IN-VIVO MONITORING OF GLUTAMATE IN THE BRAIN BY MICRODIALYSIS AND CAPILLARY ELECTROPHORESIS WITH LASER-INDUCED FLUORESCENCE DETECTION

Glutamic acid, an excitatory neurotransmitter, was monitored in vivo i n the corpus striatum of freely moving rats by brain microdialysis and capillary electrophoresis with laser-induced fluorescence detection. A procedure to derivatize glutamate in complex matrices was developed. Capillary electrophoresis in 12 mu m I.D. capillaries was performed t o determine glutamate with a migration time of 195 s. Laser-induced fl uorescence detection with 488-nm radiation from an argon ion laser and with collinear geometry was used. An injection of haloperidol decreas ed the concentration of glutamic acid in the dialysates. These experim ents support the hypothesis that dopamine receptor blockade decreases glutamate release. The potential of these techniques for the study of chemicals in biomedical experiments is discussed.