电针对大鼠海马兴奋性突触后电位长时程增强的作用

背景海马长时程增强(1ong-termpotentiation,LTP)与行为学研究相结合,已被广泛用于包括中医药在内的改善学习记忆功能和治疗老年性痴呆的研究.目的观察电针对麻醉状态下正常和东莨菪碱引起的学习记忆减退模型大鼠海马兴奋性突触后电位(excitatorypostsynaptic potential,EPSP)LTP的作用.设计随机对照研究.地点和材料SD大鼠40只,体质量270～310g,单纯随机分成为对照组、电针组、模型组和模型+电针治疗组,每组10只.干预引导大鼠海马齿状回颗粒细胞层突触后兴奋性电位群(EPSPs),强直刺激大脑皮质前穿质区引起海马突触LTP反应;用东莨菪碱制备学习记忆障碍模型;电针(疏密波3～5mA,30 min)大椎和双侧肾俞穴;观察电针对正常和模型大鼠海马LTP的影响.主要观察指标强直刺激前和强直刺激诱发后0,60,120min LTP群发电位信号(PS),PS的EPSP潜伏期,PS锋值潜伏期,EPSP的斜率,PS锋值和PS锋面积(PSa).结果①电针对强直刺激诱发的海马突触LTP效应的作用强于对照组.与对照组比,EPSP潜伏期明显缩短[相对于强直刺激前的变化率对照组与电针组分别为(-7.8±2.6)%比(-14.4±7.7)%,差异有显著性意义(t=2.5681,P＜0.05)];EPSP的斜率增加(t=2.436 4,P＜0.05);PS锋面积增大(t=2.750 8～2.9909,P＜0.05),且维持时间长于对照组.②东莨菪碱可显著抑制强直刺激诱发的海马突触LTP,表现为EPSP潜伏期和PS锋值潜伏期延长,与对照组比较差异均有非常显著性意义(t=4.5648～5,996 5,P均＜0.01);EPSP的斜率下降,PS锋值和PS锋面积变小.③电针能显着对抗东莨菪碱对海马突触LTP的抑制作用,与模型组比较各参数均有统计学意义.结论电针对强直刺激引起的海马突触LTP有一定的易化作用,并对东莨菪碱引起的学习记忆障碍有显著的对抗作用.

Effects of electrical acupuncture on long-term potentiation of excitatory postsynaptic potential in rat hippocampus

BACKGROUND: The combination of the researches between long-term potentiation(LTP) of hippocampus and behavioral method of animals has been widely introduced into the researches of improving the functions of study and memory, and the treatments of Alzheimer' s disease including Traditional Chinese Medicine treatments.OBJECTIVE: To observe the impacts of electrical acupuncture(EA) on LTP of excitatory postsynaptic potential(EPSP) in rat hippocampus in normal and scopolamine-induced hypomnesia models under anesthesia conditions.DESIGN: A randomized controlled study.SETTING and MATERIALS; Forty SD rats with a body weight of 270 -310 g were randomly grouped into control group, EA group, model group,and model + EP group with 10 rats each.INTERVENTIONS: EPSPs of granular cell layer at rat hippocampus dentate gyms were induced and recorded. LTP reaction of hippocampal synapse was aroused by high frequency stimulating(HFS) anterior perforated substance of cerebral cortex. Hypomnesia model was established by intraperitoneal injection of scopolamine. Dazhui(DU14) and both Shenshu(BL23) acupoints were acupunctured with EA with 3 - 5 mA of sparse and dense alternation wave for 30 minutes. The impacts of EA on normal and model hippocampal LTP were observed.MAIN OUTCOME MEASURES: Population spike (PS) , latency of EPSP,latency of PS peak, EPSP slope, PS peak value and PS peak area(PSa) of LTP before and at 0, 60 and 120 minutes after HFS.HFS was stronger than that of control group. Compared with control group,EPSP latency significantly shortened[compared with the change rate before HFS, the latencies were( -7.8 ±2.6)% and( - 14.4 ±7.7)% respectively(t=2.568 1, P ＜ 0.05), EPSP slope increased(t=2.436 4, P ＜0.05); PSa incrensed(t=2.750 8-2.990 9, P ＜ 0.05), with longer synapse LTP induced by HFS, which expressed in the prolongation of latencies of EPSP, PS peak value with significances compared with control group(t =4.564 8 -5.996 5, P ＜0.01) and, EPSP slope decreased, PS the inhibiting reaction of scopolamine in LTP. All parameters were with statistical significances compared with that of model group.CONCLUSION: EA has facilitative reactions in LTP of hippocampal synapse induced by HFS, and furthermore, EA has significant antagonizing reactions in scopolamine-induced hypomnesia.