Stephanova D I
Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Sofia.
Biol Cybern. 1987;57(3):207-11. doi: 10.1007/BF00364152.
The method of mathematical modelling was used to study the excitability changes of the membrane of a frog skeletal muscle fibre and the parameters of the action potentials, membrane and ionic currents during the first 30 ms of the recovery cycle. The threshold current for a fibre at rest was found to be 0.32 microA and the durations of the absolute and relative refractory periods were respectively 4 ms and 5.2 ms. With increasing interpulse interval, the subnormality of the membrane excitability is followed by supernormality. Under the same condition the supernormality in the velocity recovery cycle is not obtained. In the recovery cycle, the shape (polarity, sequence and number of phases) of the action potentials, of the membrane and ionic currents and their conductances, are unchanged. Only the time and amplitude parameters of the quantities listed above are known to vary. With increasing the interpulse interval, the amplitudes of the quantities increase and their durations are shortened attaining the values of the corresponding quantities of the initial action potential. The membrane properties are recovered 30 ms after application of the initial pulse, but the supernormality of the excitability is still preserved.
采用数学建模方法研究了蛙骨骼肌纤维膜在恢复周期前30毫秒内的兴奋性变化、动作电位参数、膜电流和离子电流。发现静息纤维的阈电流为0.32微安，绝对不应期和相对不应期的持续时间分别为4毫秒和5.2毫秒。随着脉冲间期的增加，膜兴奋性先出现低于正常，随后出现高于正常。在相同条件下，速度恢复周期中未出现高于正常的情况。在恢复周期中，动作电位、膜电流和离子电流及其电导的形状（极性、相序和相数）不变。已知仅上述量的时间和幅度参数会发生变化。随着脉冲间期的增加，这些量的幅度增加，持续时间缩短，达到初始动作电位相应量的值。施加初始脉冲30毫秒后，膜特性恢复，但兴奋性的高于正常状态仍保留。
