加味五子衍宗方总黄酮对大鼠海马锥体细胞VGCC通道的影响

Effect of total flavonoids of Jiawei Wuzi Yanzong prescription on VGCCs induced by amyloid-β_(25-35) peptide in CA1 pyramidal neurons of rat hippocampal slice

目的:探讨加味五子衍宗方总黄酮成分对Aβ25-35作用后的大鼠海马CA1区锥体神经元电压门控钙通道电流的作用。方法:应用全细胞膜片钳技术记录海马神经元ICa电流,采用内向电流的幅度作为观察指标,观察模型药物及干预药物对其的作用。采用出生7d的乳鼠取海马后制成脑片,选取立体感强、状态好的锥体细胞形成全细胞膜片钳记录,从-50mV到+50mV范围(步进为5mV)一系列去极化电压脉冲刺激(脉冲宽度500ms),以激发出电压依赖性的内向钙离子电流。记录电流后加入Aβ25-35后,再加入总黄酮进行干预。结果:Aβ25-35淀粉蛋白可以通过增强ICa可引起胞内钙超载,正常幅度平均为-(157.1±19.9)pA,Aβ25-35作用后增大为-(323.2±23.4)pA,125,250,500mg.L-1的总黄酮作用之后,分别下降为-(257.9±31.6),-(196.4±29.8),-(169.3±34.0)pA。结论:引起胞内钙离子超载可能是Aβ25-35产生神经毒性作用的机制之一,加味五子衍宗方总黄酮成分可通过抑制钙离子内流对神经元起一定保护作用。

Objective： To explore the effect of the total flavonoids of Jiawei Wuzi Yanzong prescription on the Voltage-gated calcium channel of the CA1 pyramidal cell of rat hippocampus. Method： The inward calcium current was recorded by the whole-cell patch clamp and the amplitude of it was thought to observe the effect of Aβ25-35 and the total flavonoids. The hippocampus of rat was separated and cut into slices. Active pyramidal cells of slices were chosen for the whole-cell patch clamp recording. After exposure to Aβ25-35, voltage steps （500 ms） were used to depolarize stepwise in a range from 50 to ＋ 50 mV （ increment ： 5 mV）. An inward Ca2 ＋ current which was suggested to be survey was evoked. Application of the total flavonoids was to be observed if it had effect on this volt- age-depended inward current. Result： Aβ25-35 could enhance the calcium current to induce intracellular calcium overload. The amplitude of the control group was - （ 157.1 ± 19. 9） pA, but after application of Aβ25-35 the current enhanced to - （323.2 ±23.4） pA. When the total flavonoids at concentration of 125, 250, 500 g · L^-l were added, the current declined to - （257.9 ± 31.6）, - （ 196.4 ±29. 8） and - （ 169.3 ±34. 0） pA, respectively. Conclusion： Aβ-induced intracellular calcium overload may be one of neurotoxic ofβ-amyloid peptide. The total flavonoids of Jiawei Wuzi Yanzong prescription can suppress inward calcium current to protect neurons.