Cl~-通道在内皮素-1引起的血管平滑肌细胞增殖中的作用

目的　研究Cl-通道在内皮素 1(endothelin 1,ET 1)引起的血管平滑肌细胞增殖中的作用 ,并探讨其可能的作用机制。方法　通过细胞计数和3H TdR参入实验 ,并结合fura 2 /AM荧光测定胞浆游离Ca2 + 浓度 (Ca2 + ]i)等技术 ,观察了Cl-通道阻断剂对ET 1引起的 Ca2 + ]i 变化及血管平滑肌细胞增殖的影响。结果　Cl-通道阻断剂DIDS可呈浓度依赖性地抑制 10nmol·L-1ET 1引起的血管平滑肌细胞增殖 ,其它Cl-通道阻断剂如IAA 94、NPPB、SITS、DPC和速尿均无此作用 ,DIDS也能抑制 10nmol·L-1ET 1引起的内流相 Ca2 + ]i 升高 ,而对ET 1引起的Ca2 + 释放无影响 ;预先将细胞与 1μmol·L-1nifedipine作用后 ,3μmol·L-1DIDS对 10nmol·L-1ET 1引起的内流相 Ca2 + ]i 升高及血管平滑肌细胞增殖不再有效 ,将细胞与 10 μmol·L-1SK&F96 36 5预孵后 ,DIDS却能进一步抑制ET 1的上述作用 ;3μmol·L-1DIDS对 30mmol·L-1KCl引起的胞浆Ca2 + ]i升高无影响。结论　DIDS可通过阻断Cl-通道来抑制ET 1因促发Cl-通道开放经电压依赖性钙通道的Ca2 +内流及细胞增殖 ,DIDS敏感的Cl-通道可能在ET 1促发的Ca2 + 内流及血管平滑肌细胞增殖的调控上都起着重要的作用

Role of Cl- channels in endothelin-1-induced proliferation of vascular smooth muscle cells

AIM To examine the role of Cl - channels in endothelin 1 (ET 1) induced proliferation of vascular smooth muscle cells (VSMCs). METHODS Through cell counting and 3H TdR incorporation, together with Ca 2+ ] i measurement by fura 2/AM fluorescence, we studied the effects of Cl - channel blockers on proliferation of VSMCs induced by ET 1. RESULTS Cl - channel blocker, DIDS, inhibited 10 nmol·L -1 ET 1 induced proliferation of VSMCs in a concentration dependent manner, however,other Cl - channel blockers such as IAA 94, NPPB, SITS, DPC and furosemide, all failed to inhibit ET 1 induced proliferation of VSMCs. DIDS reduced 10 nmol·L -1 ET 1-induced sustained Ca 2+ ] i elevation but not Ca 2+ release from internal stores; Pretreatment of cells with 1 μmol·L -1 nifedipine abolished the inhibitory effect of 3 μmol·L -1 DIDS on proliferation of VSMCs and Ca 2+ ] i elevation evoked by 10 nmol·L -1 ET 1 , while after cells were pretreated with 10 μmol·L -1 SK&F96365, the same concentration of DIDS could also inhibit the aforecited effects of ET 1;3 μmol·L -1 DIDS had no effect on 30 mmol·L -1 KCl induced elevation of Ca 2+ ] i. CONCLUSION DIDS inhibited Ca 2+ influx and VSMCs proliferation induced by ET 1 through blockade of DIDS sensitive Cl - channels, and these channels may play important roles in modulating Ca 2+ influx and VSMCs proliferation induced by ET 1.