Characterization of the effects of amphotericin B on ion channels in MDCK cells using the patch-clamp technique.
Characterization of the effects of amphotericin B on ion channels in MDCK cells using the patch-clamp technique.
复制标题
使用膜片钳技术表征两性霉素 B 对 MDCK 细胞离子通道的影响。
DOI：
10.1016/s0005-2736(97)00055-2
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Burnette,RR
中科院分区：
文献类型：
--
作者：
Hsu,S;Burnette,RR
以培养的Madin-Darby犬肾细胞为模型，采用膜片钳技术研究两性霉素B的肾毒性机制。在全细胞水平上，两性霉素B改变了根据全细胞钾电流分类的两种类型的细胞的钾电导。第一种细胞类型，归类为类型I，没有表现出显著的全细胞钾电流。第二种类型为II型，表现为去极化诱导的外向钾电流，该电流随着时间的推移而减弱。在这两个亚群中，长时间(∼30-45min)暴露于浓度为68 nM的两性霉素B会导致全细胞钾电导的增加。在I型细胞中，它增加了16倍，在II型细胞中，增加了3.5倍。此外，在两性霉素B处理后的I型细胞中观察到的钾电流与通过人工膜中两性霉素B形成的孔的电流不同。在单通道水平上，与两性霉素B孵育后，由内向外和由外向外的膜片钾通道活性均显著升高。内向外斑块的动力学研究表明，通道活动的增加与平均关闭时间的减少和平均开放时间的总体增加有关。综上所述，我们的数据表明，两性霉素B的直接毒性主要与其干扰正常离子通道功能的能力有关，而不是与细胞膜上形成孔有关。
Cultured Madin–Darby Canine Kidney cells were used as a model to study the mechanism of nephrotoxicity of amphotericin B using the patch-clamp technique. At the whole-cell level, amphotericin B altered potassium conductances in two types of these cells categorized on the basis of whole-cell potassium currents. The first cell type, classified as Type I, exhibited no significant whole-cell potassium currents. The second type, Type II, exhibited depolarization-induced outward potassium currents that rundown over time. In both of these subpopulations, exposure to amphotericin B at a concentration of 68 nM for a prolonged period of time (∼30–45 min) led to an increased whole-cell potassium conductance. In Type I cells, it increased by a factor of 16 and in Type II cells, by a factor of 3.5. Furthermore, the potassium currents observed in Type I cells following amphotericin B treatment bore no resemblance to currents through pores formed by amphotericin B in artificial membranes. At the single-channel level, incubation with amphotericin B led to a significantly higher potassium channel activity in both inside-out and outside-out patches. Kinetic studies in inside-out patches revealed that the increases in channel activity were associated with a decrease in the mean closed time and an overall increase in the mean open time. In summary, our data suggest that the direct toxicity of amphotericin B is primarily related to its ability to disturb normal ion channel functioning rather than to formation of pores in cell membranes.