丹参酮ⅡA对Aβ25-35引起的Meynert核团神经元钙电流变化的影响

Effect of tanshinone ⅡA on the change of calcium current induced by β-amyloid protein 25-35 in neurons of nucleus basalis of Meynert

目的:探讨丹参酮IIA(TanⅡA)和β淀粉样蛋白25-35(Aβ25-35)对Meynert核团(nbM)神经元电压依赖钙电流的影响。方法:运用细胞急性分离和单细胞膜片钳技术,采用全细胞记录方式,检测SD大鼠nbM神经元电压依赖钙电流、TanⅡA对nbM神经元钙电流的影响、加入亚毒性剂量Aβ25-35后钙电流的变化以及TanⅡA对其引起钙电流变化的作用。结果:通过灌流分别给予含有不同浓度TanⅡA的细胞外液,记录到的峰值电流与正常峰值电流基本一致,在0 mV时对峰值电流密度进行比较,差异没有统计学意义(P>0.05);给予亚毒性剂量Aβ25-35的细胞外液灌流,峰值电流明显增大,与对照组比较差异有统计学意义(P<0.05);不同浓度TanⅡA与200 nmol/L Aβ25-35同时加入细胞外液灌流,其电压依赖钙电流与对照组比较,差异均无统计学意义(P>0.05)。结论:在体外,Tan IIA能抑制Aβ引起的nbM神经元细胞膜上钙电流放大,减少钙内流,以保护神经元。

Objective To explore the effect of tanshinone ⅡA（TanⅡA） on calcium current induced by β-amyloid protein 25-35（Aβ25-35） in neurons of nucleus basalis of Meynert（nbM）.Methods Cell acute dissociated technique and the whole-cell recording model of patch-clamp technique of single-cell were used.The voltage-dependent calcium current in neurons of nbM was recorded in SD rats first.Then the effect of TanⅡA on the voltage-dependent calcium current in the neurons was assayed.The change of calcium current induced by Aβ25-35 as well as the effect of TanⅡA on the change of calcium current induced by Aβ25-35 in neurons of nbM were analyzed.Results Extracellular fluid containing different concentrations of TanⅡA was irrigated,respectively.The peak current did not change obviously.There was no difference in current density between the TanⅡA group and the control group at 0 mV（P0.05）.Extracellular fluid containing 200 nmol/L Aβ25-35 was irrigated after the normal calcium current recorded under whole patch clamp,and the peak current changed obviously.There was distinct difference in the current density between the Aβ group and the control group at 0 mV（P0.05）.Extracellular fluid containing Aβ25-35 and different concentrations of TanⅡA were irrigated after the normal calcium current was recorded under whole patch clamp,respectively,and the peak current did not change.There was no difference in current density between the TanⅡA ＋Aβ group and the control group at 0 mV（P0.05）.Conclusion In vitro,TanⅡA could inhibit the calcium current amplification induced by Aβ25-35 in neurons of nbM.TanⅡA may protect neurons against the toxicity of Aβ and decrease the inward flow of Ca2＋.