Molecular and cytobiological study on regulation of synapse

突触调控的分子和细胞生物学研究

基本信息

批准号：
11694295
负责人：
MIYAMOTO Eishichi
金额：
$ 4.42万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The elucidation of molecular mechanisms of learning and memory is one of the most important and attractive projects in the field of neuroscience in the 21st century. High frequency stimulation of Schaffer collateral/commissural pathway in the slices of the hippocampus can cause long-lasting potentiation of synaptic transmission efficacy in the pyramidal cells of the CA1 area. This effect is called long-term potentiation (LTP), which is a possible model for a molecular mechanism for learning and memory.The present study elucidated the following findings. 1) LTP induction was associated with a significant decrease in protein phosphatase (PP) 2A activity. 2) A 55-kDa protein was phosphorylated during LTP induction. 3) Analysis with the specific antibody to the regulatory subunits of PP2A demonstrated that the 55-kDa protein is the B'α regulatory subunit of PP2A.4) CaM kinase IV and mitogen-activated protein kinase (MAPK) were transiently activated during LTP induction and returned to the original level within 30 min. Especially CaM kinase IV was activated in neuronal nuclei. 5) Activation of both kinases was associated with cyclic AMP-responsive elementbinding protein (CREB) phosphorylation. The use of inhibitors for CaM kinases and MAPK such as KN93 and U0126, respectively, indicated that CaM kinase IV and MAPK are each involved in CREB phosphorylation. Furthermore, c-Fos expression was stimulated 60 min after high frequency-stimulated LTP.The increase in c-Fos expression was inhibited by addition of calmidazolium and U0126.These results suggest that LTP induction is primarily performed by activation of CaM kinase II and its related reactions through Ca^<2+> influx into postsynaptic neurons by activation of NMDA glutamate receptors. Furthermore, LTP maintenance is associated with stimulation of gene expression and protein synthesis which may be necessary for synthesis of synaptic components and formation of new circuits.

阐明学习和记忆的分子机制是21世纪神经科学领域中最重要，最有吸引力的项目之一。海马切片中Schaffer侧支/合并途径的高频刺激可能会导致CA1区域的锥体细胞中突触传播有效性的长期增强。这种效果称为长期增强（LTP），这是用于学习和记忆的分子机制的可能模型。目前的研究阐明了以下发现。 1）LTP诱导与蛋白质磷酸酶（PP）2a活性的显着降低有关。 2）在LTP诱导期间，将55 kDA蛋白磷酸化。 3）对PP2A调节亚基的特异性抗体的分析表明，PP2A.4）CAM激酶IV和有丝分裂原激活的蛋白激酶（MAPK）的B'α调节亚基（MAPK）在LTP诱导过程中暂时激活，并在LTP诱导过程中暂时激活，并返回30分钟内。特别是在神经元核中激活CAM激酶IV。 5）两种激酶的激活与环状AMP响应元素构成蛋白（CREB）磷酸化有关。分别用于CAM激酶和MAPK（例如KN93和U0126）的抑制剂，表明CAM激酶IV和MAPK均参与CREB磷酸化。 Furthermore, c-Fos expression was stimulated 60 min after high frequency-stimulated LTP.The increase in c-Fos expression was inhibited by addition of calmazolium and U0126.The results suggest that LTP induction is primarily performed by activation of CaM kinase II and its related reactions through Ca^<2+>influx into postsynaptic neurons by activation of NMDA glutamate receptors.此外，LTP维持与基因表达和蛋白质合成的模拟有关，这对于合成突触组件和新电路的形成可能是必需的。