GLUTAMATE AND SENSORY PROCESSING IN THE OLFACTORY SYSTEM

嗅觉系统中的谷氨酸和感官处理

• 批准号: 2126815
• 负责人: THOMAS PATRICK SEGERSON
• 金额: $ 16.15万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2126815
• 关键词: G protein; Xenopus oocyte; biophysics; complementary DNA; glutamate receptor; glutamates; immunocytochemistry; lateral olfactory area; limbic system; membrane channels; neural information processing; neuroanatomy; olfactions; olfactory lobe; protein structure function; receptor coupling; receptor expression; receptor sensitivity; synapses; tissue /cell culture; voltage /patch clamp

DESCRIPTION (Adapted from the Investigator's Abstract): The olfactory system of vertebrates has become an increasingly important model for the study of processing of sensory information. The olfactory bulb and primary olfactory paleocortex are the major sites of sensory processing in this system. Although the anatomy and synaptic circuitry of this system have been studied extensively, the molecular events at olfactory synapses and within olfactory neurons mediating olfactory information processing, associative learning and memory have not been characterized. Glutamate couples to two classes of receptors: ligand-gated ion channels (ionotropic receptors), and those coupled to intracellular signalling pathways through guanyl nucleotide binding proteins or G proteins (metabotropic receptors). The latter group is potentially important in effects of glutamate involving calcium, kinases and modulation of synaptic strength. Expression of this class of receptors is remarkably prevalent in olfactory regions by physiologic and molecular studies, suggesting an essential role in glutamate signaling and information processing. However, the lack of specific pharmacologic tools has limited our understanding of the function of G protein-coupled glutamate receptors. This proposal will use Xenopus oocytes and neuronal cells that express cloned receptors to address three questions: 1) What are the structural features of different G protein-coupled receptors in the olfactory system that determine their pharmacology? 2) What are the cellular effects of G protein coupled glutamate receptors that determine their function in olfactory neurons? 3) How do G protein-coupled glutamate receptors in olfactory neurons contribute to the normal function of these neurons? The investigators will use cDNAs for metabotropic glutamate receptors and isolate others from olfactory bulb and olfactory cortex to test hypotheses about the features of these receptors that determine their pharmacology. This will be crucial to understand the receptors that mediate effects of known pharmacologic reagents and perhaps allow the development of more specific and effective pharmacologic tools. They will determine by patch-clamp recording of neuronal cell lines and primary neuronal cultures expressing the receptor cDNAs the effects of these receptors on gating and modulation of specific ion channels to determine how these receptors affect neuronal excitation. They will also determine the anatomic expression of these receptors mRNAs in olfactory neurons and use antisera to determine whether they are expressed in specific areas of the olfactory circuitry, including at olfactory synapses. They will also try to dissect the important signals that individual G protein-coupled glutamate receptors activate in olfactory neurons by combining physiologic and molecular studies in individual neurons and by blocking their expression of individual metabotropic receptors and measuring differences in glutamate effects on ion channel modulation and intracellular signaling pathways. By defining the precise pharmacology of these receptors, understanding their cellular effects in neurons and determining their pattern of expression in olfactory neurons and synapses, the investigators will begin to elucidate the molecular events underlying processing of olfactory sensory information.

描述（改编自研究者摘要）：嗅觉 脊椎动物系统已经成为一个越来越重要的模型， 对感官信息处理的研究。 嗅球和 初级嗅觉古皮层是感觉加工的主要部位 在这个系统中。虽然这种神经元的解剖结构和突触回路 系统已被广泛研究，分子事件在嗅觉 突触和嗅觉神经元内的嗅觉信息 加工、联想学习和记忆尚未被表征。 谷氨酸与两类受体偶联：配体门控离子通道 （离子型受体），以及那些与细胞内信号传导 通过鸟苷酸结合蛋白或G蛋白的途径 （代谢型受体）。后一组潜在的重要性， 涉及钙、激酶和调节的谷氨酸的作用 突触强度 这类受体的表达是显著的 通过生理学和分子学研究， 这表明它在谷氨酸信号和信息传递中起着重要作用， 处理. 然而，由于缺乏特定的药理学工具， 限制了我们对G蛋白偶联谷氨酸功能的理解 受体。 这项提议将使用非洲爪蟾卵母细胞和神经元细胞 表达克隆受体来解决三个问题：1） 不同G蛋白偶联受体的结构特征， 嗅觉系统决定了它们的药理作用？ 2)有哪些 G蛋白偶联谷氨酸受体的细胞效应， 它们在嗅觉神经元中的功能 3)G蛋白偶联 嗅觉神经元中的谷氨酸受体有助于正常的 这些神经元的功能？ 研究人员将使用cDNA 代谢型谷氨酸受体和从嗅球分离的其它受体 和嗅觉皮层来测试关于这些特征的假设。 决定其药理作用的受体。 这将对 了解介导已知药理学作用的受体 试剂，也许可以开发更具体的， 有效的药物工具。 他们将通过膜片钳技术 神经元细胞系和原代神经元培养物的记录 表达受体cDNA，这些受体对门控的影响 和特定离子通道的调节来确定这些受体 影响神经元兴奋。 他们还将确定解剖 这些受体mRNA在嗅觉神经元中的表达和用途 抗血清，以确定它们是否在细胞的特定区域表达。 嗅觉回路，包括嗅觉突触。 他们也会尝试 来分析单个G蛋白偶联的重要信号， 谷氨酸受体在嗅觉神经元中通过结合 在单个神经元中进行生理和分子研究， 它们的单个代谢型受体的表达和测量 谷氨酸盐对离子通道调节的作用的差异， 细胞内信号通路。通过定义精确的药理学 了解这些受体在神经元中的细胞效应， 确定它们在嗅觉神经元中的表达模式， 研究人员将开始阐明突触的分子事件 嗅觉信息的潜在处理。