虎杖苷对VSMC内钙信号的调节机制初探

目的　观察虎杖苷对大鼠主动脉平滑肌细胞(VSMC)内游离钙浓度的变化 ,以探讨虎杖苷对血管平滑肌细胞的调节机制。方法　用荧光染料Fluo 3 AM标记细胞 ,在粘附式细胞仪上测定细胞内游离钙的变化。结果　给予虎杖苷 5min后 ,VSMC内游离钙浓度升高。当虎杖苷加入前 10min用河豚毒素和优降糖分别预处理后 ,其VSMC内游离钙都不再明显升高 ;而给予普萘洛尔、甲氰咪胍及亚甲蓝分别预处理时 ,细胞内钙浓度反而升得更高 ,与单纯虎杖苷作用相比差异都有显著性。结论　虎杖苷可增加细胞内游离钙浓度 ,其作用可能与钠、钾通道开放有关 ,并且受 β肾上腺素能受体、H2 受体系统及鸟苷酸环化酶系统的反向调节。

Regulation mechanism of polydatin on the signal transduction of calcium of vascular smooth muscle cells in rats

AIM To elucidate the regulation mechanism of polydatin on the cytosolic free calcium concentration Ca 2+ ] i of vascular smooth muscle cells(VSMC) isolated from the aortas of rats. METHOD VSMC were labelled with fluo 3 AM, a calcium sensitive fluorescent dye, and Ca 2+ ] i was determined by the use of the adherent cells analysis and sorting apparatus(ACAS 570). RESULT Ca 2+ ] i of VSMC was elevated 5 min after polydatin(0 6 mmol·L -1 ) adding (16%±1 3% vs baseline, P<0 01). The effect of polydatin was inhibited remarkably by pretreated 10 min before polydatin adding with tetrodotoxin ( 1 μmol·L -1 ), a sodium channel blocker and glybenclamide (1 μmol·L -1 ), a potassium channel blocker, the fluorescence value were 103 5%±4 36% and 107%±5 66% respectively vs baseline. But it was enhanced significantly by pretreating with propranolol (3 mmol·L -1 , a blocker of β adrenegic receptor, 130%±6 7% vs baseline, P<0 01), cimetidine (1 mmol·L -1 ,a blocker of histamine receptor, 149 2%±5 2% vs baseline, P<0 01) and methylene blue (0 8 mmol·L -1 ,a inhibitor of cGMP cyclase, 157%±16 7% vs baseline, P<0 01). CONCLUSION Polydatin can increase the cytosolic Ca2+ ] i, which may be related with the open of sodium channel and /or potassium channel, and down regulated by β adrenegic receptor system, histamine receptor system and cGMP.