beta-Amyloid polypeptide increases calcium-uptake in PC12 cells: a possible mechanism for its cellular toxicity in Alzheimer's disease.

Calcium-uptake into PC12 cells was measured by incubation with 45Ca after the cells were exposed for 24 h to beta-amyloid peptide(1-40) at concentrations between 0 and 46 microM. The rate of influx of 45Ca into PC12 cells was constant for the first 10 min. For 46 microM beta-amyloid peptide(1-40), the rate of influx was about 1,300 ions/s/microns 2 and the number of cells decreased significantly. There was no significant decrease in cell number when cells were exposed to beta-amyloid in calcium-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.