Effect of a 6 hour exposure of Domoic acid on neonatal rat brain microglia and primary cerebellar granule cell viability as determined by the WST-1 assay (See Materials and Methods). Domoic acid did not affect viability of neonatal rat brain microglia in either a (A) concentration or (B) time-dependent manner. Domoic acid [10 μM – 1 mM] significantly affected viability of primary cerebellar granule cells in both a (C) concentration and (D) time-dependent manner. Data (absorbance of formazan formation at 450 nM) are expressed as mean ± SD of values obtained from one representative experiment (n = 4–8). *p < 0.05 vs vehicle control.