兔界嵴细胞离子通道特性研究  

Ion channels characteristics of crista terminalis cells in rabbits

作　　者：金立军[1] 黄从新[2] 刘学银[1] 杨沙宁[1] 吴刚[2] 王腾[2] 谢强[3] 

机构地区：[1]长江大学附属第一医院心内科,湖北荆州434000 [2]武汉大学人民医院心内科,湖北武汉430060 [3]厦门大学附属第一医院心内科,福建厦门361003

出　　处：《中国心脏起搏与心电生理杂志》2012年第4期329-332,共4页Chinese Journal of Cardiac Pacing and Electrophysiology

摘　　要：目的研究生理状态下及异丙肾上腺素灌流对兔界嵴(CT)与梳状肌(PM)细胞动作电位(AP)及钠电流(INa)、短暂外向钾电流(Ito)、L型钙电流(ICa-L)、延迟整流钾电流(IK)及内向整流性钾电流(IK1)的影响,探讨CT与房性心律失常的关系。方法酶解法分离兔CT及PM细胞,利用全细胞膜片钳技术,记录生理状态下及异丙肾上腺素灌流后CT与PM细胞AP及INa、Ito、ICa-L、IK及IK1的变化。结果①生理状态下,CT细胞动作电位时程(APD)较长,可见明显的平台期;PM细胞AP形态与普通心房肌细胞相似,1期复极迅速,平台期短,类似三角形。②生理状态下,CT细胞Ito电流密度比PM细胞明显降低(7.13±0.38 pA/pF vs 10.70±0.62 pA/pF,n=9,P<0.01),而INa、Ito、ICa-L、IK及IK1则无明显差别。③异丙肾上腺素灌流时CT与PM细胞APD20、APD50、APD90均延长(n=8,P<0.01);指令电位+50 mV时,CT与PM细胞Ito电流密度均减少(n=9,P<0.01)而IK均增加(n=8,P<0.05);指令电位+10 mV时,CT与PM细胞ICa-L电流密度均增加(n=9,P<0.01);IK1在两种心肌细胞均无明显差异。结论 CT与PM细胞AP差异与Ito有关。异丙肾上腺素灌流时ICa-L与IK增强,Ito抑制使CT与PM细胞APD延长,触发机制可能是CT参与房性心律失常的机制之一。Objective To investigate the action potential （AP） and sodium currents （INa）, transient outward potassium current （Ito）, L-type calcium current （ICa-L）, the delayed rectifier potassium current （IK） and inward rectifier potassium current （[KI） of both crista terminalis （CT） and pectinate muscles （PM） cells on the physiological state in rabbits and the effects of isoproterenol perfusion in order to explore the relationship between CT and atrial tachycardia. Methods The CT and PM cells were obtained by enzymatic dissociation, then AP and INa, Ito, ICa-L, IK, IKI were recorded via whole-cell patch- clamp technique both on the physiological state and after isoproterenol perfusion. Results （1）On the physiological state, the action potential duration （APD） of CT cells was long and showing a clear plateau; AP configuration of PM ceils was simi- lar to that of regular atrial myocytes, phase I repolarization was rapid, and the plateau was short and triangle-like. （2）Under physiological conditions, Ito current density of CT cells was significantly lower than PM cells（7.13 ±0.38 pA/pF vs 10.70 ± 0.62 pA/pF,n = 9,P 〈 0.01 ）, while INa, Ito, ICa-L, IK and IKI current density had no significantly difference between them. （3） After isoproterenol perfusion, 20%, 50% and 90% duration of action potentials （ APD20, APD50 and APD90 ） were prolonged in both CT cells and PM cells（ n = 8 ,P 〈 0.01 ）. When the command potential at＋ 50 mV, Ito current density was reduced （n = 9, P 〈0.01 ） while the IK current densitywas increased （n = 8, P 〈 0. 05 ） both in CT cells and PM cells; When the command potential at ＋ 10 mV, ICa-L current density was increased （ n = 9, P 〈 0.01 ） while the IKI had no significantly difference （n = 8, P 〈 0. 05） in them. Conclusion The difference of AP is related with I,o in CT and PM cells. ICa-L and Ix enhance while Ito inhibition after isoproterenol perfusion, which results in APD prolonged, thus trigger mechanism in C

关 键 词：电生理学 离子通道 膜片钳技术 界嵴 梳状肌 动作电位 兔 

分 类 号：R331.38[医药卫生—人体生理学]