电针抑制iGluRs激动剂鞘内给药易化的大鼠脊髓背角突触传递LTP  

INHIBITIVE EFFECTS OF ELECTROACUPUNCTURE ON LTP OF SYNAPTIC TRANSMI SSION TO FACILITATED BY EXCITOMOTOR OF IGLURS INTRATHECAL ADMINI STRATION IN SPINAL DORSAL HORN OF RATS

作　　者：马骋[1] 冯克辉[1] 闫丽萍[1] 

机构地区：[1]南京中医药大学江苏省针灸学重点实验室,南京210029

出　　处：《中国疼痛医学杂志》2009年第4期236-239,共4页Chinese Journal of Pain Medicine

基　　金：江苏省自然科学基金资助项目(BK2006239;BK2008458);江苏省高校自然科学重大基础研究项目基金(05KJA36011)

摘　　要：目的:观察电针对离子型谷氨酸受体(iGluRs)激动剂易化脊髓背角神经元而形成的长时程增强(LTP)的抑制作用,并探讨其机制。方法:大鼠脊髓L4/L5节段细胞外记录脊髓背角C-纤维诱发场电位的LTP。iGluRs激动剂NMDA或[±]-AMPA HBr 40pg鞘内给药(i.t.)易化脊髓背角神经元;对照组i.t.生理盐水2μl。2 Hz,1 mA电针(EA)环跳和委中穴。观察电针对iGluRs激动剂i.t.易化的LTP的抑制作用。结果:对照组低强度强直刺激(HFS)前、后脊髓背角LTP的变化率无统计学差异;i.t.NMDA或[±]-AMPA HBr后低强度HFS,可引起显著的LTP,与对照组比较P<0.01;先EA然后i.t.NMDA或[±]-AMPAHBr和低强度HFS,LTP被显著抑制(P<0.01);先i.t.iGluRs激动剂和低强度HFS诱导出LTP再EA,也可显著抑制已形成的LTP(P<0.05)。结论:低频低强度电针,可抑制iGluRs激动剂易化的脊髓C纤维诱发场电位LTP的形成和维持。提示低频电针可降低脊髓背角神经元的异常兴奋性,此突触后机制可能是电针干预神经病理痛的作用机制之一。Objective ：To observe the inhibitive tion （LTP） of C-fiber evoked potentials in the effects of electroacupuncture（EA） on long-term potentiaspinal dorsal horn facilitated by excitomotor of NMDA or AMPA receptors, and explore the analgesia mechanism of acupuncture in neuropathic pain. Methods： Sprague-Dawley rats were divided into 7 groups ： control, NMDA （NMDA） Intrathecal administration （ i. t. ） ,AMPA （[ ±]-AMPA HBr） i.t. ,EA ＋NMDA i. t. ,EA ＋AMPA i. t. ,NMDA i.t. ＋EA,and AMPA i. t ＋ EA. The rats were fixed on stereotaxic instrument after anesthesia. C-fiber evoked field potentials in the spinal dorsal horn （L4/L5 ） were recorded by extracellular recording. The test stimulus was given in single pulse with 2mA ,0.5ms, 100Hz,5min each once on the sciatic nerve. The lower intensity high- frequency train plus stimulus（HFS） was given in 4 trains of Is duration at 10s intervals with 2mA,0. 5ms,10OHz on same place. The NMDA or [ ±]-AMPA HBr （40pg） was injected with i. t. ,to excite the related receptor. On GB30 and BL0, EA was acupunctured with 1 mA,2Hz,30min. Results ： In the control , the variation rate of evoked potentials showed no significant differences compared with before or after HFS. After excitomotor i. t then lower intensity HFS, the LTP was induced significantly and compared with control （P 〈0. 01 ）. The excitomotor i.t. and HFS after EA,the LTP was inhibited markedly （P 〈 0. 01 ）. After the LTP was steady kept 1 hr induced by the excitomotor i.t. and HFS, the EA was operated. In NMDA i.t. ＋ EA,LTP was inhibited markedly（P 〈0. 01 ） ; In AMPA i. t. ＋ EA,the LTP was step down significantly （P 〈 0. 05 ）. Conclusions ： These data suggest that the development and retain of LTP on spinal dorsal horn to facilitated by excitomotor of iGluRs was inhibited by EA. The results indicate that the abnormal excitability of neuron in the spinal dorsal horn with neuropathic pain was inhibited by EA, which might be the postsynaptic mecharism unde

关 键 词：离子型谷氨酸受体 易化 脊髓背角 长时程增强 电针 

分 类 号：R245[医药卫生—针灸推拿学]