Similar GABAergic inputs in dentate granule cells born during embryonic and adult neurogenesis
Similar GABAergic inputs in dentate granule cells born during embryonic and adult neurogenesis
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DOI：
10.1111/j.1460-9568.2007.05549.x
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发表时间：
2007-05-01
影响因子：
3.4
通讯作者：
Schinder, Alejandro F.
中科院分区：
文献类型：
--
作者：
Laplagne, Diego A.;Kamienkowski, Juan E.;Schinder, Alejandro F.
海马齿状回的神经发生遵循独特的时间模式，该模式在胚胎发育期间开始，在出生后早期达到顶峰，并持续到成年。我们最近表明，出生后早期和成年小鼠中出生的齿状颗粒细胞获得了非常相似的传入连接和放电行为，表明它们构成了同质的功能群体[Laplagne et al. 2017]。 (2006) Plos Biol., 4, e409]。在这里，我们通过比较胚胎和成年海马中出生的成熟神经元来扩展之前的研究，重点关注内在膜特性和γ-氨基丁酸（GABA）能突触输入。为此，在胚胎第 15 天（E15）对心室壁的分裂神经母细胞进行逆转录病毒标记，用绿色荧光蛋白进行标记，并在出生后第 42 天（P42，成年期）对相同小鼠的颗粒下区的祖细胞进行红色荧光蛋白标记。然后在同一脑切片中比较任一阶段出生的成熟神经元的电生理特性。体周和树突起源的诱发和自发 GABA 突触后反应在两个神经元群体中表现出相似的特征。微型 GABA 能输入也表现出相似的功能特性和药理学特征。对当前数据与我们之前的观察进行的比较分析表明，从胚胎、出生后早期和成年小鼠中出生的神经元记录的 GABA 能输入之间没有显着差异。然而，胚胎产生的神经元表现出膜兴奋性降低，表明网络活动的参与度较低。我们的结果表明，不同年龄、位置和兴奋程度的颗粒细胞接收具有相同功能特征的 GABA 能输入。
Neurogenesis in the dentate gyrus of the hippocampus follows a unique temporal pattern that begins during embryonic development, peaks during the early postnatal stages and persists through adult life. We have recently shown that dentate granule cells born in early postnatal and adult mice acquire a remarkably similar afferent connectivity and firing behavior, suggesting that they constitute a homogeneous functional population [Laplagne et al. (2006) Plos Biol., 4, e409]. Here we extend our previous study by comparing mature neurons born in the embryonic and adult hippocampus, with a focus on intrinsic membrane properties and gamma-aminobutyric acid (GABA)ergic synaptic inputs. For this purpose, dividing neuroblasts of the ventricular wall were retrovirally labeled with green fluorescent protein at embryonic day 15 (E15), and progenitor cells of the subgranular zone were labeled with red fluorescent protein in the same mice at postnatal day 42 (P42, adulthood). Electrophysiological properties of mature neurons born at either stage were then compared in the same brain slices. Evoked and spontaneous GABAergic postsynaptic responses of perisomatic and dendritic origin displayed similar characteristics in both neuronal populations. Miniature GABAergic inputs also showed similar functional properties and pharmacological profile. A comparative analysis of the present data with our previous observations rendered no significant differences among GABAergic inputs recorded from neurons born in the embryonic, early postnatal and adult mice. Yet, embryo-born neurons showed a reduced membrane excitability, suggesting a lower engagement in network activity. Our results demonstrate that granule cells of different age, location and degree of excitability receive GABAergic inputs of equivalent functional characteristics.