Objective:To observe the inhibitive effects of electroacupuncture(EA)on long-term potentia- tion(LTP)of C-fiber evoked potentials in the spinal 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)wag given in 4 trains of 1 S duration at 10s intervals with 2mA,0. 5ms,lOOHz on same place.The NMDA or[±]-AMPA HBr(40pg)was injected with i.t.,to excite the related receptor.On GB30 and BL40,EA Wag acupunctured with 1mA,2Hz,30min.Results:In the con- trol,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 com- pared with control(P<0.01).The exeitomotor i.t.and HFS after EA,the LTP was inhibited markedly (P<0.01).After the LTP was steady kept lhr 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展开▼
