Inhibition of IgE-mediated histamine release by myosin light chain kinase inhibitors. |
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| Authors: | S Kitani R Teshima Y Morita K Ito Y Matsuda Y Nonomura |
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| Institution: | Department of Medicine and Physical Therapy, University of Tokyo School of Medicine, Japan. |
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| Abstract: | Wortmannin, a specific inhibitor of myosin light chain kinase (MLCK) blocked IgE mediated histamine release from rat basophilic leukemia cell (RBL-2H3) and human basophils dose-dependently. Its IC50 was 20 nM for RBL-2H3 cells and 30 nM for human basophils. There was complete inhibition at the concentration of 1 microM. Wortmannin inhibited partially the A23187 induced histamine release from RBL-2H3 cells (40% inhibition at 1 microM). This inhibition was not accompanied by any significant effect on cytosolic free calcium concentration ( Ca2+]i). KT5926, another MLCK inhibitor, inhibited histamine release comparably with wortmannin and blocked to some degree the increase of Ca2+]i in RBL-2H3 cells. Thus, the phosphorylation of myosin seems to be involved in signal transduction through Fc epsilon RI. |
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