13C and 15N MRS Study of glutamate control in epilepsy

谷氨酸控制癫痫的 13C 和 15N MRS 研究

基本信息

批准号：
7340429
负责人：
BRIAN David ROSS
金额：
$ 32.47万
依托单位：
HUNTINGTON MEDICAL RESEARCH INSTITUTES
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-01-01 至 2009-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7340429
关键词：
Animal Model Astrocytes Behavioral Binding Brain Brain region Chronic Chronic Phase Collection Contralateral Convulsions Epilepsy Event Exocytosis Extracellular Fluid Gas Chromatography Glutamate Receptor Glutamate Transporter Glutamates Glutamine Hippocampus (Brain)Human In Situ Invasive Ipsilateral Isotopes Kinetics Laboratories Lead Lesion Link Localized Magnetic Resonance Spectroscopy Mass Fragmentography Mass Spectrum Analysis Measurement Measures Mediating Metabolic Control Metabolism Microdialysis Modeling Monitor Motor Cortex Nerve Degeneration Neuroglia Neurons Neurotransmitters Numbers Process Rate Rattus Recycling Research Personnel Role Seizures Surgical Management Synapses Temporal Lobe Epilepsy Thinking Time excitotoxicity extracellular in vivo kainate nervous system disorder neurotransmission neurotransmitter uptake novel strategies programs quantum receptor system N protein 1 uptake

项目摘要

Glutamate excitotoxicity has been implicated in epileptic seizures. Our objectives are 1) to clarify the mechanisms that control the metabolic flux and intercompartmental transport of glutamate and glutamine in the intact mammalian brain and 2) determine how glutamate excitotoxicity may cause epileptic seizures. Impaired glial uptake of GLU in the extracellular fluid (GLUECF) can lead to excessive stimulation of the GLU receptors and to neuronal degeneration (GLU excitotoxicity). The rate of uptake of neurotransmitter GLU from the extracellular fluid into astrocytes and subsequent metabolism to GLN has been measured through a) selective 13C enrichment of neurotransmitter GLU by isotope chase, b) collection of extracellular GLU by microdialysis and analysis of its 13C enrichment by gas-chromatography/mass spectrometry and c) observation of [5-13C, 5-15N] GLN formed in astrocytes using localized in vivo 13C and 15N MRS. Now, Specific Aim #1, a 'missing-link' in the GLN/GLU cycle, the kinetics and mechanism of transport of GLN from astrocytes to neurons will be determined using in vivo 15N, 1H-15N HMQC and 13C MRS. The results will clarify the roles of recently identified GLN transporters in the intact normal brain and determine whether the rate of glial GLN efflux (hypothesis #1) or of neuronal GLN uptake (hypothesis #2) limits the GLN/GLU cycle rate in vivo. Specific Aim #2 Kinetics of GLU release and uptake in temporal lobe epilepsy will be studied using the chronic kainate-induced epileptic (KA) rats model. In vivo flux rates will be measured in the lesioned and contralateral hippocampus and correlated with electrophysiological and behavioral seizures, to determine whether the onset and propogation of seizures is the result of (hypothesis #3) abnormal GLU release, (hypothesis #4) impaired GLU clearance by glial transporters, or (hypothesis #5) a combination of these processes. Together these studies will contribute to a better understanding of the regulatory events of the GLN/GLU cycle in KA and increase potential to replace surgical management of temporal lobe epilepsy.

谷氨酸兴奋性毒性与癫痫发作有关。我们的目标是1）澄清控制谷氨酸和谷氨酰胺的代谢通量和室间转运的机制完整的哺乳动物大脑和2）确定谷氨酸兴奋性如何引起癫痫发作。细胞外液（GLUECF）中GLU的神经胶质吸收受损会导致过度刺激 GLU受体和神经元变性（GLU兴奋毒性）。神经递质的摄取率已经测量了从细胞外流体到星形胶质细胞的GLU，并已测量了随后的新陈代谢为GLN 通过A）通过同位素追逐的选择性13C富集神经递质GLU，b）收集细胞外的通过微透析和通过气体色谱/质谱法和C对其13c富集进行GLU的分析）使用体内13C和15N MRS局部化的星形胶质细胞形成的[5-13C，5-15N] GLN的观察。现在，特定目标＃1，GLN/GLU周期中的“缺失链接”，GLN运输的动力学和机理神经元的星形胶质细胞将使用体内15N，1H-15N HMQC和13C MRS确定。结果将阐明最近确定的GLN转运蛋白在完整大脑中的作用，并确定是否是否神经胶质GLN外排（假设＃1）或神经元GLN摄取（假设2）限制了GLN/GLU循环体内速率。将研究特定的目标＃2 GLU释放和颞叶癫痫的吸收动力学使用慢性海藻酸盐诱导的癫痫（KA）大鼠模型。体内通量率将在病变和对侧海马，与电生理和行为癫痫发作相关，与确定癫痫发作和促进是否是（假设＃3）异常GLU的结果释放，（假设＃4）神经胶质转运蛋白的GLU清除率受损，或（假设5）这些过程。这些研究将共同有助于更好地理解 KA中的GLN/GLU循环增加了替代颞叶癫痫的手术管理的潜力。