Monitoring glutamate and ascorbate in the extracellular space of grain tissue with electrochemical microsensors
Monitoring glutamate and ascorbate in the extracellular space of grain tissue with electrochemical microsensors
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DOI：
10.1021/ac990636c
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发表时间：
1999-11-15
影响因子：
7.4
通讯作者：
Michael, AC
中科院分区：
文献类型：
--
作者：
Kulagina, NV;Shankar, L;Michael, AC
本文描述了用于体内测量脑组织细胞外空间中谷氨酸和抗坏血酸的电化学微传感器。为了制备谷氨酸微传感器，用含有酶的交联氧化还原聚合物膜对碳纤维微电极（直径10μm，长300-400μm）进行修饰。微传感器在使用前涂有薄薄的 Nafion 薄膜。谷氨酸微传感器对谷氨酸具有选择性和敏感性，检测限在低微摩尔范围内。在脑组织中发现的几种电活性化合物的生理相关浓度在谷氨酸微传感器上没有产生任何反应，也不会影响它们的谷氨酸反应，唯一的例外是谷氨酰胺，在谷氨酸不存在的情况下观察到轻微的反应，但在存在谷氨酸的情况下则不会观察到。抗坏血酸微传感器与循环伏安法结合使用。它们对抗坏血酸敏感且具有选择性，但对多巴胺代谢物二羟基苯乙酸表现出轻微的敏感性。进行的体内测量建立了谷氨酸微传感器监测源自脑组织神经元活动的基础细胞外谷氨酸水平成分的能力。
This paper describes electrochemical microsensors for the in vivo measurement of glutamate and ascorbate in the extracellular space of brain tissue. To prepare glutamate microsensors, carbon fiber microelectrodes (10 mu m in diameter and 300-400 mu m long) were modified with a cross-linked redox polymer film containing enzymes. The microsensors were coated with a thin Nafion film before use. The glutamate microsensors were both selective and sensitive toward glutamate, with detection limits in the low micromolar range. Physiologically relevant concentrations of several electroactive compounds found in brain tissue produced no response at the glutamate microsensors and also did not affect their glutamate response, the only exception being glutamine, for which a small response was observed in the absence, but not in the presence, of glutamate. The ascorbate microsensors were used in conjunction with cyclic voltammetry. They were sensitive and selective toward ascorbate, but did exhibit a small sensitivity toward the dopamine metabolite, dihydroxyphenylacetic acid. The in vivo measurements performed establish the ability of the glutamate microsensors to monitor the component of the basal extracellular glutamate level that is derived from the neuronal activity of brain tissue.