FINE-STRUCTURE OF THE VENTRAL LATERAL NUCLEUS (VL) OF THE MACACA-MULATTA THALAMUS - CELL-TYPES AND SYNAPTOLOGY
FINE-STRUCTURE OF THE VENTRAL LATERAL NUCLEUS (VL) OF THE MACACA-MULATTA THALAMUS - CELL-TYPES AND SYNAPTOLOGY
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DOI：
10.1002/cne.903140209
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发表时间：
1991-12-08
影响因子：
2.5
通讯作者：
ILINSKY, IA
中科院分区：
文献类型：
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作者：
KULTASILINSKY, K;ILINSKY, IA
猴丘脑的主要小脑区域或VL的超微结构，如Ilinsky和Kultas-Ilinsky（J. Comp. Neurol. 262：331-364，'87），通过使用神经解剖追踪、免疫细胞化学和定量形态测量技术进行分析。VL核包含两种类型的神经细胞。用小麦胚芽凝集素-辣根过氧化物酶（WGA-HRP）逆行标记的中央前回多极神经元（PN）显示出近端树突的簇状分支模式，索马面积范围为200至1，000-mu-2（平均535.2-mu-m2，SD = 159.5）。小谷氨酸脱羧酶（GAD）免疫反应细胞（LCN）的大小为65至210 μ-m2（平均122.5 μ-m2，SD = 32.8），并保持皮质注射后未标记。这两种细胞类型可以通过超微结构特征进一步区分。与PN不同，LCN显示核周细胞质少，核仁小，形状不规则，近端树突中有突触小泡。PN与LCN的比例为3：1。LCN树突单独或作为复杂突触排列的一部分在PN胞体和各级树突乔木上建立突触联系。它们也是LCN树突的突触前神经。大的终扣包含圆形的囊泡，是最明显的神经节。它们在PN的胞体和近端树突以及LCN的远端树突上形成不对称接触。这些终扣的面积范围从0.7到12 μ m ~ 2，PN树突上的并置长度范围从1.1到14 μ m。除最大的外，所有LR纽扣都因在小脑深核中注射大量WGA-HRP而被顺向标记。这些终末也作为三联体和肾小球的一部分出现，但非常罕见，因为后者复杂的突触排列是罕见的。神经元中最多的轴突终末是SR型，即，小的终端（平均面积0.42-mu-m2）含有圆形小泡。在中央前回注射WGA-HRP后，SR终扣被顺行标记。它们主要在远端PN和LCN树突上形成不同的不对称接触;然而，它们的结构域在PN树突的中间水平部分重叠LR终扣。SR终扣是与LCN树突的串联突触的组成部分，LCN树突反过来又接触PN的胞体和各级树突乔木。它们还参与复杂的排列，包括LCN树突序列、串联突触和偶尔具有对称接触的终扣。这些被称为小肾小球的结构在猴VL中比具有LR终扣的经典肾小球多得多。这是一个异质性的人口包含不同大小的终扣范围从0.4到9 μ m2。终端包含多形性或几乎圆柱形的小泡和显示对称的接触。F1终扣在两种类型的细胞上形成轴体和轴树突触，并在PN的起始轴突节段上形成轴轴突触。正是这些终扣参与了复杂的突触安排与囊泡含有LCN树突和SR终扣，他们也遇到了作为三个对称的接触的三元组的一部分。该钮扣群体的代表表现出GAD免疫反应性阳性。为了测量膜和并列结构，将识别的PN树突分为三类。“二级”树突组包括所有的召唤命令短的树突片段在大约60 μ m半径的索马周围的大部分分支发生。结果发现，具有不对称接触的终扣与具有对称接触的终扣的比例在初级树突上为4：1，在“次级”树突上为9：1，在远端树突上为55：1。对称性树-树突触与轴突终末形成的对称性接触的比例在初级和“次级”树突上为3：1，在远端树突上为1：1。这表明PN树突上的兴奋性输入（LR和SR终扣）的总体优势，抑制性输入主要来自GABA能LCN dendrites.Comparison本研究结果与早期的数据在猫的小脑丘脑领土和猴子的黑丘脑领土表明运动丘脑电路的组织中的显着种间和核间差异。
Ultrastructure of the major cerebellar territory of the monkey thalamus, or VL as delineated in sagittal maps by Ilinsky and Kultas-Ilinsky (J. Comp. Neurol. 262:331-364, '87), was analyzed by using neuroanatomical tracing, immunocytochemical, and quantitative morphometric techniques. The VL nucleus contains nerve cells of two types. Multipolar neurons (PN) retrogradely labeled with wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from the precentral gyrus display a tufted branching pattern of the proximal dendrites and have a range of soma areas from 200 to 1,000-mu-2 (mean 535.2-mu-m2, SD = 159.5). Small glutamic acid decarboxylase (GAD) immunoreactive cells (LCN) exhibit sizes from 65 to 210-mu-m2 (mean 122.5-mu-m2, SD = 32.8) and remain unlabeled after cortical injections. The two cell types can be further distinguished by ultrastructural features. Unlike PN, LCN display little perikaryal cytoplasm, a small irregularly shaped nucleolus, and synaptic vesicles in proximal dendrites. The ratio of PN to LCN is 3:1. The LCN dendrites establish synaptic contacts on PN somata and all levels of dendritic arbor either singly or as a part of complex synaptic arrangements. They are also presynaptic to other LCN dendrites.Terminals known as LR type, i.e., large boutons containing round vesicles, are the most conspicuous in the neuropil. They form asymmetric contacts on somata and proximal dendrites of PN as well as on distal dendrites of LCN. The areas of these boutons range from 0.7 to 12-mu-m2 and the appositional length on PN dendrites ranges from 1.1 to 14-mu-m. All LR boutons except the largest ones become anterogradely labeled from large WGA-HRP injections in the deep cerebellar nuclei. These boutons are also encountered as part of triads and glomeruli, but very infrequently since the latter complex synaptic arrangements are rare.The most numerous axon terminals in the neuropil are the SR type, i.e., small terminals (mean area 0.42-mu-m2) containing round vesicles. The SR boutons become anterogradely labeled after WGA-HRP injections in the precentral gyrus. They form distinct asymmetric contacts predominantly on distal PN and LCN dendrites; however, their domain partially overlaps that of LR boutons at intermediate levels of PN dendrites. The SR boutons are components of serial synapses with LCN dendrites which, in turn, contact somata and all levels of dendritic arbors of PN. They also participate in complex arrangements that consist of sequences of LCN dendrites, serial synapses, and occasional boutons with symmetric contacts. These structures termed small glomeruli are much more frequent in the monkey VL than classic glomeruli with LR boutons.The third group is composed of boutons known as F1 type. This is a heterogeneous population containing boutons of varying sizes ranging from 0.4 to 9-mu-m2. The terminals contain pleomorphic or almost cylindrical vesicles and display symmetric contacts. The F1 boutons form axosomatic and axodendritic synapses on both types of cells, and axoaxonic synapses on initial axon segments of PN. It is these boutons that participate in complex synaptic arrangements with vesicle-containing LCN dendrites and SR boutons, and they are also encountered as part of triads with three symmetric contacts. Representatives of this bouton population display positive GAD immunoreactivity.For measurements of the membrane and apposing structures, the identified PN dendrites were grouped into three categories. The group of "secondary" dendrites included all consecutive-order short dendritic segments within approximately a 60-mu-m radius around the soma where most of the branching occurred. It was found that the ratios of boutons with asymmetric contacts to those with symmetric contacts were 4:1 on primary dendrites, 9:1 on "secondary," and 55:1 on distal dendrites. The ratios of symmetric dendrodendritic synapses to symmetric contacts formed by axon terminals were 3:1 on primary and " secondary" dendrites and 1:1 on distal dendrites. This suggests the overall predominance of excitatory inputs (LR and SR boutons) on PN dendrites with inhibitory inputs coming mainly from GABAergic LCN dendrites.Comparison of the present findings with earlier data on the cerebellar thalamic territory in the cat and the nigrothalamic territory in the monkey suggests significant interspecies and internuclear differences in the organization of motor thalamic circuits.