BIOELECTRIC CONTROL OF LOCOMOTION IN CILIATES
BIOELECTRIC CONTROL OF LOCOMOTION IN CILIATES
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DOI：
10.1111/j.1550-7408.1972.tb03444.x
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发表时间：
1972-01-01
期刊：
影响因子：
--
通讯作者：
NAITOH, Y
中科院分区：
文献类型：
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作者：
ECKERT, R;NAITOH, Y
纤毛虫原生动物的运动行为是由细胞膜通过在后生动物的受体、神经和效应细胞中已经熟悉的电生理学原理控制的。回避反应(15)说明了这一点。当纤毛虫前部的膜受到机械刺激时，如在碰撞过程中，它允许局部钙离子内流。这构成了一种受体电流，通过电渗性扩散使剩余的细胞膜去极化。去极化导致整个细胞膜的钙电导的二次瞬时增加，并发生钙离子的普遍内流。由此产生的细胞内钙离子浓度的增加激活了睫状肌力量的重新定位(“逆转”)，导致生物体向后游泳。当细胞皮质内钙离子的静息浓度通过扩散、主动挤出或细胞内隔离恢复时，前向运动就会恢复。纤毛虫运动的控制和协调除了取决于膜的兴奋性外，还取决于几个因素。这些包括睫状器对细胞内钙和其他调节物质浓度的敏感性，细胞膜感觉受体特性的解剖分布，以及细胞的电缆特性，该特性允许在不需要全部或全部不传导信号的情况下对分级电位信号进行电渗性传播。
Locomotor behavior in the ciliate protozoa is controlled by the cell membrane through electrophysiological principles already familiar in receptor, nerve, and effector cells of the metazoa. This is illustrated by the avoiding reaction (15). When the membrane of the anterior part of the ciliate receives a mechanical stimulus, as during collision, it permits a local influx of Ca++. This constitutes a receptor current which depolarizes the remaining cell membrane by electrotonic spread. Depolarization causes a secondary transient increase in the calcium conductance of the entire cell membrane, and a general influx of Ca++occurs. The resulting increase in concentration of intracellular Ca++activates a reorientation (“reversal”) of the ciliary power stroke, causing the organism to swim backward. Forward locomotion is restored as the resting concentration of intracellular Ca++in the cell cortex is restored by diffusion, active extrusion, or intracellular sequestering. The control and coordination of locomotion in ciliates depend on several factors in addition to the excitable properties of the membrane. These include the sensitivities of the ciliary apparatus to intracellular concentrations of calcium and other regulating substances, the anatomical distribution of sensory receptor properties of the cell membrane, and the cable properties of the cell which permit electrotonic spread of graded potential signals without need of all‐or‐none conducted signals.