PATHOLOGICAL MECHANISMS IN TRANSYNAPTIC CALCIUM OVERLOAD

描述（改编自申请人摘要）：本研究的目标是 了解突触兴奋性毒性退化的过程 使用动物模型。人类神经退行性疾病的动物模型是 对于探索细胞和生化介质以及分子具有重要价值 发病机制是缓慢进行性疾病过程。该慢通道 先天性肌无力综合征（SCCMS）是由导致 乙酰胆碱受体（AM）离子通道的延迟关闭， 神经肌肉（NMJ）。延迟通道关闭与钙离子有关 超负荷和变性的NMJ，AChR的损失，和进行性肌肉 弱点因此，SCCMS是遗传性兴奋毒性疾病的原型。 利用转基因小鼠技术和AChR亚基的定点突变 编码序列，我们已经开发了慢通道转基因小鼠， SCCS的动物模型表现出在人类中观察到的所有特征 疾病在本提案中，研究者建议：（1）确定是否 慢通道转基因小鼠具有减少的神经肌肉 突触特异性基因这将通过比较mRNA水平 对于AChR亚基基因和转基因和非转基因之间的其他NMJ特异性基因， 对照小鼠和变性NMJ核之间和远离NMJ核之间 细胞核;（2）确定细胞器损伤和终板的原因 慢通道小鼠的肌病。细胞内损伤的三种可能途径： 钙激活蛋白酶的激活，自由基的氧化损伤， 和细胞凋亡将使用特异性抗体探针的组合来探索 和染色剂来寻找NMJ和遗传学上受损的蛋白质和DNA， 这些途径的药理学操作，以改变过程中， 疾病;（3）。确定奎尼丁是否可以保护慢通道 终板退化的转基因小鼠。

DESCRIPTION (Adapted from applicant's abstract): The goal of this research is to understand the processes involved in excitotoxic degeneration of synapses using an animal model. Animal models for human neurodegenerative disease are of great value for exploring the cellular and biochemical mediators and molecular pathogenesis of a slowly progressive disease process. The slow channel congenital myasthenic syndrome (SCCMS) is caused by mutations that result in delayed closure of the ion channel of the acetylcholine receptor (AM) of the neuromuscular (NMJ). The delayed channel closure is associated with calcium overload and degeneration of the NMJ, AChR loss, and progressive muscle weakness. Thus, the SCCMS is a prototype for a hereditary excitotoxic disorder. Using transgenic mice technology and site-directed mutagenesis of AChR subunit coding sequences, we have developed the slow-channel transgenic mouse, an animal model for the SCCS that manifest all the features seen in the human disease. In this proposal, the investigator proposes to: (1) Determine whether slow-channel transgenic mice have reduced expression of neuromuscular synapse-specific genes. This will be accomplished by comparison of mRNA levels for the AChR subunit genes and other NMJ-specific genes between transgenic and control mice and between degenerating NMJ nuclei and remote from the NMJ nuclei; (2) Determine the cause(s) of the organellar damage and endplate myopathy in slow-channel mice. Three likely pathways of intracellular damage: activation of calcium-activated proteases, oxidative damage by free radicals, and apoptosis will be explored using a combination of specific antibody probes and stains to look for damaged proteins and DNA at the NMJ and genetic and pharmacological manipulation of these pathways to alter the course of the disease; and (3). Determine if quinidine can protect the slow-channel transgenic mice from endplate degeneration.