β-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 β-amyloid peptide(1-40) at concentrations between 0 and 46 μM. The rate of influx of ⁴⁵Ca into PC12 cells was constant for the first 10 min. For 46 μM β-amyloid peptide(1-40), the rate of influx was about 1,300 ions/s/μm² and the number of cells decreased significantly. There was no significant decrease in cell number when cells were exposed to β-amyloid in calcium-free medium. These results indicate that β-amyloid increases calcium uptake into PC12 cells, and suggest that the increased uptake is responsible for the toxicity of β-amyloid in PC12 cells.