Cerebellar Inhibitory Synapses in GABAR subunits KO mice

描述（申请人提供）：GABAa受体在焦虑、睡眠和许多神经系统疾病的发病机制中起关键作用。γ -氨基丁酸（GABA） A受体的分子克隆揭示了其组成亚基的相当大的异质性。不同的GABAa受体同种异构体在被亚基的特定组合转染的细胞中具有不同构象状态之间独特的通道转换速率，这决定了GABA反应的“分子动力学指纹”。利用亚基基因特异性缺失的小鼠，我们将证明这种分子指纹设定了抑制性突触电流（IPSCs）的时间过程，这是决定抑制性突触强度的关键因素，也是许多常用药物的靶标。我们关注的是小脑颗粒状和星状神经元，其中IPSCs持续时间的逐渐减少与GABAa受体亚基表达的变化相似。基于我们的初步发现，GABAa受体α 1亚基的缺失可以阻止IPSCs动力学的发育变化，我们的假设是，不同的GABAa受体亚型，在解剖学上受到限制和发育调节，导致了行为和神经疾病背后的抑制活性的特定功能特性。

DESCRIPTION (provided by applicant): GABAa receptors play a critical role in anxiety, sleep and the pathogenesis of many neurological disorders. Molecular cloning of gamma-aminobutyric A (GABA)a receptors has revealed a considerable heterogeneity of constituent subunits. Different GABAa receptor isoforms in cells transfected with specific combinations of subunits have unique rates of channel transition between distinct conformational states that determines a "molecular kinetic fingerprint" of GABA responses. Using mice with specific deletion of subunit genes we will prove that this molecular fingerprint set the time course of inhibitory synaptic currents (IPSCs) a crucial factor in determining the strength of the inhibitory synapse and a target of many commonly prescribed drugs. We focus on cerebellar granular and stellate neurons where a progressive developmental decrease in IPSCs duration parallels changes in GABAa receptor subunit expression. Supported by our preliminary finding that the deletion of the alpha1 subunit of GABAa receptor prevents developmental changes in IPSCs' kinetics, our hypothesis is that distinct GABAa receptor subtypes, anatomically restricted and developmentally regulated lead to the specific functional properties of inhibitory activity that underlie behavior and neurological disorders. The outcome of our study will allow linking the heterogeneity of molecular structures to the functional heterogeneity of inhibitory synapses. Whole-cell recordings of synaptic and extrasynaptic GABA currents in neurons of the mouse cerebellum in slices and primary neuronal cultures will be complementary to recordings of GABA-activated channel currents in outside-out patches excised from these neurons. The biophysical study of native GABA channel will be integrated by studying those recorded from cells transiently transfected with specific subunits of GABAa receptors and from transgenic mice missing specific subunits. The goal is to identify native subunit combinations and ultimately link these different receptor combinations to their particular role in GABA-mediated inhibition in cerebellar neurons.