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目的和方法：探讨脑发育不同阶段慢性铅暴露对在体海马ＬＴＰ的影响。应用细胞外微电极记录单脉冲刺激穿通路纤维在海马齿状回诱发的群体锋电位（ＰＳ），观察母体期、断乳后及出生前后持续性慢性铅暴露大鼠于高频刺激（ＨＦＳ）前后的ＰＳ幅值变化，并与对照组相比较。结果：ＨＦＳ前，基线记录的各铅暴露组ＰＳ平均幅值及峰潜伏期与对照组无显著差异；ＨＦＳ后，各铅暴露组ＬＴＰ发生率虽与对照组无显著差异，但铅暴露组的ＬＴＰ增幅减小，并出现了短时增强转为抑制及ＬＴＤ型反应。统计显示各铅暴露组ＨＦＳ后ＰＳ振幅的平均增强率显著低于对照组：对照组平均增强至基线值的１３８．２％，母体期铅暴露组为基线值的１０８．８％，断乳后铅暴露组为基线值的１０７．８％，持续铅暴露组为基线值的１０４．４％。结论：脑发育任一阶段的慢性铅暴露均可损害海马ＬＴＰ的在体诱导和维持，且以维持过程受损为主；与发育成熟海马相比，未成熟期海马对铅的神经毒性更为敏感，突触可塑性更易受损。
PURPOSE AND METHODS: To investigate the effects of chronic lead exposure on LTP in the hippocampus in different stages of brain development. The monolayer of extracellular microelectrodes was used to record the spike-induced PSF in the hippocampal dentate gyrus of rats. The effects of high frequency stimulation (HFS) on the rats with chronic lead exposure after maternal, PS amplitude before and after the change, and compared with the control group. Results: There was no significant difference in the mean amplitude and peak latency of PS between baseline exposure and baseline exposure before HFS. There was no significant difference in the incidence of LTP between control and exposure groups after HFS, but LTP Increase decreases, and there has been a short-term increase to suppress and LTD-type response. The statistics showed that the average enhancement rate of PS amplitude after HFS in each lead exposed group was significantly lower than that in the control group: the control group increased to 138.2% of the baseline value on average, 108.8% of the baseline value in the lead exposure group, The lead exposure group was 107.8% of the baseline value, and the persistent lead exposure group was 104.4% of the baseline value. CONCLUSION: Chronic lead exposure at any stage of brain development can impair the in vivo induction and maintenance of LTP in the hippocampus, with predominant maintenance of damage; neurotoxicity of lead in immature hippocampus is more pronounced than in mature hippocampus Sensitive, synaptic plasticity more vulnerable.