Du F, Schmidt W, Okuno E, Kido R, Köhler C, Schwarcz R
Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore 21228.
J Comp Neurol. 1992 Jul 15;321(3):477-87. doi: 10.1002/cne.903210313.
The localization and distribution of kynurenine aminotransferase (KAT), the biosynthetic enzyme of the excitatory amino acid receptor antagonist, kynurenic acid, was studied in the rat hippocampal formation with immunohistochemical methods. The enzyme was found mainly in glial cells that could be distinguished as 3 types on the basis of their shapes and locations. Typically, these cells shared the morphological features of astrocytes and exhibited glial fibrillary acidic protein immunoreactivity as demonstrated by a double-labeling technique. The distribution of KAT-containing glial cells was heterogeneous throughout the hippocampal formation. In the hippocampus, the stratum lacunosum-moleculare of Ammon's horn and the hilus contained a higher density of KAT-positive glial cells than other regions, whereas the lowest density of KAT glial cells was observed in the granule cell layer of the dentate gyrus and in the stratum radiatum of CA subfields. In the subicular complex, the density of KAT-containing glial cells was generally higher in the superficial than in the deep layer. Hippocampal neurons exhibiting KAT immunoreactivity, distinguished as nonpyramidal cells, were very few in number and mainly distributed in strata oriens and pyramidale of Ammon's horn. Substantially more KAT-positive neurons were observed in layers II and III of the subicular complex. The organization of cellular elements containing KAT may be of relevance for the function and possible dysfunction of kynurenic acid in the rat hippocampal formation.
采用免疫组织化学方法，研究了兴奋性氨基酸受体拮抗剂犬尿喹啉酸的生物合成酶——犬尿氨酸转氨酶（KAT）在大鼠海马结构中的定位和分布。发现该酶主要存在于神经胶质细胞中，根据其形状和位置可分为3种类型。通常，这些细胞具有星形胶质细胞的形态特征，并通过双重标记技术显示出胶质纤维酸性蛋白免疫反应性。含KAT的神经胶质细胞在整个海马结构中的分布是不均匀的。在海马中，海马角的腔隙-分子层和齿状回包含的KAT阳性神经胶质细胞密度高于其他区域，而在齿状回颗粒细胞层和CA亚区的辐射层中观察到的KAT神经胶质细胞密度最低。在海马旁回复合体中，含KAT的神经胶质细胞密度通常浅层高于深层。表现出KAT免疫反应性的海马神经元，被鉴定为非锥体细胞，数量很少，主要分布在海马角的原层和锥体细胞层。在海马旁回复合体的第II层和第III层中观察到的KAT阳性神经元明显更多。含KAT的细胞成分的组织可能与犬尿喹啉酸在大鼠海马结构中的功能及可能的功能障碍有关。
