Abstract: AIM: To investigate the influences of nimodipine on HCT cells proliferation and explore the mechanism. METHODS: HCT cells were treated with different concentrations of nimodipine, and its proliferation was inspected by MTT assay.The apex areas of sub-diploid were measured by Flow Cytometry and the DNA ladder were found by agarose gel electrophoresis.The characteristic changes in morphology were observed under the light microscopy.The cellular distribution and concentration of calcium were studied by using the laser confocus scanning microscopy. RESULTS: The growth of HCT cells was inhibited by different concentrations of nimodipine.Data from Flow Cytometry showed the apex areas of sub-diploid enlarge in the drug-treating group, suggesting that the number of apoptosis cells increased in dose-dependent manner.Gel electrophoresis displayed DNA cleavage pattern typical of apoptosis:DNA ladder in high-dose nimodipine- treated HCT cells.The light microscopy presented cellular morphological changes:cell membrane blebs, the cytoplasm and nuclear chromatin condensation.The concentration of cytosolic free calcium increased when treated with nimodipine showed by the laser confocus scanning microscopy. CONCLUSION: Nimodipine can cause inhibition of the cell proliferation of HCT cells.The mechanism of inhibition might involve the cell apoptosis.

Key words: pharmacology, nimodipine, cell apoptosis, [Ca²⁺] i