【摘要】 目的　探讨不同时期配制的 β 淀粉肽 (1 4 0 ) (Aβ1 40 )对大鼠海马CA1区锥体神经元高电压依赖性钙通道电流 (IHVA)的作用并观察铝和银杏内酯B (GB)对该作用的影响。方法　应用全细胞膜片钳技术记录海马神经元IHVA电流 ,并观察药物对其的作用。结果　 (1)细胞外给予老化处理的Aβ1 40 可以增强IHVA幅度 ,Aβ1 40 的作用具有不可逆性和浓度依赖性 ;新鲜配制的Aβ1 40 对IHVA几乎没有影响。 (2 )Aβ1 40 增强IHVA的作用可以被L 型钙通道阻断剂nifedipine抵消。 (3)PKA的抑制剂H 89可以抵消Aβ1 40 对IHVA的增强作用。 (4)Aβ1 40 增加IHVA的作用可被 1 0mmol/L的AlCl3 进一步增加。 (5 )细胞外给予GB对正常的IHVA没有影响 ,但可抵消Aβ1 40 对IHVA的增强作用。结论 β 淀粉肽(Aβ)通过增强IHVA可引起胞内钙超载 ,这可能是其产生神经毒性作用的机制之一 ,铝可以加强Aβ的毒性作用 ;GB可通过抑制钙离子内流对神经元起一定保护作用。更多还原

【Abstract】 Objective To investigate the effect of β-amyloid peptide 1 -40 (Aβ 1-40) on high voltage-dependent calcium current (I HVA) from acutely isolated hippocampal CA1 pyramidal neurons in rats and the influenc e of aluminum and ginkgolide B on the action of Aβ 1-40. Methods Whole cell patch clamp technique was used to record the I HVA in hippocampal CA1 pyramidal neurons.Results Aggregated Aβ 1-40 could inevitably increase the amplitude of I HVA in a dose-dependent manner; Fresh Aβ 1-40 almos t had no effect on I HVA. L-type of calcium channel antagonist nifedipine could abolish the increase of I HVA by Aβ 1-40. PKA antagonist H-89 could cancel the increase of I HVA by Aβ 1-40. 1 mmol/L AlCl 3 cou ld increase I HVA to a higher degree after Aβ 1-40 application. Gink golide B had no effect on I HVA in normal neurons, but could cancel the inc rease of I HVA by Aβ 1-40. Conclusion Aβ could lead to intracellular free calcium overloa d by increasing I HVA, which might be one of the reasons for its neurotoxic ity. Aluminum and Aβ 1-40 had synergistic action in neurotoxicity. Ginkgo lide B could prevent neurons from neurotoxicity by inhibiting calcium influx.更多还原