Aβ对大鼠海马CA_3区长时程增强维持阶段的影响及和铝的相互关系

目的:研究A-beta(1～40)(Aβ)对大鼠海马CA3区长时程增强(LTP)维持阶段的影响并探讨其和AlCl3之间关系。方法:实验用SD大鼠59只、乌拉坦麻醉下进行,单个脉冲刺激穿通纤维(PP),记录海马CA3区诱发的群体峰电位(PS)。待PS稳定后,给予高频刺激(HFS)引起PS波幅明显增大,诱发的LTP幅度稳定50分钟后,向海马CA3区微量注射药物,观察Aβ对CA3区LTP维持阶段的影响,以及Aβ和AlCl3共同对CA3区LTP维持阶段的影响。结果:随着Aβ浓度增加,其对海马CA3区LTP维持阶段的PS幅值抑制增强。Aβ和AlCl3共同作用时,AlCl3能加强Aβ对海马CA3区LTP维持阶段的PS幅值的抑制作用。结论:Al和Aβ可能共同参与并相互促进Alzheimer's disease(AD)的认知功能损伤。

Effects of A-beta on the Maintenance of LTP in Hippocampal CA_3 Area of Rats and Relationship between A-beta and Aluminum

Objective:To investigate the effects of A-beta on maintenance of LTP in hippocampal CA3 area of rats and relationship between A-beta and Aluminum.Methods 39 rats were anesthetized using urethan.Single pulse was used to stimulate perforant path(PP) and the population spike(PS) evoked was recorded with extracellular recording method in the hippocampal CA3 area in vivo.After PS sustained,long-term potentiation (LTP) was induced by applying high-frequency stimuli (HFS).After a further period of 50 min sustained,β-amyloid peptides1-40](Aβ) and/or Aluminum were injected into hippocampal CA3 area.Following the injection.Low-frequency stimulation was then used to evoke excitatory postsynaptic potentials (EPSPs).The effects of drugs,injected in hippocampal CA3 area, which were determined by the amplitude of the EPSP.Results Rats were microinjected aggregated Aβ(1～40).A lower dose of Aβ(50 nmol) had no significant effect;100 nmol Aβdid not impair LTP after 15 min;but 200 nmol Aβimpaired significantly LTP.AlCl_3(0.5 mmol/L) were microinjected which showed no effect;aggregated Aβ(50 nmol,100 nmol,200 nmol)+0.5 mmol/L AlCl_3 significantly impaired LTP(P<0.05,P<0.01).Conclusion Aβand Aluminum may contribute to the cognitive deficits associated with Alzheimer's disease.