MODIFICATIONS IN HIPPOCAMPAL NEURON STRUCT ASSOCIATED W/ LONG TERM POTENTIATION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。我们正在利用一种新的技术来研究长时程增强(LTP)后海马区CA1区肌动蛋白细胞骨架的变化，该技术基于鬼臼毒素对F-肌动蛋白的高亲和力，然后被曙红光氧化二氨基联苯胺，以及它们如何参与刺状树突中的蛋白质移位。光镜下观察到大鼠海马片CA1区放射状纹状体内F-肌动蛋白的鬼臼蛋白染色减弱。使用电子显微镜的观察证实了这些结果。在LTP诱导后，蘑菇状树突棘的F-肌动蛋白染色持续减少，这表明LTP在这一特定亚型的棘中产生了F-肌动蛋白的解聚。此外，我们在培养的海马神经元中观察到，Jasplikanolide和促进肌动蛋白聚合速率的药物稳定了F-肌动蛋白，抑制了GFP-CaMKII和3kD葡聚糖的转位，提示F-肌动蛋白的聚合/解聚可能参与了不同物质在树突棘中的运输。此外，我们还观察到神经纤维和CA1锥体细胞胞质中的足细胞数量显著增加。目前正在使用3-D系列重建和电子断层扫描对形态发现进行统计量化。一份详细描述这项工作的手稿正在准备中。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are studying the changes in the actin cytoskeleton after Long Term Potentiation (LTP) in hippocampal area CA1 using a novel technique based in the high affinity of phalloidin for the F-actin followed for photooxidation of diaminobenzidine by eosin and how they could be involved in the protein translocation in the spiny dendrite. At the light microscopic level we detected a decrease of phalloidin staining of F-actin in the striatum radiatum of CA1 in hippocampal slices. Observations using electron microscopy confirmed these results. Mushroom shaped dendritic spines showed a very consistent decrease in F-actin staining after LTP induction suggesting that LTP produces depolymerizaion of F-actin in this particular subtype of spines. Furthermore we observed in cultured hippocampal neurons that the stabilization of F-actin using jasplikanolide an agents that increases the rate of actin polymerization, inhibits the translocation of GFP-CAMKII and the 3kD dextran suggesting that the F-actin polymerization/depolymerization might be involved in the transport of different substances in the dendritic spines. Also we observed a dramatic increment in the number of fillopodias in the neuropil and also in the cytoplasm of the CA1 pyramidal cells. The statistical quantification of the morphological findings is currently under way using 3-D serial reconstructions and electron tomography. A manuscript detailing this work is in preparation.