Cell-attached膜片上,咖啡因对猪冠状动脉平滑肌细胞K_(Ca)的调节作用  

Regulation of caffeine on porcine coronary artery smooth muscle cell on cell-attached patch

作　　者：仲维高[1] 曾晓荣[2] 杨艳[2] 刘智飞[2] 李妙龄[2] 张维维[2] 蔡芳[2] 裴杰[2] 周文[2] 

机构地区：[1]四川中医药高等专科学校药理教研室,四川绵阳621000 [2]泸州医学院心肌电研究室,四川泸州646000

出　　处：《四川生理科学杂志》2007年第2期53-56,共4页Sichuan Journal of Physiological Sciences

基　　金：国家自然基金资助项目(No.30370527)

摘　　要：目的:研究咖啡因对猪冠状动脉平滑肌细胞KCa通道的调控机理,以期揭示胞内钙库RyR激活后,局部钙离子浓度升高和KCa的关系。方法:采用急性酶分离方法,应用膜片钳单通道电流记录技术记录大脑皮层神经元猪冠状动脉平滑肌细胞上KCa通道电流活动。电流信号经放大、滤波及A/D、D/A转换后输入微机进行采样和储存。实验数据应用CLAMP9.0软件系统进行数据采集及分析。结果:在cell-attached膜片上咖啡因对KCa通道有明显的作用,咖啡(0.1-5.0 mM)可以增加通道的开放概率(NPo),呈现出浓度依赖性,开放时间延长,关闭时间也随之缩短,而对电流幅值无明显影响,开放概率的增加是通过明显缩短平均关闭时间实现的(n=8,P<0.05);洗去药物后通道活性可以一定程度的恢复到对照水平,再加入一定浓度咖啡因(如1.0mM)可再次激活KCa,激活程度与洗脱前较接近。结论:在细胞贴附式构型上咖啡因浓度依赖性地激活KCa,有饱和性。可能是通过影响胞内信号转导过程而调控KCa活性。Objective： To investigate the mechanisms of caffeine in the regulation of Kca channels of porcine coronary artery smooth muscle cells by using the single channel current recording technlque（cell-attached） in our experiments. Methods： The coronary artery was excised from the heart of porcine. All experiments were worked on single smooth muscle cells isolated enzyrnatically in symmetric high potassium solution and recorded by patch clamp single channel recording technique. Single channel current was amplified and filtered by patch clamp amplifier （CEZ-2300） ,and pCLAMP9. 0 software was used to record and analyze data. The effects of caffeine on KCa channels were observed in cell-attached at different concentrations. Results：In cell-attached patches, caffeine showed the effect on KCa channels under the given concentration, caffeine enhanced KCa, channels open probability （NPo）, prolonged the mean open time and decreased the mean time of closure of KCa. channels with the increasing of caffeine concentration in the bath solution（about 0. 1- 5.0mM）. There were no large changes in amplitude of current （Amp）. To the maximal extent the KCa channels might be activated when caffeine concentration was about 5.0mM. The activity of KCa-channels was also recovered after throughly washout the drug at some extent. Conclusions. In cell-attached patches, Kca-channels of porcine coronary artery smooth muscle cells may be activated by caffeine in a dose-dependent manner, which has saturation; All these show that caffeine may affect the changes of intracellular components, which may influence signal transduction of smooth muscle cell.

关 键 词：咖啡因 BKCA 猪冠状动脉平滑肌细胞 离子通道 膜片钳技术 

分 类 号：R96[医药卫生—药理学]