Uematsu Masakazu, Hirai Yasuharu, Karube Fuyuki, Ebihara Satoe, Kato Megumi, Abe Kuniya, Obata Kunihiko, Yoshida Sachiko, Hirabayashi Masumi, Yanagawa Yuchio, Kawaguchi Yasuo
Laboratory of Neurochemistry, National Institute for Physiological Sciences (NIPS), Okazaki 444-8585, Japan.
Cereb Cortex. 2008 Feb;18(2):315-30. doi: 10.1093/cercor/bhm056. Epub 2007 May 20.
Although neocortical GABAergic (gamma-aminobutyric acidergic) interneurons have been the focus of intense study, especially in the rat, a consensus view of the functional diversity and organization of inhibitory cortical neurons has not yet been achieved. To better analyze GABAergic neurons in the rat, we used a bacterial artificial chromosome (BAC) construct and established 2 lines of transgenic rats that coexpress Venus, a yellow fluorescent protein, with the vesicular GABA transporter. The brain GABA content from both transgenic lines was similar to the level found in wild-type rats. In the frontal cortex, Venus was expressed in >95% of GABAergic neurons, most of which also expressed at least one of 6 biochemical markers, including alpha-actitin-2, which preferentially labeled late-spiking neurogliaform cells. Taking advantage of the fact that Venus expression allows for targeted recording from all classes of nonpyramidal cells, irrespective of their somatic morphologies, we demonstrated that fast-spiking neurons, which were heterogeneous in somatic size as well as vertical dendritic projection, had relatively uniform horizontal dimensions, suggesting a cell type-specific columnar input territory. Our data demonstrate the benefits of VGAT-Venus rats for investigating GABAergic circuits, as well as the feasibility of using BAC technology in rats to label subsets of specific, genetically defined neurons.
尽管新皮质γ-氨基丁酸能（GABA能）中间神经元一直是深入研究的焦点，尤其是在大鼠中，但对于抑制性皮质神经元的功能多样性和组织方式尚未形成共识。为了更好地分析大鼠中的GABA能神经元，我们使用了细菌人工染色体（BAC）构建体，并建立了2个转基因大鼠品系，它们共同表达黄色荧光蛋白金星（Venus）和囊泡GABA转运体。两个转基因品系的脑GABA含量与野生型大鼠中的水平相似。在额叶皮质中，金星在超过95%的GABA能神经元中表达，其中大多数还表达6种生化标志物中的至少一种，包括α-肌动蛋白-2，其优先标记晚期放电的神经胶质样细胞。利用金星表达允许对所有类型的非锥体细胞进行靶向记录这一事实，无论它们的体细胞形态如何，我们证明了快速放电神经元在体细胞大小以及垂直树突投射方面是异质的，但具有相对统一的水平尺寸，这表明存在细胞类型特异性的柱状输入区域。我们的数据证明了VGAT-金星大鼠在研究GABA能回路方面的优势，以及在大鼠中使用BAC技术标记特定的、基因定义的神经元亚群的可行性。
