CNS L-PROLINE TRANSPORTER

L-脯氨酸被认为是一种神经递质或神经调节剂 在哺乳动物的中枢神经系统(CNS)。定义角色的研究 L-脯氨酸在哺乳动物中枢神经系统中的离散通路尚未被研究 可能是由于无法阻止其生物合成或高亲和力 在神经组织中的运输。我们最近克隆了一种高亲和力的Na+- 依赖的L-脯氨酸转运蛋白在推测的亚群中的表达 谷氨酸能神经元为特定角色提供了令人信服的支持 L--兴奋性传递中的脯氨酸。谷氨酸能突触一直是 牵涉到多种生理过程，包括获得 联想学习、突触形成和神经内分泌调节。 谷氨酸能传递的异常被认为与 兴奋性中毒性神经紊乱的病理生理学。因此达成了一项谅解 L-脯氨酸转运体在特定环境中的功能作用(S) 谷氨酸能神经元可以为突触调节提供洞察力 突触可塑性和记忆获得的机制或其机制 对阿尔茨海默病等疾病的干扰。的长期目标是 本研究旨在阐明L-脯氨酸的作用及其在体内的作用。 传输器，在突触传递中。具体目标L将承担 首次对区域、细胞和亚细胞进行详细研究 高亲和力L-脯氨酸转运蛋白在大鼠体内的分布 大脑。单个神经元表达的精确投射路径 结合逆行染料测定L-脯氨酸转运体基因 原位杂交组织化学示踪。了解以下内容 这些途径将是设计生理学研究的关键。 L-脯氨酸在突触传递中的作用。研究还将检查 高亲和力L-脯氨酸和L-谷氨酸的可能共定位 谷氨酸能神经末梢的转运蛋白。《特定目标2》将使用 L-脯氨酸转运蛋白作为模型神经递质转运蛋白 探讨其结构-功能特性及其调控 利用嵌合转运蛋白策略的一类重要突触蛋白 和定点突变。最终的具体目标是调查 L-脯氨酸的潜在突触作用。非洲爪哇卵母细胞表达测定方法的建立 将被用来研究L-脯氨酸调制信号的假设 谷氨酸受体亚型的转导，类似于甘氨酸 NMDA受体的调节。这项检测还将被用于 探讨不同的L-脯氨酸受体存在的可能性 哺乳动物中枢神经系统。选择性阻断L-脯氨酸的单抗 将产生运输，用作运输抑制剂，以检查 L-脯氨酸调控细胞合成和/或释放的假说 神经末梢的谷氨酸。小说的潜在发现 谷氨酸能突触的调节机制是 推动本提案中描述的研究。

L-proline has been postulated to be a neurotransmitter or neuromodulator in the mammalian central nervous system (CNS). Studies to define the role of L-proline in discrete pathways in the mammalian CNS have not been possible due to the inability to block its biosynthesis or high affinity transport in nervous tissue. Our recent cloning of a high affinity, Na+- dependent L-proline transporter expressed in subpopulations of putative glutamatergic neurons provides compelling support for a specific role for L-proline in excitatory transmission. Glutamatergic synapses have been implicated in diverse physiologic processes including the acquisition of associative learning, synapse formation, and neuroendocrine regulation. Abnormalities of glutamatergic transmission have been implicated in the pathophysiology of excitotoxic neurologic disorders. Thus an understanding of the functional role(s) of the L-proline transporter in specific glutamatergic neurons could provide insights into synaptic regulatory mechanisms involved in synaptic plasticity and memory acquisition or their disruption in diseases such as Alzheimer's disease. The long term goal of this research is to elucidate the role(s) of L-proline, and its transporter, in synaptic transmission. Specific Aim l will undertake the first detailed studies of the regional, cellular, and subcellular distribution of the high affinity L-proline transporter protein in rat brain. The precise projection pathways of individual neurons that express L-proline transporter mRNA will be determined by combining retrograde dye tract-tracing with in situ hybridization histochemistry. Knowledge of these pathways will be crucial to the design of physiological studies of the role of L-proline in synaptic transmission. Studies will also examine the possible co-localization of high affinity L-proline and L-glutamate transporters in glutamatergic nerve terminals. Specific Aim 2 will use the L-proline transporter as a model neurotransmitter transporter, to investigate the structure-function properties and regulation of this important class of synaptic proteins using chimeric transporter strategies and site-directed mutagenesis. The final Specific Aim will investigate potential synaptic roles of L-proline. A Xenopus oocyte expression assay will be used to investigate the hypothesis that L-proline modulates signal transduction at a glutamate receptor subtype, analogous to glycine modulation of the NMDA receptor. This assay will also be used to investigate the possibility that distinct L-proline receptors exist in mammalian CNS. Monoclonal antibodies that selectively block L-proline transport will be generated, for use as transport inhibitors, to examine the hypothesis that L-proline modulates the synthesis and/or release of glutamate from nerve terminals. The potential discovery of novel regulatory mechanisms in glutamatergic synapses is the incentive which drives the research described in this proposal.