Molecular mechanism of long-term effects of neurotransmitters

神经递质长期作用的分子机制

基本信息

批准号：
04044143
负责人：
KITO Shozo
金额：
$ 6.59万
依托单位：
The University of the Air
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

As a part of the study on how biologically active substances in the brain cause long-term effects through immediate early genes, effects of steroid hormones on survival rate of cultured rat limbic neurons were investigated.It was previously confirmed that in cultured limbic neurons glucocorticoid increased kainic acid-induced cytotoxicity dose-dependently, while estrogen increased survival rate of cultured neurons at concentrations lower than 10^<-6>M.To elucidate this effect of estrogen, in situ hybridization of c-fos was performed on the rat limbic system after general administration of estrogen.As the results, we confirmed that estrogen induced c-fos activation, while glucocorticoid administration did not. It has been known that glucocorticoid inhibits AP-1 site. These results suggested that estrogen and glucocorticoid reciprocally regulated immediate early genes. Such effect of estrogen is probably related with our experimental data that estrogen sometimes causes long-term elevation of Ca^<2+> within cultured hippocampal neurons.Our hypothesis is that the next targent gene to the immediate early gene may be hepatocyte growth factor (HGF) gene since HGF is related with repairing also nervous tissue after injury and glucocorticoid inhibits HGF mRNA activation. Northern blotting analysis of HGF and c-met mRNA was performed on the rat hippocampus after general administration of kainic acid. HGF and c-met mRNA were induced 6 to 48 hours after kainic acid injection. Effect of steroid hormones on this kainic acid-induced HGF mRNA was under progress.To confirm the effect of estrogen on neurons more precisely, neuroblastoma cell line into which estrogen receptor gene was transfected was used. By adding estrogen to this cell line, the neuroblastoma cells differentiated into matured neurons. We are experimenting the effect of estrogen on neurons using this cell line differentiated by estrogen.

作为大脑中生物活性物质如何通过即早期基因引起长期影响的研究的一部分，研究了类固醇激素对培养的大鼠边缘神经元存活率的影响。先前已证实，在培养的边缘神经元中，糖皮质激素增加红藻氨酸诱导的细胞毒性呈剂量依赖性，而雌激素在浓度低于10^-6M时可增加培养神经元的存活率。为了阐明雌激素的这种作用，在一般给予雌激素后，对大鼠边缘系统进行c-fos原位杂交。结果证实，雌激素可诱导c-fos激活，而糖皮质激素则不会。已知糖皮质激素抑制AP-1位点。这些结果表明雌激素和糖皮质激素相互调节即早期基因。雌激素的这种作用可能与我们的实验数据有关，即雌激素有时会导致培养的海马神经元内 Ca^2+ 的长期升高。我们的假设是，立即早期基因的下一个目标基因可能是肝细胞生长因子（ HGF) 基因，因为 HGF 还与损伤后神经组织的修复有关，并且糖皮质激素抑制 HGF mRNA 激活。在一般施用红藻氨酸后，对大鼠海马体进行 HGF 和 c-met mRNA 的 Northern 印迹分析。红藻氨酸注射后6至48小时诱导HGF和c-met mRNA。类固醇激素对红藻氨酸诱导的HGF mRNA的影响正在进行中。为了更精确地确认雌激素对神经元的影响，使用了转染了雌激素受体基因的神经母细胞瘤细胞系。通过向该细胞系添加雌激素，神经母细胞瘤细胞分化成成熟的神经元。我们正在使用这种由雌激素分化的细胞系来实验雌激素对神经元的影响。