Open AccessNa + and K + Dependence of Morphological Changes of Cultured Rat Cortical Astrocytes
Author(s) -
Abe Kazuho,
Saito Hiroshi
Publication year - 2001
Publication title -
pharmacology & toxicology
Language(s) - English
Resource type - Journals
eISSN - 1600-0773
pISSN - 0901-9928
DOI - 10.1034/j.1600-0773.2001.880606.x
Subject(s) - ouabain , astrocyte , extracellular , biophysics , neuroglia , chemistry , choline , intracellular , channel blocker , cell culture , choline chloride , biochemistry , medicine , endocrinology , biology , calcium , sodium , organic chemistry , central nervous system , genetics
Cultured astrocytes display flattened, polygonal morphology in the absence of stimuli, and change into process‐bearing stellate cells in response to specific stimuli. In the present study, we investigated possible role of Na + , K + and Ca 2+ in this morphological change of cultured rat cortical astrocytes. Astrocyte stellation induced by dibutyryl cyclic AMP (1 mM), phorbol ester (100 nM) or amyloid β peptide (20 μM) was partly suppressed by replacing NaCl with choline chloride or LiCl in the extracellular medium or by adding KCl, and was completely abolished by replacing NaCl with KCl. Furthermore, the astrocyte stellation was blocked by the specific Na + ‐K + pump inhibitor ouabain. However, it was not significantly affected by removing CaCl 2 from the extracellular medium nor by adding the voltage‐dependent Ca 2+ channel blocker nicardipine. These results suggest that Na + and K + , but not Ca 2+ , electrochemical gradients across the plasma membrane are necessary for morphological changes of astrocytes. In addition, amyloid β25–35‐induced stellation was most susceptible to changing Na + and K + concentrations or ouabain, while phorbol ester‐induced stellation was least sensitive, demonstrating that the Na + and K + dependence differs among stimuli.