title: Maitotoxin, a Ca2+ channel activator candidate.
abstract: Effects of maitotoxin, the most potent marine toxin, were studied using a rat pheochromocytoma cell line, PC12h. A low concentration (10(-8) g/ml) of maitotoxin induced a profound increase in CA2+ influx into PC12h cells and the Ca2+-dependent release of [3H]norepinephrine from them. The effects of maitotoxin were not affected by treatment with tetrodotoxin (10(-6) M) and were observed even in the absence of external Na+. Furthermore, these effects were markedly inhibited or abolished by treatment with verapamil (30-300 microM), Mn2+ (5 mM), or tetracaine (1 mM). These results suggest that maitotoxin activates the voltage-dependent calcium channels of PC12h cells.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D008387:Marine Toxins / Q000494:pharmacology*; D009374:Neoplasms, Experimental / Q000378:metabolism; D035964:Oxocins; D010673:Pheochromocytoma / Q000378:metabolism; D051381:Rats; D013748:Tetracaine / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D000095702:Polyether Toxins
chemical_list: D002118:Calcium; D007473:Ion Channels; D008345:Manganese; D008387:Marine Toxins; D035964:Oxocins; D013748:Tetracaine; D013779:Tetrodotoxin; D014700:Verapamil; C020394:maitotoxin; D000095702:Polyether Toxins