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抗心律失常药UK-68798对家兔心脏房室结区不同细胞的电生理作用

高天礼, Beyer T, Brachmann J

北京大学生物系. 北京(100871)；德国海德堡大学心脏病学系. 德国(HD-6900)

摘要

5×10~(-9)至5×10~(-6)mol/L的UK-68798对4种细胞的动作电位幅值、静息 膜电位皆无影响。对房室结区(AVN)的自搏率有剂量依赖性减慢作用, 但不改变A-H传导时 间。在5×10~(-8)—5×10~(-6)mol/L剂量范围, 此药使动作电位时程(APD_(50))和(APD_(90))发生剂量依赖性延长。在UK-68798的作用下, 4种细胞的有效不 应期(ERP)也发生剂量依赖性延长, 但不存在像APD延长百分率那样的差别。4种细胞ERP所相当的复极化膜电位未受药物影响, 从而避免了由于兴奋性恢复的不均一性, 使AVN区成为折 返性心律失常的发源地。图4表3参15

关键词： UK－68798; 房室结; 动作电位时程; 有效不应期

Electrophysiological effects of antiarrhythmic drug UK-68798 on different AV nodal cells in rabbit heart

Gao Tianli, Beyer T, Brachmann J

Department of Biology, Beijing University. Beijing

Abstract

By means of microelectrode techniques the electrophysiological effects of a new class Ⅲantiarrhythmic agent, UK-68798 (Dofetilide), were investigated on atrionodal (AN), nodal(N), nodal-His(NH)and His (H) cells in the AVN area of rabbit heart. UK-68798(5×10~(-9)to 5×10~(-6)mol/L)had no effect on APA and RP of the 4 kinds of cells but caused a dose-dependent decrease in AVN spontaneous rhythm without changing the A-H conduction time. APD_(50) and APD_(90) were prolonged markedly by the drug in a dose-dependent manner. Among the 4 kinds of cells, N cell had the highest percentage increment in APD, indicating a prominent sensetivity to the drug. The effective refractory periods (ERP) of the 4 kinds of cells were lengthened also in a dose-dependent manner. However, ERP corresponding repolarization membrane potentials(ERP-RMP) of the 4 kinds of cells were not affected by the drug. suggested that though ERP increased in parallel with APD prolongation, the homogeneous △ERP% and unchanged ERP-RMP values of the 4 kinds of cells would prevent the AVN area from becoming a source of reentry arrhythmias under the action of UK-68798.

Key words: UK-68798;Atrioventricular node;Action potential duration;Effective refractory period

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引用本文：

高天礼, Beyer T, Brachmann J. 抗心律失常药UK-68798对家兔心脏房室结区不同细胞的电生理作用[J]. 生理学报 1994; 46 (3): .

Gao Tianli, Beyer T, Brachmann J. Electrophysiological effects of antiarrhythmic drug UK-68798 on different AV nodal cells in rabbit heart. Acta Physiol Sin 1994; 46 (3): (in Chinese with English abstract).