Nitsch R, Ohm T G
Institute of Anatomy, Humboldt University Clinic (Charité), Berlin, Germany.
J Comp Neurol. 1995 Sep 25;360(3):475-87. doi: 10.1002/cne.903600309.
The calcium-binding protein calretinin is present in an intrinsic GABAergic and an extrinsic non-GABAergic system in the rat and monkey hippocampal formation. Important species differences have been noted in hippocampal cell types immunostained for calretinin and the termination pattern of calretinin containing hypothalamic afferents in the hippocampus. In the present study, calretinin-containing neurons were visualized using immunocytochemistry in the human hippocampal formation of individuals which showed no significant neuropathological alterations. Calretinin-immunoreactivity was present exclusively in non-granule cells of the dentate gyrus and in non-pyramidal cells of Ammon's horn. Calretinin-positive neurons were found most frequently in the hilus of the fascia dentata and in strata radiatum and lacunosum-moleculare of CA1, whereas neurons in CA2 and CA3 were rarely immunostained. The majority of calretinin-immunoreactive neurons were small, bipolar or fusiform neurons. The dendritic trees of the calretinin-positive neurons were, for the most part, parallel to the dendrites of the principal cells. In the hilus, however, we observed cells with dendrites restricted to the hilar area. These dendrites were parallel to the granule cell layer. In the stratum lacunosum-moleculare, neurons with dendrites oriented parallel to the hippocampal fissure were frequently detected. In general, dendrites were smooth or sparsely spiny, displaying small conventional spines. The axons usually emerged from the proximal dendrite and could be followed over long distances. Axons were thin, had small varicosities and displayed only few collaterals which branched relatively far away from the cell body. Distinct bands of darkly stained calretinin-positive fibers occupied the innermost portion of the dentate molecular layer and the pyramidal cell layer of CA2. This distribution of calretinin-immunoreactive structures in the human hippocampus is similar to that observed in other primates but differs from that described in lower mammals, i.e., the rat. Our findings suggest that primates may share a common hippocampal calretinin-containing system, presumably both the intrinsic GABAergic and the extrinsic hypothalamic non-GABAergic components.
钙结合蛋白钙视网膜蛋白存在于大鼠和猴海马结构的一个内在γ-氨基丁酸能系统和一个外在非γ-氨基丁酸能系统中。在对钙视网膜蛋白进行免疫染色的海马细胞类型以及含钙视网膜蛋白的下丘脑传入纤维在海马中的终末模式方面，已注意到重要的物种差异。在本研究中，使用免疫细胞化学方法在无明显神经病理学改变的个体的人海马结构中观察含钙视网膜蛋白的神经元。钙视网膜蛋白免疫反应性仅存在于齿状回的非颗粒细胞和海马角的非锥体细胞中。钙视网膜蛋白阳性神经元最常见于齿状回的门区以及CA1的辐射层和分子层，而CA2和CA3中的神经元很少被免疫染色。大多数钙视网膜蛋白免疫反应性神经元是小的双极或梭形神经元。钙视网膜蛋白阳性神经元的树突大部分与主细胞的树突平行。然而，在门区，我们观察到树突局限于门区的细胞。这些树突与颗粒细胞层平行。在分子层，经常检测到树突与海马裂平行排列的神经元。一般来说，树突是光滑的或有稀疏的棘，有小的典型棘。轴突通常从近端树突发出，可追踪较长距离。轴突细，有小的膨体，仅显示很少的侧支，且侧支从细胞体相对较远的地方分支。深色染色的钙视网膜蛋白阳性纤维的明显带占据齿状分子层的最内层和CA2的锥体细胞层。人海马中这种钙视网膜蛋白免疫反应性结构的分布与在其他灵长类动物中观察到的相似，但与在较低等哺乳动物即大鼠中描述的不同。我们的发现表明，灵长类动物可能共享一个共同的含海马钙视网膜蛋白系统，大概包括内在的γ-氨基丁酸能成分和外在的下丘脑非γ-氨基丁酸能成分。
