The Septohippocampal System: Regulation by Neurotrophins

描述（由申请人提供）：细胞和亚细胞机制中的可塑性变化是神经行为表现和神经系统功能的关键决定因素。我们建议调查调节隔海马（S-H）系统的神经生长因子（NGF）。中心假设是，小鼠海马内获得NGF功能在短期内增强隔胆碱能神经元的活性，并且在长期内导致内侧隔/对角带核（MS/nDB）和海马中的突触重组，从而沿着S-H系统的神经传递。为了验证这一假设，我们将使用作为实验模型的转基因小鼠窝藏一个有针对性的海马内获得的神经生长因子功能。实验，结合膜片钳记录，免疫组织化学和PCR扩增检测的免疫反应性（PADI），被组织成三个具体的目标。具体目标1将检验GABA能MS/nDB神经元受毒蕈碱张力调节的假设，该毒蕈碱张力由MS/nDNB中的胆碱能活性维持。具体目标2将检验以下假设：海马中NGF表达的靶向激活和增加导致MS/nDNB神经元特性的变化，这与增强的毒蕈碱紧张性一致，从而与S-H通路的活性一致。具体目标3将采用隔海马共培养系统，以测试的假设，有针对性的激活神经生长因子是时间和活性依赖性。在测试这些假设的固有概念是，特定的细胞和分子的变化可以与神经生长因子激活。因此，除了电生理学实验，候选蛋白质将通过基于PCR的蛋白质检测技术在通过激光捕获显微切割分离的单个神经元中进行分析。总的来说，这个项目将有助于我们了解神经系统中神经生长因子诱导的可塑性的细胞和分子基础，并探索靶向基因转移作为一种潜在的治疗策略的价值，以改善认知功能障碍的衰弱后果，如在各种神经退行性疾病中所见。

DESCRIPTION (provided by applicant): Plastic changes in cellular and subcellular mechanisms are critical determinants of neurobehavioral manifestations; of nervous system function. We propose to investigate the regulation of the septohipppocampal (S-H) system by nerve growth factor (NGF). The central hypothesis is that an intrahippocampal gain of NGF function in mice enhances activity of septal cholinergic neurons in the short term and, in the long term, leads to synantic reorganization in both the medical septum/nucleus of Diagonal Band (MS/nDB) and hippocampus and, thereby neurotransmission along the S-H system. To test this hypothesis, we will use as experimental model transgenic mice harboring a targeted intrahippocampal gain of NGF function. The experiments, incorporating patch clamp recording, immunohistochemistry and PCR-Amplified Detection of Immunoreactivity (PADI), are organized into three specific aims. Specific Aim 1 will test the hypothesis that GABAergic MS/nDB neurons are under regulation of a muscarinic tone that is maintained by cholinergic activity in the MS/nDNB. Specific Aim 2 will test the hypothesis that a targeted activation and increase in the expression of NGF in the hippocampus leads to changes in the properties of MS/nDNB neurons that are consistent with an augmented muscarinic tone and thus activity alongthe S-H pathway. Specific Aim 3 will employ a septohippocampal coculture system to test the hypothesis that the targeted activation of NGF is time- and activity-dependent. Inherent in testing these hypothesis is the notion that specific cellular and molecular changes can be correlated with NGF activation. Thus, in addition to the electrophysiological experiments, candidate proteins will be analyzed by a PCR-based protein detection technique in single neurons isolated by laser capture microdissection. Overall, this project will contribute to our understanding of the cellular and molecular bases underlying NGF-induced plasticity in the nervous system and explore the value of targeted gene transfer as a potential therapeutic strategy to ameliorate the debilitating consequences of cognitive dysfunction as seen in a variety of neurodegenerative conditions.