Calcium transients and calcium homeostasis in adult mouse fast-twitch skeletal muscle fibers in culture.
Skeletal muscle fibers enzymatically dissociated from adult mouse flexor digitorum brevis muscles were maintained in culture for up to 8 days. After various times in culture, fibers were loaded with fura 2, and Ca2+ transients for trains of 1, 5, and 10 action potentials (100 Hz) triggered by external electrical stimulation were calculated from fluorescence ratio records corrected for noninstantaneous reaction of fura 2 with Ca2+. The decay rate constants of Ca2+ transients decreased with increasing stimulation duration, indicating a slowing of the Ca(2+)-removal properties with increased stimulation duration. After 6 days in culture, Ca2+ decay rate constants decreased dramatically for all stimulation durations and the differences in decay rate constants among 1, 5, and 10 pulses became smaller. Intracellular parvalbumin content measured by single-fiber immunofluorescence decreased with time in culture in parallel with the decrease in the decay rate constant of Ca2+ transients. Our results suggest that there is a correlation between parvalbumin content and the decay rate constant of the Ca2+ transient.
Liu
Y
Y
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore 21201, USA.
Carroll
S L
SL
Klein
M G
MG
Schneider
M F
MF
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003470:Culture Media; D016257:Fura-2; D006706:Homeostasis; D007700:Kinetics; D051379:Mice; D008856:Microscopy, Fluorescence; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D013997:Time Factors
D003470:Culture Media; D010320:Parvalbumins; D002118:Calcium; D016257:Fura-2