REGIONAL LEVELS OF GABA IN THE BRAIN: RAPID SEMIAUTOMATED ASSAY AND PREVENTION OF POSTMORTEM INCREASE BY 3‐MERCAPTO‐PROPIONIC ACID

Abstract— A simple and rapid semiautomated assay for GABA in central nervous tissue is described. The method is based on a simple manual procedure of isolating GABA from tissue extracts on small CM Sepharose Cl 6B columns, followed by an automated fluorimetric detection (continuous flow system) with o‐phthalaldehyde (OPA) and β‐mercapto‐ethanol (β‐ME) at an alkaline pH. GABA is separated from other compounds that fluoresce in our detection system. By using low concentration of OPA and β‐ME and allowing only a short reaction time with these reagents, the detection is specific towards GABA. The detection limit of the assay is 1 nmol.

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