Acute effect of β amyloid on synchronized spontaneous Ca2+ oscillations in cultured hippocampal networks

The effects of β amyloid (Aβ) on cytoplasmic Ca2+ ([Ca2+]c) have been studied extensively, but the current literature on this aspect is confusing. We reported that 20 μM Aβ25-35 significantly inhibited the synchronized spontaneous cytoplasmic Ca2+ transients immediately after application, whereas it had little effect on the baseline [Ca2+]c concentration in neurons. Aβ1-42 had a similar effect on the Ca2+ transients as Aβ25-35, while it increased baseline [Ca2+]c concentration gradually. However, Aβ1-40 had little effect on either Ca2+ transients or baseline [Ca2+]c. Such differential effects of Aβ on Ca2+ signals might explain, at least partially, the confusing observations from the previous studies and provide important therapeutic implications for preventing or reversing early neuron damage in Alzheimer's disease.