Treatment of status epilepticus

描述（由申请人提供）：癫痫持续状态（SE）是一种神经系统急症，其特征是非常长时间的，有时难治性癫痫发作，与23%的死亡率相关。SE是一种进行性疾病，癫痫发作减少海马中gaba介导的抑制，进而导致兴奋性神经传递增强和更多癫痫发作。我们建议进一步研究难治性SE的机制，通过验证突触兴奋性神经传递增强和GABAA受体表达改变维持难治性SE的假设。在之前的资助期内，NMDA受体拮抗剂被证明可以终止对gaba能药物不耐受的SE。在体外模型中，通过将海马培养物暴露于低镁环境，并记录兴奋性突触后电流（EPSCs），研究SE对兴奋性神经传递的影响。在低镁诱导SE期间，EPSCS（突触前末端谷氨酸释放）和NMDA受体的激活频率增加。这些研究提示了一种新的兴奋性增加机制。我们希望将这些研究扩展到SE的体内模型，并将它们与一种新的SE治疗方法联系起来，即神经肽丙氨酸。在特定目标1中概述的实验描述了SE和抗惊厥甘丙氨酸对海马中Schaffer侧索和CA1锥体神经元之间谷氨酸能突触突触前和突触后机制的影响。在其他研究中，从se处理的动物海马切片的颗粒细胞中记录到的微型抑制性突触后电流（mlPSCs）振幅小于对照组，衰减速度较慢。30 nM地西泮对se处理动物颗粒细胞的mlPSCs没有增强作用，但对对照动物的mlPSCs有明显增强作用。这些研究表明，由于SE，突触上存在的GABAA受体的补体发生了变化。在特定目的2中提出的实验旨在进一步表征SE对牙状颗粒细胞记录的抑制性突触后电流（IPSCs）特性的影响。抑制减弱的机制将通过生化和神经解剖学的研究进一步探讨。初步研究表明，神经元调节GABAA受体和突触外受体的内吞率可能在SE期间被募集到突触中。实验概述在特定目的3表征SE对GABAA受体运输的影响。

DESCRIPTION (provided by applicant): Status epilepticus (SE) is a neurological emergency characterized by very prolonged, sometimes refractory seizures, and is associated with a 23% mortality. SE is a progressive condition where seizures reduce GABA-mediated inhibition in the hippocampus, which in turn leads to enhanced excitatory neurotransmission and more seizures. We propose to further investigate the mechanisms refractory SE, by testing the hypothesis that enhanced excitatory neurotransmission and altered expression GABAA receptors at synapses maintain refractory SE. In the previous funding period, NMDA receptor antagonists were demonstrated to terminate SE refractory to GABAergic agents. The effect of SE on excitatory neurotransmission was examined in an in vitro model, by exposing hippocampal cultures to low magnesium, and recording excitatory post synaptic currents (EPSCs). There was increased frequency of EPSCS (glutamate release from presynaptic terminals) and activation of NMDA receptors during low-magnesium induced SE. These studies suggested a novel mechanism of increased excitability during SE. We wish to extend these studies to in vivo models of SE and link them to a novel treatment of SE, with the neuropeptide galanin. Experiments outlined in specific aim 1 characterize the effects of SE and anticonvulsant galanin on pre and post synaptic mechanisms in the glutamatergic synapses between Schaffer collaterals and CA1 pyramidal neurons in the hippocampus. In other studies, miniature inhibitory postsynaptic currents (mlPSCs) recorded from granule cells in hippocampal slices prepared from SE-treated animals were smaller in amplitude and slower in decay than those recorded from controls. These mlPSCs recorded from granule cells of SE-treated animals were not enhanced by 30 nM diazepam but those from control animals were robustly enhanced. These studies suggested that the complement of GABAA receptors present at the synapse had changed as a consequence of SE. Experiments proposed in specific aim 2 seek to further characterize the effect of SE on the properties of inhibitory postsynaptic currents (IPSCs) recorded from dentate granule cells by means of patch clamp recordings. The mechanisms of diminished inhibition will be explored further by biochemical and neuroanatomical studies. Preliminary studies suggest that neuronal modulates the rate of endocytosis of GABAA receptors and extrasynaptic receptors may be recruited into synapses during SE. Experiments outlined in specific aim 3 To characterize the effect of SE on GABAA receptor trafficking.