CHARGE MOVEMENT IN MEMBRANE OF STRIATED-MUSCLE
CHARGE MOVEMENT IN MEMBRANE OF STRIATED-MUSCLE
复制标题
DOI：
10.1113/jphysiol.1976.sp011235
复制
发表时间：
1976-01-01
影响因子：
5.5
通讯作者：
ALMERS, W
中科院分区：
文献类型：
--
作者：
ADRIAN, RH;ALMERS, W
1.通过适当比较产生大小阶跃的膜电位所需的暂态电流，可以测量明显由膜中的永久偶极子或移动电荷引起的非线性极化电流。这些暂态极化电流的积分估计了与膜偶极子或电荷运动相关的电荷转移。2.从-100 mV到0 mV的去极化需要35nC/MUF的电荷转移，此外，从-100 mV的小去极化所需的电荷的线性外推所预测的电荷转移。不同大小的退极化给出了一个S型的电荷-电压关系，它在o mV以上饱和，中点在-50 mV左右。额定去极化通过比较从-100 mV(电荷1)开始的小电压阶跃和大电压阶跃的电流来减少或消除检测到的电荷运动。然而，在去极化光纤中，从+40 mV的小电势阶跃和-20 mV的大超极化电势阶跃的电流比较显示，第二个电荷(电荷2)有很大的移动。电荷2的运动在大小和速率上都不像电荷2的运动那样依赖于电压。4.在尺寸和电压依赖关系上，这两种电荷运动对应于测量的正常极化和去极化光纤中电容的电压依赖关系(禤浩焯和阿尔默斯，1976)。
1. Non‐linear polarization currents apparently due to permanent dipoles or mobile charges in the membrane can be measured by appropriate comparison of the transient currents required to produce small and large steps of membrane potential. Integration of these transient polarization currents estimates the charge transfer associated with the movement of membrane dipoles or charges. 2. Depolarization from ‐100 to 0 mV requires a charge transfer of 35 nC/muF in addition to the charge transfer predicted by linear extrapolation of the charge required for a small depolarization from ‐100 mV. Depolarizations of varying size give a charge‐voltage relation which is sigmoid saturating beyond o mV and with a midpoint at about ‐50 mV. The ratnged depolarization reduces or removes charge movement detected by comparing currents for small and large voltage steps from ‐100 mV (Charge 1). However in depolarized fibres comparison of currents from a small potential step at +40 mV and a large hyperpolarizing potential step from ‐20 mV reveals large movements of a second charge (Charge 2). Movement of Charge 2 is less steeply dependent on voltage than movement of Charge 2 both in magnitude and in rate. 4. In size and voltage dependence these two kinds of charge movement correspond to measured voltage dependence of capacity in normally polarized and depolarized fibres (Adrian & Almers, 1976).