Boonstra J, Mummery C L, Tertoolen L G, Van Der Saag P T, De Laat S W
J Cell Physiol. 1981 Apr;107(1):75-83. doi: 10.1002/jcp.1041070110.
Cation transport and membrane potential were studied during the cell cycle of neuroblastoma cells (clone Neuro-2A) to investigate the role of these parameters in growth regulation. The cells were synchronized by selective detachment of mitotic cells. The membrane potential and intracellular K+ activity were measured with conventional and K+-selective microelectrodes respectively. Both the membrane potential and K+ activity were high in mitosis, decreased to half maximal in G1 phase, and rose again during S phase. K+ efflux across the plasma membrane was studied with 42K+ as a radioactive tracer using a washing method for cells grown in monolayer and a continuous efflux method for mitotic cells in suspension. The intracellular K+ content and unidirectional K+ efflux rate obtained from these measurements showed modulations during the cell cycle similar to those of the membrane potential. Using equations of electrodiffusion theory the membrane permeabilities to K+ and Na+ were calculated. These permeabilities were high in mitosis, decreased rapidly in G1 phase and increased during S phase, followed by a transient decrease in G2 phase. A rapid increase was observed between G2 phase and the next mitosis. A similar pattern was obtained for the K+ conductance. K+ resistance changes during the cell cycle were similar to changes in the specific membrane resistance, measured by microelectrodes, except for the early cell cycle phases (mitosis and G1). These studies clearly demonstrate large modulations of the passive membrane permeability properties during the cell cycle. These modulations can be correlated with physicochemical membrane variations during the cell cycle, such as membrane fluidity and lateral mobility of lipids.
为了研究阳离子转运和膜电位在神经母细胞瘤细胞（克隆Neuro-2A）细胞周期中的作用，对其进行了相关研究，以探讨这些参数在生长调节中的作用。通过选择性分离有丝分裂细胞使细胞同步化。分别用传统微电极和钾离子选择性微电极测量膜电位和细胞内钾离子活性。膜电位和钾离子活性在有丝分裂期均较高，在G1期降至最大值的一半，并在S期再次升高。使用42K+作为放射性示踪剂，采用单层培养细胞的洗涤法和悬浮有丝分裂细胞的连续外流法研究了钾离子跨质膜的外流情况。从这些测量中获得的细胞内钾离子含量和单向钾离子外流速率在细胞周期中表现出与膜电位类似的调节。利用电扩散理论方程计算了膜对钾离子和钠离子的通透性。这些通透性在有丝分裂期较高，在G1期迅速降低，在S期升高，随后在G2期短暂降低。在G2期和下一次有丝分裂之间观察到快速增加。钾离子电导也呈现出类似的模式。除了细胞周期早期阶段（有丝分裂期和G1期）外，细胞周期中钾离子电阻的变化与用微电极测量的比膜电阻变化相似。这些研究清楚地表明，在细胞周期中被动膜通透性特性有很大的调节。这些调节可能与细胞周期中膜的物理化学变化有关，如膜流动性和脂质的横向流动性。
