Maitotoxin-Induced Phosphoinositide Hydrolysis Is Dependent on Extracellular but Not Intracellular Ca^<2+> in Human Astrocytoma Cells [in Japanese]
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Since maitotoxin, a potent marine toxin, is known to cause not only Ca<SUP>2+</SUP> influx but also phosphoinositide hydrolysis, we investigated the Ca<SUP>2+</SUP> dependency of maitotoxin-induced phosphoinositide hydrolysis in 1321N1 human astrocytoma cells. Maitotoxin elicited inositol 1, 4, 5-trisphosphate accumulation in a time-dependent manner. In [<SUP>3</SUP>H]inositol-labeled cells, maitotoxin stimulated phosphoinositide hydrolysis in an extracellular Ca<SUP>2+</SUP>-dependent manner. Maitotoxin also caused an intracellular Ca<SUP>2+</SUP> elevation, which was abolished by an intracellular Ca<SUP>2+</SUP> chelater BAPTA-AM. Interestingly, maitotoxin still caused phosphoinositide hydrolysis in the BAPTA-AM-treated cells. These results indicate that maitotoxin-induced phosphoinositide hydrolysis is dependent on extracellular but not intracellular Ca<SUP>2+</SUP> in 1321N1 human astrocytoma cells.
- The Japanese Journal of Pharmacology
The Japanese Journal of Pharmacology 81(2), 240-243, 1999-10
The Japanese Pharmacological Society