Development of a Novel System to Study Cholinergic Synaptic Homeostasis

描述（由申请人提供）：突触稳态是神经元用来平衡全局神经活动变化的保护机制。在过去的十年里，在这一领域的神经元突触进行了深入的研究，然而，几乎没有什么是已知的突触稳态是否也介导的其他兴奋性受体，如烟碱乙酰胆碱受体（nAChRs）。事实上，胆碱能突触稳态已被牵连在重要的病理条件，如阿尔茨海默氏病（AD）和尼古丁依赖。在这个R21应用程序中，我们的目标是验证一个新的系统，用于研究胆碱能突触稳态，并在一个尚未探索的重要领域开辟新天地。果蝇中枢神经系统为研究胆碱能突触稳态提供了理想的模型，因为nAChR是果蝇中枢神经元中的主要兴奋性受体。由于哺乳动物α7 nAChRs是最丰富和最广泛的nAChRs之一，并且与阿尔茨海默病、尼古丁成瘾、尼古丁诱导的癫痫发作和精神分裂症有关，因此我们将重点放在果蝇α7样受体（Dα7）上来验证我们的模型。使用原代神经元培养平行培养的大脑准备，我们建议操纵神经活动，并测定突触强度的变化和nAChR的定位和分布的变化。我们还将通过检查对由Dα7 nAChR介导的已知行为输出（巨纤维介导的逃避行为）的影响来测试胆碱能突触稳态的生理相关性。这个新系统的开发，它涉及原代培养物，离体脑制备和可量化的行为输出的组合，将是该领域的独特之处，并使我们能够回答期待已久的关于胆碱能突触稳态的问题。

DESCRIPTION (provided by applicant): Synaptic homeostasis is a protective mechanism employed by neurons to counterbalance changes in global neural activity. The last decade has seen intensive study in this field for glutamatergic synapses, however, almost nothing is known about whether synaptic homeostasis is also mediated by other excitatory receptors, such as nicotinic acetylcholine receptors (nAChRs). Indeed, cholinergic synaptic homeostasis has been implicated in important pathological conditions, such as Alzheimer's disease (AD) and nicotine dependence. In this R21 application, our goal is to validate a new system for studying cholinergic synaptic homeostasis and break new ground in an important area that has not yet been explored. The Drosophila CNS provides an ideal model for studying cholinergic synaptic homeostasis since nAChRs are the major excitatory receptor in Drosophila central neurons. Since mammalian α7 nAChRs are among the most abundant and widespread of nAChRs, and have been implicated in Alzheimer's disease, nicotine addiction, nicotine-induced seizures, and schizophrenia, we focus on the Drosophila α7 like receptor (Dα7) to validate our model. Using primary neuronal cultures in parallel with a cultured brain preparation, we propose to manipulate neural activity, and assay for changes in synaptic strength and changes in nAChR localization and distribution. We will also test the physiological relevance of cholinergic synaptic homeostasis by examining effects on a known behavioral output mediated by Dα7 nAChRs, the giant fiber mediated escape behavior. The development of this novel system, which involves the combination of primary cultures, an ex-vivo brain preparation, and a quantifiable behavioral output, will be unique to the field and allow us to answer long-awaited questions about cholinergic synaptic homeostasis.