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|本期目录/Table of Contents|

缺血对心室浦肯野纤维跨膜电位和起搏离子流的影响(PDF)

《心脏杂志》[ISSN:1009-7236/CN:61-1268/R]

期数:
1998年第1期
页码:
5-7
栏目:
论著
出版日期:
1998-01-01

文章信息/Info

Title:
Effect of ischemia on the transmembrane potential and the pacemaker current in cardiac Purkinje′s fibers
作者:
杜友爱
温州医学院生理学教研室 温州 325000
Author(s):
Du Yoai
Department of physiology,Wenzhou Medical College ,Wenzhou 325000
关键词:
心肌缺血　浦肯野纤维　跨膜电位　起搏离子流
Keywords:
cardiac ischemia　　Purkinje′s fibre　　transmembrane potential　　pacemaker current
分类号:
-
DOI:
-
文献标识码:
-
摘要:
采用细胞内微电极和双微电极电压箝制术, 观察缺血对绵羊心室浦肯野纤维跨膜电位和起搏离子流(If)的影响。结果: 模拟缺血溶液灌流30 min, 浦肯野纤维最大舒张电位(MDP)、动作电位幅度(APA) 明显减小; 动作电位时程APD50,APD90明显缩短(P<0.01) ; If幅度降低, 激活曲线向超极化方向移位, 最大激活时间及半最大激活时间延长(P<0.01)。上述结果表明: 心肌缺血时, 心室浦肯野细胞跨膜电位及正常起搏活动不是增强, 而是减弱。提示缺血性室性心律失常不是由于正常心室自律活动异常增强引起。
Abstract:
We employed double-microelectrode voltage clamp technique to detect the effect of ischem ia-mimic solution on the transmembrane potential and the pacemaker current (If) in sheep cardiac Purkinje′sfibers. The sequence was as follows: After being perfused with ischemia-mimic solution, the maxinum diastolic potential (MDP) and the action potential amplitude(APA)were decreased, the action potential duration(APD) was shortened significantly (n=15,P<0.01),the amplitude of If was decreased,the activation curve of If was shifted to hyperpolarization,the activation time and half activation time toasteady state value of If current were prolonged (n=13,P<0.001). The above results indicated that under the ischemic condition, the transmembrane potential and the pacemaker function of cardiac Purkinje′s cell are inhibited, and acute ischemic ventricular arrhythmia may not be caused by abnormal strengthening of normal ventricular pacemaker activity. system optimization.

参考文献/References

［1］Janse MJ ,Wit AL. Electrophysiological mechanisms of ventricular arrythmias resulting from myocardial ischemia and infarction. Physiol Rev,1989; 69 (4) : 1049.

［2］Silverman HS, Stern MD. Ionic basis of ischemia cardiac injury insight fo m cellular studies. Circ Res, 1994; 28(25) : 297.

［3］徐有秋, 刘远谋. 双微电极法电压箝制术. 见: 生理学方法与技术, 第3 集. 上海: 科学出版社, 1987: 1～ 10.

［4］ Lurie KG,Argentierl TM , Sheldon J , et al. Metabolism and electrophysiology in subendocardial Purkinje fibers after infarction. Am J Physiol, 1987; 253 (3) : H662.

［5］Kimura S, Bassett AL , Kohya T , et al. Automaticity,triggered activity and responses to abrenergic stimulation in cat subendocardial Purkinje fibers after healing of myocardial infarction. Circulation, 1987; 75 (3) : 651.

[6]Nishimura M , Tanaka H, Homma N , et al. Ionic mechanisma of the depression of automaticity and conduction in rabbit atrioventricular node caused by hypoxia or metabolic inhibition and protective action of glucose and valine. Am J Cardiol, 1989; 64: 243.

[7]Mechzaki S. The effects of hypoxia and ischemia on Na+/C a2+ exchange in iso lated cardiac myocates from guinea pigs and in isolated perfustion rat heart. Japn J Physiol, 1994; 44 (Suppl) : 157.

［8］Difrancesco D, Tortora P. Direct activation of cardiac pacemaker channels by intracellular cyclic AMP. Nature, 1991; 351: 145.

备注/Memo

备注/Memo:
(收稿1997-06-05；修回1997-10-06)
更新日期/Last Update: 1998-01-01