Paskevich P A, Evans H K, Domesick V B
Laboratories for Psychiatric Research, Mailman Research Center, McLean Hospital, Belmont, Massachusetts 02178.
J Comp Neurol. 1991 Mar 15;305(3):361-9. doi: 10.1002/cne.903050302.
Regional variations in cell-packing density, culminating in the formation of cell clusters, is now a recognized morphological characteristic of the striatum that has been correlated, in some instances, with either regional histochemical variations or the distribution pattern of afferent fiber systems, or both. Within these cluster regions a further level of organization exists, in the form of discrete neuronal aggregates. The light microscopic morphology of these neurons and the nature of their intercellular contacts at the electron microscope level form the focus of this report. The neurons composing such aggregates are characterized by contiguous soma-somatic or soma-dendritic contact with extended regions of junctionlike symmetrical and consistent contacts where the distance between the cytoplasmic membranes of apposing neurons narrows to as close as 7 nm. Coated vesicles close to the contact areas are common. Three-dimensional computer reconstructions of serial 1 micron sections through aggregates in either the caudatoputamen or nucleus accumbens reveal "chains" of contiguous cells that frequently involve as many as 60 neurons. These contiguous cell aggregates are discrete entities within the larger clusters or islands. It is postulated that the cellular aggregates may represent the fundamental level of striatal organization and may be local modules for intrinsic information processing, modifying extrinsic data processed through the biochemical compartmentalization of the striatum imparted by striosomes, neuropeptides, and dopaminergic, thalamic and cortical afferents.
细胞堆积密度的区域差异最终导致细胞簇的形成，这是纹状体一种公认的形态学特征，在某些情况下，它与区域组织化学变化或传入纤维系统的分布模式，或两者都相关。在这些细胞簇区域内，存在着以离散神经元聚集体形式的进一步组织层次。这些神经元的光学显微镜形态及其在电子显微镜水平下细胞间接触的性质构成了本报告的重点。构成这种聚集体的神经元的特征是，体细胞-体细胞或体细胞-树突之间存在连续接触，接触区域具有延伸的、类似连接的对称且一致的接触，相邻神经元的细胞质膜之间的距离缩小至近7纳米。靠近接触区域的包被小泡很常见。通过对尾壳核或伏隔核中聚集体的连续1微米切片进行三维计算机重建，可揭示连续细胞的“链”，这些链通常涉及多达60个神经元。这些连续的细胞聚集体是较大细胞簇或细胞岛中的离散实体。据推测，细胞聚集体可能代表纹状体组织的基本层次，可能是用于内在信息处理的局部模块，可修改通过纹状体小体、神经肽以及多巴胺能、丘脑和皮质传入纤维赋予纹状体的生化分隔所处理的外部数据。
