Palytoxin: a potent stimulator of catecholamine release from cultured bovine adrenal chromaffin cells.
The effect of palytoxin (PTX), a potent marine toxin, on catecholamine release from cultured bovine adrenal chromaffin cells was examined. PTX at concentrations of over 10(-9) M induced catecholamine release dose-dependently. About 40-50% of the total cellular catecholamine was released during 20-min incubation with 3 x 10(-8) M PTX. PTX-induced catecholamine release was dependent on both extracellular Na+ and Ca2+, and was inhibited by organic and inorganic Ca2+ channel blockers, but not by tetrodotoxin. PTX-induced increase in 45Ca2+ influx into the cells, which was associated with catecholamine release, was also inhibited by these Ca2+ channel blockers. These results indicated that PTX-induced catecholamine release was mediated by activation of Na(+)-dependent, tetrodotoxin (TTX) insensitive voltage-dependent Ca2+ channels.
Nakanishi
A
A
Department of Pharmacology, Tokushima University School of Medicine, Japan.
Yoshizumi
M
M
Morita
K
K
Murakumo
Y
Y
Houchi
H
H
Oka
M
M
D000178:Acrylamides; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002132:Calcium Radioisotopes; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000378:metabolism*; D003064:Cnidarian Venoms / Q000494:pharmacology*; D012964:Sodium / Q000502:physiology; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D000095702:Polyether Toxins
D000178:Acrylamides; D002118:Calcium; D002132:Calcium Radioisotopes; D002395:Catecholamines; D003064:Cnidarian Venoms; D012964:Sodium; D015222:Sodium Channels; D013779:Tetrodotoxin; C010272:palytoxin; D000095702:Polyether Toxins