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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

宋英, 张咏梅, 徐洁, 武静茹, 秦霞, 花嵘

徐州医学院麻醉学重点实验室，徐州 221004；中国人民解放军第九七医院急诊科，徐州 221000

摘要

本文旨在研究慢性背根节压迫(chronic compression of dorsal 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。

关键词： 背根节慢性压迫模型; 背根节神经元; 广动力神经元; 自发放电; 后放电

分类号：R338.2

[Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn.] [Article in Chinese]

SONG Ying, ZHANG Yong-Mei, XU Jie, WU Jing-Ru, QIN Xia, HUA Rong

1Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou 221004, China； Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China

Abstract

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 intracellular 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 ± 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)/min to (92.50 ± 30.32)/min (P < 0.05). On the other side, local administration of 100 mmol/L KCl 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 concentration 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.

Key words: chronic compression of DRG; dorsal root ganglion neuron; wide dynamic range neuron; spontaneous firing; after-discharge

收稿日期：2013-02-20　　录用日期：2013-05-09

通讯作者：宋英　　E-mail: jysongying979@163.com

引用本文：

宋英, 张咏梅, 徐洁, 武静茹, 秦霞, 花嵘. 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[J]. 生理学报 2013; 65 (5): 533-539.

SONG Ying, ZHANG Yong-Mei, XU Jie, WU Jing-Ru, QIN Xia, HUA Rong. [Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn.] [Article in Chinese] . Acta Physiol Sin 2013; 65 (5): 533-539 (in Chinese with English abstract).