Yoshizumi M, Ishimura Y, Masuda Y, Houchi H, Kato I, Oka M. Inhibition by ouabain of palytoxin-induced catecholamine secretion and calcium influx into cultured bovine adrenal chromaffin cells.
Biochem Pharmacol 1994;
48:1047-9. [PMID:
7916575 DOI:
10.1016/0006-2952(94)90377-8]
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Abstract
The effect of ouabain on palytoxin (PTX)-induced catecholamine secretion from cultured bovine adrenal chromaffin cells was examined in relation to its effect on calcium (Ca2+) influx into the cells. Ouabain showed concentration-dependent inhibition of catecholamine secretion induced by PTX. Ouabain also inhibited [45Ca]2+ influx induced by PTX, this inhibition being parallel with that of catecholamine secretion. The inhibitory effects of ouabain on PTX-induced catecholamine secretion and [45Ca]2+ influx were both overcome by increasing the concentrations of PTX, indicating that ouabain inhibited the actions of PTX in a competitive manner. These results suggest that the ouabain-sensitive (or-binding) site on the cell membrane might be the target site of action of PTX, which causes an increase in Ca2+ permeability and initiation of catecholamine secretion.
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