海马齿状回星形胶质细胞的长时程增强

发布时间：2018-03-07 18:48

本文选题：长时程增强　切入点：星形胶质细胞　出处：《浙江大学》2005年博士论文　论文类型：学位论文

【摘要】：神经元是神经系统的主要功能细胞,它们通过形成突触结构,即突触前末梢和突触后神经元组成的化学性突触,执行可塑性的突触信号传递,完成神经系统的通讯功能。星形胶质细胞是中枢神经系统中存在的另一类细胞,它的数目远远多于神经元,一直以来被认为仅仅起了支持和营养神经元的作用,是维持神经元正常功能活动的辅助细胞。然而近年来,越来越多的证据支持这些星形胶质细胞也参与了神经元的信号传递,主动的调节突触传递和可塑性。在大脑皮层、海马和小脑等大量的脑区,这些胶质细胞伸出大量细长的突起,紧紧包绕着突触,与突触前末梢和突触后神经元共同构成了一个三联体突触结构,为它们之间快速而有效的相互调控提供了结构上的基础。最近10年来,胶质细胞内钙信号的发现被认为是星形胶质细胞对神经元的突触传递和可塑性调控的主要途径之一。已经发现星形胶质细胞膜上存在着神经递质谷氨酸受体,它们能结合神经元突触前末梢释放的谷氨酸,引起细胞内钙离子浓度的升高,形成所谓的钙波和钙振荡,从而诱导胶质细胞释放多种新的生物活性物质,如ATP、谷氨酸、D型丝氨酸、肿瘤坏死因子和前列腺素E_2等,反作用于神经元的突触末梢,调控突触前的释放和突触后的受体反应,改变突触传递的效率。目前已发现星形胶质细胞膜上表达有各种各样的离子通道和神经递质受体,如各种钾通道、钙通道、甚至钠通道,以及代谢型的和离子型的谷氨酸受体、γ-氨基丁酸受体等。
[Abstract]:Neurons are the main functional cells of the nervous system. They perform plastic synaptic signaling by forming synaptic structures, chemical synapses composed of presynaptic endings and postsynaptic neurons. The astrocytes are the other type of cells in the central nervous system that are far more numerous than neurons and have long been thought to only act as support and nutritional neurons. These astrocytes are auxiliaries that maintain normal neuronal function. In recent years, however, there has been increasing evidence that these astrocytes are also involved in neuronal signaling, active regulation of synaptic transmission and plasticity. A large number of brain regions, such as the hippocampus and the cerebellum, in which glial cells protrude a large number of slender protuberances that tightly encircle the synapses and form a triplet synaptic structure with presynaptic endings and postsynaptic neurons. It provides a structural basis for rapid and effective mutual regulation between them. In the last 10 years, the discovery of calcium signal in glial cells has been considered as one of the main pathways of synaptic transmission and plasticity of astrocytes. They can combine glutamate released by the presynaptic terminals of neurons and cause the increase of intracellular calcium concentration, forming so-called calcium waves and calcium oscillations, thus inducing glial cells to release many new bioactive substances. For example, ATP, glutamate D-type serine, tumor necrosis factor and prostaglandin E _ 2 counteract the synaptic endings of neurons, regulate presynaptic release and postsynaptic receptor response, and change the efficiency of synaptic transmission. A variety of ion channels and neurotransmitter receptors, such as potassium channels, calcium channels, even sodium channels, as well as metabolic and ionic glutamate receptors and 纬 -aminobutyric acid receptors, have been found in astrocytes.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R33

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