Animal model of juvenile epileptogenesis: NMDA receptors

描述（由申请人提供）：涉及遗传易感性 在超过40-50%的人类癫痫中。然而，迄今为止，只有12个基因 与人类癫痫综合征有关，这些只能解释 不到1%的癫痫患者。进一步鉴定基因， 癫痫的发病机制是至关重要的了解如何癫痫 发展并最终可能导致更好的治疗和预防 疾病我们已经建立了一个独特的突变动物模型，其中NMDA谷氨酸 在大脑皮层和海马体中选择性地敲除受体。 不像标准的NMDA敲除突变小鼠出生后不久就会死亡，我们的突变小鼠 老鼠能存活数周，但它们在晚期会出现癫痫发作。 青春期（产后3-6周）。这种突变体的一个独特之处在于， 癫痫发作活动在缺乏NMDA受体介导的活动的情况下发展。 许多癫痫动物模型都是基于NMDA活性的上调， 因此我们的模型可以提供产生超兴奋性的独特方法 导致独立于NMDA活性的癫痫样活性。初步 结果表明，NMDA受体在调节神经元 正常发育过程中的兴奋性;然而， 在这些小鼠中选择性缺乏NMDA受体导致过度兴奋， 最终自发性癫痫发作是未知的。建议的目标 实验的目的是研究发育过程中NMDA受体的缺乏 导致神经元兴奋性改变，以及这如何引起癫痫发作 活动我们将采用多学科方法，包括分子生物学方法， 生物学、遗传学、解剖学、细胞学和系统神经生理学，以及 行为技术来了解癫痫的发展， 独特的动物模型。我们计划扩展我们对自发的 癫痫发作表型，以测试我们的假设与以下具体目标：1。 为了确定在发育过程中癫痫发作是否以及何时易受 化学惊厥药在突变小鼠体内发生了改变。这些结果将提供 新皮层内过度兴奋发展的时间线。2. 为了绘制出参与癫痫发作发展和产生的神经网络， 通过研究即刻早期基因c-fos的表达， 3.为了确定抑制和兴奋之间的平衡如何改变， 突变小鼠我们假设对中间神经元的兴奋性驱动是 在正常动物和这些突变小鼠中， NMDA介导的作用的减少导致内的总体抑制解除， 新皮层最终导致癫痫样活动的理解 NMDA受体的缺乏是如何导致神经元异常兴奋的 可能会有潜在的临床影响，因为这些结果可以提供 为人类癫痫患者开发更好的治疗方法的见解， 采取干预措施，预防癫痫发作的发展和发生。

DESCRIPTION (provided by applicant): Genetic susceptibility has been implicated in more than 40-50% of human epilepsies. However to date, only 12 genes have been associated with human epilepsy syndromes, and these can only account for less than 1% of epilepsy patients. Further identification of genes that are related to the pathogenesis of epilepsy is crucial to understand how epilepsies develop and could eventually lead to better treatment and prevention of the disease. We have generated a unique mutant animal model in which NMDA glutamate receptors are selectively knocked out in the cerebral cortex and hippocampus. Unlike standard NMDA knockout mutant mice that die soon after birth, our mutant mice survive many weeks but they develop seizure activity during late adolescence (3-6 weeks postnatal). A unique feature of this mutant is that this seizure activity develops in the absence of NMDA receptor mediated activity. Many animal models of epilepsy are based on an upregulation of NMDA activity, and thus our model may provide unique means of producing hyperexcitability leading to epileptiform activity independent of NMDA activity. Preliminary results suggest an important role of NMDA receptors in regulating the neuronal excitability during normal development; however, the mechanisms by which the selective lack of NMDA receptors in these mice leads to hyperexcitability and eventually spontaneous seizures is unknown. The goal of the proposed experiments is to investigate how the lack of NMDA receptors during development leads to altered neuronal excitability, and how this gives rise to seizure activity. We will use a multidisciplinary approach including molecular biological, genetic, anatomical, cellular and system neurophysiological, and behavioral techniques to understand the development of epileptogenesis in this unique animal model. We plan to extend our characterization of the spontaneous seizure phenotype to test our hypothesis with the following specific aims: 1. To determine whether and when during development seizure susceptibility to chemical convulsants is altered in the mutant mice. These results would provide a time line for the development of hyperexcitability within the neocortex. 2. To map out neural networks involved in seizure development and generation in the mutant mice by studying the expression of the immediate early gene, c-fos. 3. To determine how the balance between inhibition and excitation is altered in the mutant mice. We hypothesize that the excitatory drive onto interneurons is dominated by NMDA receptor actions in normal animals, and in these mutant mice the reduction of NMDA-mediated actions leads to an overall disinhibition within the neocortex ultimately resulting in epileptiform activity. The understanding of how the lack of NMDA receptors leads to the abnormal excitability in neurons could have potential clinical ramifications in that these results could provide insight for the development of better treatment for human epilepsy patients and interventions to prevent the development and occurrences of seizures.