罗哌卡因和布比卡因对大鼠背根神经节钠通道阻滞作用的比较  

Comparison of blocking effect of ropivacaine and bupivacaine on sodium channels of rat dosal root ganglia

作　　者：徐龙河[1] 姜雨鸽[1] 张宏[1] 

机构地区：[1]中国人民解放军总医院麻醉科,北京100853

出　　处：《中国临床药理学与治疗学》2006年第5期501-504,共4页Chinese Journal of Clinical Pharmacology and Therapeutics

基　　金：国家自然科学基金资助(№30300327)

摘　　要：目的:比较局麻药罗哌卡因和布比卡因对大鼠背根神经节(DRG)河豚毒素(TTX)敏感(TTX-S)和TTX不敏感(TTX-R)的钠通道阻滞作用的差别,探讨罗哌卡因麻醉时产生感觉运动分离的可能机制。方法:急性分散大鼠背根神经节细胞,利用全细胞膜片钳技术记录DRG细胞TTX-S和TTX-R钠电流,通过浴槽内给药,观察罗哌卡因和布比卡因对TTX-S和TTX-R钠电流的作用。结果:TTX-S钠电流主要产生于大的DRG细胞,而TTX-R钠电流主要产生于小的DRG细胞;罗哌卡因对TTX-R钠电流的半数抑制浓度(IC50)为65.7±6.1μmol·L-1,远低于其对TTX-S钠电流的IC50(246.8±11.2μmol·L-1,P<0.01);布比卡因对TTX-R和TTX-S钠电流的IC50值基本相同(27.2±6.2μmol·L-1vs29.5±2.9μmol·L-1,P>0.05)。结论:罗哌卡因优先阻滞TTX-R钠通道,对TTX-R钠通道和TTX-S钠通道的选择性阻滞是其硬膜外麻醉时感觉运动分离的原因之一。AIM： To compare the blocking effect of ropivacaine and bupivacaine on sodium channels of rat dosal root ganglia（DRG） using whole cell recording technique. METHODS： Rat DRG neurons were enzymatically isolated , tetrodotoxin-sensitive （TTX-s） and tetrodotoxin-resistant （TTX-r） sodium currents of DRG were recorded by whole cell recording. Drugs were given in bath solution. The concentrations of ropivacaine were 10, 30,100, 1 000 μmol· L^- 1 and bupivacaine were 10, 30,100,300 μmol· L^-1. The recording number in each dose group was six. RESULTS： CsCl in extracellular fluid and TEA in intmcellular fluid were used to block the potassium channels. Sodium currents were recorded when the holding potential was - 70 mV and a serials of pulse with step 10 mV and duration 70 ms was given. TTX-s sodium channel was recorded in 80.1% large DRG cells and TTX-r sodium channel was recorded in 92.4% medium and small DRG cells, of which 56.3 % cells had no response to 1μmol·L^-1 TTX. The half-maximal blocking concentrations of ropivacaine on TTX-r sodium channel was 65.7 ±6.1 μmol· L^- 1, which was much lower than that on TTX-s sodium channel 246.8 ± 11.2 μmol· L^- 1 （ P 〈 0.01 ） ;The half-maximal blocking concentrations of bupivacaine on TTX-r and TTX-s sodium channel was essentially the same （27.2 ± 6.2 μmol· L^-1 vs 29.5 ± 2.9 μmol·L^-1 ,P 〉 0.05 ）. CONCLUSION： Ropivacaine preferentially blocks TTX-r sodium channel. Selective blocking of TTX-r and TTX-s sodium channel was one of the reasons of sepemtion of sensation and motion when it is used in epidural anesthesia.

关 键 词：罗哌卡因 布比卡因 膜片钳 钠通道 背根神经节 

分 类 号：R645.1[医药卫生—外科学]