Montero V M, Singer W
Exp Brain Res. 1985;59(1):151-65. doi: 10.1007/BF00237675.
The cat dorsal lateral geniculate nucleus (LGN) was examined at the light- and electron-microscopic level after immunocytochemistry for GAD (the synthesizing enzyme of the inhibitory neurotransmitter GABA), to identify cells and processes with GAD-like immunoreactivity. GAD-positive perikarya were distributed throughout the A and C laminae, constituting a moderate proportion of cells in the LGN. Labeled cells were characterized by small size, scant cytoplasm, relatively large nuclei with common indentations, small mitochondria, few organelles and few strands of rough endoplasmic reticulum. Unlabeled cells were of large, medium and small size. GAD-positive terminals were identified as F1 and F2 types (Guillery's nomenclature) on the basis of their synaptic relations and ultrastructure. Labeled F2 terminals were postsynaptic to retinal (RLP) boutons and presynaptic to unlabeled dendrites in synaptic glomeruli. Labeled F1 terminals made synapses on unlabeled somata and dendrites, and on labeled dendrites and F2 terminals. Presumably, most labeled F1 terminals originate from GABAergic perigeniculate axons. Retinal (RLP) and cortico-geniculate (RSD) boutons remained unlabeled in the reactive zone. These terminals made synapses with labeled and unlabeled dendrites and with labeled F2 boutons. In conjunction with previous studies on GAD-positive cells in the perigeniculate nucleus, these results provide immunocytochemical and morphological evidence suggesting that the GABAergic intrinsic and extrinsic (perigeniculate) interneurons mediate the different inhibitory phenomena which occur in relay cells of the cat LGN. The ultrastructural features and synaptic relations of GABAergic cells and processes in the cat LGN are similar to those of equivalent neural elements in the LGN of rat and monkey, suggesting general principles of organization and morphology for GABAergic neurons in the thalamus of different mammals.
在对谷氨酸脱羧酶（抑制性神经递质γ-氨基丁酸的合成酶）进行免疫细胞化学检测后，在光镜和电镜水平上对猫的背外侧膝状核（LGN）进行了检查，以识别具有谷氨酸脱羧酶样免疫反应性的细胞和突起。谷氨酸脱羧酶阳性的核周体分布在整个A层和C层，在LGN中占细胞的比例适中。标记的细胞具有体积小、细胞质稀少、核相对较大且常有凹陷、线粒体小、细胞器少以及粗面内质网少等特征。未标记的细胞有大、中、小三种尺寸。根据其突触关系和超微结构，谷氨酸脱羧酶阳性终末被鉴定为F1和F2型（吉勒里的命名法）。标记的F2终末在突触小球中是视网膜（RLP）终扣的突触后成分，且是未标记树突的突触前成分。标记的F1终末与未标记的胞体和树突、标记的树突以及F2终末形成突触。推测，大多数标记的F1终末起源于γ-氨基丁酸能的膝状体周轴突。视网膜（RLP）和皮质-膝状体（RSD）终扣在反应区未被标记。这些终末与标记和未标记的树突以及标记的F2终扣形成突触。结合先前对膝状体周核中谷氨酸脱羧酶阳性细胞的研究，这些结果提供了免疫细胞化学和形态学证据，表明γ-氨基丁酸能的内在和外在（膝状体周）中间神经元介导了猫LGN中继细胞中发生的不同抑制现象。猫LGN中γ-氨基丁酸能细胞和突起的超微结构特征和突触关系与大鼠和猴LGN中相应神经元件的相似，这表明不同哺乳动物丘脑γ-氨基丁酸能神经元的组织和形态存在一般原则。
