亚低温、异丙酚与异氟烷对缺氧大鼠海马脑片谷氨酸释放的影响

Effects of isoflurane,propofol and mild hypothermia on glutamate releases evoked by chemical anoxia in hippocampus brain slices of rats

目的:比较亚低温、异丙酚与异氟烷对缺氧大鼠海马脑片兴奋性氨基酸释放的影响。方法:采用分离孵育的大鼠海马脑片,以化学性方法(100μM KCN)造成缺氧,采用荧光检测仪连续测定脑片中谷氨酸的释放含量,观察28℃,31℃与37℃温度下的释放量以及分别应用1MAC异氟烷与200μM异丙酚后谷氨酸释放量的变化。结果:28℃与31℃的亚低温较37℃均有效减少了海马脑片谷氨酸的释放(P<0.01),异氟烷可减少37℃下脑片谷氨酸的释放量(27.8%,P<0.01),但在28℃下则无此作用,且异氟烷组与31℃对谷氨酸的减少幅度相近。异丙酚对大鼠海马脑片谷氨酸的释放无明显影响。结论:亚低温与异氟烷的脑保护作用与减少海马兴奋性氨基酸的释放有关。

Objective:To determine whether mild hypothermia,isoflurane and propofol reduce gultamate release in rat hippocampus brain slices after hypoxia. Method: Brain slices preparations were separated and incubated from rat hippocampus. Glutamate released from rat brain slices during chemical anoxia(100μM KCN)were measured with a fluorescence assay,at 28℃,31℃ and 37℃ after anoxia and after administration of 1 MAC of isoflurane and 200 μm propofol respectively. Result: Glutamate release was significantly reduced at 28℃ or 31℃ compare with that at 37℃ (P<0.01). Isoflurane reduced glutamate release at 37C (27.8%, P<0.01),but did not at 28℃. The reduction in glutamate release at 31℃ hypothermia was similar to that with isoflurane. Propofol has no effect on the glutamate release. Conclusion: Mild hypothermia (31℃)and isoflurane protect brain through decreasing glutamate release from hippocampus