Nakashima Miki, Ikegaya Yuji, Morikawa Shota
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan; Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka 565-0871, Japan.
Neurosci Res. 2022 May;178:33-40. doi: 10.1016/j.neures.2022.02.002. Epub 2022 Feb 18.
GABAergic neurons are classified into multiple subtypes based on morphology, physiological properties, and gene expression profiles. Although traditionally defined axo-axonic cells (AACs) are a unique type of interneuron that expresses parvalbumin and innervates the axon initial segment (AIS) of pyramidal neurons, a genetic marker for AACs in the basolateral amygdala (BLA) has not been identified. Here, we show that vasoactive intestinal peptide receptor 2 (Vipr2)-expressing interneurons exhibit anatomical and electrophysiological properties of AACs in the BLA. Using a reporter mouse expressing fluorescent proteins specifically in Vipr2 cells, we analyzed the distribution, postsynaptic targeting and electrophysical properties of Vipr2 cells in the BLA. More than half of the Vipr2 cells showed parvalbumin immunoreactivity and innervated the AIS of pyramidal neurons in the BLA of Vipr2-tdTomato mice. Notably, most of the Vipr2 cells showed fast-spiking properties. Furthermore, the use of a Cre-dependent adeno-associated virus led to more selective labeling of AACs in the BLA. These results suggest that AACs are genetically identifiable in the BLA without anatomical or physiological analysis.
γ-氨基丁酸能神经元根据形态、生理特性和基因表达谱被分为多种亚型。尽管传统定义的轴突-轴突细胞（AACs）是一种独特的中间神经元类型，表达小白蛋白并支配锥体神经元的轴突起始段（AIS），但基底外侧杏仁核（BLA）中AACs的遗传标记尚未被确定。在这里，我们表明表达血管活性肠肽受体2（Vipr2）的中间神经元表现出BLA中AACs的解剖学和电生理特性。使用一种在Vipr2细胞中特异性表达荧光蛋白的报告小鼠，我们分析了BLA中Vipr2细胞的分布、突触后靶向和电生理特性。超过一半的Vipr2细胞显示小白蛋白免疫反应性，并支配Vipr2-tdTomato小鼠BLA中锥体神经元的AIS。值得注意的是，大多数Vipr2细胞表现出快速放电特性。此外，使用依赖于Cre的腺相关病毒导致对BLA中AACs的更具选择性的标记。这些结果表明，无需解剖学或生理学分析，BLA中的AACs在基因上是可识别的。
