Abstract
It was investigated by electron microscope that subcellular calcium is existed in specific sites in skeletal and uterine muscles.
Tissue was fixed with 2% osumium tetroxide after incubation for 5 minutes in the mixed solution containing 100 mM sodium tartaric acid, 100 mM sodium hydroxide and 10 mM sodium dihydroxytararate osazone.
Skeletal muscle: Calcium precipitate was consistently found densely concentrated in Z-band, myofilament and about triad, but sarcoplasmic reticulum had no precipitate at the muscle contraction.
At the muscle relaxation, on the other hand, precipitate was found about sarcoplasmic reticulum and lateral sac, but Z-band, myofilament, cell-interstitium and the inside of T-vesicle had no precipitate.
Uterine muscle: At the muscle contraction, calcium precipitate was present in myofilament and matrix of mitochondxia, but was not present in the inside of pinocytotic vesicle. At the muscle relaxation, precipitate was localized about pinocytotic vesicle and in cell-interstitium, but in myofilament it distinctly decreased.
We recognized that the mechanism of the contraction and relaxation in skeletal was different from that of uterine muscle.
