替米沙坦对牵张刺激乳大鼠心房肌细胞短暂外向钾电流和动作电位的影响  

Effects of telmisartan on transient outward potassium current and action potential in stretched atrial neonatal myocytes

作　　者：胥亚楠[1] 杨龙[1,2] 杨天和[1] 何炯红[1] 

机构地区：[1]贵阳医学院附属人民医院,贵州贵阳550002 [2]遵义医学院第三附属医院

出　　处：《中国心脏起搏与心电生理杂志》2014年第4期337-340,共4页Chinese Journal of Cardiac Pacing and Electrophysiology

基　　金：国家自然科学基金(项目批准号:81060018)

摘　　要：目的探讨替米沙坦对牵张刺激乳大鼠心房肌细胞瞬时外向钾电流(Ito)和动作电位(AP)的影响。方法利用胰酶与Ⅱ型胶原酶混合酶解,并结合差速贴壁和5-溴脱氧尿嘧啶核苷处理得到纯化的乳大鼠心房肌细胞。实验分对照组、牵张组、替米沙坦(1μmol/L)组。采用全细胞膜片钳技术分别记录三组Ito和AP。结果在+20^+60 mV刺激电压水平,Ito电流密度(pA/pF):牵张组低于对照组[+20 mV和+60 mV分别为(0.8±0.3)vs(2.1±0.8)和(1.6±0.4)vs(12.1±3.0);P均<0.01],替米沙坦组[+20 mV和+60 mV分别为(1.4±0.3)和(6.7±1.3)较牵张组增大,P均<0.01]。牵张组AP复极50%、90%时程(APD50、APD90)较对照组明显缩短[(9.6±1.3 ms)vs(15.5±2.4)ms,(29.9±2.9)ms vs(56.3±3.6)ms,P均<0.01,n=9],替米沙坦组[APD50、APD90分别为(11.7±2.0)和(41.4±4.6)ms]较牵张组APD延长(P均<0.05)。结论牵张刺激可降低乳大鼠心房肌细胞Ito电流密度、缩短APD;替米沙坦干预可抑制牵张刺激的此作用。Objective To investigate the effects of telrnisartan on transient outward potassium current （Ito） and action potential （AP） of cultured atrial neonatal myocytes under condition of stretch. Methods Atrial myoeytes were isolated using mixed enzyme and then were purified with the differential adhesion and the 5-bromo-2-deoxyuridine process method. Cells were divided into control, stretched and telmisartan groups according to the treatment administered, ho and AP of single atrial myocytes were recorded by whole-cell patch-clamp technique. Result With the ＋20 ~ ＋60 clamp potential, the den- sitys of Ito （pA/pF） in stretched group [ （0.8±0.3） and （1.6±0.4） at ＋20 and ＋60 clamp potential respectively] were significantly decreased compared with that of control [ （2.1±0.8） and （12. 1±3.0） ; P〈0.01, respectively]. Telmisartan [ （1. 4±0.3 ） and （6.7± 1.3 ） ] increased Ito density of stretched group （ P〈0.01, respectively） ; Compared with that of control group, the AP duration at 50% and 90% level of repolarization （APD50 and APD90 ） were decreased in stretched group [ （15.5±2.4） ms vs （9.6±1.3） ms, （56.3±3.6） ms vs （29.9±2.9） ms; P〈0.01, respectively]. Telmisartan [（11.7±2. 0） ms, （41.4±4.6） ms） ] elongated APDs0 and APDg0 in stretched group （P〈0.05, respectively）. Conclusion Stretch stimulation leads to the reduce of Ito density and APD of cultured atrial neonatal myocytes, which are attenuated by incubated with telmisartan.

关 键 词：心血管病学 替米沙坦 牵张 心房肌细胞 短暂外向钾电流 动作电位 膜片钳 

分 类 号：R331.38[医药卫生—人体生理学]