脑死亡过程中谷氨酸与场电位的同步检测微电极阵列研究

Study of Microelectrode Array Probe for Simultaneous Detection of Glutamate and Local Field Potential during Brain Death

高浓度胞外K+会引起神经元的去极化、谷氨酸释放、甚至细胞死亡。为研究高浓度K+对在体神经元的影响,采用微机电系统(MEMS)方法制作了一种植入式微电极阵列(MEA),其上包含形状、位置固定的电化学(50×150μm)和电生理(直径为15μm)检测位点,可同时进行脑内神经递质谷氨酸、局部场电位信号(LFP)双模检测。将这种MEA植入到大鼠纹状体后,给大鼠皮层施加高浓度K+刺激,结果表明,高钾刺激增加了纹状体内谷氨酸浓度,同时抑制了神经电生理活动。这是首次采用双模MEA研究神经元在体死亡过程,结果验证了双模微电极阵列在体检测的可行性,可用于研究脑内神经电化学、电生理的时空关系。

High extracellular potassium can induce spreading depression-like depolarizations, elevations of extracellular glutamate and even neuronal death in normal brain. To investigate the contribution of high potassium in vivo, a microelectrode arrays （ MEAs ） probe integrated with recording sites for glutamate concentration （50x150 μm） and local field potential （ LFP） （ diameter=15 μm） was fabricated by Micro-electro-mechanical-systems （ MEMS） technologies. We implanted the MEA probe acutely in the rat brain and exposed the brain to a high potassium solution. During these multi-modal recordings, it was observed that high potassium elevated extracellular glutamate while suppressing the LFP irreversibly. This is one of the first studies in which a dual mode MEA probes is applied in vivo for neuronal death, and it is concluded that our MEA probes are capable of examining specific spatiotemporal relationships between electrical and chemical signaling in the brain.