The method used was described previously (31 (link)–33 (link)). At 150 min after modeling, six randomly selected rats in each group were euthanized. First, 3% pentobarbital sodium was intraperitoneally injected at a dosage of 60 mg/kg and when the righting reflex disappeared, rats were decapitated. The brain was taken out and rapidly frozen at −80°C.
For testing for NE and 5-HT, a standard curve was recorded and analysis was performed using an Acquity Ultra-Performance Liquid Chromatography/Synapt G2 Quadrupole Time-of-Flight mass spectrometer (Waters China, Ltd.). The entire brain was collected for amino acid detection. Analysis of Asp, GABA and Glu was performed using the Agilent 1260 Infinity system (Agilent Technologies, Inc.) coupled with a Nova-Pak® C18 (5 µm) column (Waters China, Ltd). The chromatographic analysis method used was that described in the AccQ-Tag amino acid chemical reagent package (Waters China, Ltd.). The Waters AccQ-Tag amino acid chemical reagent package contains Amino acid derivatization reagent, Nova-Pak® C18 (5 µm) column, amino acid standards and an instruction of operation and analysis.