Avtor/Urednik		Šuput, Dušan; Frangež, Robert; Bunc, Matjaž
Naslov		Cardiovascular effects of equinatoxin III from the sea anemone Actinia equina (L.)
Tip		članek
Vir		Toxicon
Vol. in št.		Letnik 39, št. 9
Leto izdaje		2001
Obseg		str. 1421-7
Jezik		eng
Abstrakt		Equinatoxin III is the most hemolytic, and the least lethal of the three basic proteins isolated from the sea anemone Actinia equina (L.). Its LD(50) in mice is 83&mgr;g/kg. Preliminary results on Wistar rats have suggested cardiorespiratory arrest as a putative cause of death, but the mechanism of its action has not yet been studied. So far only equinatoxin II has been investigated more thoroughly. As equinatoxin II is less lythic, but more toxic, than equinatoxin III (its LD(50) in mice=35&mgr;g/kg), it may be assumed that haemolysis with a consequent rise in plasma potassium level is not the major factor in the lethality of equinatoxins. To assess the relative contribution of hyperkalemia in the lethality of the toxin in rat, the effects of equinatoxin III were compared to the effects of hyperkalemia caused by the injection of KCl giving the same final concentration of K(+) in the plasma as that observed after an i.v. injection of 3LD(50) of equinatoxin III. As coronary vasoconstriction may be an important mechanism of the cardiotoxic action of equinatoxins, the effect of EqT III on isolated porcine coronary arteries was studied by measurements of smooth muscle tension in the presence of 1-100nM equinatoxin III. The results revealed that animals survive the elevated K(+) plasma concentration caused by an i.v. application of KCl. This suggests that equinatoxin III induced haemolysis is not the major mechanism of equinatoxin III lethality. However, equinatoxin III increases the potassium induced contractions of coronary smooth muscle for 289+/-29%, suggesting that coronary vasoconstriction may be an important factor in the cardiotoxic effects of equinatoxin III.
Deskriptorji		CNIDARIAN VENOMS SEA ANEMONES CARDIOVASCULAR SYSTEM HYPERKALEMIA CORONARY VESSELS VASOCONSTRICTION SWINE RATS, WISTAR POTASSIUM CHLORIDE ELECTROCARDIOGRAPHY PLATELET AGGREGATION LETHAL DOSE 50