Gutiérrez-Igarza K, Fogarty D J, Pérez-Cerdá F, Doñate-Oliver F, Albus K, Matute C
Departamento de Neurociencias, Universidad del Pais Vasco, Leioa, Spain.
Vis Neurosci. 1996 Jan-Feb;13(1):61-72. doi: 10.1017/s0952523800007136.
We have studied the presence and distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-selective glutamate receptor subunits (GluR1, 2, 3, and 4) in the adult cat visual cortical areas 17, 18, 19, and the lateral suprasylvian areas (LSA). Reverse transcription-polymerase chain reaction (RT-PCR) amplification indicated that the genes encoding GluR1, 2, 3, and 4 are expressed in these areas and Western blot analysis revealed that the size of the corresponding peptides is similar to those described in the rat brain. In situ hybridization (ISH) using digoxigenin-labeled riboprobes showed that mRNAs coding for GluR1 and GluR3 were located in cells in all layers of the areas examined and also in the underlying white matter. GluR1 mRNA was relatively abundant throughout layers II-VI while GluR3 mRNA revealed a more laminated pattern of expression, preferentially labeling cells in layers II, III, V, and VI. The distribution of AMPA-selective receptor subunit peptides was studied by immunohistochemistry using subunit specific antibodies and found to be consistent with ISH results. In addition, we observed that most of the cells strongly labeled by the anti-GluR1 antibody were non-pyramidal neurons and that intense GluR2/3 immunoreactivity was seen preferentially in pyramidal neurons. Interestingly, double-labeling experiments indicated that neurons expressing gamma-aminobutyric acid (GABA) as well as the GluR1 subunit were particularly abundant in deeper layers. The GluR4 peptide was predominantly found in a relatively low number of layer III and layer V neurons with either pyramidal or non-pyramidal morphology. Finally, the distribution of neurons expressing the various receptor subunits was similar in all the visual cortical areas studied. These findings indicate a high expression of GluR1-3 subunits in the cat visual cortex and that GluR1 and GluR2/3 subunits are particularly abundant in non-pyramidal and pyramidal neurons, respectively. In addition, the results described here provide a reference for future studies dealing with the effect of visual deprivation on the expression of this receptor type.
我们研究了α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）选择性谷氨酸受体亚基（GluR1、2、3和4）在成年猫视皮层17区、18区、19区以及外侧上薛氏区（LSA）中的存在情况和分布。逆转录-聚合酶链反应（RT-PCR）扩增表明，编码GluR1、2、3和4的基因在这些区域表达，蛋白质免疫印迹分析显示相应肽段的大小与大鼠脑中描述的相似。使用地高辛标记的核糖探针进行原位杂交（ISH）表明，编码GluR1和GluR3的mRNA位于所检查区域的所有层的细胞中，也位于深层白质中。GluR1 mRNA在整个II-VI层相对丰富，而GluR3 mRNA显示出更分层的表达模式，优先标记II、III、V和VI层中的细胞。使用亚基特异性抗体通过免疫组织化学研究了AMPA选择性受体亚基肽段的分布，发现与ISH结果一致。此外，我们观察到，被抗GluR1抗体强烈标记的大多数细胞是非锥体神经元，并且在锥体神经元中优先观察到强烈的GluR2/3免疫反应性。有趣的是，双重标记实验表明，表达γ-氨基丁酸（GABA）以及GluR1亚基的神经元在深层特别丰富。GluR4肽主要存在于相对较少数量的具有锥体或非锥体形态的III层和V层神经元中。最后，在所研究的所有视皮层区域中，表达各种受体亚基的神经元分布相似。这些发现表明GluR1-3亚基在猫视皮层中高表达，并且GluR1和GluR2/3亚基分别在非锥体神经元和锥体神经元中特别丰富。此外，这里描述的结果为未来研究视觉剥夺对这种受体类型表达的影响提供了参考。
