[Ca2+ ]i plays an important role in the life of a cell (e.g. cell-cell- communication) and therefore its concentration is kept in tight limits through various mechanisms. Since a high [Ca2+ ]i also induces apoptosis, we use the change of [Ca2+ ]i to measure the effects of platin-compounds on human neuroblastoma cells (SY-5Y). The tested substances are cis-platin (CDDP), oxali-platin (oPt) and carbo-platin (cPt).

The cells were loaded with calcium sensitive dye Fluo-4 which fluorescence is an indicatior for [Ca2+ ]i. All substances (1mM, 10mM) were applied by flow-system for at least 60min. [Ca 2+ ]i was measured by a confocal laser-scanning-microscope (Zeiss 510) with a 40x water immersion lens at room-temperature. An increase of [Ca2+ ]i in SY-5Y cells can be observed during the application of all three substances while the degree of the [Ca2+ ]i- increase differs. [Ca2+ ]i increases only slightly when oPt was applied (16.06±25.72%) while CDDP (98.8±54.38%) and cPt (76.37±16.27%) cause an higher rise of [Ca2+ ]i (results for 10mM). There is a clear specificity of cell reaction in regard to the substance. This should be taken into consideration when choosing an appropriate therapy. In future work we want to address the problem, which mechanisms elevate [Ca2+ ]i and if this increase is sufficient to trigger apoptosis.