电磁场对青蛙骨骼肌单根肌纤维效应的研究

电磁场对完整和去膜青蛙肌纤维作用的比较研究表明，交变电场通过改变膜电位引起肌肉收缩，在此过程中收缩蛋白质的空间位置而非自身构象发生变化，横桥尤其是S－2片段，在伴随横桥从弱耦合状态向强耦合状态过渡时远离粗肌丝而向细肌丝运动，使其与粗肌丝骨架的平均取向比松弛状态或静息状态时相对增大．一般强度恒定磁场对肌纤维膜电位状态及肌纤维内部蛋白质分子的运动及其相互作用影响极其微弱．

Effects of Electric and Magnetic Fields on Contraction of Single Skeletal Muscles of Frog

The effects of electric and magnetic fields on single intact and chemically skinnedmuscle fibres of frog are comparativelystudied. The results show that alternative pulse electric field obviously decreases the depolarization ratio of the diffracted light from intact fibers but it does not change that from skinned fibres. Static magnetic field does not affect the depolarization ratio from either intact or skinned fibers. It is suggested that changes of spatial disposition but not conformation of the contractile proteins take place during muscle contraction caused by electric field and that during the transition from weakly-binding state to strongly-binding state the crossbridges (particularly subsegment-2)move towards actins, thus the average tilt of crossbridges relative to the backbone of thick filaments is increased. It is also shown that static magnetic field with field strength could not exert apparent influence on both the electric properties of cell membrane and the contractile protein movement within skeletal muscle fiber.