Ikeda T, Nagata K, Shono T, Narahashi T
Institute of Agriculture and Forestry, University of Tsukuba, Japan.
Neuroreport. 1998 Oct 5;9(14):3189-95.
The insecticide dieldrin is known to suppress the GABA(A) receptor-channel complex in a manner similar to that of picrotoxin. To elucidate the more detailed mechanisms of dieldrin and picrotoxin interactions with the GABA system, single-channel patch clamp experiments were performed using rat dorsal root ganglion neurons in primary culture. Dieldrin did not alter the open time distribution and mean current amplitude or the distribution of burst duration and the mean burst duration. However, the mean closed time was prolonged indicating that dieldrin decreased the channel open probability. Previous studies have demonstrated that dieldrin and picrotoxin share the common binding site on the GABA receptor. Thus, the effects of picrotoxinin on the GABA(A) receptor single channels were also examined. Dieldrin and picrotoxinin had similar effects at the single-channel level. These changes of single-channel parameters explain the suppressive effects of these chemicals on GABA-induced whole-cell currents.
已知杀虫剂狄氏剂以类似于印防己毒素的方式抑制GABA(A)受体通道复合物。为了阐明狄氏剂和印防己毒素与GABA系统相互作用的更详细机制，使用原代培养的大鼠背根神经节神经元进行了单通道膜片钳实验。狄氏剂并未改变开放时间分布、平均电流幅度、爆发持续时间分布或平均爆发持续时间。然而，平均关闭时间延长，表明狄氏剂降低了通道开放概率。先前的研究表明，狄氏剂和印防己毒素在GABA受体上具有共同的结合位点。因此，还研究了印防己毒素对GABA(A)受体单通道的影响。狄氏剂和印防己毒素在单通道水平上具有相似的作用。单通道参数的这些变化解释了这些化学物质对GABA诱导的全细胞电流的抑制作用。
