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硫化氢对家兔窦房结起搏细胞的电生理效应

许萌, 武宇明, 李茜, 王昕, 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

该研究应用细胞内微电极技术，观察了硫化氢(hydrogen sulfide, H_(2)S)对家兔窦房结起搏细胞的电生理效应。结果表明：(1) NaHS (H_(2)S供体) 50、100、200 #mu#mol/L浓度依赖地降低家兔窦房结起搏细胞4相去极化速率及起搏放电频率。(2) ATP敏感性钾(ATP--sensitive K~(+), K_(ATP))通道阻断剂格列苯脲(glybenclamide, Gli, 20#mu#mol/L)，阻断NaHS (100 #mu#mol/L)的电生理效应。(3)预先应用起搏离子流(pacemaker current,{sl I}_(f))通道阻断剂氯化铯(CsCl, 2 mmol/L)对NaHS (100 #mu#mol/L)的电生理效应无影响。(4)胱硫醚--#gamma#裂解酶(cystathionine #gamma#--lyase,CSE)的不可逆抑制剂{sl DL}--propargylglycine (PPG, 200 #mu#mol/L)对家兔窦房结起搏细胞的动作电位参数无影响。以上结果提示，H_(2)S对家兔窦房结搏细胞有负性变时作用，这些效应可能与其开放K_(ATP)通道，增加K~(+)外流有关，与{sl I}_(f)无关。该实验没有发现窦房结搏细胞内有CSE催化产生的内源性H_(2)S的合成。

关键词： 电生理; 硫化氢; 动作电位; 窦房结

Electrophysiological effects of hydrogen sulfide on pacemaker cells in sinoatrial nodes of rabbits

Xu Meng, Wu Yuming, Li Qian, Wang Xin, He Ruirong

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

Abstract

The cardiac electrophysiological effects of hydrogen sulfide (H_(2)S) were examined on pacemaker cells in sinoatrial (SA) nodes of rabbits using intracellular microelectrode technique. The results obtained were as follows: (1) The velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF) in normal pacemaker cells in SA nodes were decreased by NaHS (H_(2)S donor) (50, 100, 200 #mu#mol/L) in a concentration-dependent manner; (2) ATP-sensitive K~(+) (K_(ATP)) channel blocker glybenclamide (Gli, 20 #mu#mol/L) blocked the effects of NaHS (100 #mu#mol/L) on pacemaker cells; (3) Pretreatment with CsCl (2 mmol), a blocker of pacemaker current (I_(f)), did not affect the effects of NaHS (100 #mu#mol/L) on SA node pacemaker cells; (4) DL-propargylglycine (PPG, 200 #mu#mol/L), an inhibitor of cystathionine #gamma#-lyase (CSE), did not affect parameters of action potentials in pacemaker cells in SA nodes. All these results suggest that H_(2)S exerts a negative chronotropic action on pacemaker cells in SA nodes of rabbits. These effects are likely due to an increase in potassium efflux through opening K_(ATP) channels; If is unlikely to play a major role in these effects. In our study, there was no evidence for the generation of endogenous H_(2)S by CSE in SA node pacemaker cells.

Key words: Electrophysiology;hydrogen sulfide;Action potential;Sinoatrial node

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引用本文：

许萌, 武宇明, 李茜, 王昕, 何瑞荣. 硫化氢对家兔窦房结起搏细胞的电生理效应[J]. 生理学报 2008; 60 (2): 175-180.

Xu Meng, Wu Yuming, Li Qian, Wang Xin, He Ruirong. Electrophysiological effects of hydrogen sulfide on pacemaker cells in sinoatrial nodes of rabbits. Acta Physiol Sin 2008; 60 (2): 175-180 (in Chinese with English abstract).