar I‐band sites until the fourteenth to seventeenth days of incubation. The fact that myofibrils first form and later in development accumulate a Ca +2 ‐binding component suggests that this Ca +2 ‐binding component is not necessary for the formation of myofibrils, but is added to myofibrils before hatching to serve a probable regulatory role in contraction.