重复膜片钳法研究MPP^+对神经元钙电流作用

Investigation of the Effect of MPP + on Calcium Current of MN9D Cells with Repatched Whole Cell Method.

细胞膜片钳技术是研究膜离子通道的有效方法．在单个细胞上反复形成多次全细胞构型从而在同一细胞上观察某些药物的长时间作用对于通道膜电流的影响．利用全细胞构型下胞浆与电极内液的连通可以方便地向胞内引入药物．以此法研究ＭＰＰ＋多巴胺能神经瘤细胞（ＭＮ９Ｄ）的毒性作用表明ＭＰＰ＋导致细胞电压依赖性钙电流（ＩＣａ）显著下降；ＭＰＰ＋作用１ｈ以内高去极化电压较低去极化电压诱发的钙电流先受ＭＰＰ＋影响而下降；ＭＰＰ＋对未分化细胞的钙电流无显著作用（ｎ＝３）．

Patch clamp is a useful method to study ion channels in cell membrane. By means of repatched whole cell, it becomes available to monitor the long term effect of some kinds of reagents on ion currents of a single cell without wash out problem. After the cell was whole cell patched, drugs can be conveniently dialyzed into the cell from the pipette. The neurotoxicity of MPP + in dopaminergic neuronal cell line (MN9D) was investigated with repatched whole cell method. It was found that the voltage dependent calcium current ( I Ca ) was significantly suppressed in differentiated cells and I Ca induced by high depolarizing pulse decreased earlier than that induced by low depolarizing pulse during MPP + treating for up to 1 h. In undifferentiated cells, no apparent change happened under the same condition.