BETA-AMYLOID POLYPEPTIDE INCREASES CALCIUM-UPTAKE IN PC12 CELLS - A POSSIBLE MECHANISM FOR ITS CELLULAR TOXICITY IN ALZHEIMERS-DISEASE

Calcium-uptake into PC12 cells was measured by incubation with Ca-45 a fter the cells were exposed for 24 h to beta-amyloid peptide(1-40) at concentrations between 0 and 46 mu M. The rate of influx of Ca-45 into PC12 cells was constant for the first 10 min. For 46 mu M beta-amyloi d peptide(1-40), the rate of influx was about 1,300 ions/s/mu m(2) and the number of cells decreased significantly. There was no significant decrease in cell number when cells were exposed to beta-amyloid in ca lcium-free medium. These results indicate that beta-amyloid increases calcium uptake into PC12 cells, and suggest that the increased uptake is responsible for the toxicity of beta-amyloid in PC12 cells.