Relations between ameboid movement and membrane-controlled electrical currents.
Relations between ameboid movement and membrane-controlled electrical currents.
复制标题
DOI：
10.1085/jgp.69.6.743
复制
发表时间：
1977-06
期刊：
影响因子：
--
通讯作者：
Jaffe LF
中科院分区：
文献类型：
--
作者：
Nuccitelli R;Poo MM;Jaffe LF
我们用超灵敏的细胞外振动探针研究了变形虫（主要是混沌变形虫）的电流模式。变形虫自身既能驱动稳定电流，也能驱动电流脉冲。相对稳定的电流，平均表面密度为0.1-0.2 μ a /cm2，进入变形虫的后四分之一，并离开它的假足。流逆转发生之前，这种电流模式发生了变化，新向内电流最大的区域成为新的尾部。离子取代研究表明，一些稳定的内向电流是由钙离子携带的。特征受激电流脉冲有时会随着振动探头靠近前进的假足的侧面而产生。这种脉冲通过探针附近的一小片膜进入细胞质（并似乎穿过邻近的膜离开），通常随后是透明帽，然后是伪足起始，是钙依赖的，持续约5-10秒，峰值密度约为0.4 muA/cm2。类似形状和持续时间的自发脉冲可以进入或离开动物的任何部位。它们的局限性更小，往往具有更高的峰值密度，并且在生理盐溶液中以每分钟0.2-4次的速度发生。假足的缩回总是伴随着或先于一个自发的脉冲离开它的两侧。
We have studied the pattern of electrical currents through amebas (mainly Chaos chaos) with an ultrasensitive extracellular vibrating probe. Amebas drive both steady currents and current pulses through themselves. Relatively steady current with an average surface density of 0.1-0.2 muA/cm2 enters the rear quarter of an ameba and leaves its pseudopods. Streaming reversals are preceded by changes in this current pattern and the region with the largest new inward current becomes the new tail. Ion substitution studies suggest that some of the steady inward current is carried by calcium ions. Characteristic stimulated pulses of current sometimes follow the close approach of the vibrating probe to the side of an advancing pseudopod. Such a pulse enters the cytoplasm through a small patch of membrane near the probe (and seems to leave through the adjacent membrane), is usually followed by hyaline cap and then by pseudopod initiation, is calcium dependent, lasts about 5-10 s, and has a peak density of about 0.4 muA/cm2. Spontaneous pulses of similar shape and duration may enter or leave any part of an animal. They are much less localized, tend to have higher peak densities, and occur in physiological salt solutions at about 0.2-4 times per minute. Retraction of a pseudopod is always accompanied or preceded by a spontaneous pulse which leaves its sides.