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目的探讨锌缺乏对小鼠海马区域锌离子含量以及长时程增强(LTP)的影响。方法 3周龄CD-1小鼠饲以低锌饲料(0.85mg/kg)和去离子水5周进行实验。应用金属自显影技术(AMG)检测低锌饲料喂养对小鼠海马游离锌离子含量的影响;在小鼠海马齿状回的苔藓纤维层插入刺激电极,在CA3区锥体细胞层插入记录电极,记录高频刺激后海马苔藓纤维CA3区引起的峰电位(PS)和兴奋性突触后电位(f-EPSP)的变化,分析锌缺乏对小鼠海马LTP形成的影响。结果 AMG结果显示锌缺乏小鼠海马CA1,CA3和齿状回区域的锌离子含量明显降低(P<0.05-0.01);电生理检测结果表明锌缺乏小鼠在高频刺激后海马苔藓纤维的PS和f-EPSP均显著下降(P<0.01),提示锌缺乏抑制小鼠海马长时程增强的形成。结论锌缺乏使小鼠海马游离锌离子含量下降,参与对海马长时程增强形成的抑制。
Objective To investigate the effect of zinc deficiency on zinc ion content and long-term potentiation (LTP) in hippocampus of mice. Methods Three-week-old CD-1 mice were fed low zinc diet (0.85 mg / kg) and deionized water for 5 weeks. The effects of low zinc diets on free zinc ion in hippocampus of mice were detected by metal autoradiography (AMG). Stimulation electrodes were inserted into the mossy fiber layer in the hippocampal dentate gyrus of mice and the recording electrode was inserted into the pyramidal cell layer of CA3. The change of peak potential (PS) and excitatory postsynaptic potential (f-EPSP) induced by hippocampal CA3 in hippocampus after high-frequency stimulation were recorded. The effect of zinc deficiency on the formation of LTP in hippocampus of mice was analyzed. Results The results of AMG showed that the content of zinc ion in hippocampal CA1, CA3 and dentate gyrus of zinc-deficient mice was significantly decreased (P <0.05-0.01). The results of electrophysiological examination showed that the zinc-deficient mice exhibited higher PS And f-EPSP were significantly decreased (P <0.01), suggesting that zinc deficiency inhibits the formation of hippocampal long-term potentiation in mice. Conclusion Zinc deficiency can decrease the content of free zinc ion in the hippocampus of mice and is involved in the inhibition of hippocampal long-term potentiation.