Nakajima S, Bastian J
J Gen Physiol. 1974 Feb;63(2):235-56. doi: 10.1085/jgp.63.2.235.
Passive electrical properties (internal conductance, membrane conductance, low frequency capacity, and high frequency capacity obtained from the foot of the action potential) of normal and glycerol-treated muscle of Xenopus were determined with the intracellular microelectrode technique. The results show that the electrical properties of Xenopus muscle are essentially the same as those of frog muscle. Characteristics of the action potential of Xenopus muscle were also similar to those of frog muscle. Twitch tension of glycerol-treated muscle fibers of Xenopus recovered partially when left in normal Ringer for a long time (more than 6 h). Along with the twitch recovery, the membrane capacity increased. Single isolated muscle fibers of Xenopus were subjected to the double sucrose-gap technique. Action potentials under the sucrose gap were not very different from those obtained with the intracellular electrode, except for the sucrose-gap hyperpolarization and a slight tendency toward prolongation of the shape of action potential. Twitch contraction of the artificial node was recorded as a change of force from one end of the fiber under the sucrose gap. From the time-course of the recorded force and the sinusoidal stress-strain relationship at varying frequencies of the resting muscle fiber, the time-course of isotonic shortening of the node was recovered by using Fourier analysis. It was revealed that the recorded twitch force can approximately be regarded as isotonic shortening of the node.
采用细胞内微电极技术测定了非洲爪蟾正常肌肉和甘油处理后肌肉的被动电学特性（从动作电位波底获得的内向电导、膜电导、低频电容和高频电容）。结果表明，非洲爪蟾肌肉的电学特性与青蛙肌肉基本相同。非洲爪蟾肌肉动作电位的特征也与青蛙肌肉相似。当将非洲爪蟾甘油处理的肌肉纤维长时间（超过6小时）置于正常任氏液中时，其抽搐张力部分恢复。随着抽搐恢复，膜电容增加。对非洲爪蟾单个分离的肌肉纤维采用双蔗糖间隙技术。蔗糖间隙下的动作电位与细胞内电极记录的动作电位并无太大差异，只是存在蔗糖间隙超极化以及动作电位形状略有延长的趋势。在蔗糖间隙下，将人工节点的抽搐收缩记录为纤维一端力的变化。根据记录的力随时间的变化过程以及静息肌肉纤维在不同频率下的正弦应力 - 应变关系，通过傅里叶分析恢复了节点等张收缩的时间过程。结果表明，记录的抽搐力大致可视为节点的等张收缩。
