Semilunar Granule Cells: Glutamatergic Neurons in the Rat Dentate Gyrus with Axon Collaterals in the Inner Molecular Layer
Semilunar Granule Cells: Glutamatergic Neurons in the Rat Dentate Gyrus with Axon Collaterals in the Inner Molecular Layer
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DOI：
10.1523/jneurosci.4053-07.2007
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发表时间：
2007-12
期刊：
影响因子：
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通讯作者：
Philip A. Williams;P. Larimer;Yuan Gao;B. Strowbridge
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文献类型：
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作者：
Philip A. Williams;P. Larimer;Yuan Gao;B. Strowbridge
齿状回内分子层（IML）的突触重组是一个病理生理过程，可能有助于颞叶癫痫患者的癫痫发作。IML神经元的两种亚型最初由Ramón y Cajal（1995）描述，但尚未得到彻底研究。我们使用双光子成像，红外差分干涉对比显微镜和膜片钳记录大鼠海马切片，以确定内在的生理和突触目标的棘，颗粒样神经元的IML，称为半月颗粒细胞（SGCs）。这些神经元类似于齿状颗粒细胞，但在分子层中有轴突侧支，在分子层中有显著更大的树突状分支，并且比颗粒细胞更三角形的细胞体。与颗粒细胞不同，SGCs发射整个长时间的去极化步骤，并有斜坡状的去极化期间interspike期间。配对记录表明，SGCs是神经元能和单突触兴奋门部中间神经元和苔藓细胞。半月形颗粒细胞似乎代表了一个独特的兴奋性神经元群体在齿状回，可能是一个重要的目标苔藓纤维发芽的患者和啮齿动物模型的颞叶癫痫。
Synaptic reorganization of the dentate gyrus inner molecular layer (IML) is a pathophysiological process that may facilitate seizures in patients with temporal-lobe epilepsy. Two subtypes of IML neurons were originally described by Ramón y Cajal (1995), but have not been thoroughly studied. We used two-photon imaging, infrared-differential interference contrast microscopy and patch clamp recordings from rat hippocampal slices to define the intrinsic physiology and synaptic targets of spiny, granule-like neurons in the IML, termed semilunar granule cells (SGCs). These neurons resembled dentate granule cells but had axon collaterals in the molecular layer, significantly larger dendritic arborization in the molecular layer, and a more triangular cell body than granule cells. Unlike granule cells, SGCs fired throughout long-duration depolarizing steps and had ramp-like depolarizations during interspike periods. Paired recordings demonstrated that SGCs are glutamatergic and monosynaptically excite both hilar interneurons and mossy cells. Semilunar granule cells appear to represent a distinct excitatory neuron population in the dentate gyrus that may be an important target for mossy fiber sprouting in patients and rodent models of temporal lobe epilepsy.