To isolate seizure-related genes, we applied differential screening technique to the cDNA library which constructed from primary cultured cerebral cortical cells treated with pentylenetetrazol (PTZ). Northern blotting analysis of mRNA levels in the cerebra after systemic administration of PTZ confirmed the results of differential screening procedure: 6 clones showed increased mRNA level and 3 clones showed decreased expression with PTZ. Interestingly, 4 genes which were isolated by this technique were related to intracellular calcium action. They were cytosolic phospholipase A2, 78 kDa glucose regulated protein, SEZ-15 which has an EF hand motif and PTZ-17 that causes calcium current inXenopusoocyte with PTZ application. These data and our previous results suggest that intracellular calcium may play an important role for seizure-related pathophysiological changes in neuronal cells.