TROPHIC FACTOR INDUCED SYNAPTIC REGROWTH IN THE CNS

营养因子诱导中枢神经系统突触再生

基本信息

批准号：
2738910
负责人：
A CLAUDIO CUELLO
金额：
$ 4.21万
依托单位：
MCGILL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-09-30 至 1998-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2738910
关键词：
acetylcholine age difference brain injury cerebral cortex experimental brain lesion immunocytochemistry infarct intercellular connection laboratory rat nervous system regeneration neuroprotectants neurotrophic factors nonhuman therapy evaluation synaptogenesis

项目摘要

The long term objectives of the present proposal are to determine the limits of trophic factor-induced synaptic remodelling in the cerebral cortex of lesioned animals. The proposed research addresses two key issues: (l) the extent of functional restoration in the damaged CNS and (2) the possible therapeutic use of neurotrophic factors. This research group demonstrated that, alter cortical infarct, the administration of nerve growth factor causes a regrowth of the atrophied cholinergic input to the cortex as manifested by an increase in the number of cortical cholinergic varicosities, in the size of the presynaptic elements and in the number of synaptic contacts. In the proposed research, we will address the following questions: how widespread are these changes in the cortical mantle; are they specific for the cholinergic system; does synaptic remodelling persist alter the end of therapy; can these events also be induced in the injured CNS of aged animals. These studies will be carried out in young adult and aged Fischer 344 rats. Cortical devascularizing lesions will be performed on anesthetized animals. An Alzet minipump containing either vehicle or putative neurotrophic agents (nerve growth factor and/or GM1) will be connected to a permanent cannula placed in the contralateral lateral ventricle. After one week of therapy (or longer for aged animals) the minipumps will be removed and the animals allowed to survive for various times. The cortical cholinergic fiber network will be studied by means of light and electron microscopy quantitative immunocytochemistry, with the help of image analysis. Parameters to be assessed are the density of the fiber network, the number and size of varicosities and number of synapses. These studies will be carried out in the remaining cortex, at several distances from the edge of the lesion. Furthermore, the noradrenergic and the somatostatin-immunoreactive networks will be studied in order to assess the neurochemical specificity of the neurotrophic factor induced effects on cortical synaptic circuits. Studies of the postsynaptic cholinergic targets in the remaining cortex will be carried out using double-labeling light and electron microscopic immunocytochemistry. For this purpose, choline acetyltransferase immunocytochemistry will be combined to the immunocytochemical detection of glutamate, GABA, somatostatin and VIP and the relative percentage of cholinergic synapses on each transmitter specific postsynaptic target will be assessed by quantitative electron microscopy. These studies should provide important information relevant to the issue of the potential use of neurotrophic agents to treat neurodegenerative diseases on a long term basis, on the assumption that besides the recovery of damaged perikarya, the stimulation and maintenance of neoformed synapses, as a replacement for lost circuits, is a desirable effect.

本提案的长期目标是确定营养因子诱导的大脑突触重塑的极限病变动物的皮质。拟议的研究涉及两个关键问题：（l）受损中枢神经系统的功能恢复程度（2）神经营养因素的可能使用。这项研究小组表明，改变皮质梗塞，给药神经生长因子导致萎缩胆碱能输入的再生皮质数量的增加表现为皮质胆碱能静脉曲张，突触前元素的大小和突触接触的数量。在拟议的研究中，我们将解决以下问题：这些变化在皮质地幔；它们是针对胆碱能系统的；做突触重塑持续存在改变治疗的终结；这些事件可以吗？也会在老年动物的受伤中枢神经系统中诱导。这些研究会在年轻人和老年菲舍尔344只大鼠中进行。皮质血管性病变将对麻醉动物进行。一个含有媒介物或推定的神经营养剂的Alzet Minipump （神经生长因子和/或GM1）将连接到永久性套管放置在对侧外侧心室中。经过一周的治疗（或更长的年龄动物）将去除Minipump，并将动物可以在不同的时间生存。皮质胆碱能光纤网络将通过光和电子显微镜进行研究定量免疫细胞化学，借助图像分析。要评估的参数是光纤网络的密度，静脉曲张的数量和大小和突触的数量。这些研究将在其余皮层中进行，距离病变的边缘。此外，去甲肾上腺素和将研究生物抑素 - 免疫反应性网络，以评估神经营养因子诱导作用的神经化学特异性在皮质突触电路上。突触后胆碱能的研究剩余皮层中的靶标将使用双标签进行光和电子微型免疫细胞化学。为此，胆碱乙酰基转移酶免疫细胞化学将合并到谷氨酸，GABA，生长抑素和VIP的免疫细胞化学检测以及每个发射器上胆碱能突触的相对百分比特定的突触后靶标将通过定量电子评估显微镜。这些研究应提供重要的信息相关对于潜在使用神经营养剂来治疗的问题长期神经退行性疾病，假设除了恢复受损的植物植物外，刺激和维持新型突触，以替代丢失的电路，是理想的效果。