急性低氧大鼠肺动脉平滑肌内质网钙信号的变化及意义  

Effects of acute hypoxia on calcium signal of sarcoplasmic reticulum in pulmonary artery smooth muscle in rats

作　　者：杨朝[1,2] 张珍祥[1] 徐永健[1] 汪涛[1] 马丹[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所,湖北武汉430030 [2]山东烟台毓璜顶医院呼吸内科,山东烟台264000

出　　处：《中国病理生理杂志》2008年第10期2016-2019,共4页Chinese Journal of Pathophysiology

摘　　要：目的:观察急性低氧大鼠肺动脉平滑肌内质网钙信号的变化及意义。方法:细胞水平:钙荧光探针(Fura-2/AM)负载大鼠肺动脉平滑肌细胞(PASMCs),荧光分光光度法,细胞外液无Ca2+及含Ca2+,在常氧(37℃、5%CO2、21%O2、74%N2)和急性低氧(37℃、5%CO2、2%O2、93%N2)时,检测理阿诺碱(RD)和环匹阿尼酸(CPA)等对细胞浆内游离钙离子浓度([Ca2+]i)的影响;离体血管环水平:相同条件,离体血管灌流方法检测肺动脉环张力变化。结果:(1)急性低氧时[Ca2+]i升高:常氧组[Ca2+]i为(96.99±7.16)nmol/L,低氧组为(257.06±32.48)nmol/L(P<0.01)。(2)与低氧组比较,预先用RD或普鲁卡因(procain)抑制内质网理阿诺碱受体敏感钙库,随后再给予低氧刺激时[Ca2+]i不升高,为(100.91±11.21)nmol/L(P<0.01);而用CPA或thapsigargin(TG)抑制内质网摄取Ca2+,再给低氧刺激时[Ca2+]i呈升高状态(P>0.05),而在细胞外液含钙及低氧下CPA及TG引起[Ca2+]i进一步升高(P<0.05)。(3)低氧引起肺动脉环收缩:常氧对基础张力无影响,低氧引起肺动脉环收缩,最大收缩张力达(49.28±8.64)g/g,P<0.01。(4)与低氧组比较,预先用RD或procain抑制内质网理阿诺碱受体敏感钙库,再给予低氧刺激,肺动脉环不收缩,最大收缩张力(3.75±1.14)g/g,P<0.01;而用CPA或TG后,再给予低氧刺激,肺动脉环呈收缩状态(P>0.05),而在细胞外液含钙及低氧下CPA及TG引起肺动脉环进一步收缩(P<0.05)。结论:急性低氧可以引起内质网释放Ca2+,至少来自理阿诺碱受体敏感钙库的Ca2+释放参与了低氧肺血管收缩的发病机制;这可能是PASMCs自身具有的,既不依赖细胞外Ca2+内流,也不依赖血管内皮。AIM： To investigate the effects of acute hypoxia on calcium of sarcoplasmic reticulum in pulmonary artery smooth muscle in rats. METHODS： The fluorescence Ca^2＋ indicator Fura -2/AM was used to observe intracellular free Ca^2＋ concentration （ [ Ca^2＋ ] i ） in rat pulmonary artery smooth muscle cells （PASMCs） in the presence of ryanedine （RD） and cyclopiazonic acid （CPA） in normal （37 ℃, 5%CO2, 21%O2, 74~N2）, acute hypoxic （37 ℃, 5%CO2, 2% O2, 93% N2 ） under Ca^2＋ and Ca^2＋ free conditions. Pulmonary artery ring was used to determine the pulmonary artery tension by using routine blood vascular perfusion in vitro under the same conditions. RESULTS： （ 1 ） Under acute hypoxic conditions, [Ca^2＋ ]i was increased [ （96.99 ±7.16） nmol/L in normoxic condition and （257.06 ±32.48） nmol/L in hypoxic condition, P 〈0. 01 ]. （2） Ryanodine or procain, an agent that blocks ryanodine receptor- seneitive （RyR） Ca^2＋ stores, inhibited hypoxia - induced increases in [ Ca^2＋ ] i ｜ [ Ca^2＋ ]i decreased to （ 100. 91 ±11.21 ） nmol/L, P 〈 0. 01 ）. CPA or thapsigargin （TG）, the agent that inhibits sarcoplasmic reticulum （SR） Ca^2＋ -ATPase and inhibits SR uptake Ca^2＋, increased [ Ca^2＋ ] i. Under acute hypoxic and Ca^2＋ conditions, CPA or thapsigargin （TG） increased [ Ca^2＋ ] i more than that in Ca^2＋ free conditions. （3） Acute hypoxia evoked pulmonary artery contractions. Pulmonary artery tension had no effects under normoxic and increased under acute hypoxia condition. （4） Ryanodine or procain inhibited hypoxia - evoked contractions in the pulmonary artery. CPA or TG increased artery tension. Under acute hypoxic and Ca^2＋ conditions, CPA or TG increased tension more than that in Ca^2＋ free condition. CONCLUSION： The results indicate that release of Ca^2＋ from the SR, at least, RyR Ca^2＋ store, contributes to the mechanism of hypoxic pulmonary vasoconstriction in rat. This is a mechanism intrinsic to pulmonary

关 键 词：低氧性肺血管收缩 理阿诺碱受体敏感钙库 IP3受体敏感钙库 肺动脉平滑肌 肌浆网 

分 类 号：R331[医药卫生—人体生理学]