中文摘要：

目的：研究内侧隔核（MS）注射淀粉样蛋白25-35片段（Aβ25-35）对大鼠海马CA1区theta节律和长时程增强（LTP）的影响。方法：选用成年雄性SD大鼠,在其MS分别注射Aβ25-35和生理盐水,经一周恢复后,乌拉坦麻醉状态下进行海马CA1区theta节律和场兴奋性突触后电位的在体记录。结果：MS注射Aβ25-35后,经夹尾诱发的大鼠海马CA1区theta节律（3-4 Hz）的功率（22.7±1.84 dB）明显较对照组（30.6±1.91 dB）降低（P〈0.01）,但与对照组相比Aβ25-35不影响海马CA1区基础性突触传递和高频刺激诱发的LTP（P〉0.05）。结论：MS注射Aβ25-35可显著抑制海马CA1区theta节律,提示这可能会影响动物的探索行为,但Aβ对MS造成的伤害尚不足以改变海马CA1区的突触可塑性。

英文摘要：

Objective： To study the effects of amyloid β protein fragment 25-35（Aβ 25-35） injection into medial septum on the theta rhythm and long-term potentiation（LTP） in the hippocampal CA1 region of rats.Methods：Aβ25-35 and saline were injected separately into the medial septum（MS） of adult male SD（Sprague-Dawley） rats.After one-week recovery,theta rhythm and field excitatory postsynaptic potential（fEPSP） in hippocampal CA1 area were recorded in vivo under urethane anesthesia.Results： The power of theta rhythm（3-4 Hz） in CA1 region induced by tail pinch in Aβ25-35 treatment group was significantly lower than that in the control group（22.7±1.84 dB,P〈0.01）.But compared with control group,MS injection of Aβ25-35 did not affect the baseline fEPSPs and high frequency stimulation-induced long-term potentiation（P〉0.05）.Conclusion： These results indicate that Aβ25-35 injection into MS could suppress theta rhythm in the hippocampal CA1 region,implying that the exploring behavior of animals may be affected by the impairment of MS with Aβ.However,the Aβ-induced lesion in MS is still not sufficient to change the hippocampal synaptic plasticity.