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植物性雌激素三经异黄酮对家兔房室结细胞自发活动的电生理效应

程岩萍, 马韬, 何瑞荣

河北医科大学基础医学研究所生理室. 石家庄 050017

摘要

研究旨在应用经典玻璃微电极方法观察植物性雌激素三轻异黄酮( genistein , GS T)对家兔房室结细胞自发活动的电生理效应及其作用机制。GST (1。一100 umol/ L)不仅以剂量依赖性方式抑制房室结起搏细胞的动作电位。相最大上升速度(Vma、) , 4期去极化速率(VDD)、自发起搏频率(RP F)和动作电位幅值(APA)，而且延长复极化90%的时间(AP D9 o)。如提高灌流液中钙离子浓度以及应用L型钙通道开放剂Bay K8644 (0.25 umol/ L)，则可拮抗GS T对起搏细胞的上述电生理效应，但NO合酶阻断剂L- NAME (0.5 mmol/L)对GS T的效应并无影响。以上结果提示，GS T可抑制家兔房室结的自发活动，这些效应可能与其抑制钙离子内流有关，但此作用机制中并无NO参与。

关键词： 植物性雌激素; 三轻异黄酮; 房室结; 钙电流

Electrophysiological effects of phytoestrogen genistein on sporntx neous activity of rabbit atrioverntricular nodecells

Cheng Yanping, Ma Tao, HE Rui- Rong

Department of Physiology，Institute of Basic Medicine，Hebei Medical Univesity，Shijiazhuang 050017

Abstract

The purpose of this study was to determine the elect rophysiological effects of genistein(GS T) on spontaneous activity of atrioventricular(A均node and the underlying mechanisms).Action potentials in AV node cells were recorded
using intracellular microelectrode technique .GST not only reduced the amplitude of action potential(AP A)，maximal rate of depolarization(V _j，velocity of diastolic(phase 4) depolarization(V D D)，and rate of spontaneous firing(RS F)，but also prolonged 90%duration of action potential(AP马。)in a concentratiorr dependent manner.The effects of GS T(50 umol/ L)
could be blocked completely by pretreatment with Bay K8644(0. 25 umol/ L)，an agonist of L -type calcium channel.Pretreatment with N'-nitro- L-arginine methyl ester(L-NAME，0.5 m mol/ L)，a nitric oxide(NO) synthase inhibitor，did
not affect the effects of GST on AV node cells .Elevation of Cat+concentration(5 m mol/ L) in superfusate antagonized the effects of GS T(50 umol/ L).These results suggest that GST exerted a negative elect rophysiological effects of spontaneous activity of AV node cells in rabbits .These effects were likely due to reduction in calcium influx，but had no association with NO release.

Key words: Phytoestrogen;genistein;Atrioventricular node;calcium currents

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引用本文：

程岩萍, 马韬, 何瑞荣. 植物性雌激素三经异黄酮对家兔房室结细胞自发活动的电生理效应[J]. 生理学报 2003; 55 (1): .

Cheng Yanping, Ma Tao, HE Rui- Rong. Electrophysiological effects of phytoestrogen genistein on sporntx neous activity of rabbit atrioverntricular nodecells . Acta Physiol Sin 2003; 55 (1): (in Chinese with English abstract).