Strässle M, Wilhelm M, Stark G
Fakultät für Biologie, Universität Konstanz, FRG.
Int J Radiat Biol. 1991 Jan;59(1):71-83. doi: 10.1080/09553009114550071.
The electrical capacitance of lipid membranes may increase by up to 50% on exposure to ionizing radiation. This is the consequence of lipid peroxidation induced by primary or secondary radicals of water radiolysis in the presence of oxygen. The polar products of this process give rise to an increase of the dielectric constant of the membrane. This in turn leads to the increase of membrane capacitance observed. An important consequence of this phenomenon is the reduction of the inner energy barrier between the two membrane/water interfaces influencing the movement of charged particles across the membrane. Thus the comparatively small change of the dielectric constant gives rise to the large increase in membrane conductance (by up to several orders of magnitude) observed in the presence of macrocyclic ion carriers of the valinomycin type (Strässle et al. 1987b). The results were obtained applying a novel method to measure time-dependent changes of the capacitance of planar lipid membranes.
脂质膜暴露于电离辐射时，其电容可能会增加高达50%。这是在有氧存在的情况下，水辐射分解产生的初级或次级自由基诱导脂质过氧化的结果。该过程的极性产物导致膜介电常数增加。这反过来又导致观察到的膜电容增加。这一现象的一个重要结果是，影响带电粒子跨膜移动的两个膜/水界面之间的内部能垒降低。因此，在缬氨霉素类型的大环离子载体存在的情况下（Strässle等人，1987b），介电常数相对较小的变化会导致观察到的膜电导大幅增加（高达几个数量级）。这些结果是通过一种测量平面脂质膜电容随时间变化的新方法获得的。
