Identifying the Role of Serotonergic Signaling in the Maturation ofDendritic Spines

项目摘要 功能性大脑发育需要神经化学物质的精确协调，使神经元能够 形成突触并相互交流。关键发育期间突触成熟不当 时间窗口通常会导致认知障碍，例如在自闭症谱系障碍中观察到的那些， 坚持到成年。对人类和啮齿动物的研究表明， 产前和产后早期发育，行为和认知缺陷以及不规则 神经元发育前额叶皮层（PFC）是大脑的一个区域，在处理过程中起着关键作用 当5-HT水平改变时，高级认知功能被破坏。在PFC的早期开发过程中， 回路的形成依赖于兴奋性突触的功能成熟和稳定，位于 树突棘我们的初步研究发现5-HT在树突棘的发育中起着关键作用 在PFC内，表明在操纵5-HT水平后， 产后早期该建议包括两个目的，旨在验证5-HT可以 在单个突触水平增强和稳定树突棘。第一个目标使用的技术组合 包括5-HT和谷氨酸神经递质的双色双光子释放，电生理学， 光遗传学和药理学，以确定5-HT是否可以诱导功能性长时程增强， 单独的树突棘第二个目的是确定内源性5-HT信号是否可以 稳定新生树突棘，这将通过使用光遗传学，双光子5-HT uncaging 和机制研究，包括药理学方法和荧光寿命成像。我们一起努力， 这些研究试图确定5-HT依赖性信号传导在突触成熟和稳定中的作用， 细胞和分子水平。该项目的结果将是更好地减轻 由于发育中的大脑中早期5-HT失衡而导致的认知障碍。

PROJECT SUMMARY Functional brain development requires the precise coordination of neurochemicals that allow neurons to form synapses and communicate with one another. Improper synaptic maturation during critical developmental time windows often lead to cognitive disabilities, such as those observed in autism spectrum disorders, that can persist into adulthood. Studies in humans and rodents have linked disbalances of serotonin (5-HT) during prenatal and early postnatal development to increased rates of behavioral and cognitive deficits and irregular neuronal development. The prefrontal cortex (PFC) is a region of the brain that plays a key role in processing higher order cognitive functions that are disrupted when 5-HT levels are altered. During early PFC development, circuit formation is dependent on the functional maturation and stabilization of excitatory synapses, located on dendritic spines. Our preliminary studies identified a critical role for 5-HT in the development of dendritic spines within the PFC, indicating that both spine density and size are directly altered after manipulating 5-HT levels in early postnatal periods. This proposal is comprised of two aims which seek to test the hypothesis that 5-HT can potentiate and stabilize dendritic spines at a single synapse level. The first aim uses a combination of techniques including two-color, two-photon uncaging of 5-HT and glutamate neurotransmitters, electrophysiology, optogenetics, and pharmacology to determine whether 5-HT can induce functional long-term potentiation of individual dendritic spines. The second aim is designed to identify whether endogenous 5-HT signaling can stabilize nascent dendritic spines, which will be investigated by using optogenetics, two-photon 5-HT uncaging and mechanistic studies that include pharmacological approaches and fluorescence lifetime imaging. Together, these studies seek to establish the role of 5-HT dependent signaling in synapse maturation and stabilization at a cellular and molecular level. Results from this project will be essential knowledge towards better mitigating the cognitive disabilities that result from early 5-HT disbalances in the developing brain.