[Ca^(2+)]_i对大鼠肺动脉平滑肌细胞膜钙激活氯离子通道的调节作用  

Role of intracellular free Ca^(2+) concentration in the regulation of calcium-activated chloride channels in rat pulmonary artery smooth muscle cells

作　　者：杨朝[1] 张珍祥[1] 徐永健[1] 李亚清[1] 叶涛[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院呼吸疾病研究室,湖北武汉430030

出　　处：《中国病理生理杂志》2007年第6期1116-1119,共4页Chinese Journal of Pathophysiology

摘　　要：目的:探讨细胞浆内游离钙离子浓度([Ca2+]i)在常氧、急性和慢性低氧条件下对大鼠肺动脉平滑肌细胞(PASMCs)膜钙激活氯离子通道(ClCa)的调节作用。方法:常规离体血管灌流法检测急性低氧时肺动脉环张力变化;钙荧光探针(Fura-2/AM)负载培养PASMCs,观察常氧和慢性低氧条件下[Ca2+]i的变化并由此对ClCa的影响;同时用四唑盐(MTT)比色法观察当[Ca2+]i变化时ClCa对PASMCs增殖的影响。结果:(1)ClCa阻断剂尼氟灭酸(NFA)和indaryloxyaceticacid(IAA-94)可以舒张急性低氧引起的肺动脉环收缩。(2)慢性低氧时[Ca2+]i升高:常氧状态下,PASMCs[Ca2+]i为(123.63±18.98)nmol/L,低氧时为(281.75±16.48)nmol/L(P<0.01)。(3)常氧时,NFA和IAA-94对[Ca2+]i无明显影响(P>0.05)。(4)慢性低氧时,NFA和IAA-94使PASMCs[Ca2+]i由(281.75±16.48)nmol/L降低到(117.66±15.36)nmol/L(P<0.01)。(5)MTT比色法中,慢性低氧状态下NFA和IAA-94引起升高的吸光度(A)值降低,由0.459±0.058到0.224±0.025(P<0.01)。结论:低氧引起[Ca2+]i升高,这可能激活ClCa,对[Ca2+]i起正反馈作用,ClCa可能在低氧肺动脉高压中起作用;慢性低氧条件下ClCa可能参与促进大鼠PASMCs的增殖。AIM： To investigate the role of intracellular free Ca^2 ＋concentration （ [Ca^2＋i） in the regulation of calcium - activated chloride （ Clca ） channels in pulmonary artery smooth muscle cells （PASMCs） of rats under normoxic, acute and chronic hypoxic conditions. METHODS： Acute hypoxia -induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusion in vitro. The fluorescence Ca^2＋ indicator Fura - 2/AM was used to observe [Ca^2＋]i of rat PASMCs in normal and chronic hypoxic condition. The influences of Clca channels on PASMCs proliferation were assessed by MTr assay. RESULTS： （1） The Clca channel blockers niflumic acid （NFA） and indaryloxyacetic acid （IAA - 94） produced inhibitory effects on acute hypoxia- evoked contractions in pulmonary artery. （2） Under chronic hypoxic condition, [Ca^2＋]i was increased. In normoxic condition, [Ca^2＋i was （123. 63 ± 18. 98） nmol/L, and in hypoxic condition, [Ca^2＋]i was （281.75 ± 16. 48）nmol/L （P 〈 0. 01 ）. （3） In normoxic condition, [Ca^2＋]i had no significant change and no effect on Clca channels was observed （P 〉 0. 05）. （4） Chronic hypoxic increased [Ca^2＋]i which opened Clca channels. The NFA and IAA -94 blocked them and decreased [Ca^2＋]i from （281.75 ± 16. 48） nmoL/L to （117. 66 ± 15. 36）nmol/L （P 〈 0.01）. （5） MTr assay showed that in chronic hypoxic condition NFA and IAA -94 decreased the value of absorbing light degree （A value） from 0. 459 ± 0. 058 to 0. 224 ± 0. 025 （ P 〈 0. 01 ）. CONCLUSION： Hypoxia increased [Ca^2＋]i which opened Clc channels and had a positive -feedback to [Ca^2＋]i. This may play an important role in hypoxic pulmonary hypertension. In chronic hypoxic condition, Clca channel may play a role in the regulation of PASMCs proliferation.

关 键 词：氯化物通道 钙 肺动脉 肌 平滑 低氧肺血管收缩 

分 类 号：R363[医药卫生—病理学]