ESTABLISHMENT OF AN ONLINE ASSAY SYSTEM OF INTRACEREBRALLY RELEASED GLUTAMATE BY MEANS OF MICROBIOCENSOR

本研究采用固定在机械臂上的微透析探针组成的小体积铂黑在线传感器，测定体内脑内神经元细胞外谷氨酸释放浓度。作为第一步，利用BAS100B/W工作站和低电流模块进行体外研究，获得传感器输出测定l -谷氨酸的线性校准曲线，以提高灵敏度和降低噪声水平。将生成的过氧化氢在600mV的Pt电极上进行电化学氧化，并将氧化电流监测为传感器输出与谷氨酸浓度之间的线性关系。在体内实验中，我们试图去除干扰检测系统的细胞外抗坏血酸。我们还进行了用碳体香炉代替铂黑的实验。在这种方法中，电极的电位可以保持在0毫伏，这样儿茶酚胺或抗坏血酸就不会干扰。活体在线测量的另一个问题是，我们无法避免这种检测系统中谷氨酰胺的污染，我们需要一种谷氨酸氧化酶它对谷氨酸具有极强的特异性。这种酶的纯化目前正在进行中。随着这种酶的出现，整个测定系统的建立就完成了。

This study was undertaken to assay concentrations of extracellular L-glutamate release from imtracerebral neurons in vivo with a small-volume online sensor made of platinum black consisted of microdialysis probe fixed at the manipulator.As the first step, in vitro studies to get a linear calibration curve of L-glutamate determined with sensor output with use of the BAS100B/W workstation and low current module to increase the sensitivity and lower the noise level.The generated hydrogen peroxide is oxidized electrochemically at a Pt electrode held at 600mV and the oxidized current was monitored as a linear relationship between sensor output and glutamate concentration.As for in vivo experiments, we tried to remove extracellular ascorbic acid which interfere the assay system. We also performed experiments using carbon bulk censer with Os poly meditator instead of platinum black. In this method, the potential of the electrode can be held at 0 mV so that there is no interference by either catecholamine or ascorbic acid.An another problem in vivo online measurement is that we can not avoid, contamination with glutamine from this assay system, we need a glutamate oxidase which is extremely specific to glutamate. Purification of this kind of enzyme is currently in progress. With this enzyme coming up, establishment of the whole assay system is completed.