INTRACELLULAR MAGNESIUM AND EXCITOTOXICITY

细胞内镁与兴奋性毒性

• 批准号: 6054356
• 负责人: IAN J REYNOLDS
• 金额: $ 2.5万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6054356
• 关键词: calcium flux; fluorescence microscopy; fluorescent dye /probe; glutamate receptor; glutamates; intracellular; laboratory rat; magnesium; neural degeneration; neurotoxins; prosencephalon; tissue /cell culture

Mg2+ is an abundant intracellular cation that is critical for the control of a wide array of intracellular processes. However, relatively little is known about the homeostatic mechanisms that control intracellular free Mg2+ ([Mg2+]i, nor about mechanisms that might perturb (Mg2+]i. It has recently been shown that stimuli that are normally considered excitotoxic to neurons produce millimolar increases in [Mg2+]i in cultured neurons. The long term goal of this project is to understand the role of [Mg2+]i in processes associated with neuronal injury and to develop effective treatment strategies based on manipulation of Mg2+ homeostasis. This will be accomplished by the following specific aims: 1. characterization of mechanisms that alter [Mg2+]i. [Mg2+]i will be measured in cultured rat forebrain neurons using Mg2+-sensitive fluorescent dyes. The characteristics of the (Mg2+]i response to glutamate receptor activation will be established, and the hypothesis that the [Mg2+]i is proportional to Ca2+ will be tested. Fluorescence imaging techniques will be used to determine the source of the intracellular Mg2+ release. 2. Elucidation of the mechanisms of [Mg2+]i homeostasis. The role of a number of putative cellular Mg2+ buffering mechanisms will be established. In particular, the hypothesis that Na+/Mg2+ exchange contributes to neuronal Mg2+ buffering will be examined. 3. Determination of the role of changes in intracellular Mg2+ in excitotoxicity. Preliminary results show that excitotoxic stimuli are very effective at raising [Mg2+]i. The role of elevated [Mg2+]i as well as the effect of tissue Mg2+ loss in excitotoxicity will be investigated. This will establish the role of intracellular Mg2+ in excitotoxic cell death and highlight novel therapeutic approaches to ameliorating neuronal injury. 4. Regulation of neuronal Ca2+ homeostasis by intracellular Mg2+. There is very little information available about the role of intracellular Mg2+ in regulating neuronal function. The influence of [Mg2+]i changes on Ca2+ entry and Ca2+ homeostasis will be investigated, and will provide another link between [Mg2+]i changes and excitotoxicity. These studies will provide substantial new information about the role of a poorly understood cation in the regulation of neuronal function. More importantly, these studies will reveal the involvement of Mg2+ in excitotoxic neuronal injury and thereby highlight mechanism that contribute to neuronal death. We also anticipate that these studies will generate novel concepts about the treatment of neuronal injury based on manipulation of the Mg2+ environment and thereby positively impact the treatment of stroke and traumatic brain injury.

Mg 2+是一种丰富的细胞内阳离子，对于控制 一系列的细胞内过程。然而，相对来说， 已知控制细胞内游离 Mg ~（2+）~（[Mg ~（2+）]i）的影响机制。它有 最近的研究表明，通常被认为是兴奋性毒性的刺激， 在培养的神经元中产生[Mg 2 +]i的毫摩尔增加。 本项目的长期目标是了解[Mg 2 +]i在 与神经元损伤相关的过程，并开发有效的 基于Mg 2+稳态操纵的治疗策略。这将 通过以下具体目标实现： 1.改变[Mg 2 +]的机制的表征i. [Mg2[I Will Be] 在培养的大鼠前脑神经元中使用Mg 2+敏感的 荧光染料。[Mg ~（2+）]_i对谷氨酸的反应特性 受体激活将建立，并假设， [Mg2+]i与Ca 2+成正比。荧光成像 技术将用于确定细胞内Mg 2+的来源 release. 2.阐明[Mg 2 +]i稳态的机制。的角色 将建立许多假定的细胞Mg 2+缓冲机制。 特别是，Na+/Mg 2+交换有助于 将检查神经元Mg 2+缓冲。 3.确定细胞内Mg 2+变化在细胞内的作用， 兴奋性毒性初步结果表明，兴奋性毒性刺激是非常 有效提高[Mg 2 +]i.升高的[Mg 2 +]i以及 将研究组织Mg 2+损失在兴奋性毒性中的作用。这 将确立细胞内Mg 2+在兴奋性毒性细胞死亡中的作用 并强调新的治疗方法，以改善神经元 损伤 4.细胞内Mg ~（2+）对神经元Ca ~（2+）稳态的调节有 关于细胞内Mg 2+在细胞内的作用的信息很少， 调节神经元功能[Mg ~（2+）]i变化对Ca ~（2+）的影响 进入和Ca 2+稳态将进行研究，并将提供另一个 [Mg 2 +]i变化与兴奋性毒性之间的联系。 这些研究将提供大量新的信息， 一种在调节神经元功能方面知之甚少的阳离子。更 重要的是，这些研究将揭示Mg 2+参与 兴奋性毒性神经元损伤，从而突出机制， 导致神经元死亡我们还预计，这些研究将 产生关于神经元损伤治疗的新概念， 操纵Mg 2+环境，从而积极影响 中风和创伤性脑损伤的治疗。