Biophysics Laboratory, School of Biological Sciences, Flinders University, 5042, Bedford Park, South Australia.
J Membr Biol. 1970 Dec;3(1):335-71. doi: 10.1007/BF01868023.
It has been suggested that electro-kinetic coupling may be involved in the mechanism of the action potential and that there should therefore be both consequent volume flows and pressure changes associated with such excitation. In a previous paper, such measurements were reported in cells ofChara australis, from which it is also known that during excitation there is an increase in KCl permeability and an efflux of KCl. In this paper, a number of theoretical analyses have been considered and developed pertaining to such measurements and the time-dependent relationships between apparent measured volume flows, true volume flows and turgor pressure changes in cells in various experimental situations. Such volume flows are quantitatively explained primarily from the frictional coupling of water by both K(+) and Cl(-) ions and to a lesser extent by the local osmotic flow owing to KCl enhancement at the wall-membrane interface of the cell. The measured pressure changes of 12×10(-3) to 28×10(-3) atm during excitation are also correctly predicted as the result of such a volume outflow from the cell which behaves as a hydraulically leaky elastic cylinder and thereby drops in pressure. These conclusions then indicate that the volume flows and pressure changes measured are the incidental consequences of a change in membrane permeability and do not necessarily imply any electro-kinetic mechanism for the action potential itself.
有人认为电动耦合可能与动作电位的机制有关，因此，这种激发应该同时伴随着连续的体积流和压力变化。在之前的一篇论文中，报告了对这种激发的观察，这种激发伴随着澳大利亚卷柏细胞中 KCl 通透性的增加和 KCl 的外流。在本文中，考虑并发展了一些理论分析，这些分析涉及到在各种实验情况下对细胞的表观测量体积流、真实体积流和膨压变化之间的时间依赖性关系的测量。这些体积流主要是由 K(+)和 Cl(-)离子的摩擦耦合以及细胞壁膜界面处 KCl 增强引起的局部渗透流来定量解释的。实验中观察到的 12×10(-3)到 28×10(-3)atm 的测量压力变化也被正确预测为细胞内体积流出的结果，细胞内体积流出使细胞表现为水力渗漏弹性圆柱，从而导致压力下降。这些结论表明，测量到的体积流和压力变化是膜通透性变化的偶然结果，并不一定意味着动作电位本身存在任何电动机制。
