GABAA receptor subunit alteration-dependent diazepam insensitivity in the cerebellum of phospholipase C-related inactive protein knockout mice
GABAA receptor subunit alteration-dependent diazepam insensitivity in the cerebellum of phospholipase C-related inactive protein knockout mice
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DOI：
10.1111/j.1471-4159.2010.06754.x
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发表时间：
2010-07-01
影响因子：
4.7
通讯作者：
Hirata, Masato
中科院分区：
文献类型：
--
作者：
Mizokami, Akiko;Tanaka, Hiroto;Hirata, Masato
GABA(A)受体是一种主要由α、β和γ亚基组成的五聚体，介导快速抑制性突触传递。我们之前报道过磷脂酶c相关失活蛋白（PRIP）是GABA(a)受体运输的调节剂，并且敲除（KO）小鼠在海马中表现出地西安定不敏感表型。α亚基影响安定敏感性；α 1、2、3和5亚基与任何形式的β和γ 2亚基结合产生地西泮敏感受体，而α 4或α 6/ β / γ 2受体对地西泮不敏感。在这里，我们利用主要表达α 6亚基的动物的小脑颗粒细胞研究了PRIP与地西泮不敏感表型的关系。通过放射配体结合试验评估，PRIP-1和2双KO小脑中α 1/ β / γ 2地西泮敏感受体的表达减少，但苯二氮卓结合位点的总数未发生变化。由于α 6亚基水平升高，α 1/ β / γ 2受体可能被含有α 6亚基的受体所取代。然后我们进一步进行放射自显影和电生理分析。这些结果表明，α 6/ δ受体在小脑颗粒神经元中表达减少，α 6/ γ 2受体表达增加。PRIP-1和2双KO小鼠表现出地西泮不敏感表型，因为小脑颗粒细胞中地西泮敏感（α 1/ γ 2）减少，而地西泮不敏感（α 6/ γ 2） GABA(a)受体增加。
P>The GABA(A) receptor, a pentamer composed predominantly of alpha, beta, and gamma subunits, mediates fast inhibitory synaptic transmission. We have previously reported that phospholipase C-related inactive protein (PRIP) is a modulator of GABA(A) receptor trafficking and that knockout (KO) mice exhibit a diazepam-insensitive phenotype in the hippocampus. The alpha subunit affects diazepam sensitivity; alpha 1, 2, 3, and 5 subunits assemble with any form of beta and the gamma 2 subunits to produce diazepam-sensitive receptors, whereas alpha 4 or alpha 6/beta/gamma 2 receptors are diazepam-insensitive. Here, we investigated how PRIP is implicated in the diazepam-insensitive phenotype using cerebellar granule cells in animals expressing predominantly the alpha 6 subunit. The expression of alpha 1/beta/gamma 2 diazepam-sensitive receptors was decreased in the PRIP-1 and 2 double KO cerebellum without any change in the total number of benzodiazepine-binding sites as assessed by radioligand-binding assay. Since levels of the alpha 6 subunit were increased, the alpha 1/beta/gamma 2 receptors might be replaced with alpha 6 subunit-containing receptors. Then, we further performed autoradiographic and electrophysiologic analyses. These results suggest that the expression of alpha 6/delta receptors was decreased in cerebellar granule neurons, while that of alpha 6/gamma 2 receptors was increased. PRIP-1 and 2 double KO mice exhibit a diazepam-insensitive phenotype because of a decrease in diazepam-sensitive (alpha 1/gamma 2) and increase in diazepam-insensitive (alpha 6/gamma 2) GABA(A) receptors in the cerebellar granule cells.