Vasodilating effects of tetrazepam in isolated vascular smooth muscles: Comparison with cromakalim and diltiazem

被引:5
作者
PerezGuerrero, C
Suarez, J
Herrera, MD
Marhuenda, E
机构
[1] Laboratorio de Farmacología, Facultad de Farmacia, Universidad de Sevilla, Sevilla
[2] Laboratorio de Farmacología, Facultad de Farmacia, Sevilla
关键词
tetrazepam; benzodiazepine; rat aorta; rat portal vein; vasodilators;
D O I
10.1006/phrs.1997.0221
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
The vasodilating effects of tetrazepam (1,4-benzodiazepine derivative) were studied and compared with those of the K-channel activator, cromakalim and the Ca-channel blocker, diltiazem, in rat aorta smooth muscle and on the spontaneous contractile activity of the rat portal vein. In the aorta, tetrazepam (3 X 10(-7) - 10(-4) M) and diltiazem (10(-8) - 3 X 10(-6) M) concentration-dependently relaxed aortic rings contracted by 30 mM as well as 80 mM KCl. Although cromakalim (10(-8) - 3 X 10(-6) M) concentration-dependently relaxed aortic rings contracted by 30 mM KCl, it did not relax those contrated by 80 mM KCl. In the presence of the ATP-sensitive K-channel blocker, glibenclamide (10(-6) and 3 X 10(-6) M), 30 mM KCl concentration-response curves for the relaxant effect of tetrazepam and diltiazem were unaffected but cromakalim caused a progressive shift of these curves upwards. In the portal vein, tetrazepam inhibited spontaneous contractions, decreased amplitude and increased frequency. Similar behaviour was shown with diltiazem (10(-8) - 10(-5) M) and in both cases, pre-treatment with glibenclamide (10(-6) M) was ineffective. Although cromakalim (10(-5) - 10(-6) M) decreased both amplitude and frequency, this effect was blocked by glibenclamide. These results indicate that the vasodilator action of tetrazepam is not mediated to the opening of ATP-sensitive K-channels, unlike cromakalim. This may be mediated, like those of diltiazem, by the blockade of calcium movements across the cell membrane. (C) 1997 The Italian Pharmacological Society.
引用
收藏
页码:237 / 242
页数:6
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