慢性痛大鼠背根节神经元自发放电对脊髓背角广动力神经元的影响  

Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn

作　　者：宋英[1] 张咏梅[1] 徐洁[1] 武静茹[1] 秦霞[1] 花嵘[2] 

机构地区：[1]徐州医学院麻醉学重点实验室,徐州221004 [2]中国人民解放军第九七医院急诊科,徐州221000

出　　处：《生理学报》2013年第5期533-539,共7页Acta Physiologica Sinica

基　　金：supported by the Youth Project of National Natural Science Foundation of China(No.31200836);the Natural Science Foundation for Colleges and Universities in Jiangsu Province;China(No.12KJD320005);Zhen Xing Project/the Special Talent Fund of Dean of Xuzhou Medical College;Jiangsu Province;China(No.2012KJZ15)

摘　　要：本文旨在研究慢性背根节压迫(chronic compression ofdorsal root ganglion,CCD)模型大鼠背根节(dorsal root ganglion,DRG)神经元自发放电活动对脊髓背角广动力(wide dynamic range,WDR)神经元兴奋性的影响。以大鼠为实验对象,随机分为正常对照组和CCD组,在体情况下对DRG和脊髓背角WDR神经元分别进行细胞内和细胞外记录。结果显示,CCD术后,WDR神经元自发放电发生率及放电频率与正常对照组比较均增加(P<0.05),分别为59.46%和(4.30±0.69)Hz。在CCD大鼠DRG局部给予50 nmol/L河豚毒素(tetrodotoxin,TTX),WDR神经元自发放电活动从加药前的(191.97±45.20)/min降至(92.50±30.32)/min,差异有统计学意义(P<0.05);而正常对照组没有自发放电活动的WDR神经元在DRG局部给予100 mmol/L氯化钾后出现高频放电,洗脱后恢复(n=5)。给予坐骨神经非痛电刺激在正常对照组WDR神经元没有记录到后放电,在CCD组可以在36.36%(12/33)WDR神经元记录到后放电,L4、L5 DRG局部表面直接给予TTX(50 nmol/L),后放电频率从加药前的(263±56.5)Hz降至(117±30)Hz,差异有统计学意义(P<0.05)。研究结果提示外周神经损伤后,DRG神经元的异位自发放电活动对脊髓WDR神经元兴奋性改变有重要的作用。The aim of the paper is to study the effect of spontaneous firing of injured dorsal root ganglion （DRG） neuron in chronic compression of DRG （CCD） model on excitability of wide dynamic range （WDR） neuron in rat spinal dorsal horn. In vivo intracellu- lax recording was done in DRG neurons and in vivo extracellular recording was done in spinal WDR neurons. After CCD, incidence of spontaneous discharge and firing frequency enhanced to 59.46% and （4.30 ~ 0.69） Hz respectively from 22.81% and （0.60 a： 0.08） Hz in normal control group （P 〈 0.05）. Local administration of 50 nmol/L tetrodotoxin （TTX） on DRG neuron in CCD rats decreased the spontaneous activities of WDR neurons from （191.97 ＋ 45.20）/rain to （92.50 ＋ 30.32）/rain （P 〈 0.05）. On the other side, local admin- istration of 100 mmol/L KC1 on DRG neuron evoked spontaneous firing in a reversible way （n = 5） in silent WDR neurons of normal rats. There was 36.36% （12/33） WDR neuron showing after-discharge in response to innocuous mechanical stimuli on cutaneous receptive field in CCD rats, while after-discharge was not seen in control rats. Local administration of TTX on DRG with a concentra- tion of 50 nmol/L attenuated innocuous electric stimuli-evoked after-discharge of WDR neurons in CCD rats in a reversible manner,and the frequency was decreased from （263± 56.5） Hz to （117 ± 30） Hz （P 〈 0.05）. The study suggests that the excitability of WDR neurons is influenced by spontaneous firings of DRG neurons after CCD.

关 键 词：背根节神经元 背根节慢性压迫 广动力神经元 自发放电 后放电 

分 类 号：R338[医药卫生—人体生理学]