Nicotinic Receptors in Septally Innervated Hippocampus

描述：烟碱型胆碱能神经功能障碍和变性 大脑中的系统是大脑中不可或缺的生理病理指标之一 对社会影响最大的神经疾病是阿尔茨海默病(AD)。在……里面 AD，胆碱能神经元和烟碱受体(NAChRs)的永久性丧失 在处理认知功能的大脑区域，特别是海马体 和额叶皮质，与认知能力的下降和 记忆。到目前为止，AD患者的治疗在很大程度上依赖于使用 乙酰胆碱酯酶。这些药物，通过增加胆碱能功能 系统，部分逆转AD患者的症状。最近，临床部 试验表明，尼古丁激动剂(包括尼古丁)和 变构增强nAChRs的活性对 阿尔茨海默病患者的治疗。其有效性背后的机制 这些药物仍不为人所知，因为关于这些药物如何使用的信息很少 脑内神经元nAChRs的功能和表达受 胆碱能传入。此外，对nAChR的调控进行了详细的分析 隔区胆碱能传入在海马区的表达和功能 受到缺乏一种可行的生物制剂的限制 类似于体内的尼古丁胆碱感受性海马体系统。我们最初的 大鼠海马神经元烟碱特性的研究 器官型、海马区和隔区-海马区培养构成 本提案的主要部分，因为它建立了隔区-海马体 共培养作为体外研究黄曲霉毒素影响的良好模型 隔神经支配对海马区nAChR表达的影响因此，这项提议 旨在使用融合的多学科方法来解决 中央假设隔区神经支配和尼古丁动态改变 海马胆碱能系统。这项研究的第一个目标是使用 电生理学、共聚焦显微镜、配体结合和免疫细胞化学 为了确定隔神经支配是否改变了大鼠的尼古丁特性 器官发育过程中不同类型海马神经元的变化 文化。第二个目标是使用电生理测试，重组 DNA技术和基因零突变的“敲除”小鼠 编码α7尼古丁受体，研究nAChR靶向和 研究构成最终受体的nAChR亚基中的基序 以海马神经元为靶点。最终目标是使用 电生理、生化和分子生物学技术 评估尼古丁对小鼠脑内α7和α4beta2 nAChR表达的影响 海马体。这些研究的结果将产生深远的影响。 在确定调控nAChR表达的细胞和分子机制方面 和海马区的功能，为发育提供基础 针对阿尔茨海默病患者大脑受影响区域的治疗剂。

DESCRIPTION: The dysfunction and degeneration of the nicotinic cholinergic system in the brain are integral physiopathological indicators of one of the most socially impacting neurological disorders, Alzheimer's disease (AD). In AD, the permanent loss of cholinergic neurons and nicotinic receptors (nAChRs) in brain areas that process cognitive functions, particularly the hippocampus and the frontal cortex, correlates well with the decline in cognition and memory. To date, treatment of patients with AD relies heavily on the use of acetylcholinesterases. These drugs, by increasing function of the cholinergic system, partially reverse the symptoms of AD patients. Recently, clinical trials have shown that nicotinic agonists (including nicotine) and drugs that allosterically potentiate the activity of nAChRs are more effective for treatment of patients with AD. The mechanisms underlying the effectiveness of these drugs remain unknown, because there is very little information on how function and expression of neuronal nAChRs in the brain are regulated by cholinergic afferents. In addition, detailed analysis of regulation of nAChR expression and function in the hippocampus by septal cholinergic afferents has been limited by the lack of a viable biological preparation that closely resembles the nicotinic cholinoceptive hippocampal system in vivo. Our initial characterization of the nicotinic properties of hippocampal neurons in organotypic, hippocampal and septal-hippocampal cultures constitutes the mainstay of the present proposal, as it establishes the septal-hippocampal co-cultures as an excellent model for in vitro study of the influences of septal innervation on nAChR expression in the hippocampus. Thus, this proposal is designed to use convergent, multidisciplinary approaches to address the central hypothesis that septal innervation and nicotine dynamically modify the hippocampal cholinergic system. The first goal of this study is to use electrophysiology, confocal microscopy, ligand binding and immunocytochemistry to determine whether septal innervation alters the nicotinic properties of different types of hippocampal neurons during development in organotypic cultures. The second goal is to use electrophysiological assays, recombinant DNA technology and "knock-out" mice, which have a null mutation in the gene encoding alpha7 nicotinic receptors, to study nAChR targeting and to investigate the motifs in the nAChR subunits that account for final receptor targeting in hippocampal neurons. The final goal is to use electrophysiological, biochemical and molecular biological techniques to evaluate how nicotine affects alpha7 and alpha4beta2 nAChR expression in the hippocampus. The results of these studies will have far reaching implications in identifying cellular and molecular mechanisms regulating nAChR expression and function in the hippocampus and provide the basis for developing therapeutic agents targeting regions of the brain affected in AD.