Microelectrode array studies of basal and potassium-evoked release of L-glutamate in the anesthetized rat brain
Microelectrode array studies of basal and potassium-evoked release of L-glutamate in the anesthetized rat brain
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DOI：
10.1111/j.1471-4159.2006.03673.x
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发表时间：
2006-03-01
影响因子：
4.7
通讯作者：
Gerhardt, GA
中科院分区：
文献类型：
--
作者：
Day, BK;Pomerleau, F;Gerhardt, GA
谷氨酸（Glu）是哺乳动物中枢神经系统中主要的兴奋性神经递质。它通过与膜结合Glu受体结合在正常神经生理学和许多脑部疾病中发挥重要作用。为了克服空间和时间上的限制，在以前的体内细胞外谷氨酸的研究中遇到的，我们采用酶涂层微电极阵列来测量基础和钾诱发释放的谷氨酸在麻醉大鼠脑。我们还讨论了信号同一性的问题，这是对这些记录技术的主要批评。体内自参考记录表明，我们的Glu信号是酶和电压依赖性的，支持L-谷氨酸的身份。此外，基础谷氨酸积极调节，河豚毒素（TTX）依赖性，并在低微摩尔范围内（约2 μ m），使用多个自我参考减法鉴定的谷氨酸的方法进行测量。此外，钾诱发的Glu释放表现出快速的动力学，浓度依赖性和可重复性。这些数据支持Glu释放受到高度调节的假设，需要非常接近突触的检测技术，并以秒为单位进行测量，以最好地表征Glu系统的动态。
L-glutamate (Glu) is the predominant excitatory neurotransmitter in the mammalian central nervous system. It plays major roles in normal neurophysiology and many brain disorders by binding to membrane-bound Glu receptors. To overcome the spatial and temporal limitations encountered in previous in vivo extracellular Glu studies, we employed enzyme-coated microelectrode arrays to measure both basal and potassium-evoked release of Glu in the anesthetized rat brain. We also addressed the question of signal identity, which is the predominant criticism of these recording technologies. In vivo self-referencing recordings demonstrated that our Glu signals were both enzyme- and voltage-dependent, supporting the identity of L-glutamate. In addition, basal Glu was actively regulated, tetrodotoxin (TTX)-dependent, and measured in the low micromolar range (approximately 2 mu m) using multiple self-referencing subtraction approaches for identification of Glu. Moreover, potassium-evoked Glu release exhibited fast kinetics that were concentration-dependent and reproducible. These data support the hypothesis that Glu release is highly regulated, requiring detection technologies that must be very close to the synapse and measure on a second-by-second basis to best characterize the dynamics of the Glu system.