Abstract: Objective To investigate the effect of endoplasmic reticulum(ER) calcium stores on calcium overload induced by β-amyloid peptide (25-35)(AβSUB>25-35/SUB>) in hippocampal neurons. Methods The hippocampal neurons were loaded with calcium-sensitive fluorescent indicator Fluo-3/AM.Intracellular calcium concentration (［CaSUP>2+/SUP>］i)changes were measured in different conditions of drug intervention by using laser scanning confocal microscopy. Results Groups of 2, 10, 20μmol/L AβSUB>25-35/SUB> all increased ［CaSUP>2+/SUP>］i in hippocampal neurons(EM>n/EM>=5, EM>P/EM><0.05). 2-APB, an inhibitor of ER CaSUP>2+/SUP> release through channels associated to inositol trisphosphate receptor(IP3R), was shown to prevent the aggregated AβSUB>25-35/SUB>induced rise of ［CaSUP>2+/SUP>］i, suggesting the involvement of CaSUP>2+/SUP>released by ER. However, dantrolene, an inhibitor of ER CaSUP>2+/SUP> release through channels associated to ryanodine receptor(RyR), could not prevent the rise of ［CaSUP>2+/SUP>］i induced by AβSUB>25-35/SUB>. Treatment with aggregated AβSUB>25-35/SUB> for 1 hour induced a significant decrease in the ER CaSUP>2+/SUP> content (EM>P/EM><0.01), which was more pronounced 24 hours after the addition of aggregated AβSUB>

Key words: β-amyloid peptide（25-35）, Hippocampal neuron, Alzheimer disease, Endoplasmic reticulum calcium stores, Laser scanning confocal microscopy, Immunocytochemistry, Rat