Regulation of Inhibitory Activity at Hippocampal Slices by Synapsin II and Rab3a

描述（由申请人提供）：癫痫是一种复杂的多因素神经系统疾病，现在人们广泛认识到，突触传递的变化往往是这种疾病的核心。这使得人们对突触蛋白在这种疾病中的作用越来越感兴趣。最好的例子是突触蛋白突触素，这是本申请的主要焦点。在小鼠中，突触蛋白I或突触蛋白II蛋白的缺失导致强烈的癫痫表型，并且临床研究表明，突触蛋白缺乏也与人类的特发性癫痫有关。有人认为，兴奋/抑制失衡是观察到的过度兴奋的可能原因之一。申请人最近的研究通过直接证明突触蛋白II缺失差异性地影响突触能神经元， 和GABA能传递，而SynII（-）脑片的癫痫样活动可能是抑制受损所致。有趣的是，突触蛋白结合伴侣Rab 3a的缺失可以抑制在突触蛋白II缺失动物中观察到的癫痫表型。这显然是一个潜在的重要观察，可以帮助确定癫痫治疗的新靶点。本申请中提出的实验应有助于阐明突触蛋白II缺失的致癫痫作用的突触机制以及Rab 3a缺失的抗致癫痫作用的生理学基础。具体目标1提出研究突触蛋白II在同步和异步抑制性传递调节中的作用。抑制性异步释放高频放电后被认为是调节癫痫样活动，我们的初步数据表明，突触蛋白II删除减少了抑制性异步组件CA 1海马中间神经元。为了阐明突触蛋白II的缺失抑制异步释放成分的机制，我们将采用成对的海马切片抑制性传递的记录来严格检查突触蛋白II缺失动物的同步和异步量子释放。具体目标2提出了解Rab 3a缺失如何改变Syn II缺失对同步和异步抑制性传递的影响。由于Rab 3a的缺失可以中和突触蛋白依赖性癫痫发作，我们建议研究Rab 3a（-）和SynII（-）/Rab 3a（-）双敲除（DKO）神经元中的异步释放成分。我们的初步数据表明，Rab 3a的删除可以恢复抑制性异步组件减少突触蛋白II的删除。为了理解Rab 3a缺失如何拯救SynII（-）表型，我们将系统地研究Rab 3（-）和SynII（-）/Rabs 3（-）DKO海马切片的同步和异步释放组分，并测试Rab 3a掺入SynII（-）/Rab 3a（-）突触是否可以恢复SynII（-）表型。

DESCRIPTION (provided by applicant): Epilepsy is a complex and multifactorial neurological disorder, and now it is widely appreciated that changes in synaptic transmission often lie at the core of this disease. This has led to an increased interest in the role of synaptic proteins in thi disease. The best example of this are synaptic proteins synapsins, the main focus of this application. In mice, the deletion of synapsin I or synapsin II proteins results in a strong epilepic phenotype, and clinical studies demonstrated that synapsin deficiency is also associated with idiopathic epilepsy in humans. It was suggested that excitatory/inhibitory imbalance is one of the possible causes of the observed overexcitability. The applicant's recent study supports this hypothesis by directly demonstrating that synapsin II deletion differentially affects glutamatergic and GABAergic transmission at hippocampal slices and that epileptiform activity in SynII(-) slices is likely to result from impaired inhibition. Interestingly, deletion of the synapsin bindin partner Rab3a can suppress the epileptic phenotype observed in synapsin II deleted animals. This is obviously a potentially important observation that could help identify novel targets for th treatment of epilepsy. The experiments proposed in this application should help clarify the synaptic mechanisms that underlie the epileptogenic effects of synapsin II deletion as well as the physiological basis for the anti- epileptogenic effects of Rab3a deletion. The Specific Aim 1 proposes to investigate the role of synapsin II in the regulation of synchronous and asynchronous inhibitory transmission. Inhibitory asynchronous release following high-frequency discharges is thought to regulate epileptiform activity, and our preliminary data suggests that synapsin II deletion decreases the inhibitory asynchronous component in CA1 hippocampal interneurons. To elucidate the mechanism by which the deletion of synapsin II inhibits asynchronous release component, we will employ paired recordings of inhibitory transmission at hippocampal slices to rigorously examine synchronous and asynchronous quantal release at synapsin II deleted animals. The Specific Aim 2 proposes to understand how Rab3a deletion modifies the effect of Syn II deletion on synchronous and asynchronous inhibitory transmission. Since the deletion of Rab3a can neutralize synapsin-dependent epileptic seizures, we propose to investigate the asynchronous release component in the Rab3a(-) and in the SynII(-)/Rab3a(-) double knockout (DKO) neurons. Our preliminary data suggests that Rab3a deletion can restore the inhibitory asynchronous component reduced by the deletion of synapsin II. To understand by how Rab3a deletion can rescue the SynII(-) phenotype, we will investigate systematically synchronous and asynchronous release component at Rab3(-) and SynII(-)/Rabs3(-) DKO hippocampal slices and test whether the Rab3a incorporation into the SynII(-)/Rab3a(-) synapses can restore the SynII(-) phenotype.