Dual effects of amphotericin B on ion permeation in toad urinary bladder epithelium.
Dual effects of amphotericin B on ion permeation in toad urinary bladder epithelium.
复制标题
两性霉素 B 对蟾蜍膀胱上皮离子渗透的双重作用。
作者：
L. Reuss;J. Gatzy;A. Finn
采用微电极技术研究了两性霉素B对蟾蜍膀胱上皮电学特性的作用机制。在暴露于不同离子成分的沐浴介质期间，在不存在和存在药物的情况下测量细胞膜和跨上皮电位和电阻。正如其他研究人员之前所观察到的，两性霉素 B 会显着降低跨上皮电阻 (Rt) 并增加钠转运速率。我们的结果表明，药物对 Rt 的影响部分取决于穿过管腔细胞膜的 Na 电导的增加（阿米洛利不敏感），但主要是由与刺穿细胞平行的位点处的离子电导增加（序列 GK 大于 GNa 大于 G 胆碱大于 GCI）引起的（即，穿过微电极测量未研究的细胞类型或穿过细胞旁路）。
The mechanisms of action of amphotericin B on the electrical properties of the toad urinary bladder epithelium were studied with microelectrode techniques. Cell membrane and transepithelial electrical potentials and resistances were measured in the absence and in the presence of the drug during exposure to bathing mediums of different ionic compositions. As observed previously by other investigators, amphotericin B produces a dramatic decrease of transepithelial electrical resistance (Rt) and an increase of the rate of sodium transport. Our results indicate that the effect of the drug on Rt depends in part on an increase in Na conductance across the luminal cell membrane (amiloride-insensitive), but is caused mainly by an increase of ionic conductances (with the sequence GK greater than GNa greater than G choline greater than GCI) at a site in parallel with the impaled cells (i.e., across a cell type not investigated by the microelectrode measurements or across the paracellular pathway.