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; 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.

MG2+是一种丰富的细胞内阳离子，对控制至关重要 各种各样的细胞内过程。但是，相对较少是 知道控制细胞内的稳态机制 mg2+（[mg2+] i，也不是关于可能扰动的机制（mg2+] i。它具有 最近被证明通常被认为是兴奋性毒性的刺激 神经元在培养的神经元中[Mg2+] I的毫摩尔增加。 该项目的长期目标是了解[mg2+] i在 与神经元损伤相关的过程并发展有效 基于MG2+稳态操纵的治疗策略。这会 可以通过以下特定目的完成： 1。改变[mg2+] i的机制的表征。 [mg2+]我会的 使用MG2+敏感的培养大鼠前脑神经元测量 荧光染料。 （MG2+] I对谷氨酸的反应的特征 将建立受体激活，并假设 [MG2+] I与Ca2+成正比。荧光成像 技术将用于确定细胞内MG2+的来源 发布。 2。阐明[MG2+] I稳态的机制。一个角色 将建立推定的细胞MG2+缓冲机制的数量。 特别是，Na+/Mg2+交换的假设有助于 将检查神经元MG2+缓冲。 3。确定细胞内Mg2+的变化的作用 兴奋性毒性。初步结果表明兴奋性刺激非常 有效地提高[mg2+] i。升高[mg2+] i的作用以及 将研究组织MG2+损失对兴奋性毒性的影响。这 将确定细胞内Mg2+在兴奋性细胞死亡中的作用 并突出了新型的治疗方法来改善神经元 受伤。 4。通过细胞内MG2+对神经元Ca2+稳态调节。有 关于细胞内MG2+在中的作用的信息很少 调节神经元功能。 [mg2+] i对Ca2+的影响 进入和CA2+稳态将进行调查，并将提供另一个 [mg2+] i改变与兴奋性毒性之间的联系。 这些研究将提供有关有关作用的大量新信息 在调节神经元功能方面的阳离子知之甚少。更多的 重要的是，这些研究将揭示MG2+参与 兴奋性神经元损伤，从而突出了机制 导致神经元死亡。我们还期望这些研究将 产生有关基于神经元损伤治疗的新颖概念 操纵MG2+环境，从而对 治疗中风和创伤性脑损伤。