Egr1 的表达与小鼠成年齿状颗粒细胞的突触活动相关,但与固有膜特性无关

IF 2.4 3区 医学 Q3 NEUROSCIENCES
Hippocampus Pub Date : 2024-10-15 DOI:10.1002/hipo.23644
Shane M. Ohline, Barbara J. Logan, Stephanie M. Hughes, Wickliffe C. Abraham
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引用次数: 0

摘要

在海马齿状回中发现成体颗粒细胞(aDGCs)后,人们对它们如何发育、如何融入海马回路以及如何促进学习和记忆产生了疑问。在这里,我们利用贴片钳电生理学研究了小鼠 aDGCs 成熟过程中的内在兴奋性和突触兴奋性,并通过使用他莫昔芬诱导的遗传标记来确定不同动物年龄段 aDGCs 的出生日期。重要的是,我们还对直接早期基因 Egr1 的表达进行了免疫荧光研究,并将这些发现与同一动物的电生理学数据进行了比较。我们对两组动物进行了研究,分别是出生日期为 2 个月的小鼠和 7-9 个月大的小鼠。在这两组小鼠中,4周大的细胞的电流诱发动作电位阈值低于较大的细胞,但在长电流脉冲期间发射的尖峰较少,对突触激活的反应较差。有趣的是,这种内在兴奋性的变化模式与 Egr1 的表达模式并不相关。相反,Egr1 表达的发展与自发兴奋性突触后电流的频率相关。这些结果表明,尽管年轻的aDGCs具有较高的输入阻抗和较低的点燃阈值,但为了让aDGCs充分参与海马电路(如Egr1表达所显示的那样),它们必须发展出足够的突触输入。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Egr1 Expression Is Correlated With Synaptic Activity but Not Intrinsic Membrane Properties in Mouse Adult-Born Dentate Granule Cells

The discovery of adult-born granule cells (aDGCs) in the dentate gyrus of the hippocampus has raised questions regarding how they develop, incorporate into the hippocampal circuitry, and contribute to learning and memory. Here, we used patch-clamp electrophysiology to investigate the intrinsic and synaptic excitability of mouse aDGCs as they matured, enabled by using a tamoxifen-induced genetic label to birth date the aDGCs at different animal ages. Importantly, we also undertook immunofluorescence studies of the expression of the immediate early gene Egr1 and compared these findings with the electrophysiology data in the same animals. We examined two groups of animals, with aDGC birthdating when the mice were 2 months and at 7–9 months of age. In both groups, cells 4 weeks old had lower thresholds for current-evoked action potentials than older cells but fired fewer spikes during long current pulses and responded more poorly to synaptic activation. aDGCs born in both 2 and 7–9-month-old mice matured in their intrinsic excitability and synaptic properties from 4–12 weeks postgenesis, but this occurred more slowly for the older age animals. Interestingly, this pattern of intrinsic excitability changes did not correlate with the pattern of Egr1 expression. Instead, the development of Egr1 expression was correlated with the frequency of spontaneous excitatory postsynaptic currents. These results suggest that in order for aDGCs to fully participate in hippocampal circuitry, as indicated by Egr1 expression, they must have developed enough synaptic input, in spite of the greater input resistance and reduced firing threshold that characterizes young aDGCs.

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来源期刊
Hippocampus
Hippocampus 医学-神经科学
CiteScore
5.80
自引率
5.70%
发文量
79
审稿时长
3-8 weeks
期刊介绍: Hippocampus provides a forum for the exchange of current information between investigators interested in the neurobiology of the hippocampal formation and related structures. While the relationships of submitted papers to the hippocampal formation will be evaluated liberally, the substance of appropriate papers should deal with the hippocampal formation per se or with the interaction between the hippocampal formation and other brain regions. The scope of Hippocampus is wide: single and multidisciplinary experimental studies from all fields of basic science, theoretical papers, papers dealing with hippocampal preparations as models for understanding the central nervous system, and clinical studies will be considered for publication. The Editor especially encourages the submission of papers that contribute to a functional understanding of the hippocampal formation.
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