NEUROCHEMICAL STUDIES IN GENETIC MODELS OF EPILEPSY

这项研究的目的是研究神经化学， 两种不同类型癫痫的生理和遗传学机制 遗传性癫痫小鼠模型。这些小鼠包括 听源性惊厥(AGS)易感DBA/2(D2)小鼠 全身性失神发作)和E1(癫痫)小鼠(一种模型 对于颞叶癫痫)。先前的证据表明，AGS D2小鼠的易感性与遗传相关 脑外钙-ATPase活性缺乏。高AGS 易感性和低脑外钙ATPase活性是 由不同品种杂交产生的F_1代共同遗传 菌株。这种胞外钙离子的生物化学基础。ATPase 目前尚不清楚是否存在缺陷。以确定缩减后的 D2小鼠的活动是由于D2小鼠的 酶，我们将研究胞外-钙-ATPase的动力学性质 在D2小鼠的微粒体和突触质膜中 抗癫痫C57BL/6(B6)和F1杂交鼠。我们建议 胞外钙离子。ATPase是快速水解酶的关键。 D2小鼠体内释放的三磷酸腺苷及其缺陷参与癫痫发作 通过允许三磷酸腺苷在突触中保持活跃而易感性 克里夫特。这一假设得到了B6和B6最近研究的支持 D2海马片，并将在B6 x D2中进行进一步研究 重组近交系；哺乳动物的一种强大的分析工具 遗传学。初步研究还表明，主效基因 对于AGS，asp1与ah位点和一种新的限制因素相关联 12号染色体上的片段长度DNA多态性。 这些基因的定位将使用孟德尔回交法进行定位 几代人。因为这是已知的第一个 一个DNA多态和一个癫痫基因，可以获得洞察力 癫痫的分子遗传学研究。中的一个重要问题 癫痫研究一直难以解决的担忧 与病因相关的神经化学缺陷的区别 与反复发作的影响相关的癫痫发作和缺陷 癫痫发作活动。已经在E1小鼠身上开发了一种范式来处理 在这个问题上。因为我们的初步结果显示，e1小鼠 在海马区表达反应性胶质细胞增生，并增加脑组织中 小脑中神经节苷脂GD3和天冬氨酸释放增加 在海马片中，这一范例将被用来确定 这些缺陷是海马区天冬氨酸释放增加。 切片，这个范例将被用来确定这些缺陷 与癫痫发作的原因或后果有关。因为 D2和E1小鼠的癫痫发作是自然发生的，这种神经化学物质 与这些癫痫发作相关的缺陷将是相关的基本 癫痫的发病机制。

The purpose of this research is to study the neurochemical, physiological and genetic mechanisms of epilepsy in two different genetic mouse models of epilepsy. These mice include the audiogenic seizure (AGS) susceptible DBA/2 (D2) mouse (a model for generalized absence seizures), and the E1 (epilepsy) mouse (a model for temporal lobe epilepsy). Previous evidence indicates that AGS susceptibility in D2 mice is genetically associated with a deficiency of a brain ecto-Ca2+-ATPase activity. High AGS susceptibility and low brain ecto-Ca2+- ATPase activity are inherited together in Fl hybrids produced from crossing various strains. The biochemical basis for this ecto-Ca2+. ATPase deficiency is presently unknown. To determine if the reduced activity in D2 mice results from a qualitative defect in the enzyme, kinetic properties of the ecto-Ca2+-ATPase will be studied in microsomes and synaptic plasma membranes of the D2 mice and the seizure resistant C57BL/6 (B6) and Fl hybrid mice. We suggest that the ecto-Ca2+. ATPase is essential for the rapid hydrolysis of released ATP and its deficiency in D2 mice contributes to seizure susceptibility by allowing ATP to remain active in the synaptic cleft. This hypothesis is supported from recent studies in B6 and D2 hippocampal slices and will be studied further in B6 x D2 recombinant inbred strains; a powerful analytical tool in mammalian genetics. Preliminary studies also indicate that the major gene for AGS, aspl, is linked to the Ah locus and to a novel restriction fragment length DNA polymorphism on chromosome 12. The relative location of these genes will be mapped using mendelian backcross generations. Since this is the first genetic linkage known between a DNA polymorphism and an epilepsy gene, insight can be obtained on the molecular genetics of epilepsy. An important problem in epilepsy research that has been difficult to resolve concerns the distinction between neurochemical defects associated with the cause of seizures and defects associated with the effects of repeated seizure activity. A paradigm has been developed in E1 mice to deal with this problem. Since our preliminary results show that E1 mice express a reactive gliosis in hippocampus, and elevated content of ganglioside GD3 in cerebellum, and elevated aspartic acid release in hippocampal slices, this paradigm will be used to determine if these defects are elevated aspartic acid release in hippocampal slices, this paradigm will be used to determine if these defects are associated with the cause or effect of seizures. Because the seizures in the D2 and E1 mice occur naturally, the neurochemical defects associated with these seizures will be relevant basic mechanism of epilepsy.