Avtor/Urednik		Drevenšek, Gorazd; Budihna, Metka V; Šuput, Dušan; Bunc, Matjaž
Naslov		Nicardipine dose-dependently reduces the effect of equinatioxin II on coronary flow in isolated porcine heart
Tip		članek
Vir		Pflugers Arch
Vol. in št.		Letnik 440, št. 5 Suppl
Leto izdaje		2000
Obseg		str. R145-6
Jezik		eng
Abstrakt		Death after i.v. administration of equinatoxin 2 (EqT 2) has been attributed to the circulatory failure resulting from cardiotoxic effects. The mechanism of action is unknown. The aim of the present work was to study the effects of the toxin on vascular tone in the isolated porcine coronary artery and on coronary flow in the isolated pig heart. EqT 2 caused concentration-dependent contractions of rings of the isolated epicardial porcine coronary artery with an EC50 value of 89+-5 nM (n=5-6) and maximal effect of about 140% of the concentration induced by 20 nM KCI. On Langendorff's porcine heart preparation EqT 2 caused a dose-dependent decrease of coronary flow. At EqT 2 doses lower than 0.05 micro mol/100 g of heart weight there were no measurable effects of the toxin. At dose 0.5 micro mol/100 g the toxin decreased coronary flow to Iess Than 9.8+-2.5 % of the control value. The constrictory effect of the toxin on isolated porcine coronary arteries was diminished by the L-type calcium channel antagonist nicardipine (NC). NC in 1 micro M concentration almost completely abolished the effect of EqT 2 on coronary flow. Our results confirmed involvement of L-type calcium channels in the vasoconstrictory effects of EqT 2 on epicardial coronary arteries.
Deskriptorji		CORONARY VESSELS CNIDARIAN VENOMS CORONARY VASOSPASM NICARDIPINE SWINE