Neuroprotective strategies in seizure-induced damage

说明(申请人提供)：2-雌二醇(EB)对几种神经退行性疾病具有神经保护作用。此外，EB对癫痫持续状态(SE)诱导的海马齿状回门区神经元损伤具有保护作用。这种保护只发生在雌性大鼠身上，而不是雄性大鼠身上。初步研究表明，神经保护与由成对脉冲刺激确定的齿状回晚期抑制增加有关。由于这一发现表明参与慢的，G蛋白连接的神经递质系统，代谢性谷氨酸受体(MGluR)和神经肽Y(NPY)被研究。NPY和mGlu受体似乎都参与其中，并相辅相成。当齿状回过滤来自内嗅皮层的活动时，EB对肺门神经元的神经保护作用可能与增强过滤功能有关。这一建议的主要假设是，在女性中，EB增加了对齿状回的抑制。变性回抑制的增加是由NPY和mGluR系统介导的，并导致传入癫痫活动进入海马区的过滤增强，从而对肺门神经元产生神经保护作用。具体目的是确定：是否为1A。EB增加对齿状回的抑制。1B.EB诱导的抑制增加涉及NPY和mGlu受体。1C。EB既影响前馈抑制，又影响反馈抑制，1D。EB诱导NPY和mGluR表达的改变。2a.EB通过激活NPY和mGlu受体，阻止癫痫样活动通过齿状回扩散。2B。EB改变了齿状颗粒细胞输入端谷氨酸的释放及其固有特性。3.阻断NPY和mGlu受体对EB对SE所致肝门损伤的神经保护作用组包括用EB、黄体酮、EB黄体酮或油治疗的性腺切除的雌性大鼠，以及用EB或油治疗的性腺完整的雌性大鼠。方法包括联合内嗅皮层-海马片的体外研究、成对脉冲刺激、特异性NPY和mGluR拮抗剂的使用、细胞内记录、免疫组织化学、组织学、体视学细胞计数、体内SE的诱导以及NPY和mGlu受体的阻断。在这里，EB在海马区的作用涉及NPY和mGluR相互作用的新机制被提出。我们的研究结果还将有助于理解抑郁/焦虑、应激处理、记忆和认知等过程的性别特异性表达。2-雌二醇在包括癫痫诱导的海马区损伤在内的几种神经退行性疾病中具有神经保护作用。这项建议的重点是确定参与2-雌二醇诱导的海马区神经保护的机制。我们发现，给药2-雌二醇诱导神经肽Y的表达，神经肽Y是一种抑制性和神经保护性多肽，在齿状回。这个结构是进入海马体本身的入口，具有过滤功能。我们将研究这种抑制神经肽的增加如何增强对癫痫等传入活动的齿状回过滤，以及这种增加的过滤如何影响癫痫诱导的海马区损伤。

DESCRIPTION (provided by applicant): 2-Estradiol (EB) has neuroprotective effects in several neurodegenerative diseases. Additionally, EB protects against status epilepticus (SE)-induced neuronal damage in the hilus of the hippocampal dentate gyrus. This protection occurs only in female but not in male rats. Preliminary studies have shown that neuroprotection is associated with increased late phase inhibition in the dentate gyrus determined by paired pulse stimulation. As this finding suggests participation of slow, G-protein linked neurotransmitter systems, metabotropic glutamate receptors (mGluR) and neuropeptide Y (NPY) were investigated. Both NPY and mGlu receptors seem to be involved and complement each other. As dentate gyrus filters the activity coming from the entorhinal cortex, neuroprotective effects of EB on hilar neurons may be associated with enhanced filtering features. Main hypothesis of this proposal is that in females, EB increases inhibition in the dentate gyrus. The increase in the denatate gyrus inhibition is mediated by the NPY and mGluR systems and results in enhanced filtering of incoming seizure activity to the hippocampus leading thus to neuroprotective effects on hilar neurons. Specific aims are to determine: Whether 1A. EB increases dentate gyrus inhibition. 1B. EB-induced increase in inhibition involves NPY and mGlu receptors. 1C. EB affects both feed-forward and feed-back inhibition, 1D. EB induces changes in NPY and mGluR expression. 2A. EB prevents spread of epileptiform activity through the dentate gyrus via activation of NPY and mGlu receptors. 2B. EB changes glutamate release at the inputs of dentate granule cells and their intrinsic properties. 3. The effects of blockade of NPY and mGlu receptors on EB-induced neuroprotection against SE-induced hilar damage. Groups include gonadectomized female rats treated with EB, progesterone, EB+progesterone or oil, and also gonadally intact female rats treated with EB or oil. Methods include in vitro studies in combined entorhinal cortex-hippocampus slices, paired pulse stimulation, use of specific NPY and mGluR antagonists, intracellular recordings, immunohistochemistry, histology, stereological cell counting, in vivo induction of SE as well as blockade of NPY and mGlu receptors. Here, novel mechanisms of EB action in the hippocampus involving NPY and mGluR interactions are proposed. The findings from our studies will also bring insights into understanding of gender-specific expression of such processes as depression/anxiety, stress processing, memory, and cognition.2-Estradiol has neuroprotective effects in several neurodegenerative diseases including the seizure-induced hippocampal damage. This proposal is focused on determining the mechanisms involved in 2-estradiol-induced neuroprotection in the hippocampus. We found that administration of 2-estradiol induces expression of neuropeptide Y, an inhibitory and neuroprotective peptide, in the dentate gyrus. This structure is an entry to the hippocampus proper and has filtering function. We will investigate how this increase of inhibitory neuropeptide will enhance the dentate gyrus filtering of incoming activity such as seizures and how this increased filtering can affect seizure-induced hippocampal damage.