Campbell M J, Morrison J H
Department of Basic and Clinical Research, Research Institute of Scripps Clinic, La Jolla, California 92037.
J Comp Neurol. 1989 Apr 8;282(2):191-205. doi: 10.1002/cne.902820204.
A monoclonal antibody that recognizes a nonphosphorylated epitope on the 168 kDa and 200 kDa subunits of neurofilament proteins has been used in an immunohistochemical study of cynomolgus monkey (Macaca fascicularis) and human neocortex. This antibody, SMI-32, primarily labels the cell body and dendrites of a subset of pyramidal neurons in both species. A greater proportion of neocortical pyramidal neurons were SMI-32 immunoreactive (ir) in the human than in the monkey. SMI-32-ir neurons exhibited consistent differences in the intensity of their immunoreactivity that correlated with cell size. The cellular specificity of SMI-32 immunoreactivity suggests that a subpopulation of neurons can be distinguished on the basis of differences in the molecular characteristics of basic cytoskeletal elements such as neurofilament proteins. The size, density, and laminar distribution of SMI-32-ir neurons differed substantially across neocortical areas within each species and between species. Differences across cortical areas were particularly striking in the monkey. For example, the anterior parainsular cortex had a substantial population of large SMI-32-ir neurons in layer V and a near absence of any immunoreactive neurons in the supragranular layers. This contrasted with the cortical area located more laterally on the superior temporal gyrus, where layers III and V contained substantial populations of large SMI-32-ir neurons. Both areas differed significantly from the posterior inferior temporal gyrus, which was distinguished by a bimodal distribution of large SMI-32-ir neurons in layer III. Differences across human areas were less obvious because of the increase in the number of SMI-32-ir neurons. Perhaps the most notable differences across human areas resulted from shifts in the density of the larger SMI-32-ir neurons in deep layer III. A comparison between the species revealed that isocortical areas exhibited greater differences in their representation of SMI-32-ir neurons than primary sensory or transitional cortical areas. A comparison of distribution patterns of SMI-32-ir neurons across monkey cortical areas and data available on the laminar organization of cortical efferent neurons suggests that a common anatomic characteristic of this chemically identified subpopulation of neurons is that they have a distant axonal projection. Such correlations of cell biological characteristics with specific elements of cortical circuitry will further our understanding of the molecular and cellular properties that are critically linked to a given neuron's role in cortical structure and function.
一种识别神经丝蛋白168 kDa和200 kDa亚基上非磷酸化表位的单克隆抗体已用于食蟹猴（猕猴）和人类新皮质的免疫组织化学研究。这种抗体SMI - 32主要标记这两个物种中一部分锥体神经元的细胞体和树突。与猴子相比，人类新皮质中更多比例的锥体神经元是SMI - 32免疫反应性（ir）的。SMI - 32 - ir神经元在免疫反应强度上表现出与细胞大小相关的一致差异。SMI - 32免疫反应性的细胞特异性表明，可以根据神经丝蛋白等基本细胞骨架成分分子特征的差异来区分神经元亚群。每个物种内不同新皮质区域以及不同物种之间，SMI - 32 - ir神经元的大小、密度和分层分布存在显著差异。在猴子中，不同皮质区域之间的差异尤为显著。例如，前岛旁皮质在V层有大量大型SMI - 32 - ir神经元，而颗粒上层几乎没有任何免疫反应性神经元。这与位于颞上回更外侧的皮质区域形成对比，在该区域III层和V层含有大量大型SMI - 32 - ir神经元。这两个区域与颞下后回有显著差异，颞下后回的特点是III层大型SMI - 32 - ir神经元呈双峰分布。由于SMI - 32 - ir神经元数量增加，人类不同区域之间的差异不太明显。也许人类不同区域最显著的差异是由深层III中较大的SMI - 32 - ir神经元密度变化导致的。物种间比较显示，同型皮质区域在SMI - 32 - ir神经元的表现上比初级感觉或过渡性皮质区域表现出更大差异。对猴子皮质区域SMI - 32 - ir神经元分布模式与皮质传出神经元分层组织现有数据的比较表明，这种化学鉴定的神经元亚群的一个共同解剖特征是它们有远距离轴突投射。细胞生物学特征与皮质回路特定元素的这种相关性将加深我们对与给定神经元在皮质结构和功能中作用密切相关的分子和细胞特性的理解。
