Department of Physiology 1, Faculty of Medicine, Kansai Medical University, Hirakata, Osaka, Japan.
Eur J Neurosci. 2018 Dec;48(11):3344-3353. doi: 10.1111/ejn.14200. Epub 2018 Nov 1.
The hippocampal marginal zone contains Cajal-Retzius (C-R) cells and participates in the regulation of cortical development. Two subtypes of group I metabotropic glutamate receptors (mGluRs), mGluR1 and mGluR5, are found in the central nervous system and are considered to regulate neuronal excitability. The release of Ca from intracellular stores is thought to be a main consequence of activation of these receptor subtypes. In hippocampal C-R cells, the expression of mGluR1 has been showed using immunohistochemical techniques, but its function has not been elucidated. In this study, Ca mobilization through mGluR1 activation was demonstrated in the neonatal rat hippocampus. In marginal zone C-R cells, intracellular Ca elevation was detected by fluorescence imaging after the application of a group I mGluR-specific agonist. This response was prevented by application of an mGluR1 antagonist but was not changed by application of an mGluR5 antagonist. The intracellular Ca elevation induced by mGluR1 activation was still observed in Ca -free perfusate, indicating the release of Ca from intracellular stores. γ-Aminobutyric acid and ionotropic glutamate receptor-mediated intracellular Ca elevation was also detected in mGluR1-possessing neurons, although the former was much smaller than that mediated by mGluR1. These results indicate that mGluR1 is functionally expressed in C-R cells in the neonatal marginal zone and regulates cell function through the elevation of intracellular Ca .
海马边缘区含有 Cajal-Retzius (C-R) 细胞，参与皮质发育的调节。两种类型的 I 组代谢型谷氨酸受体 (mGluR)，mGluR1 和 mGluR5，存在于中枢神经系统中，被认为调节神经元兴奋性。这些受体亚型的激活被认为会导致细胞内储存的 Ca 释放。在海马 C-R 细胞中，已经使用免疫组织化学技术显示了 mGluR1 的表达，但尚未阐明其功能。在这项研究中，在新生大鼠海马中证明了 mGluR1 激活引起的 Ca 动员。在边缘区 C-R 细胞中，应用 I 组 mGluR 特异性激动剂后，通过荧光成像检测到细胞内 Ca 升高。该反应被 mGluR1 拮抗剂阻断，但 mGluR5 拮抗剂的应用并未改变。在无 Ca 灌注液中，mGluR1 激活诱导的细胞内 Ca 升高仍然可以观察到，表明 Ca 从细胞内储存中释放。γ-氨基丁酸和离子型谷氨酸受体介导的细胞内 Ca 升高也在具有 mGluR1 的神经元中检测到，尽管前者远小于 mGluR1 介导的升高。这些结果表明，mGluR1 在新生边缘区的 C-R 细胞中功能性表达，并通过细胞内 Ca 升高调节细胞功能。
