Fig 4. Initial screening results of the compounds in the LOPAC and NINDS chemical libraries using the cystine-induced glutamate release assay.

CCF-STTG-1 cells were seeded and grown to confluence. On Day 3, cells were washed with pre-warmed EBSS and transport initiated upon the addition of cystine (80 μM). Cystine-induced glutamate released over 2h at 37°C, in the presence and absence of inhibitors, was measured directly using glutamate oxidase, horse radish peroxidase and Amplex UltraRed and the rate of change of fluorescence monitored at ex 530, em 590. Results were normalized to totals and blanks and the IC₅₀ values determined as a function of the normalized values.