Mikkonen M, Soininen H, Pitkänen A
Department of Neuroscience and Neurology, University Hospital, Kuopio, Finland.
J Comp Neurol. 1997 Nov 10;388(1):64-88.
Parvalbumin, calretinin, and calbindin-D28k are calcium-binding proteins that are located in largely nonoverlapping neuronal populations in the brain. The authors studied the distribution of parvalbumin-, calretinin-, and calbindin-D28k-immunoreactive (ir) cells, fibers, terminals, and neuropil in the eight subfields of the human entorhinal cortex. The distribution of each of the three calcium-binding proteins largely followed the cytoarchitectonic borders of the eight entorhinal subfields, although the regional and laminar distributions of the three proteins were segregated rather than overlapping. The highest density of parvalbumin-ir neurons and terminals was found in the caudal and lateral subfields of the entorhinal cortex. Calretinin and calbindin-D28k immunoreactivities were high rostromedially, although a large number of calretinin and calbindin-D28k neurons were also found in the caudal subfields. All parvalbumin-ir cells had a morphological appearance of nonpyramidal neurons. Parvalbumin-ir terminals formed basket-like formations around unstained somata and cartridges, suggesting that parvalbumin neurons compose a subpopulation of gamma-aminobutyric acid (GABA)ergic basket cells and chandelier cells, respectively. Although calretinin and calbindin-D28k were also found in numerous nonpyramidal neurons, both were also located in pyramidal-shaped neurons in layers V and VI (calretinin) and in layers II and III (calbindin) of the entorhinal cortex, suggesting that they play roles in projection neurons as well. Moreover, the high density of nonpyramidal neurons containing calcium-binding proteins in layers II and III of the entorhinal cortex suggests that they form an integral component of a network that controls the entorhinal outputs to the hippocampus. Furthermore, the largely nonoverlapping distributions of the parvalbumin-, calretinin-, and calbindin-ir neuronal populations in the entorhinal cortex indicate that each of them may modulate a different subset of topographically organized entorhinal outputs.
小白蛋白、钙视网膜蛋白和钙结合蛋白-D28k是钙结合蛋白，主要位于大脑中互不重叠的神经元群体中。作者研究了人类内嗅皮质八个亚区中小白蛋白、钙视网膜蛋白和钙结合蛋白-D28k免疫反应性（ir）细胞、纤维、终末和神经毡的分布。三种钙结合蛋白各自的分布在很大程度上遵循了八个内嗅亚区的细胞构筑边界，尽管这三种蛋白的区域和层状分布是分离的而非重叠的。在内嗅皮质的尾侧和外侧亚区发现了最高密度的小白蛋白-ir神经元和终末。钙视网膜蛋白和钙结合蛋白-D28k免疫反应性在吻内侧较高，尽管在尾侧亚区也发现了大量的钙视网膜蛋白和钙结合蛋白-D28k神经元。所有小白蛋白-ir细胞都具有非锥体神经元的形态外观。小白蛋白-ir终末在未染色的胞体和小体周围形成篮状结构，表明小白蛋白神经元分别构成了γ-氨基丁酸（GABA）能篮状细胞和吊灯细胞的一个亚群。尽管在许多非锥体神经元中也发现了钙视网膜蛋白和钙结合蛋白-D28k，但它们也位于内嗅皮质V层和VI层（钙视网膜蛋白）以及II层和III层（钙结合蛋白）的锥体神经元中，这表明它们在投射神经元中也发挥作用。此外，内嗅皮质II层和III层中含有钙结合蛋白的非锥体神经元的高密度表明，它们构成了控制内嗅向海马输出的网络的一个组成部分。此外，内嗅皮质中小白蛋白、钙视网膜蛋白和钙结合蛋白-ir神经元群体在很大程度上互不重叠的分布表明，它们各自可能调节拓扑组织的内嗅输出的不同子集。
