Radial stiffness characteristics of the overlap regions of sarcomeres in isolated skeletal myofibrils in pre-force generating state

DOI Web Site 被引用文献1件 参考文献22件
  • Miyashiro Daisuke
    Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science
  • Ohtsuki Misato
    Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science
  • Shimamoto Yuta
    Department of Physics, Faculty of Science and Engineering, Waseda University Present address: Quantitative Mechanobiology Laboratory, Center for Frontier Research, National Institute of Genetics
  • Wakayama Jun’ichi
    Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science Present address: Nanobiotechnology Laboratory (Food Engineering Division), National Food Research Institute, National Agriculture and Food Research Organization
  • Kunioka Yuki
    Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science Present address: Hokuriku Industrial Advancement Center
  • Kobayashi Takakazu
    Department of Electronic Engineering, Shibaura Institute of Technology Deceased
  • Ishiwata Shin’ichi
    Department of Physics, Faculty of Science and Engineering, Waseda University
  • Yamada Takenori
    Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science

抄録

<p>We have studied the stiffness of myofilament lattice in sarcomeres in the pre-force generating state, which was realized by a relaxing reagent, BDM (butane dione monoxime). First, the radial stiffness for the overlap regions of sarcomeres of isolated single myofibrils was estimated from the resulting decreases in diameter by osmotic pressure applied with the addition of Dextran. Then, the radial stiffness was also estimated from force-distance curve measurements with AFM technology. The radial stiffness for the overlap regions thus obtained was composed of a soft and a rigid component. The soft component visco-elastically changed in a characteristic fashion depending on the physiological conditions of myofibrils, suggesting that it comes from cross-bridge structures. BDM treatments significantly affected the soft radial component of contracting myofibrils depending on the approach velocity of cantilever: It was nearly equal to that in the contracting state at high approach velocity, whereas as low as that in the relaxing state at low approach velocity. However, comparable BDM treatments greatly suppressed the force production and the axial stiffness in contracting glycerinated muscle fibers and also the sliding velocity of actin filaments in the in vitro motility assay. Considering that BDM shifts the cross-bridge population from force generating to pre-force generating states in contracting muscle, the obtained results strongly suggest that cross-bridges in the pre-force generating state are visco-elastically attached to the thin filaments in such a binding manner that the axial stiffness is low but the radial stiffness significantly high similar to that in force generating state.</p>

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