Differential effects of maitotoxin on ATP secretion and on phosphoinositide breakdown in rat pheochromocytoma cells

FEBS Letters

Gusovsky, Fabian²  Daly, John W.²  Rojas, Eduardo¹  Yasumoto, Takeshi³ 

[1] Cell and Biology and Genetics, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA;Laboratories of Bioorganic Chemistry and NIDDK, National Institutes of Health, Bethesda, MD 20892, USA;Faculty of Agriculture, Tohoku University, Sendai, Japan

关键词: ATP secretion;    Phosphoinositide breakdown;    Maitotoxin;    (PC12 cell);   

DOI  :  10.1016/0014-5793(88)81371-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Maitotoxin (MTX) induced exocytotic secretion of ATP from PC12 rat pheochromocytoma cells. The threshold for stimulation of secretion was at concentrations of about 2 ng/ml of MTX. Maximal release occurred at 40 ng/ml. MTX-induced ATP release required the presence of calcium in the extracellular medium and could be inhibited by nifedipine, a specific blocker of voltage-dependent calcium channels. In addition to the effects on ATP secretion from PC12 cells, MTX stimulated the breakdown of phosphoinositides, as measured by the accumulation of [³H]inositol phosphates. Maximal stimulation of phosphoinositide breakdown was reached at only 0.5–1.0 ng/ml MTX. MTX at concentrations required to evoke ATP release ( >2 ng/ml) had lesser or no effect on phosphoinositide breakdown. Although stimulation of phosphoinositide breakdown by MTX was dependent on extracellular calcium, it was insensitive to the calcium channel blockers nifedipine, D-600 and cobalt ions. The different concentration range required to elicit these responses and the varying sensitivity to calcium channel blockers indicate that MTX-evoked secretion and MTX-stimulated phosphoinositide breakdown are independent phenomena in PC12 cells.

【 授权许可】

Unknown