MECHANISMS OF EPILEPTOGENESIS

癫痫发生机制

• 批准号: 6126213
• 负责人: EDWARD H BERTRAM
• 金额: $ 31.39万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6126213
• 关键词: brain electrical activity; dentate gyrus; disease /disorder model; electroencephalography; entorhinal cortex; epilepsy; evoked potentials; experimental brain lesion; gamma aminobutyrate; glutamates; laboratory rat; limbic system; neural inhibition; neural transmission; partial seizure; pathologic process; pyramidal cells; synapses; temporal lobe /cortex disorder; voltage /patch clamp

Epilepsy is a chronic neurological condition that affects about 1% of the population in the United States. Although it is usually readily treatable with medications, about 25-30% of epileptic patients continue to experience recurrent seizures in spite of multiple drug therapy. A very common form of difficult to control human epilepsy is the mesial temporal lope epilepsy syndrome, which involves limbic structures such as the hippocampus, entorhinal cortex and amygdala. Understanding the pathophysiological basis for this condition is essential for the development of improved treatments. Human studies have suggested that the process of seizure initiation may involve multiple sites. In these situations the seizures often begin simultaneously at several of the limbic sites. These observations raise the possibility that seizure onset may be triggered in part through a subcortical mechanism that has input to multiple limbic structures. Testing this idea has not been possible until recently with the development of several new rat models of limbic epilepsy that have similarities to the human condition. These limbic epilepsy models are characterized by spontaneous seizures as well as limbic pathology and seizure physiology on EEG that are morphologically similar to the human condition (mesial temporal lobe epilepsy). Work completed or nearing completion has suggested that all of the limbic sites demonstrated to participate in seizure onset have hyperexcitable responses to stimulation. More importantly, we have recently discovered that the midline thalamic nuclei have significant excitatory input to these areas (amygdala, hippocampus and entorhinal cortex). We have also found that the midline thalamic nuclei participate in, and may regulate, the seizure activity in the limbic system. These observations suggest that these thalamic regions may have an important role in seizure initiation and modulation. In this project we propose to evaluate the role of the midline thalamic nuclei in limbic seizures and epilepsy to answer the following questions: 1) What role does the midline thalamic nuclei play in limbic seizures and epilepsy to answer the following questions: 2) How are the interactions between the midline thalamic nuclei and its limbic targets altered in limbic epilepsy? 3) How is the physiology of the midline thalamic nuclei changed in chronic limbic epilepsy? These experiments will combine in vitro and in vivo physiology of several rat models of limbic seizures, including chronic limbic seizures, to examine these issues, which are the first steps to understanding the role of this region in limbic epilepsy. These results will provide new insights into the network changes and basis for these conditions.

癫痫是一种慢性神经系统疾病，影响美国约1%的人口。虽然它通常很容易用药物治疗，但约25-30%的癫痫患者继续经历反复发作，尽管有多种药物治疗。难以控制的人类癫痫的一种非常常见的形式是内侧颞叶癫痫综合征，其涉及边缘系统结构，如海马体、内嗅皮层和杏仁核。了解这种情况的病理生理学基础是必不可少的改进治疗的发展。人体研究表明，癫痫发作的启动过程可能涉及多个部位。在这些情况下，癫痫发作通常开始同时在几个边缘部位。这些观察结果提出了癫痫发作可能部分通过向多个边缘结构输入的皮质下机制触发的可能性。直到最近，随着几种新的边缘系统癫痫大鼠模型的开发，测试这一想法才成为可能，这些模型与人类的情况相似。这些边缘癫痫模型的特征在于自发性癫痫发作以及EEG上的边缘病理学和癫痫发作生理学，其在形态上与人类状况（内侧颞叶癫痫）相似。已完成或接近完成的工作表明，所有参与癫痫发作的边缘系统部位对刺激都有过度兴奋反应。更重要的是，我们最近发现丘脑中线核团对这些区域（杏仁核、海马和内嗅皮层）有显著的兴奋性输入。我们还发现丘脑中线核参与并可能调节边缘系统的癫痫发作活动。这些观察结果表明，这些丘脑区域可能有一个重要的作用，在癫痫发作的启动和调制。在本项目中，我们建议评估中线丘脑核在边缘系统发作和癫痫中的作用，以回答以下问题：1）中线丘脑核在边缘系统发作和癫痫中起什么作用？回答以下问题：2）中线丘脑核与边缘系统靶点之间的相互作用在边缘系统癫痫中是如何改变的？3)慢性边缘系统癫痫患者丘脑中线核团的生理学改变如何？这些实验将结合联合收割机在体外和体内生理学的几个大鼠模型的边缘癫痫发作，包括慢性边缘癫痫发作，以检查这些问题，这是第一步，了解该地区的作用，边缘癫痫。这些结果将为网络变化提供新的见解，并为这些条件提供依据。