Measurement of GABA in rat brain microdialysates using o-phthaldialdehyde-sulphite derivatization and high-performance liquid chromatography with electrochemical detection.

A number of recent studies have detected gamma-aminobutyric acid (GABA) in brain microdialysates by measuring an electroactive o-phthaldialdehyde (OPA)-alkylthiol derivative using HPLC with electrochemical detection. A particular problem of this approach is the stench of the thiol reagents involved, and the poor stability of the electroactive GABA derivative. Here we report that these practical disadvantages can be overcome by substitution of the OPA-alkylthiol reaction with an OPA-sulphite reaction. This provides a simple, sensitive and reliable means for determination of GABA in microdialysates of rat brain.