| 16829109 |
Usta C, Eksert B, Golbasi I, Bigat Z, Ozdem SS: The role of potassium channels in the vasodilatory effect of levosimendan in human internal thoracic arteries. Eur J Cardiothorac Surg. 2006 Aug;30(2):329-32. Epub 2006 Jul 7.
OBJECTIVE: We investigated the role of potassium channels in vasodilatory effect of levosimendan in human internal thoracic arteries. METHODS: Samples of redundant internal thoracic arteries obtained from patients undergoing a coronary artery bypass graft surgery were cut into 3 mm wide rings and suspended in 20 ml organ baths. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. RESULTS: Levosimendan (10 (-8)-10 (-5) M) or cromakalim (10 (-8)-10 (-5) M) produced concentration-dependent relaxation responses in human internal thoracic arteries precontracted by 10 (-6) M phenylephrine. The relaxant responses to levosimendan did not differ significantly between endothelium-intact and endothelium-denuded preparations. Incubation of human internal thoracic artery rings with adenosine 3',5'-triphosphate (ATP)-dependent potassium channel blocker glibenclamide (10 (-6) M) for 30 min significantly inhibited the relaxant responses to both levosimendan and cromakalim. The Ca2+-activated potassium channel blocker iberiotoxin (10 (-7) M) also caused a significant but smaller inhibition on relaxant responses to levosimendan. Incubation of the rings with the voltage-dependent potassium channel blocker 4-aminopyridine (5 mM) for 10 min did not cause significant alterations in relaxant responses to levosimendan. CONCLUSIONS: The findings of this study suggested that levosimendan-induced relaxation responses in human internal thoracic arteries were depended on the activation of ATP-dependent and Ca2+-activated potassium channels. |
2(0,0,0,2) |