反复力竭运动大鼠心脏窦房结细胞T-型钙离子通道的变化  

T-type calcium channel in sinoatrial node cells of rats after repeated exhaustive exercise

作　　者：薄冰[1] 

机构地区：[1]河南大学体育学院,河南省开封市475000

出　　处：《中国组织工程研究》2014年第24期3829-3834,共6页Chinese Journal of Tissue Engineering Research

基　　金：河南省教育厅科学技术重点研究项目(14A890008)~~

摘　　要：背景:目前,运动医学领域关于运动对窦房结细胞T-型钙离子通道(T-Ca2+通道)的影响鲜见报道。目的:分析2周力竭跑台运动对大鼠心脏窦房结T-Ca2+通道亚基Cav3.1 mRNA表达及通道电流密度的影响。方法:健康雄性SD大鼠50只共分5组。对照组10只大鼠不进行任何运动训练,一次力竭组20只大鼠在正常饲养2周后,进行一次速度25 m/min,坡度为0°跑台训练至力竭;反复力竭组20只大鼠运动方式及强度同一次力竭组,跑台训练1次/d,每周运动6 d,休息1 d,共训练2周。运动组大鼠分别于运动后0 h及24 h(各10只)取材,应用实时荧光定量PCR技术测定T-Ca2+通道亚基Cav3.1 mRNA表达变化,应用细胞急性分离及全细胞膜片钳技术测定通道电流密度变化,以观察跑台训练运动对大鼠心脏窦房结细胞膜上T-Ca2+通道的影响。结果与结论:与对照组相比,反复力竭运动0 h和反复力竭运动24 h组Cav3.1 mRNA表达明显下降(P<0.01)。反复力竭运动0 h和反复力竭运动24 h组T-Ca2+通道ICa,T电流密度明显低于对照组及一次力竭组(P<0.01)。结果表明,2周反复力竭跑台训练可引起窦房结细胞膜T-Ca2+通道亚基Cav3.1 mRNA表达及ICa,T电流密度减少,这可能引起窦房结细胞舒张期自动除极及自律活动减慢,提示反复力竭运动对于T-Ca2+通道的影响可能成为运动引发窦房结功能障碍及运动性心律失常的离子通道机制之一。BACKGROUND： At present, there is little evidence about the effect of exercise on T-type caloium channel （T-Caz＋ channel） in sinoatrial node cells. OBJECTIVE： To analyze the subunit Cav3.1 mRNA and current density of T-Ca2＋ channel of sinoatrial node cells after 2 weeks of repeated exhaustive treadmill exercise in rats. METHODS： Fifty healthy male Sprague-Dawley rats were equally assigned into five groups, including one control groups （n=10; no exercise）, two exhaustive exercise groups （n=20; single treadmill running at 25 m/rain, 0° slope） and two repeated exhaustive exercise groups （n=20; repeated treadmill running at 25 m/rain, 0° slope, once per day, 6 days per week, for 2 weeks. The samples were drawn from 10 rats in the exercise groups at 0 and 24 hours after exhaustive treadmill running respectively. The mRNA expression of T-Ca2＋ channel subunit Cav3.1 in sinoatrial node was analyzed by real-time fluorescent quantitative PCR. The current density of T-Ca2＋ channel was analyzed with acute isolation and whole-cell patch clamp techniques, to observe the effect of repeated treadmill exercise on T-Ca2＋ channel. RESULTS AND CONCLUSION： The Cav3.1 mRNA expression of the repeated exhaustive exercise groups at 0 and 24 hours were significantly lower than that of control group （P 〈 0.01）. The current density of T-Ca2＋ channel of the repeated exhaustive exercise groups at 0 and 24 hours were significantly lower than that of control groupand single exhaustive exemise group （P 〈 0.01, P 〈 0.01）. Two-week repeated exhaustive treadmill exercise can decrease the subunit Cav3.1 mRNA expression and the current density of T-Ca＋channel in the sinoatrial node cells. The exhaustive exercise induced diastolic automatic depolarization and slowed down spontaneous activity of sinoatdal node cells, which may be one of the most important mechanism of exercise-induced sinoatdal node dysfunction and arrhythmia.

关 键 词：组织构建 组织工程 运动医学 跑台训练 窦房结 T-型钙离子通道 亚基Cav3 1 

分 类 号：R318[医药卫生—生物医学工程]