Immunoreactivity for the GABAA receptor α1 subunit, somatostatin and connexin36 distinguishes axoaxonic, basket, and bistratified interneurons of the rat hippocampus
Immunoreactivity for the GABAA receptor α1 subunit, somatostatin and connexin36 distinguishes axoaxonic, basket, and bistratified interneurons of the rat hippocampus
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DOI：
10.1093/cercor/bhl117
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发表时间：
2007-09-01
期刊：
影响因子：
3.7
通讯作者：
Klausberger, Thomas
中科院分区：
文献类型：
--
作者：
Baude, Agnes;Bleasdale, Catherine;Klausberger, Thomas
白细胞蛋白（PV）表达中间神经元通过γ-氨基幼虫（GABA能）突触使皮质神经元同步。三种类型的含PV的中间神经元填充了海马CA1区域的锥体层：靶向somata和近端树突的篮细胞，轴突轴的轴突细胞支配轴突初始段以及靶向靶向吡啶层细胞树突的bistratized细胞。我们测试了这种轴突专业化是否伴随着参与神经元信号的分子的差异表达。神经蛋白在体内标记的中间神经元的免疫荧光评估表明，轴突膜细胞在质膜中表现出明显较小的GABA（a）受体α1亚基，而不是篮子和basket的细胞。电子显微镜免疫金标记表明，该亚基有助于外交受体，从而提供了补品抑制作用的底物。额外的免疫荧光实验的结果与只有生殖细胞表达神经肽生长抑素的发现一致。从分子曲线中，我们估计，在CA1金字塔层中，含有PV的细胞的篮子，分类和轴突轴细胞分别代表约60％，25％和15％。此外，所有3个中间神经元类均形成connexin36-免疫阳性树状gap隙连接。信号分子的差异表达和细胞的相对频率反映了3种类型的PV阳性中间神经元对网络中GABA释放的专业时间贡献。
Parvalbumin (PV)-expressing interneurons synchronize cortical neurons through gamma-aminobutyric acidergic (GABAergic) synapses. Three types of PV-containing interneurons populate stratum pyramidale of the hippocampal CA1 area: basket cells targeting somata and proximal dendrites, axoaxonic cells innervating axon initial segments, and bistratified cells targeting the dendrites of pyramidal cells. We tested whether this axonal specialization is accompanied by a differential expression of molecules involved in neuronal signaling. Immunofluorescence evaluation of interneurons labeled by neurobiotin in vivo shows that axoaxonic cells express significantly less GABA(A) receptor alpha 1 subunit in the plasma membrane than basket and bistratified cells. Electron microscopic immunogold labeling reveals that this subunit contributes heavily to extrasynaptic receptors providing a substrate for tonic inhibition. Results from additional immunofluorescence experiments were consistent with the finding that only bistratified cells express the neuropeptide somatostatin. From the molecular profiles, we estimate that basket, bistratified, and axoaxonic cells represent about 60%, 25%, and 15%, respectively, of PV-containing cells in CA1 stratum pyramidale. In addition, all 3 interneuron classes form connexin36-immunopositive dendrodendritic gap junctions. The differential expression of signaling molecules and the relative frequency of cells reflect the specialized temporal contribution of the 3 types of PV-positive interneurons to GABA release in the network.