依托咪酯对大鼠海马CA1区神经元突触结构电流-电压曲线的离子通道机制研究  

Etomidate on current-voltage(I-V)curve ion channel mechanisms of hippocampal CA1 excitatory postsynaptic currents

作　　者：于婵娟[1] 刘亚华[1] 田亮[1] 黄春阳[1] 刘涛[1] 蒋晖[1] 

机构地区：[1]新疆医科大学附属肿瘤医院麻醉科,乌鲁木齐830011

出　　处：《新疆医科大学学报》2014年第8期985-988,共4页Journal of Xinjiang Medical University

基　　金：国家自然科学基金(81160414)

摘　　要：目的探讨静脉麻醉药物依托咪酯对大鼠海马CA1区兴奋性突触后电流(excitatory postsynaptic currents,EPSCs)的电流-电压(I-V)曲线在离子通道层面的影响机制。方法采用断头法分离Wistar大鼠海马脑半球,运用切片机制作400μm厚度的海马脑部切片。切片分别置于60μL脂肪乳剂和依托咪酯(相当于10μmol/L)乳剂中孵育40min。在Schaeffer侧支/联合纤维处给予单个刺激,同时改变CA1锥体神经元细胞膜钳制电位(-100^+40mV时,变化幅度为20mV),绘制I-V曲线,并且采用膜片钳内面向外式记录技术全程记录外向整流特性的单通道氯电流。结果在保持膜钳制电位-70mV的条件下,10μmol/L的依托咪酯降低反转电位,其电位由-53mV左右降低为-60mV左右,I-V曲线左移,相应的单通道氯电流明显增强,通道开放程度增加。结论在静息状态下,依托咪酯主要作用于兴奋性突触后膜GABAA受体,通过使其EPSCs的离子构成发生变化抑制兴奋性突触活动,此过程中外向的电流分量增加,发生的主要改变可能为氯离子的跨膜转运。Objective To observe the intravenous anesthetic etomidate on hippocampal CA1 excitatory postsynaptic currents （excitatory postsynaptic currents,EPSCs）currentvoltage （I-V）curve in the level of ion channel mechanisms.Methods Decapitation wistar rat hippocampal hemispheres were separated by using slicing machine production 400 μm thickness hippocampal brain slices.Slices were placed in 60 μl fat emulsion or etomidate （equivalent to 10 μmol/L）of emulsions,and incubated for 40 minutes.In Schaeffer collateral/Allied Fiber was given a single stimulus,while changing the CA1 pyramidal neuron membrane holding potential （-100 mV to~＋40 mV,the variation amplitude of 20 mV）,drawing current-voltage （I-V）curve,and the use of membrane inside-out patch-clamp recording technique full record outwardly rectifying chloride current channel characteristics.Results Maintaining membrane potential of - 70 mV clamped condition,10 μmol/L reduced etomidate emulsion reversal potential,the electric potential of＆amp;nbsp;about -53 mV to -60 mV or so reduced,the I-V curve to the left,the corresponding channel chlorine current occurs significantly enhanced channel opening degree increases.Conclusion In the resting state, etomidate played a major role in the excitatory postsynaptic membrane GABAA receptors,ion composition by making changes EPSCs inhibition of excitatory synaptic activity,this process foreign to the current component increases,major changes may occur as transmembrane transport of Cl- .

关 键 词：海马 CA1 区 依托咪酯 兴奋性突触后电流 I-V 曲线 单通道氯电流 

分 类 号：R246.2[医药卫生—针灸推拿学]