Separation and analysis of the soluble trimer of Aβ_(1-40) and its effects on the rise in intracellular calcium  

作　　者：ZHENG Xiaohui WANG Lijun ZHANG Lan HONG Yuankai HUANG Lixin SHA Yinlin 

机构地区：[1]Single-molecule and Nanobiology Laboratory. Department of Biophysics School of Basic Medical Sciences, Peking University, Beijing 100083, China

出　　处：《Chinese Science Bulletin》2006年第7期830-838,共9页

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.20273002&20103001).

摘　　要：The oligomers of Aβ1-40 peptide in PBS buffer solution were analyzed by SEC and native PAGE, and the trimer of Aβ1-40 was also isolated by SEC. In addition, the effects of the soluble Aβ1-40 trimer on intracellular free calcium (Ca2+) balance of hippocampal neurons of postnatal rats were investi- gated by fluorescence microscopy. The experimental results indicated that Aβ1-40 peptide existed in the form of low molecular weight oligomers in 0.231 mmol/L fresh Aβ1-40 solution (20 mmol/L sodium phosphate buffer, pH 7.4, 0.02% sodium azide) within 24 h and the soluble trimer was the most abundant species. Both the trimeric and the fibrillar Aβ1-40 were able to increase the intracellular Ca2+ concentration, but the Aβ1-40 trimer caused a gradual rise and the potential was also stronger than that of the fibrils at the same concentration. In addition there were dif- ferent response modes for trimeric and fibrillar Aβ1-40, meaning that there are different mechanisms of in- crease in intracellular Ca2+ caused by Aβ1-40.The oligomers of Aβ（1-40）peptide in PBS buffer solution were analyzed by SEC and native PAGE, and the trimer of Aβ（1-40） was also isolated by SEC. In addition, the effects of the soluble Aβ（1-40） trimer on intracellular free calcium （Ca^2＋） balance of hippocampal neurons of postnatal rats were investigated by fluorescence microscopy. The experimental results indicated that Aβ（1-40） peptide existed in the form of low molecular weight oligomers in 0.231 mmol/L fresh Aβ（1-40） solution （20 mmol/L sodium phosphate buffer, pH 7.4, 0.02% sodium azide） within 24 h and the soluble trimer was the most abundant species. Both the trimeric and the fibrillar Aβ（1-40） were able to increase the intracellular Ca^2＋ concentration, but the Aβ（1-40） trimer caused a gradual rise and the potential was also stronger than that of the fibrils at the same concentration. In addition there were different response modes for trimeric and fibrillar Aβ（1-40）. meaning that there are different mechanisms of increase in intracellular Ca^2＋ caused by Aβ（1-40）.

关 键 词：钙 三聚物 分离 SEC 色谱分析 

分 类 号：R96[医药卫生—药理学]