ABSTRACT
To study the prevention of dauricine (Dau) on bradykinin (BK) induced alteration of intracellular calcium homeostasis and tau phosphorylation, fluorescence spectrophotometer with dual excitation was utilized to measure the intracellular calcium concentration ([Ca2+]i), MTT to detect cell viability and immuncytochemistry to examine tau phosphorylation. The results showed (1) cells treated with BK 1 μmol/L induced a transit increase in [Ca2+]i in all the cell lines detected, among them, the sustained increase of [Ca2+]i level was only seen in PS1Δ9/APPswe cell at 2 h and 24 h after the treatment. Dau (3μmol/L or 6 μmol/L) prevented BK-induced transit and sustained elevation and fluctuation of [Ca2+]i;(2) BK treatment decreased the cell metabolism detected at 2 h in PS1Δ9/APPswe and Dau antagonized the effect; (3) BK induces Alzheimer-like tau hyperphosphorylation at tau-1 epitope and Dau partially antagonized this effect. In conclusion,Dau inhibits BK-induced disturbance in intracellular calcium homeostasis and tau hyperphosphorylation at tau-1 sites.