Determination of amino acid neurotransmitters in cerebral cortex of rats administered with baicalin prior to cerebral ischemia by capillary electrophoresis-laser-induced fluorescence detection.

An efficient, sensitive and rapid analysis of the amino acid neurotransmitters in the cerebral cortex of rats was developed by capillary electrophoresis with laser-induced fluorescence detection and fluorescein isothiocyanate (FITC) derivatization. This method was used to investigate the pharmacological effect of baicalin during cerebral ischemia. Different parameters which influenced derivatization and separation were optimized. The separation of amino acids was carried out in an uncoated fused-silica capillary (57 cm x 75 microm I.D.) with a buffer of 15 mM borate at pH 9.2 and an applied voltage of 17.5 kV. The detection limits for six amino acids were in the range of 2.1 x 10(-11)-6.3 x 10(-10) M. The changes in the level of amino acid neurotransmitters in brain cortex of three experimental rat groups were studied by this capillary electrophoresis-laser-induced fluorescence detection method. The results show that cerebral ischemia can cause a significant elevation in the concentrations of Glu, Asp, GABA, and Gly in cerebral cortex. Baicalin administration can attenuate the elevations of Glu and Asp induced by cerebral ischemia. This research demonstrates that baicalin may act as a neuroprotectant during cerebral ischemia.