Studies on neurotoxic mechanisms by excitotoxins

兴奋性毒素的神经毒性机制研究

基本信息

批准号：
10044328
负责人：
YONEDA Yukio
金额：
$ 8.45万
依托单位：
Kanazawa University (1999-2000)Setsunan University (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044328/
关键词：
Neuronal death Neurotoxins NMDA receptors KA receptors Transcription factors CA1 and CA3 subfields Dentate granule cells c-Fos protein カインシ酸レセプター CA1野,CA3野錐体細胞歯状,回顆粒細胞 c-Fros蛋白質 NMDA 遊離カルシウム初代培養神経細胞共焦点レーザー顕微鏡神経毒性 MAP-

项目摘要

The present study deals with modulation of gene transcription in the brain, in order to evaluate possible involvement of particular ionotropic receptor subtypes for L-glutamic acid in mechanisms underlying neuronal toxicity by excitotoxins. Transcription factors are nuclear proteins with high affinity for a particular core nucleotide sequence to modulate the activity of RNA polymerase II that is responsible for formation of mRNA from genomic DNA in the nucleus. The systemic administration of N-methyl-D-aspartic acid (NMDA) led to selective and drastic potentiation of DNA binding activity of the transcription factor activator protein-1 (AP1) in murine hippocampus. Frozen coronal sections were made with the aid of a cryostat, followed by punching out of the desired regions by a plastic capillary on dry ice under a binocular microscope. The potentiation was only seen in the dentate granule cells, but not in the CA1 and CA3 pyramidal cells. The potentiation in the dentate gyrus was transient with a peak at 2 h after administration and a decline within 4 h later, which occurred in a manner sensitive to antagonism by an NMDA channel blocker. Immunohistochemical analysis revealed that NMDA induced expression of both c-Jun and c-Fos proteins in the dentate gyrus, but not in the CA1 and CA3 subfields. By contrast, kainic acid (KA) induced drastic and prolonged potentiation of AP1 DNA binding in the CA1 and CA3 pyramidal layers in addition to dentate granule layers. The administration of KA but not NMDA led to marked potentiation of AP1 binding in areas neighboring but excluding pyramidal and granule layers. KA induced severe neuronal death in the CA1 and CA3 pyramidal layers without affecting dentate granular neurons. These results suggest that modulation of de novo synthesis of particular proteins may underlie mechanisms associated with neuronal cell death induced by excitotoxins.

本研究涉及大脑基因转录的调节，以评估特定的离子型受体亚型可能参与L-谷氨酸在兴奋性毒素中神经元毒性基础的机制中。转录因子是对特定核心核苷酸序列具有高亲和力的核蛋白，以调节负责从核中基因组DNA形成mRNA的RNA聚合酶II的活性。 N-甲基-D-天冬氨酸（NMDA）的全身给药导致了鼠海马中转录因子激活剂-1（AP1）的DNA结合活性的选择性和急剧增强。借助低温恒温器将冷冻的冠状切片制成，然后通过双眼显微镜下的干冰上的塑料毛细管从所需的区域猛击。该增强仅在牙齿颗粒细胞中可见，而在CA1和CA3锥体细胞中则没有看到。齿状回的增强是瞬态的，在给药后2小时，峰值在4小时内下降，这是以NMDA通道阻滞剂对拮抗作用敏感的方式发生的。免疫组织化学分析表明，NMDA诱导齿状回中C-JUN和C-FOS蛋白的表达，但在CA1和CA3子场中诱导了表达。相比之下，除牙齿颗粒层外，海藻酸（KA）诱导了CA1和CA3锥体层中AP1 DNA结合的急剧和延长的增强。 KA的给药而不是NMDA导致AP1结合在邻近区域但不包括锥体和颗粒层的明显增强。 KA在CA1和CA3锥体层中诱导严重的神经元死亡，而不会影响齿状颗粒神经元。这些结果表明，从头合成特定蛋白质的调节可能是与兴奋毒素诱导的神经元细胞死亡相关的机制的基础。