Chouaf L, Didier-Bazes M, Aguera M, Tardy M, Sallanon M, Kitahama K, Belin M F
INSERM U171-CNRS UA 1195, Centre Hospitalier Lyon-Sud, Pierre Bénite, France.
Cell Tissue Res. 1989 Aug;257(2):255-62. doi: 10.1007/BF00261828.
The subcommissural organ (SCO), classified as one of the circumventricular organs, is composed mainly of modified ependymal cells, attributable to a glial lineage. Nevertheless, in the rat, these cells do not possess glial markers such as glial fibrillary acidic protein (GFAP), protein S100, or the enzyme glutamine synthetase (GS). They receive a synaptic 5-HT input and show pharmacological properties for uptake of GABA resembling the uptake mechanism of neurons. In this study, we examine the phenotype of several mammalian SCO (cat, mouse, rabbit) and compare them with the corresponding features of the rat SCO. In all these species, the SCO ependymocytes possess vimentin as an intermediate filament, but never express GFAP or neurofilament proteins. They do not contain GS as do glial cells involved in GABA metabolism, and when they contain protein S100 (rabbit, mouse), its rate is low in comparison to classical glial or ependymal cells. Thus, these ependymocytes display characteristics that differentiate them from other types of glial cells (astrocytes, epithelial ependymocytes and tanycytes). Striking interspecies differences in the capacity of SCO-ependymocytes for uptake of GABA might be related to their innervation and suggest a species-dependent plasticity in their function.
室管膜下器官（SCO）被归类为室周器官之一，主要由源自神经胶质谱系的特化室管膜细胞组成。然而，在大鼠中，这些细胞不具有诸如胶质纤维酸性蛋白（GFAP）、蛋白S100或谷氨酰胺合成酶（GS）等神经胶质标志物。它们接受5-羟色胺（5-HT）的突触输入，并表现出与神经元摄取机制相似的γ-氨基丁酸（GABA）摄取药理学特性。在本研究中，我们检测了几种哺乳动物（猫、小鼠、兔）室管膜下器官的表型，并将它们与大鼠室管膜下器官的相应特征进行比较。在所有这些物种中，室管膜下器官的室管膜细胞都具有波形蛋白作为中间丝，但从不表达GFAP或神经丝蛋白。它们不像参与GABA代谢的神经胶质细胞那样含有GS，并且当它们含有蛋白S100（兔、小鼠）时，与典型的神经胶质或室管膜细胞相比，其含量较低。因此，这些室管膜细胞表现出与其他类型神经胶质细胞（星形胶质细胞、上皮室管膜细胞和伸长细胞）不同的特征。室管膜下器官室管膜细胞摄取GABA能力的显著种间差异可能与其神经支配有关，并提示其功能存在物种依赖性可塑性。
