title: Effects of highly purified maitotoxin extracted from dinoflagellate Gambierdiscus toxicus on action potential of isolated rat heart.
abstract: Maitotoxin is a substance extracted from a dinoflagellate and certain tropical poisonous fish. It is considered as the most potent marine toxin (50 times more potent than tetrodotoxin). In isolated mammalian atria, maitotoxin produces at low doses a positive inotropic effect not modified by reserpine pretreatment and suppressed by Mn2+ ions. In the anaesthetized cat, it induces cardiac arrhythmias and tachycardia leading to cardiac failure. On the other hand, maitotoxin strongly inhibits Na+-K+ ATP-ase from microsomes of cat and human kidneys. In a rat pheochromocytoma cell line, it has been shown to promote a norepinephrine release and an increase in Ca2+ influx. The purpose of this work is to study the effect of maitotoxin on action potential of isolated perfused rat heart to check the existence of a direct effect on the myocardium.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004141:Dinoflagellida / Q000032:analysis*; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D008345:Manganese / Q000494:pharmacology; D008387:Marine Toxins / Q000494:pharmacology*; D035964:Oxocins; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D016276:Ventricular Function; D014700:Verapamil / Q000494:pharmacology; D000095702:Polyether Toxins
chemical_list: D002118:Calcium; D008345:Manganese; D008387:Marine Toxins; D035964:Oxocins; D012964:Sodium; D014700:Verapamil; C020394:maitotoxin; D000095702:Polyether Toxins