【摘要】 目的:研究蛋白合成抑制剂在成年大鼠海马CA1区长时程增强和去强化中的作用。方法:实验采用海马脑组织切片细胞外场电位记录技术,记录海马CA1区突触后场电位,在长时程增强诱导前和诱导后分别给予蛋白合成抑制剂,探讨其在海马脑片CA1区长时程增强和去强化中的作用。结果:对海马脑片CA1区长时程增强诱导后2 h给予两组高强度双脉冲低频刺激(HI-PP-LFS),引起长时程增强去强化,其翻转率是59.81%;对海马脑组织切片CA1区长时程增强诱导刺激前给予茴香霉素和放线茵酮,可明显减小长时程增强的幅度,与对照组差异具有统计学意义(P<0.05)。在此条件下HI-PP-LFS可以使长时程增强去强化至基线水平;对海马脑组织切片CA1区长时程增强诱导90 min后给予茴香霉素和放线茵酮,HI-PP-LFS仍然诱导了去强化,长时程增强的翻转率与对照组差异无统计学意义(P>0.05)。结论:对海马脑片组织切片CA1区长时程增强诱导前给予蛋白合成抑制剂可明显减弱长时程增强,并且这种情况下HI-PP-LFS可以翻转长时程增强至基线水平;在长时程增强诱导后给予蛋白合成抑制剂对长时程增强的维持及翻转均没有影响。更多还原

【Abstract】 Objective:To study the roles of protein synthesis inhibitors in long-term potentiation(LTP) and depotentiation(DP) in hippocampal CA1 region of adult rats.Methods:Standard extracellular recording technique was used to record field EPSP(fEPSP) evoked by Schaffer collateral stimulation from the CA1 subfield of adult rat hippocampal slices.Paired-pulse low-frequency stimulation(PP-LFS) or high-intensity paired-pulse low-frequency stimulation(HI-PP-LFS) was delivered to induce depotentiation 2 h after LTP induction induced by six theta-burst stimulations.Protein synthesis inhibitors were applied before and after LTP induction to study their roles in LTP and DP in hippocampal CA1 region of adult rats.Results:When HI-PP-LFS was applied at 2 h after LTP induction,the depotentiation was induced.The mean fEPSP slopes reduced from 346.2%±26.3%to 207.1%±21.6%.This depotentiation was named as partial LTP depotentiation and maintained at least for 30 min.The percentage of depotentiation was 59.81%.Application of protein synthesis inhibitors,anisomycin and cycloheximide prior to tetanus resulted in smaller LTP compared to control group,and almost complete depotentiation was induced by HI-PP-LFS.With application of protein synthesis inhibitors anisomycin and cycloheximide 90 min after LTP induction,HI-PP-LFS still induced partial LTP depotentiation.However,there was no significant difference in the percentage of depotentiation between this group and control group.Conclusion:HI-PP-LFS partially reverses late phase LTP.When protein synthesis inhibitors are applied prior to tetanus,LTP amplitude is markedly reduced,and HI-PPLFS completely reverses late-phase LTP.Application of protein synthesis inhibitors after LTP induction does not significantly affect either the amplitude or depotentiation of LTP.更多还原