马桑内酯对锥体神经元ATP敏感钾通道的作用

目的　研究致痫剂马桑内酯 (CL)对大鼠海马锥体神经细胞膜 ATP敏感钾通道 (KATP)的影响及KATP在癫痫发病中的作用。方法　用膜片钳单通道电流记录和组织培养技术对锥体神经元 ATP敏感钾通道进行研究。结果　对称性高钾溶液条件下 ,KATP的翻转电位接近 0 m V,通道可被 TEA阻断 ;0 .5 mol/ L的 ATP可抑制通道活动 ;30μmol/ L的二磷酸核苷 (DNP)可使通道开放增多 ;其电流 -电压曲线可被直线拟合 ,通道电导值为78.2 3± 12 .0 4 p S。 CL可明显激活 KATP,优降糖能抑制激活的通道。结论　在 CL诱导的癫痫发作中 ,ATP敏感钾通道开放的作用是降低动作电位频率、保护神经元 ,可能起一种负反馈调节作用

Effect of Coriaria Lactone on the ATP-sensitive Potassium Channels in Pyrimidal Neurons of Rats

OBJECTIVE: To acquire knowledge about the effect of Coriaria lactone (CL) on ATP-sensitive potassium channels (KATP) in cultured pyrimidal neurons of rats and the role of KATP in epileptogenesis. METHODS: Experiments were conducted by the use of cell culture technique and single channel patch clamp technique. RESULTS: The reversion potential of neuron KATP was nearly 0 mV under the condition of the same high K+ level in both bath solution and pole solution. The channel could be blocked by TEA, and the channel current could be induced by 30 mumol/L DNP but inhibited by 0.5 mol/L ATP. The conductance of KATP channel current was 78.23 +/- 12.04 pS, and this KATP channel could be remarkably activated by CL and specifically blocked by Glibenclamide. CONCLUSION: The activation of neuron KATP may play a role of decreasing the action potential and thus protecting the neurons from the seizure induced by CL.