Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France.
Institute for Neuroanatomy, UMG, Georg-August-University Göttingen Göttingen, Germany.
Front Neuroanat. 2014 Jun 24;8:52. doi: 10.3389/fnana.2014.00052. eCollection 2014.
Cortical calretinin (CR)-expressing interneurons represent a heterogeneous subpopulation of about 10-30% of GABAergic interneurons, which altogether total ca. 12-20% of all cortical neurons. In the rodent neocortex, CR cells display different somatodendritic morphologies ranging from bipolar to multipolar but the bipolar cells and their variations dominate. They are also diverse at the molecular level as they were shown to express numerous neuropeptides in different combinations including vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), neurokinin B (NKB) corticotrophin releasing factor (CRF), enkephalin (Enk) but also neuropeptide Y (NPY) and somatostatin (SOM) to a lesser extent. CR-expressing interneurons exhibit different firing behaviors such as adapting, bursting or irregular. They mainly originate from the caudal ganglionic eminence (CGE) but a subpopulation also derives from the dorsal part of the medial ganglionic eminence (MGE). Cortical GABAergic CR-expressing interneurons can be divided in two main populations: VIP-bipolar interneurons deriving from the CGE and SOM-Martinotti-like interneurons originating in the dorsal MGE. Although bipolar cells account for the majority of CR-expressing interneurons, the roles they play in cortical neuronal circuits and in the more general metabolic physiology of the brain remained elusive and enigmatic. The aim of this review is, firstly, to provide a comprehensive view of the morphological, molecular and electrophysiological features defining this cell type. We will, secondly, also summarize what is known about their place in the cortical circuit, their modulation by subcortical afferents and the functional roles they might play in neuronal processing and energy metabolism.
皮质钙结合蛋白 (CR) 表达中间神经元代表 GABA 能中间神经元的一个异质亚群，约占 10-30%，而 GABA 能中间神经元总共占皮质神经元的约 12-20%。在啮齿动物新皮层中，CR 细胞表现出不同的体树突形态，从双极到多极，但双极细胞及其变体占主导地位。它们在分子水平上也具有多样性，因为它们被证明以不同的组合表达多种神经肽，包括血管活性肠肽 (VIP)、胆囊收缩素 (CCK)、神经激肽 B (NKB)、促肾上腺皮质释放因子 (CRF)、脑啡肽 (Enk)，但也包括神经肽 Y (NPY) 和生长抑素 (SOM)，但程度较低。CR 表达中间神经元表现出不同的放电行为，如适应、爆发或不规则。它们主要起源于尾状神经节隆起 (CGE)，但一小部分也起源于内侧神经节隆起 (MGE)的背侧部分。皮质 GABA 能 CR 表达中间神经元可分为两个主要群体：来自 CGE 的 VIP-双极中间神经元和起源于背侧 MGE 的 SOM-Martinotti 样中间神经元。尽管双极细胞占 CR 表达中间神经元的大多数，但它们在皮质神经元回路中的作用以及在大脑更普遍的代谢生理学中的作用仍然难以捉摸和神秘。本综述的目的首先是提供对定义这种细胞类型的形态、分子和电生理特征的全面了解。其次，我们还将总结它们在皮质回路中的位置、它们受皮质下传入的调节以及它们在神经元处理和能量代谢中可能发挥的功能作用。
