摘要
目的评价不同浓度右美托咪定对大鼠肠系膜动脉平滑细胞大电导钙激活钾通道（BK_Ca）的影响。方法SD大鼠，雌雄不拘，体重180～220g，经两步法酶消化分离肠系膜动脉平滑肌细胞。选取10个肠系膜动脉平滑肌细胞，采用单通道内面向外式膜片钳技术进行记录，钳制电压为40mV，游离钙离子浓度为10～mol／L，采用浓度累积法加入右美托咪定，分别于0（基础值）、10^-9、10^-8、10^-7、10^-6、10^-5mol／L右美托咪定时记录BK_Ca开放概率（NPo）、电流幅度（Am）、平均开放时间（To）和平均关闭时间（Tc）。结果与基础值比较，10^-7、10^-6、10^-5mol／L右美托咪定时NPo升高，且呈浓度依赖性，10^-9、10^-8、10^-7、10-^6、10^-5mol／L右美托咪定时Tc缩短（P〈0．05或0．01）；与10^-9mol／L右美托咪定比较，10^-8mol／L右美托咪定时R缩短（P〈0．05），不同浓度右美托咪定时Am和To差异无统计学意义（P〉0．05）。结论10^-7、10^-6、10^-5mol／L右美托咪定可呈浓度依赖性地激活大鼠肠系膜动脉平滑肌细胞BK_Ca通道，是其降压作用的机制之一。
Objective To evaluate the effects of different concentrations of dexmedetomidine on large-con- ductance Ca2＋ -activated K＋ （BK_ca） channels in the rat mesenterie arterial smooth muscle （MASM） cells. Methods Sprague-Dawley rats of both sexes, weighing 180-220 g, were used in this study. Single MASM cell was freshly isolated from mesenteric arteries in two steps. Ten cells were chosen and studied. When holding potential was 40 mV and the concentration of free calcium ions was 10-7 mol/L, inside-out patch-clamp technique was used to record the single BKca channel current before and after application of different concentrations of dexmedetomidine （0, 10^-9, 10^-8, 10^-7, 10^-6, 10^-5 mol/L）. Total open probability （NPo）, amplitude （Am）, mean open time （To） and mean close time （Tc） of single BK_ca channel were observed and recorded. Results Compared with the baseline value, dexmedetomidine 10^-7, 10^-6 and 10^-5 mol/L increased NPo in a concentration-dependent man- ner, and dexmedetomidine 10^-9 , 10^-8 , 10^-7 , 10^-6 , 10^-5mol/L shortened Te （ P 〈 0.05 or 0.01）. Compared with the value obtained when the concentration of dexmedetomidine was 10^-9 mol/L, Tc was significantly shortened when the concentration of dexmedetomidine was 10^-8 mol/L （P 〈 0.05）, and no significant change was found in Am and To obtained when different concentrations of dexmedetomidine were applied （ P 〉 0.05 ）. Conclusion Dexmedetomidine 10^-7 , 10^-6 and 10^-5 mol/L activate BK_cachannels in rat MASM cells in a concentration-depen- dent manner, which is one of the mechanisms of decrease in blood pressure by dexmedetomidine.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2013年第4期424-426,共3页
Chinese Journal of Anesthesiology
基金
泸州医学院附属医院基金（12252）
关键词
右美托咪啶
大电导钙激活钾通道
肠系膜动脉
肌
平滑
血管
Dexmedetomidine
Large-conductance Ca2＋ -activated potassium channels
Mesentericarteries
Muscle, smooth, vascular
