Author/Editor		Arh, Maja; Budihna, Metka V
Title		Opening of plasmalemmal KATP channels is involved in mibefradil-induced preservation of the post-hypoxic functionality of porcine coronary artery
Type		članek
Source		Period Biol
Vol. and No.		Letnik 106, št. 4
Publication year		2004
Volume		str. 343-53
Language		eng
Abstract		Background and Purpose: Mibefradil is a Ca2+ channel blocker with higher selectivity to T-than to L-type Ca2+ channels and can protect myocardium against functional damage and cell death due to ischaemia/reperfusion. To study the possible protective effect of mibefradil and some possible mechanisms of this effect we used the rings of isolated porcine left descending coronary artery (LADs) impaired by hypoxia/reoxygenation and recorded changes in their isometric tension. Material and Method: The LADs were exposed to 60 min of hypoxia followed by 30 min of reoxygenation. Some LADs were pre-treated with mibefradil (0.1microM and I microM), and others with combination of ImicroM mibefradil and either 1 microM glibenclamide (a non-selective blocker of ATPdependent K+ channels, KATP), or 100 microM 5-hydroxydecanoate (a selective mitochondrial KATP blocker) or 3 microM pinacidil (a non-selective KATP opener). Then the LADs functionality was verified by KCl-induced contractions and by substance P-induced relaxations following nitric oxide synthase and cyclooxygenase inhibition. Results and Conclusion: After hypoxia/reoxygenation, the contraction increased and the relaxation was reduced compared to controls. Pre-treatment with I microM (but not 0.1 microM) mibefradil reduced contraction and recovered relaxation. So, 1 microM mibefradil was used in further experiments. (Abstract truncated at 2000 characters)
Descriptors		CORONARY VESSELS CALCIUM CHANNEL BLOCKERS ANOXIA GLYBURIDE SUBSTANCE P VASOCONSTRICTION POTASSIUM CHLORIDE SWINE