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内皮素对家兔窦房结起搏细胞电活动的影响

张朝, 李玉龙, 何瑞荣

河北医科大学基础医学研究所生理室. 河北, 石家庄 050017

摘要

在以ET-1作表面灌流时, 起搏细胞的4相自动去极化的速度(VDD)显著减慢, 且呈浓度依赖性, 结果导致起搏细胞的自发放电频率(RPF)降低; 由EF1引起的VDD和RPF下降, 可由事先投用ET_(A)受体选择性阻断剂BQ-123所阻断; 事先投用K_(ATP)通道阻断剂格列苯脲, 可完全消除ET-1对起搏细胞的负性频率作用。

关键词： 内皮素; 内皮素受体; 窦房结; 格列苯脲; BQ－123; 电生理

Effects of endothelin on the electrical activity of sino-atrial pacemaker cells of rabbit

Zhang Zhao, Li Yulong, He Ruirong

Department of Physiology, Institute of Basic Medicine, Hebei Medical University. Shijiazhuang 050017, Hebei

Abstract

The effects of endothelin-1 (ET-1) on the electrophysiological activity of pacemaker cells of rabbit sino-atrial node were examined by using intracellular microelectrode technique. The results obtained were as follows: (1) With superfusion of ET-1 (1-30 nmol/L), the velocity of diastolic depolarization (VDD) of pacemaker cells was significantly decreased in a concentration dependent manner, resulting in a reduced rate of pacemaker firing (RPF). (2) The decreases in RPF and VDD induced by ET-1 could be virtually blocked by pretreatment with ET_(A) receptor blocker BQ-123(20 or 100#mu#g/L). It was strongly suggested that the electrophysiological effects of ET-1 on the pace maker cells were mediated by the ET_(A) receptor. (3) The negative chronotropic action of ET-1 on the pacemaker cells was totally abolished by pretreatment with a kind of K_(ATP) channel blocker glibenclamide(10 #mu#mol/L).

Key words: Endothelin;Endothelin receptor;Sino-atrial node;Glibenclamide;BQ-123;Electrophysiology

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引用本文：

张朝, 李玉龙, 何瑞荣. 内皮素对家兔窦房结起搏细胞电活动的影响[J]. 生理学报 1996; 48 (1): .

Zhang Zhao, Li Yulong, He Ruirong. Effects of endothelin on the electrical activity of sino-atrial pacemaker cells of rabbit. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).