De La Rosa-Prieto Carlos, De Moya-Pinilla Miguel, Saiz-Sanchez Daniel, Ubeda-Banon Isabel, Arzate Dulce M, Flores-Cuadrado Alicia, Liberia Teresa, Crespo Carlos, Martinez-Marcos Alino
Neuroplasticity and Neurodegeneration Laboratory, Department of Medical Sciences, Ciudad Real Medical School, El Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha Ciudad Real, Spain.
Department of Cellular and Molecular Neurobiology, Neurobiology Institute, Universidad Nacional Autónoma de México Querétaro, México.
Front Neuroanat. 2015 Feb 2;9:4. doi: 10.3389/fnana.2015.00004. eCollection 2015.
New neurons are continually generated in the subependymal layer of the lateral ventricles and the subgranular zone of dentate gyrus during adulthood. In the subventricular zone, neuroblasts migrate a long distance to the olfactory bulb where they differentiate into granule or periglomerular interneurons. In the hippocampus, neuroblasts migrate a short distance from the subgranular zone to the granule cell layer of the dentate gyrus to become granule neurons. In addition to the short-distance inputs, bulbar interneurons receive long-distance centrifugal afferents from olfactory-recipient structures. Similarly, dentate granule cells receive differential inputs from the medial and lateral entorhinal cortices through the perforant pathway. Little is known concerning these new inputs on the adult-born cells. In this work, we have characterized afferent inputs to 21-day old newly-born neurons. Mice were intraperitoneally injected with bromodeoxyuridine. Two weeks later, rhodamine-labeled dextran-amine was injected into the anterior olfactory nucleus, olfactory tubercle, piriform cortex and lateral and medial entorhinal cortices. One week later, animals were perfused and immunofluorescences were carried out. The data show that projection neurons from the mentioned structures, establish putative synaptic contacts onto 21-day-old neurons in the olfactory bulb and dentate gyrus, in some cases even before they start to express specific subpopulation proteins. Long-distance afferents reach middle and outer one-third portions of the molecular layer of the dentate gyrus and granule and, interestingly, periglomerular layers of the olfactory bulb. In the olfactory bulb, these fibers appear to establish presumptive axo-somatic contacts onto newly-born granule and periglomerular cells.
在成年期，新的神经元持续在侧脑室的室管膜下层和齿状回的颗粒下区生成。在脑室下区，神经母细胞远距离迁移至嗅球，在那里它们分化为颗粒神经元或球周中间神经元。在海马体中，神经母细胞从颗粒下区短距离迁移至齿状回的颗粒细胞层，成为颗粒神经元。除了短距离输入外，嗅球中间神经元还接收来自嗅觉接收结构的长距离离心传入纤维。同样，齿状颗粒细胞通过穿通通路接收来自内侧和外侧内嗅皮质的不同输入。关于这些对成年新生细胞的新输入知之甚少。在这项研究中，我们对21日龄新生神经元的传入输入进行了表征。给小鼠腹腔注射溴脱氧尿苷。两周后，将罗丹明标记的葡聚糖胺注入前嗅核、嗅结节、梨状皮质以及外侧和内侧内嗅皮质。一周后，对动物进行灌注并进行免疫荧光检测。数据表明，来自上述结构的投射神经元在嗅球和齿状回中与21日龄神经元建立了假定的突触联系，在某些情况下，甚至在它们开始表达特定亚群蛋白之前就已建立联系。长距离传入纤维到达齿状回分子层的中三分之一和外三分之一部分以及颗粒层，有趣的是，也到达嗅球的球周层。在嗅球中，这些纤维似乎在新生的颗粒细胞和球周细胞上建立了推测的轴-体突触联系。
