依托咪酯对大鼠海马CA1区兴奋性突触后电流成分的影响

Effects of etomidate on spontanous excitatory postsynaptic current in hippocampal CA1 region of rats

目的观察依托咪酯对大鼠海马CA1区兴奋性突触后电流成分(EPSC)的影响。方法 20张脑片分为2组:对照组(脂肪乳剂组,n=10)和实验组(10μmol·L-1依托咪酯组,n=10)。以脂肪乳剂或依托咪酯孵育海马脑片40 min,在Schaeffer侧支/联合纤维连续给予配对刺激,记录EPSC2/EPSC1值。给予单刺激,同时改变膜钳制电压,制作电流-电压(I-V)曲线。结果在膜钳制电压为-70 mV,2组EPSC2/EPSC1值比较差异无统计学意义(P>0.05)。依托咪酯组反转电位由-53 mV降为-60 mV,I-V曲线左移。结论本浓度的依托咪酯对突触前膜的影响较小,主要使构成EPSC的离子成分发生了变化。

Objective To observe the effect of etomidate on composition of excitatory postsynaptic currents（ EPSC） at hippocampal CA1 of rats. Methods The 20 hippocampal slices were evenly divided into two groups. They were emulsion group,etomidate of 10 μmol·L1group. The pairing stimulation was used to observe the effect of 10 μmol·L1etomidate emulsion on the ratio of EPSC 2 / EPSC 1 of hippocampal CA1. Single stimulation was used to obtain the effect of 10 μmol·L1etomidate emulsion,and the change of the curve of current and voltage（ IV） was recorded. Results At a holding potential of 70 mV,there was no difference of 10 μmol·L1etomidate emulsion on the ratio of EPSC 2 / EPSC 1 compared with 10 μmol·L1emulsion（ P 0. 05）. The etomidate emulsion of 10 μmol· L1reduced reversal potential from-53 mV to-60 mV and make curve IV shift left. Conclusion There are rare effect of etomidate emulsion to the function of GABA A receptor on the presynaptic membrane. Etomidate emulsion may reduce action potential firing through opening Cl-channel.