New method for determining total calcium content in tissue applied to skeletal muscle with and without calsequestrin.
Bottom Line: This suggests that the Ca concentration of smaller muscles might be increased relative to that in larger muscles, thereby increasing the specific force to compensate for the smaller mass.Knocking out the high capacity Ca-binding protein calsequestrin (CSQ) did not significantly reduce [CaT]WM in mouse EDL or soleus muscle.Because greater reductions in [CaT]WM would be predicted in both muscle types, we hypothesize that there is a substantial increase in Ca bound to other sites in the CSQ knockout muscles.
Affiliation: Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria 8001, Australia.Show MeSH
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Mentions: Fig. 4 shows the same absorbance spectra from Fig. 3 corrected for stray light using the procedure described in Section 3 of the supplemental text. As in Fig. 3 B, the solid red curve shows the least-squares best fit of the A0 − AM spectrum to the A0 − A∞ spectrum over the wavelength range of 282 to 340 nm. In contrast to Fig. 3, the A0 − AM difference spectrum matches well with that of A0 − A∞ over the nonfitted region of the spectrum (250–282 nm). The solid and dashed black curves give the corresponding fit of A0 − A∞ to the AM − AS difference spectrum. These black curves are difficult to see because, again, the fit is excellent for the full wavelength range. Likewise, the corresponding fits without muscle present in Fig. 4 D are excellent for the full measured wavelength range. Similar good matches were obtained in other experiments with uncorrected spectra if the effects of stray light were greatly decreased by decreasing the magnitude of the absorbance signals. The lower absorbance values were achieved by either diluting the muscle and BAPTA concentrations by a factor of ∼3 or by using quartz cuvettes with shorter path lengths (1 or 3 mm) compared with that used for all of the data given in this article (path length of 1 cm).
Affiliation: Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria 8001, Australia.