van Egeraat J M, Stasaski R, Barach J P, Friedman R N, Wikswo J P
Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235.
Biophys J. 1993 Apr;64(4):1299-305. doi: 10.1016/S0006-3495(93)81496-6.
The response of a crayfish medial giant axon to a nerve crush is examined with a biomagnetic current probe. The experimental data is interpreted with a theoretical model that incorporates both radial and axial ionic transport and membrane kinetics similar to those in the Hodgkin/Huxley model. Our experiments show that the effects of the crush are manifested statically as an elevation of the resting potential and dynamically as a reduction in the amplitude of the action current and potential, and are observable up to 10 mm from the crush. In addition, the normally biphasic action current becomes monophasic near the crush. The model reflects these observations accurately, and based on the experimental data, it predicts that the crush seals with a time constant of 45 s. The injury current density entering the axon through the crush is calculated to be initially on the order of 0.1 mA/mm2 and may last until the crush seals or until the concentration gradients between the intra- and extracellular spaces equilibrate.
用生物磁电流探头研究小龙虾内侧巨轴突对神经挤压的反应。实验数据用一个理论模型来解释，该模型结合了径向和轴向离子运输以及类似于霍奇金/赫胥黎模型中的膜动力学。我们的实验表明，挤压的影响静态地表现为静息电位的升高，动态地表现为动作电流和电位幅度的降低，并且在距挤压处10毫米范围内都可观察到。此外，正常情况下双相的动作电流在挤压处附近变为单相。该模型准确地反映了这些观察结果，并基于实验数据预测挤压以45秒的时间常数封闭。计算得出通过挤压进入轴突的损伤电流密度最初约为0.1 mA/mm²，可能会持续到挤压封闭或细胞内和细胞外空间之间的浓度梯度平衡。
