小电导钙激活钾通道在人心房肌细胞中的表达及功能  

Expression and functional role of small conductance Ca^(2+)-activated K^+ channels in human atrial myocytes

作　　者：于涛[1,2,3] 吴若彬[1,2] 郭惠明[1,2] 邓春玉[1,4] 郑少忆[1,2] 邝素娟[1,4] 

机构地区：[1]广东省心血管病研究所/广东省人民医院 [2]广东省医学科学院心外科,广东广州510080 [3]广州医学院第二附属医院心外科,广东广州510260 [4]广东省医学科学院医学研究中心,广东广州510080

出　　处：《南方医科大学学报》2011年第3期490-494,共5页Journal of Southern Medical University

基　　金：广东省自然科学基金(8151008002000017)

摘　　要：目的探讨小电导钙激活钾通道在人心房肌细胞中的表达情况和功能意义。方法收集行心内直视手术的窦性心律先心病患者8例,取右心耳组织,行免疫组化分析3种SK通道亚型(SK1、SK2和SK3)表达情况;使用经典两步酶解法分离心房肌细胞,应用穿孔膜片钳和传统电压钳技术分别记录心房肌细胞动作电位(APs)和全细胞的钙激活钾电流(IK,Ca),比较给予SK通道特异性阻断剂apamin(100 nmol/L)前、后动作电位时程(APD)变化。结果 SK1、SK2和SK3通道亚型在心房肌细胞中均呈阳性表达,膜片钳记录证实IK,Ca的存在,且apamin明显延长复极化90%的动作电位时程(APD90),而对APD50无明显影响。结论 3种SK通道亚型在人心房肌细胞中均有表达;与SK通道在神经元细胞中介导动作电位后超极化过程的功能不同,在心房肌细胞中,SK通道是参与APs复极末期过程的重要离子通道。Objective To investigate the expression and functional role of the small conductance Ca2＋-activated K＋ channels in human atrial myocytes.Methods We collected the right atrial appendage tissues from 8 patients with congenital heart defect with sinus rhythm undergoing open-heart surgery.Immunohistochemistry was performed to identify the expression of 3 isoforms of SK channel（SK1,SK2 and SK3）.Using the classical two-step enzymatic isolation method,perforated patch clamp and conventional voltage-clamp techniques were performed to record the action potentials（APs） and the whole-cell Ca2＋-activated K＋ current（IK,Ca） in the single atrial myocyte.We compared the changes in action potential duration（APD） before and after the application of a specific SK channels blocker apamin（100 nmol/L）.Results Human atrial myocytes showed positivity for all the SK1,SK2 and SK3 isoform channels.Patch-clamp recording confirmed the presence of IK,Ca,and apamin significantly prolonged APD at 90% repolarization（APD90）,but produced no obvious effect on APD50.Conclusion The three isoforms of SK channels are all expressed in human atrial myocytes.SK channels play a prominent role in the late phase of repolarization in human atrial myocytes,which is distinct from their functional roles in neurons where they mediate the process of afterhyperpolarization following APs.

关 键 词：小电导钙激活钾通道 人 心房肌细胞 膜片钳 

分 类 号：R331.3[医药卫生—人体生理学]