%0 Journal Article
%T Cellular mechanism for spontaneous calcium oscillations in astrocytes
%A Wang Tong-fei
%A Zhou Chen
%A Tang Ai-hui
%A Wang Shi-qiang
%A Chai Zhen
%J Acta Pharmacologica Sinica
%D 2016
%B 2016
%9 
%! Cellular mechanism for spontaneous calcium oscillations in astrocytes
%K 
%X Aim: To determine the Ca2+ source and cellular mechanisms of spontaneous Ca2+ oscillations in hippocampal astrocytes.  Methods: The cultured cells were loaded with Fluo-4 AM, the indicator of intracellular Ca2+, and the dynamic Ca2+ transients were visualized with confocal laser-scanning microscopy.  Results: The spontaneous Ca2+ oscillations in astrocytes were observed first in co-cultured hippocampal neurons and astrocytes. These oscillations were not affected by tetrodotoxin (TTX) treatment and kept up in purity cultured astrocytes. The spontaneous Ca2+ oscillations were not impacted after blocking the voltage-gated Ca2+ channels or ethylenediamine tetraacetic acid (EDTA) bathing, indicating that intracellular Ca2+ elevation was not the result of extracellular Ca2+ influx. Furthermore, the correlation between the spontaneous Ca2+ oscillations and the Ca2+ store in endoplasmic reticulum (ER) were investigated with pharmacological experiments. The oscillations were: 1) enhanced when cells were exposed to both low Na+ (70 mmol/L) and high Ca2+ (5 mmol/L) solution, and eliminated completely by 2 μmol/L thapsigargin, a blocker of sarcoplasmic reticulum Ca2+-ATPase; and 2) still robust after the application with either 50 mol/L ryanodine or 400 μmol/L tetracaine, two specific antagonists of ryanodine receptors, but depressed in a dose-dependent manner by 2-APB, an InsP3 receptors (InsP3R) blocker.  Conclusion: InsP3R-induced ER Ca2+ release is an important cellular mechanism for the initiation of spontaneous Ca2+ oscillation in hippocampal astrocytes.
%U http://www.chinaphar.com/article/view/4012
%V 27
%N 7
%P 861–868
%@ 1745-7254