Nicotinic Receptors in Septally Innervated Hippocampus

描述：烟碱胆碱能神经元的功能障碍和变性。 脑中的神经系统是一个完整的病理生理指标， 最具社会影响力的神经系统疾病，阿尔茨海默病（AD）。在 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 和额叶皮层，与认知能力的下降密切相关， 记忆迄今为止，AD患者的治疗严重依赖于使用 乙酰胆碱酯酶这些药物通过增加胆碱能神经的功能 系统，部分逆转AD患者的症状。最近，临床 试验表明，烟碱激动剂（包括尼古丁）和药物， 变构增强nAChR的活性对于 治疗AD患者。有效性的机制 这些药物仍然是未知的，因为很少有信息， 脑中神经元nAChR的功能和表达受以下因素调节： 胆碱能传入神经此外，还详细分析了nAChR的调节 隔胆碱能传入在海马中的表达和功能 由于缺乏一种可行的生物制剂， 类似于体内的烟碱胆碱感受海马系统。我们最初 海马神经元烟碱特性的表征 器官型、海马和隔-海马培养构成了 本提案的支柱，因为它建立了隔海马 共培养物作为体外研究 隔神经支配对海马nAChR表达的影响。因此，本提案 旨在使用融合的多学科方法来解决 中心假说，隔神经支配和尼古丁动态地改变 海马胆碱能系统本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 以确定隔神经支配是否改变了 不同类型的海马神经元在发育过程中的器官型 cultures.第二个目标是使用电生理测定，重组 DNA技术和“基因敲除”小鼠，它们在基因中具有无效突变 编码α 7烟碱受体，研究nAChR靶向， 研究nAChR亚基中的基序， 定位于海马神经元。最终目标是使用 电生理学、生物化学和分子生物学技术， 评估尼古丁如何影响alpha 7和alpha 4 beta2 nAChR在 海马体。这些研究的结果将产生深远的影响 在确定调节nAChR表达的细胞和分子机制方面， 并在海马体中发挥作用， 靶向受AD影响的脑区域的治疗剂。

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.