Related to the pathogenesis of acquired epilepsy, PDS are the central topic of discussion. PDS are abnormal neuronal activities and can be the result of increased LTCC activity. Calcitriol can reduce the activity of these channels. The mentioned facts raise the question if calcitriol can reduce or prevent PDS. Experiments with hippocampal cells, using the patch clamp technique, were made. There were two groups of cell cultures, one calcitriol treated (50nM) and one placebo group. In the cells of these groups PDS have been induced chemically and compared to each other afterwards. A further experiment was made to test if calcitriol actually decreases the activity of these calcium channels. Calcitriol reduced the expression of PDS significantly, up to 36%. The results indicate, that the reduced expression of PDS is triggered from a decreased LTCC activity. It was shown that the LTCC activity is reduced by calcitriol, but not significant.