克罗卡林对不同年龄大鼠血管平滑肌张力作用的影响  

Effects of cromakalim on rats vascular smooth muscle with different age

作　　者：陈琦[1] 王晓良[2] 

机构地区：[1]扬州大学医学院生理学教研室,扬州225001 [2]中国医学科学院药物研究所,北京100050

出　　处：《中国药理学通报》2001年第2期171-174,共4页Chinese Pharmacological Bulletin

摘　　要：目的研究钾通道开放剂克罗卡林（ｃｒｏｍａｋａｌｉｍ）对不同年龄大鼠血管平滑肌张力作用的影响。方法大鼠离体血管平滑肌张力记录法。结果ｃｒｏｍａｋａｌｉｍ可抑制由苯肾上腺素（Ｐｈｅ）介导弓；起的血管收缩，其作用在老年大鼠明显减弱；血管内皮的去除或分别应用ＮＯ合酶抑制剂Ｌ．ＮＡＭＥ、环氧酶抑制剂亚甲蓝，均可明显降低ｃｒｏｍａｋａｌｉｍ的舒血管反应，但内皮去除或ＮＯ作用被抑制却消除了ｃｒｏ－ｍａｋａｌｉｍ作用与年龄变化的关系。此外研究还表明：内源性和外源性ＮＯ供体Ａｃｈ及ＳＮＰ的舒血管反应在老年大鼠明显弱于幼年大鼠。结论ＮＯ释放量的减少或血管对ＮＯ反应性的降低可能是引起ｃｒｏｍａｋａｌｉｍ舒血管作用在老年大鼠明显减弱的重要原因。AIM To study the effects and mechanisms of cromakalim, an ATP-sensitive K+ (KATP) channel opener, on rat vascular smooth muscle. METHODS Isometric tension r^ng of aorta rings. RESULTS Vasorelaxant effects to cromakalim which contracted by phenylephrine were markedly reduced in the old rats. Endothelium removal or treatment either with the NO synthesis inhibitor L-NAME or the guanylate cyclase inhibitor methylene blue reduced the effects, however with the change of age, the IC50 values and maximal relaxation responses to Cromakalim had little difference. Ach and SNP, which are the endogenous and exogenous donors of NO respectively, induced a lesser vasodila- tor effect in aortic segments from old compared with the other groups of rats. CONCLUSIONS The vasodilator responses to cromakalim decreased in old rats, its mechanism may be involved the lower release of NO or the lower sensitivity of vascular smooth muscle to NO.

关 键 词：钾通道开放剂 克罗卡林 CROMAKALIM 一氧化氮 血管平滑肌张力 

分 类 号：R972[医药卫生—药品]