Neurotransmitter glycine in the nano gram range was analyzed using a paste electrode (PE) in cyclic voltammetry (CV) and square-wave stripping voltammetry (SWSV). An anodic peak caused by oxidation of the glycine ion appeared at the 0.4 V (versus Ag/AgCl/KCl) potential in a 0.1 M NH4H2PO4 electrolyte solution. At optimized conditions, the working range of the SWSV and CV concentration was found to be 5-60 ngL-1 glycine; precision of R2 = 0.9816 (SWSV) and 0.9986 (CV); and detection limit of 0.65 ngL-1 (5.82 × 10-12 molL-1) (S/N = 3). The optimized conditions were applied to an assay in a fish brain tissue and a living brain cell in real time.