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Microtubule Dynamics Regulates the Level of Endothelin‐B Receptor in Rat Cultured Astrocytes
Author(s) -
Ozawa Fujiko,
Kasuya Yoshitoshi,
Hama Hiroshi,
Asada Sachie,
Inada Tetsuo,
Goto Katsutoshi
Publication year - 1997
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1997.69020562.x
Subject(s) - colchicine , nocodazole , biology , receptor , astrocyte , microbiology and biotechnology , cytochalasin b , neuroglia , cytochalasin , cell , cytoskeleton , endocrinology , biochemistry , central nervous system , genetics
We investigated the effect of cytoskeleton modulators on endothelin‐B (ET B ) receptor expression in rat primary cultured astrocytes. Northern blot analysis and a binding study revealed that colchicine and nocodazole, microtubule‐disrupting agents, decreased the levels of both ET B receptor mRNA and the number of ET‐1 binding sites in quiescent astrocytes. Down‐regulation of both ET B receptor mRNA and the number of binding sites for ET‐1 was also observed in quiescent astrocytes treated with taxol, a microtubule‐stabilizing agent. In contrast, neither β‐lumicolchicine, an inactive isomer of colchicine, nor cytochalasin D, a microfilament‐disrupting agent, influenced ET B receptor expression. The level of ET B receptors in astrocytes was affected by the cell state, namely, proliferative, quiescent, or differentiated state. The order of ET B receptor expression according to the cell state was proliferative state < quiescent state ≪ differentiated state induced by dibutyryl cyclic AMP. Also, in proliferative astrocytes and differentiated astrocytes, colchicine significantly down‐regulated both ET B receptor mRNA and the number of binding sites for ET‐1. However, thymidine assay revealed that colchicine did not change quiescent astrocytes and differentiated astrocytes to a proliferative state. Furthermore, the increase in glutamine synthetase activity in differentiated astrocytes was not affected by colchicine. These results suggest that microtubule dynamics possibly regulates ET B receptor expression in astrocytes without affecting the cell state.