心肌内向整流钾通道激动剂抑制异丙肾上腺素所致大鼠心室重构  

Cardiac Ⅰ_(K1) agonist inhibits isoproterenol-induced ventricular remodeling in rats

作　　者：杨迎[1] 郭云飞[1] 翟旭雯[2] 张研[1] 李盼[1] 张莉[3] 吴博威[2] 刘清华[1] 

机构地区：[1]山西医科大学病理生理学教研室,山西太原030001 [2]山西医科大学生理学教研室,山西太原030001 [3]山西省儿童医院,山西太原030013

出　　处：《中国病理生理杂志》2017年第3期399-404,共6页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.31200864);山西省回国留学人员科研资助项目(No.2016-059)

摘　　要：目的:观察和探讨内向整流钾通道(Ⅰ_(K1))激动剂盐酸扎考必利(zacopride,Zac)对异丙肾上腺素(isoproterenol,Iso)所致心室重构的影响及作用机制。方法:SD大鼠随机分为正常对照组、Iso模型组、Zac干预组、Zac+氯喹干预组和卡托普利阳性对照组。腹腔注射异丙肾上腺素3 mg/kg,每天1次,连续给药10 d,观测各组全心质量/体质量比和左心室质量/体质量比。用全细胞膜片钳技术检测大鼠心室肌细胞电压门控钙电流(Ⅰ_(Ca-L))、静息膜电位(RMP)及动作电位时程(APD)的变化。选用新生1~3 d的SD乳鼠,用0.08%胰蛋白酶和0.04%Ⅱ型胶原酶消化心脏组织,经差速贴壁法和5-溴脱氧尿嘧啶核苷纯化心肌细胞后随机分成正常对照组、Iso模型组、Zac干预组、Zac+BaCl_2干预组和Zac+氯喹干预组,培养24 h后用激光共聚焦显微镜检测心肌细胞内游离钙离子浓度。结果:Iso模型组与正常对照组比较,全心肥厚指数、左心室肥厚指数明显增加,膜片钳结果提示RMP减小APD明显延长;Zac干预组明显抑制心肌肥大,并增大RMP,缩短APD。同时应用低剂量Ⅰ_(K1)抑制剂氯喹可明显抑制Zac的抗心室重构作用,并逆转Zac对RMP和APD影响。在乳鼠心肌细胞,Iso可使细胞表面积增大,细胞内[Ca^(2+)]_i增高;Zac干预后细胞形态恢复至正常或接近正常水平,并显著减轻钙超载。Ⅰ_(K1)阻断剂BaCl_2和氯喹可阻断Zac的效应。结论:Ⅰ_(K1)选择性激动剂Zac明显抑制异丙肾上腺素所致的心室重构,其机制可能为增强Ⅰ_(K1),进而增大RMP,缩短APD,从而阻断心肌细胞内钙超载依赖的信号通路。AIM： To investigate the effect of inward rectifier potassium channels （ IK1 ） agonist zacopride on isoproterenol （ Iso）-induced ventricular remodeling and the involved mechanisms .METHODS：SD rats were randomly di-vided into 5 groups： control, Iso model, Iso＋zacopride, Iso＋zacopride ＋chloroquine and Iso ＋captopril groups.The model of cardiac hypertrophy was developed by intraperitoneal injection of Iso （3 mg＆#183; kg-1 ＆#183; d-1 for 10 d） and verified by determination of heart-to-body weight ratio and left ventricle-to-body weight ratio .The changes of voltage-gated calcium cur-rent （ICa-L）, resting membrane potential （RMP） and action potential duration （APD） of the rat ventricular myocytes were detected by the technique of whole-cell patch clamp.Neonatal rat cardiomyocytes were isolated by 0.08% trypsin and 0. 04%type II collagenase , and purified using differential adherence method and 5-bromodeoxyuridine .Cultured neonatal rat cardiomyocytes were randomly divided into 5 groups： control, Iso, Iso ＋zacopride, Iso ＋zacopride ＋BaCl2 and Iso ＋zacopride＋chloroquine groups .After harvested for 24 h, the [ Ca2 ＋] i of the cardiomyocytes was recorded using a laser confocal scanning microscope .RESULTS：Compared with control group , the whole heart hypertrophic index and left ven-tricular hypertrophic index in Iso group were increased significantly （P〈0.01）.Patch clamp data suggested that RMP was reduced , and APD was obviously prolonged .Zacopride treatment obviously inhibited myocardial hypertrophy , increased the RMP and shortened APD （P〈0.01）.At the same time, application of low dose of I K1 atagonist chloroquine reversed the effect of zacopride .In cultured neonatal rat cardiomyocytes , Iso increased the cell area and [ Ca2 ＋] i .Zacopride treatment restored the hypertrophic morphology of the cells to normal or nearly normal levels , and significantly attenuated calcium overload.IK1 blocker, BaCl2 or chloroquine, reversed the effect of zacopride

关 键 词：内向整流钾通道 异丙肾上腺素 钙超载 心室重构 扎考必利 

分 类 号：R541.7[医药卫生—心血管疾病] R363.2[医药卫生—内科学]