Novel and transient populations of corticotropin-releasing hormone-expressing neurons in developing hippocampus suggest unique functional roles: A quantitative spatiotemporal analysis
Novel and transient populations of corticotropin-releasing hormone-expressing neurons in developing hippocampus suggest unique functional roles: A quantitative spatiotemporal analysis
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DOI：
10.1523/jneurosci.21-18-07171.2001
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发表时间：
2001-09-15
影响因子：
5.3
通讯作者：
Baram, TZ
中科院分区：
文献类型：
--
作者：
Chen, YC;Bender, RA;Baram, TZ
神经肽促肾上腺皮质激素释放激素（CRH）对海马锥体神经元的强大生理作用已被证明，这可能有助于突触效能和学习记忆过程。肽的这些兴奋作用，以及介导它们的CRH受体类型的表达，在产后早期尤为突出，这表明内源性CRH可能参与了海马回路成熟的过程。为了进一步阐明内源性CRH在发育海马中的功能，我们使用神经化学和定量体视学方法详细表征了出生后海马分化过程中表达CRH的神经元群。这些实验表明，发育中的海马中表达crh的神经元数量逐渐增加，在出生后11-18天达到峰值，然后急剧下降到成人水平。这些细胞属于几个离散的群体，通过GAD67 mRNA的表达、形态和不同的时空分布特征来区分。重要的是，一种新的cajal - retzius样表达crh的神经元群体被表征为仅在出生后早期海马中短暂存在，并且定位于促进海马连接的建立。这些发现表明，CRH在调节海马形成的早期发育事件中具有新颖的、年龄特异性的作用。
Robust physiological actions of the neuropeptide corticotropin-releasing hormone (CRH) on hippocampal pyramidal neurons have been demonstrated, which may contribute to synaptic efficacy and to learning and memory processes. These excitatory actions of the peptide, as well as the expression of the CRH receptor type that mediates them, are particularly prominent during early postnatal life, suggesting that endogenous CRH may contribute to processes involved in maturation of hippocampal circuitry. To further elucidate the function(s) of endogenous CRH in developing hippocampus, we used neurochemical and quantitative stereological methods to characterize in detail CRH-expressing neuronal populations during postnatal hippocampal differentiation. These experiments revealed progressively increasing numbers of CRH-expressing neurons in developing hippocampus that peaked on postnatal day 11-18 and then declined drastically to adult levels. These cells belonged to several discrete populations, distinguished by GAD67 mRNA expression, morphology, and distinct spatiotemporal distribution profiles. Importantly, a novel population of Cajal-Retzius-like CRH-expressing neurons was characterized that exists only transiently in early postnatal hippocampus and is positioned to contribute to the establishment of hippocampal connectivity. These findings suggest novel, age-specific roles for CRH in regulating early developmental events in the hippocampal formation.