Author/Editor     Arh, Maja
Title     Vpliv kalcijevega blokatorja mibefradila na hipoksično-reoksigenacijske okvare koronarne arterije poskusne živali
Type     monografija
Place     Ljubljana
Publisher     Univerza v Ljubljani, Medicinska fakulteta
Publication year     2004
Volume     str. 69
Language     slo
Abstract     Aims and methods: Mibefradil, a voltage gated Ca2+channel (VGCC) blocker acting at T-type VGCC at lower concentrations, and at both T- and L-type VGCC at higher concentrations, can preserve some functions of coronary arteries impaired by hypoxia-reoxygenation. To study some possible mechanisms of this effect of mibefradil we used isolated porcine left descending coronary artery rings and recorded changes in their isometric tension. At the beginning of all experiments the KCl-induced contraction was tested. In some groups of experiments the artery rings were exposed to normoxia only, in others to 60 min of hypoxia and 30 min of reoxygenation. At the end of experiments or after hypoxia-reoxygenation, the artery rings functionality was verified by means of the KCl-induced contraction and by the substance P-induced relaxation (mediated by endothelium-derived hyperpolarisation factor, EDHF). To exclude the possible effects on smooth muscle cells of nitric oxide (NO) and of prostacyclins, released from endothelium, L-NNA (inhibitor of NO synthase) and indomethacin (inhibitor of cyclooxygenase) were added to artery rings before the substance Pinduced relaxation was tested. Before hypoxia-reoxygenation or at the respective time of normoxia, the artery rings were pre-treated with mibefradil (0.1 microM or 1 microM) in some groups, and additionally with either 1 microM glibenclamide (the non-selective blocker of ATP-dependent K+ channels, KATP channels), or 100 microM 5-hydrohydecanoate (the selective mitochondrial KATP channels blocker) microM pinacidil (the non-selective opener of KATP channels) in others. All drugs were washed out at the end of reoxygenation or at the respective time in normoxia, before final contraction and relaxation were tested. Number of experiments in individual group was between 7 and 29. (Abstract truncated at 2000 characters)
Descriptors     CORONARY VESSELS
CALCIUM CHANNEL BLOCKERS
VASOCONSTRICTION
POTASSIUM CHLORIDE
ANOXIA
RECEPTORS, THROMBOXANE
SUBSTANCE P
NITROARGININE
INDOMETHACIN
GLYBURIDE
SWINE