异鼠李素对兔主动脉血管平滑肌细胞胞内游离钙浓度的影响

EFFECTS OF ISORHAMNETIN ON INTRACELLUAR FREE CALCIUM CONCENTRATION IN CULTURED RABBIT AORTIC SMOOTH MUSCLE CELLS

目的：观察异鼠李素（Iso）对血管平滑肌细胞胞内游离钙浓度（[Ca2+]i）的影响。方法：采用新一代钙荧光深剂Fluo-3／AM检测Iso对培养的兔主动脉血管平滑肌细胞（VSMC）[Ca2+]i在高K+、去甲肾上腺素（NE）、血管紧张素Ⅱ（AngⅡ）刺激作用下的改变，并与Verapamil进行对照研究。结果：Iso（10-6、10-4moL／l）呈剂量依赖性抑制高K+去极化引起[Ca2+]；的升高，与Verapamil作用相似，但弱于Verapamil;Iso（10－6-10-4mol／L）对NE、AngⅡ通过受体介导引起的[Ca2+]i；增高，也具有一定程度的抑制作用；在无外Ca2+时Iso（10-5、10-4mol／L）对NE引起的[Ca2+]i升高的抑制效应较为显著；Iso对静息状态的VSMC[Ca2+]i；无明显影响。结论：Iso通过对血管平滑肌细胞电压依赖性钙通道和受操纵性钙通道双重抑制作用，降低细胞内[Ca2+]i，这可能是其舒血管降压机制之一。

Objective: To explore the effects of isorhamntin (Iso) on intracelluar free calcium concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). Methods: The effects of Iso on changes in [Ca2+]i that occurred in cultured rabbit aortic smooth muscle cells following exposure to high K+, norepinephrine(NE) and Angiotensin Ⅱ(Ang Ⅱ) were determined by using the new generation of fluorescent Ca2+ -indicator fluo-3/AM, and then compared with those of verapamil. Results: It was found that Iso(10-6~10-4mol/L) inhibited the elevation of [Ca2+], in duced by high potassium-depolarization in aconeentraion-dependentmanner. These effects were similar to but weaker than those of verapamil. In addition, it was shown that Iso(10-6~10-4mol/L) inhibited the elevation of [Ca2+], induced by NE and Ang Ⅱin the presence of extracellular Ca2+. In the absence of extracellular Ca2+, Iso (10-5、10-4mol/L) also had some blocking effects on the NE-induced [Ca2+]i increase. Conclusions: The results suggest that Iso might decreas the [Ca2+]i ofVSMC by blocking both voltage-dependent calcium channels and receptor-operated calcium channels, which minght be is one of hypotensive mechanisms.