Simantov R, Liu W, Broutman G, Baudry M
Neuroscience Program, University of Southern California, Los Angeles, USA.
J Neurochem. 1999 Nov;73(5):1828-35.
Organotypic rat hippocampal slice cultures were used to study the role of excitatory amino acid transporters (EAATs) in kainate-induced cell death. Expression of the neuronal (EAAT3) or glial (EAAT2) transporters was inhibited with antisense phosphothioate oligonucleotides, and cytotoxicity was assessed with propidium iodide uptake. In control cultures, a concentration of 10 microM kainate was more cytotoxic in CA3 than in CA1. Treatment for 24 h with EAAT3 antisense oligonucleotide decreased kainate toxicity in CA1 but had an opposite effect in CA3. Neither antisense oligonucleotide to EAAT2 nor mismatch oligonucleotide to EAAT3 decreased kainate toxicity in CA1. Immunoblotting with affinity-purified antibodies showed that EAAT3 antisense oligonucleotide decreased selectively EAAT3 but not EAAT2 protein levels, and vice versa. NMDA was more cytotoxic in CA1 than in CA3, and antisense oligonucleotides to either EAAT3 or EAAT2 did not decrease the NMDA effect in CA1 or CA3. Dihydrokainate and DL-threo-beta-hydroxyaspartic acid were more cytotoxic in CA1 than in CA3, suggesting that the higher vulnerability of CA3 to kainate was not the result of its activity as transporter blocker. We conclude that glutamate transporters differentially regulate excitotoxicity in different hippocampal subfields.
利用器官型大鼠海马切片培养物来研究兴奋性氨基酸转运体（EAATs）在海藻酸盐诱导的细胞死亡中的作用。用硫代磷酸反义寡核苷酸抑制神经元转运体（EAAT3）或胶质转运体（EAAT2）的表达，并用碘化丙啶摄取来评估细胞毒性。在对照培养物中，10微摩尔/升的海藻酸盐浓度在CA3区比在CA1区具有更强的细胞毒性。用EAAT3反义寡核苷酸处理24小时可降低CA1区的海藻酸盐毒性，但在CA3区却产生相反的效果。针对EAAT2的反义寡核苷酸和针对EAAT3的错配寡核苷酸均未降低CA1区的海藻酸盐毒性。用亲和纯化抗体进行免疫印迹分析表明，EAAT3反义寡核苷酸选择性地降低了EAAT3而非EAAT2的蛋白水平，反之亦然。NMDA在CA1区比在CA3区具有更强的细胞毒性，针对EAAT3或EAAT2的反义寡核苷酸均未降低CA1区或CA3区的NMDA效应。二氢海藻酸盐和DL-苏式-β-羟基天冬氨酸在CA1区比在CA3区具有更强的细胞毒性，这表明CA3区对海藻酸盐更高的易损性并非其作为转运体阻滞剂活性的结果。我们得出结论，谷氨酸转运体在不同的海马亚区对兴奋性毒性具有不同的调节作用。
