Action of ciguatoxin on human atrial trabeculae.
This report describes the action of ciguatoxin-1, the major ciguatoxin present in fishes that cause ciguatera, on the contractile activity of human cardiac musculature. Ciguatoxin-1 caused a large, sustained and concentration-dependent positive inotropy in human atrial trabeculae that were obtained during coronary artery bypass surgery from otherwise healthy hearts. Atenolol (a beta 1-adrenoceptor selective antagonist without local anaesthetic-type activity) or low concentrations of tetrodotoxin abolished the positive inotropy caused by ciguatoxin-1, indicating that ciguatoxin-1 stimulated neural elements present in this tissue to release noradrenaline. The positive inotropic action of ciguatoxin-1 did not stem from a significant direct action on myocardial voltage-dependent sodium channels, nor did it stem from significant alpha 1- or beta 2-adrenoreceptor stimulation. Ciguatoxin-1 caused positive inotropy in preparations stimulated at between 0.02 and 2.0 Hz. Mannitol, currently the treatment of choice for ciguatera, did not significantly reverse the positive inotropy induced by ciguatoxin-1 in human atrial trabeculae.
Lewis
R J
RJ
Southern Fisheries Centre, QDPI, Australia.
Hoy
A W
AW
McGiffin
D C
DC
D000328:Adult; D000368:Aged; D002922:Ciguatoxins / Q000633:toxicity*; D005260:Female; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006325:Heart Atria / Q000187:drug effects; D006801:Humans; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology
D002922:Ciguatoxins; D008353:Mannitol