A glass capillary microelectrode based on capillarity and its application to the detection of L-glutamate release from mouse brain slices.
A new glass capillary microelectrode for L-glutamate is described using pulled glass capillaries (tip size, approximately 12.5 microm) with a very small volume (approximately 2 microl) of inner solution containing glutamate oxidase (GluOx) and ascorbate oxidase. The operation of the electrode is based on capillary action that samples L-glutamate into the inner solution. The enzyme reaction by GluOx generates hydrogen peroxide that is detected at an Os-gel-HRP polymer modified Pt electrode in a three-electrode configuration. The amperometric response behavior of the electrode was characterized in terms of the capillarity, response time, sensitivity and selectivity for measurements of L-glutamate. The currents at 0 V vs. Ag/AgCl increased linearly with the L-glutamate concentration from 10 to 150 microM for in vitro and in situ calibrations. The response was highly selective to L-glutamate over ascorbate, dopamine, serotonin and other amino acids. The detection of L-glutamate in the extracellular fluids of different regions of mouse hippocampal slices under stimulation of KCl was demonstrated.
Nakajima
Kumiko
K
Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo 156-8550, Japan.
Yamagiwa
Takashi
T
Hirano
Ayumi
A
Sugawara
Masao
M
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002138:Calibration; D005898:Glass; D018698:Glutamic Acid / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008839:Microelectrodes; D012680:Sensitivity and Specificity
D018698:Glutamic Acid