2 Hz电针诱导神经病理痛大鼠脊髓背角突触传递长时程抑制  

Electroacupuncture of 2 Hz induces long-term depression of synaptic transmission in the spinal dorsal horn in rats with neuropathic pain

作　　者：邢国刚[1] 刘风雨[1] 万有[1] 姚磊[1] 韩济生[1] 

机构地区：[1]北京大学神经科学研究所

出　　处：《北京大学学报（医学版）》2003年第5期453-457,共5页Journal of Peking University:Health Sciences

基　　金：国家重点基础研究发展规划项目 (九七三 )基金 (G19990 5 40 0 0 );国家自然科学基金项目 ( 3 983 0 160;3 0 170 3 19;3 0 2 40 0 5 9)~~

摘　　要：目的 :观察 2Hz电针对神经病理痛大鼠脊髓背角突触传递长时程抑制 (long termdepression ,LTD)的诱导 ,以阐明电针治疗慢性神经病理痛的神经生物学机制。方法 :将Sprague Dawley大鼠的腰 5 /腰 6 (L5 /L6 )脊神经紧结扎 ,造成神经病理痛模型。采用电生理学技术记录脊髓背角C 纤维诱发场电位 ,作为 2Hz电针诱导LTD的指标。电针采用韩氏穴位神经刺激仪 (HANS)输出 ,参数是 :频率 2Hz ,波宽 0 .6ms,强度 1、2、3mA各 10min递增 ,刺激时间 30min ;电针的正极接“三阴交”穴 ,负极接“足三里”穴。结果 :(1)在神经病理痛大鼠 ,2Hz电针作用于“三阴交”和“足三里”穴位 30min ,脊髓背角C 纤维诱发场电位的最大幅值 ,可由基础对照水平的 (10 0 .1±1.2 ) % ,降低到 (4 9.4± 0 .6 ) % ,并且在长达 3h的记录时间内均维持在此较低的水平 ,经非配对t检验 ,差异有显著性 (P <0 .0 0 1,n =6 ) ,即 2Hz电针可以诱导神经病理痛大鼠脊髓背角C 纤维诱发场电位产生显著的LTD ;(2 )静脉注射NMDA 受体阻断剂MK 80 1(0 .5mg·kg-1) ,或阿片受体阻断剂纳洛酮 (1mg·kg-1) ,均可以阻止这种 2Hz电针诱导的LTD。结论 :2Hz电针 (HANS穴位电刺激 )可以诱导神经病理痛大鼠脊髓背角伤害性感受的突触传递 ,产生NMDAObjective: To observe the effect of 2 Hz electroacupuncture (EA) on long term depression (LTD) of synaptic transmission in the spinal dorsal horn in rats with neuropathic pain, so as to explore the central mechanisms of the antinociceptive effects of 2 Hz electroacupuncture on neuropathic pain. Methods: The neuropathic pain models were produced by tight ligation of the L5/L6 spinal nerves in Sprague Dawley rats. The C fiber evoked field potentials in the spinal dorsal horn were recorded with extracellular recording techniques. The parameters of the electroacupuncture were as follows: frequency of 2 Hz, wavelength of 0.6 ms, intensity of 1,2,3 mA lasting 10 min for each intensity, stimulation time of 30 min. The positive stimulating electrode was placed in acupoint “sanyinjiao” and the negative electrode in “zusanli”. Results: (1) 2 Hz electroacupuncture significantly decreased the amplitudes of C fiber evoked field potentials in the spinal dorsal horn in rats with neuropathic pain to (49.4±0.6)% of the control, compared with that (100.1±1.2) % of the control before EA (unpaired t test, P < 0.001, n = 6), which lasted for at least 3 hours. (2) This EA suppression on long term depression of C fiber evoked field potentials in the spinal dorsal horn in rats with neuropathic pain could be blocked significantly by intravenous application of NMDA receptor antagonist MK 801 (0.5 mg·kg -1 ), or by opioid receptor antagonist naloxone (1 mg·kg -1 ). Conclusion: EA of 2 Hz could induce long term depression of the nociceptive synaptic transmission in the spinal dorsal horn in rats with neuropathic pain. This kind of 2 Hz EA suppression on LTD was NMDA receptor dependent and the endogenous opioid system may be involved in it. These data indicate that the NMDA receptor dependent LTD at the nociceptive sensory synapses in the spinal dorsal horn in rats with neuropathic pain induced by activating the endogenous opioid system may play the primary role in the antinociceptive effects o

关 键 词：2Hz电针 诱导 神经痛 脊髓 病理生理学 突触传递 神经元可塑性 

分 类 号：R338[医药卫生—人体生理学]