运动疲劳大鼠心肌细胞L-型钙通道生物物理特性的研究

Study of Biophysical Properties of L-type Calcium Channel in Rat Myocardial Cells with Exercise-induced Fatigue

目的:研究运动疲劳对大鼠心肌细胞L-型钙通道电流及生物物理学特性的影响,证明L-型钙通道直接参与到运动疲劳导致的细胞内钙浓度变化中。方法:48只大鼠雌雄不拘,随机分成对照组和运动疲劳组。采用连续15天游泳耐力训练方法建立运动疲劳大鼠模型;应用膜片钳技术检测运动疲劳对大鼠心肌细胞L-型钙通道电流的影响。结果:1)运动疲劳大鼠全细胞L-型钙电流峰值(IpeakCaL)显著增加:全细胞IpeakCaL电流从-470±11.73 pA变化到-819.90±10.78 pA,n=8,P<0.05,运动性疲劳组较对照组增幅74.60%;2)膜片钳技术检测L-型钙电流的激活和失活通道动力学特性:运动疲劳模型组大鼠心肌细胞的L-型钙电流的失活曲线右移,而激活曲线与对照组相比没有变化。结论:运动疲劳引起大鼠L-型钙通道特性改变,使得钙电流增强,导致心肌细胞内钙平衡调节紊乱。

Objective：To study the effects of exercise-induced fatigue on myocardial cells L-type calcium currents and biophysical properties in rats;to prove that L-type Ca2＋ channel participates directly in the change of i.due to exercise-induced fatigue.Methods：48 rats,male or female,were divided into control group and exercise-induced fatigue group randomly.15 days endurance swimming training was adopted to establish exercise-induced fatigue models;patch clamp technique was applied to examine the effects of exercise-induced fatigue on myocardial L-type calcium currents in rats.Results：1）The whole cell L-type Ca2＋ channel peak currents obviously increased in exercise-induced fatigue rats：the whole cell L-type Ca2＋ channel peak currents increased from-470±11.73pA to-819.90±10.78pA（n=8,P0.05）,the exercise-induced fatigue group increased 74.60% compared with the control group.2） Using patch clamp technique to examine the activation of L-type Ca2＋ channel currents and dynamic properties of inactivation channel：Inactivation curve shifted to the right in the exercise-induced fatigue group compared with the control group,activation curve in the exercise-induced fatigue group did not alter compared with the control group.Conclusion：Exercise-induced fatigue changes biophysical property of L-type Ca2＋ channel,and enhances L-type Ca2＋ channel currents and causes disorders in calcium balance adjustment.