慢性染铝对大鼠海马长时程增强及Ca^(2+)浓度影响

Effect of postweaning chronic aluminum exposure on long-term potentiation and intracellular Ca^(2+) concentration in hippocampus of rats

目的探讨慢性铝暴露对断乳后大鼠海马CA1区长时程增强及细胞内Ca2+浓度的影响。方法54只大鼠随机分为3组,对照组(蒸馏水)和实验组(0.2%,0.6%AlCl3溶液)。采用自由饮水方式染毒,连续80~90 d。测定血铝和脑铝含量、大鼠海马CA1区群体锋电位和大鼠海马细胞内Ca2+浓度。结果各铝暴露组血铝和脑铝均明显高于对照组(P<0.01);高频刺激后,0.2%AlCl3组海马CA1区群体锋电位幅值增强率为117.70%;0.6%AlCl3组为109.77%,均明显低于对照组(P<0.01);且有随铝暴露浓度增加,群体锋电位幅值增强率逐渐降低的趋势;0.2%与0.6%AlCl3组海马细胞内Ca2+浓度分别为(228.38±51.74)和(195.43±36.95)nmol/L,与对照组比较,差异有统计学意义(P<0.01)。结论铝所致海马细胞内Ca2+浓度的降低可能是其影响长时程增强的机制之一。

Objective To explore the effect of aluminium on long-term potentiation（LTP） in hippocampal CA1 area and intracellular Ca^2＋ concentration in postweaning rats.Methods Postweaning Wistar rats were administered with alumi-nium chloride in water at the doses of 0.2% and 0.6% for 80-90 days.Atomic absorption spectrometry（AAS） was used to detect the content of aluminium in blood and brain.The technique of extracellular electrophysiological test was used to record LTP in hippocampal CA1 area and Fura-2/AM calcium ions fluorescence indicator was used to measure intracellular Ca^2＋ concentration in hippocampal cells.Results The contents of aluminium in blood and brain of aluminium exposed rats were remarkably higher than that of the control group.The population spike（PS） of LTP in hippocampal CA1 area and the intracellular Ca^2＋ concentration were significantly reduced in aluminium exposed groups.Conclusion Aluminium can impair the induction and maintenance of LTP in hippocampal CA1 area,and the impairment maybe results from the reduction of intracellular Ca^2＋ concentration.