Maitotoxin-induced phosphoinositide hydrolysis is dependent on extracellular but not intracellular Ca2+ in human astrocytoma cells

Jpn J Pharmacol. 1999 Oct;81(2):240-3. doi: 10.1254/jjp.81.240.

Abstract

Since maitotoxin, a potent marine toxin, is known to cause not only Ca2+ influx but also phosphoinositide hydrolysis, we investigated the Ca2+ 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 [3H]inositol-labeled cells, maitotoxin stimulated phosphoinositide hydrolysis in an extracellular Ca2+-dependent manner. Maitotoxin also caused an intracellular Ca2+ elevation, which was abolished by an intracellular Ca2+ 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 Ca2+ in 1321N1 human astrocytoma cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytoma / metabolism*
  • Brain Neoplasms / metabolism*
  • Calcimycin / pharmacology
  • Calcium / metabolism*
  • Chelating Agents / pharmacology
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Extracellular Space / metabolism*
  • Humans
  • Hydrolysis
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Ionophores / pharmacology
  • Marine Toxins / toxicity*
  • Oxocins*
  • Phosphatidylinositols / metabolism*
  • Tumor Cells, Cultured

Substances

  • Chelating Agents
  • Ionophores
  • Marine Toxins
  • Oxocins
  • Phosphatidylinositols
  • 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
  • Calcimycin
  • Egtazic Acid
  • Inositol 1,4,5-Trisphosphate
  • maitotoxin
  • Calcium