摘要
目的观察长时程增强(long-termpotentiation,LTP)引导后的不同时期,电刺激Aδ纤维对脊髓LTP的抑制效应。方法以10～20V,0.5ms的刺激强度刺激坐骨神经,同时细胞外记录脊髓背角C-纤维诱发电位。强直刺激坐骨神经诱导C-纤维诱发电位LTP后不同时期刺激Aδ。结果诱导出LTP15min后,电刺激Aδ纤维使LTP抑制了(44.1±4.2)%(n=7),持续(69.3±18.5)min。LTP引导出1h后,用同样的刺激参数刺激Aδ纤维使LTP抑制了(16.9±3.1)%(n=7),持续(21.9±2.0)min。然而,LTP引导出3h后,电刺激Aδ纤维不但不能抑制LTP反而使LTP的幅度进一步增大犤(31.9±6.3)%,n=7犦并持续到实验结束(1～3h)。结论重复刺激Aδ纤维对业已建立的C-纤维诱发电位LTP的抑制效应具有时间依赖性。
Aim To study the anti-effects of Aδfiber stimulation on the spinal long-term potentiation(LTP)at different time points following LTP in-duction.Methods Twenty-one male Sprague-Dawley rats underwent laminectomy to expose the intumescentia lumbalis.Their left sciatic nerves were isolated.The C-fiber evoked potentials were recorded extracellul arly.Single square pulses(10-20V,0.5ms )were used to evoke the spinal field potential.Tetanic stimulation(40V,0.5ms ,100Hz ,1s ,with an interval pf 10s ,4times)was used to induce the LTP of C-fiber e voked field potential.Continued stimulation of Aδfiber(100Hz ,10V,0.1ms ,1s,with an interval of 10s,90times)was used to inhibit spinal LTP .Results15min after LTP induction,Aδstimulation depressed the LTP by(44.1±4.2)%(n=7)with a duration of(69.3±18.5)min.1h after LTP induction,the same Aδstimu-lation depressed the spinal LTP only by(16.9±3.1)%for(21.9±2.0)min(n=7).3h after LTP induction,however,Aδstimulation produced an in-crease of the amplitude of LTP by(31.9±6.3)%(n=7)that lasted to the end of experiment (1to 3h ).Conclusion The anti-effects of repetitive stimulation of Aδ-fibers on established spinal LTP of C-fiber evoked potentials are time-dependent.
出处
《中国临床康复》
CSCD
2003年第10期1510-1512,共3页
Chinese Journal of Clinical Rehabilitation
基金
国家自然科学基金(30070256)
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