COBRE: UND: TACHYKININ MODULATION OF EPILEPSY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 癫痫是美国最常见的神经系统疾病之一，目前影响着250多万人。目前可用的抗癫痫药物虽然有些有效，但也有副作用，而且针对的机制有限。探索治疗癫痫的新机制或新策略仍然是一项艰巨的任务。速激肽家族的神经肽包括P物质、神经激动素A和神经激肽B，它们都是促惊厥性的。然而，速激肽发挥致痫作用的细胞和分子机制基本上是未知的。我们有强有力的初步数据表明，速激肽通过抑制突触前终末的延迟整流钾通道，显著增加了海马区多个突触的谷氨酸释放。通过基因敲除小鼠和药理学方法，我们还表明磷脂酶C和蛋白激酶C的活性是完全的，而细胞内钙的释放是P物质诱导的谷氨酸释放增加所必需的部分。我们还使用海马片证明了速激肽显著增加了印防己毒素诱导的癫痫模型中的癫痫活动。该项目的目的是确定速激肽诱导谷氨酸释放和致痫活性增加的详细细胞和分子机制。我们将检验这一假说，即速激肽介导的谷氨酸释放增加是导致它们的致痫活性的原因。具体目标1将确定速激肽促进谷氨酸释放的详细离子机制。我们将确定所涉及的延迟整流K通道的亚型。具体目标2将确定速激肽介导的促进谷氨酸释放的信号转导机制。因为我们的初步数据表明蛋白激酶C的活性是必不可少的，所以我们将确定速激肽诱导的谷氨酸释放增加所涉及的蛋白激酶C的异构体。具体目标3将确定速激肽在癫痫发作中的作用和机制。我们将测量癫痫诱发的速激肽释放的增加，以确定内源性释放的速激肽在癫痫发生中的作用。我们还将使用印防己毒素诱导的海马片癫痫模型来确定速激肽诱导癫痫发作活动的信号转导机制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Epilepsy is one of the most prevalent neurological diseases in the USA, currently affecting more than 2.5 million individuals. The currently available antiepileptic drugs, while somewhat effective, have side effects and target a limited number of mechanisms. Exploring novel mechanisms or strategies to treat epilepsy is still an arduous task. The tachykinin family of neuropeptides that include substance P, neurokinin A and neurokinin B are proconvulsant. However, the cellular and molecular mechanisms whereby tachykinins exert epileptogenic activities are essentially unknown. We have strong preliminary data demonstrating that tachykinins dramatically increased glutamate release at multiple synapses of the hippocampus by inhibiting the delayed rectifier K+ channels at presynaptic terminals. With knock-out mice and pharmacological approaches, we have also shown that the activities of phospholipase C and protein kinase C were fully, whereas intracellular Ca2+ release was partially required for substance P-induced increases in glutamate release. We also demonstrated that tachykinins significantly increased seizure activities in a picrotoxin-induced seizure model using hippocampal slices. The objective of this project is to determine the detailed cellular and molecular mechanisms underlying tachykinin-induced increases in glutamate release and epileptogenic activities. We will test the hypothesis that tachykinin-mediated increases in glutamate release are responsible for their epileptogenic activities. Specific Aim 1 will identify the detailed ionic mechanisms by which tachykinins facilitate glutamate release. We will identify the subtype of the delayed rectifier K+ channels involved. Specific Aim 2 will identify the signal transduction mechanisms underlying tachykinin-mediated facilitation of glutamate release. Because our preliminary data indicated that the activity of protein kinase C was essential, we will determine the involved isoform of protein kinase C in tachykinin-induced increases in glutamate release. Specific Aim 3 will determine the roles and mechanisms of tachykinins in seizures. We will measure seizure-induced increase in the release of tachykinins to determine the roles of endogenously released tachykinins in seizure generation. We will also use the picrotoxin-induced seizure model in hippocampal slices to identify the signal transduction mechanisms underlying tachykinin-induced facilitation of seizure activities.