Tsuboi T, Watanabe A
Department of Basic Human Sciences, School of Human Sciences, Waseda University, Saitama, Japan.
J Muscle Res Cell Motil. 1998 Jun;19(5):505-13. doi: 10.1023/a:1005356425650.
The optical rotation signal of a single frog skeletal muscle fibre was recorded and its properties were examined. To reduce movement of the fibre associated with its excitation, fibre was immersed in Ringer solution made of 90-95% D2O, stretched, and lightly pressed from above with a cylindrical lens. After these procedures no mechanical movements were recognizable under the dissection microscope, and the optical rotation signal appeared consistently as a brief transient increase in dextrorotation with a duration of about 23 ms. The shape and polarity of the signal did not change among preparations and remained unchanged when the direction of impulse conduction along the fibre was reversed. The influence of the birefringence change associated with excitation was found to be small in most preparations. Ryanodine (10 micron) reduced the amplitude of the signal to about half that of the control, and increased the duration slightly. Nitrendipine (10 micron) reduced the duration of the signal to about half that of the control, and reduced the amplitude to about two-thirds of the control. The effects of the chemicals took place within 10 minutes and remained constant for the periods examined. The intracellular action potentials were not appreciably altered by these chemicals. It is concluded that the optical rotation signal of the single muscle fibre reports the molecular conformational change of proteins during the early stage of the contraction process.
记录了单个青蛙骨骼肌纤维的旋光信号，并对其特性进行了研究。为减少纤维在兴奋时的移动，将纤维浸入由90 - 95%重水制成的林格氏液中，拉伸并在上方用柱面透镜轻轻按压。经过这些操作后，在解剖显微镜下未观察到机械运动，旋光信号始终表现为右旋短暂瞬态增加，持续时间约为23毫秒。信号的形状和极性在不同标本间未发生变化，且当沿纤维的冲动传导方向反转时也保持不变。在大多数标本中，发现与兴奋相关的双折射变化影响较小。ryanodine（10微米）将信号幅度降低至对照的约一半，并略微增加了持续时间。尼群地平（10微米）将信号持续时间缩短至对照的约一半，并将幅度降低至对照的约三分之二。这些化学物质的作用在10分钟内发生，并在所检查的时间段内保持恒定。这些化学物质未明显改变细胞内动作电位。得出结论，单个肌肉纤维的旋光信号反映了收缩过程早期蛋白质的分子构象变化。
