Oudar O, Ferrary E, Feldmann G
Département de Physiologie and INSERM U.251, Faculté de Médecine Xavier Bichat, Université Paris, France.
Anat Rec. 1988 Mar;220(3):328-34. doi: 10.1002/ar.1092200316.
The ultrastructure of the nonsensory cells (dark cells, transitional cells, and undifferentiated cells) of the frog semicircular canal was studied by using transmission electron microscopy in an attempt to correlate the structure with the functions of these epithelial cells. All the nonsensory cells were linked by tight junctions and desmosomes; this suggested that there is little paracellular ionic transport from perilymph to endolymph. In the dark cell epithelium, the apical intercellular spaces were dilated; in the basal part, numerous basolateral plasma membrane infoldings, containing mitochondria, delimited electron-lucent spaces. The undifferentiated cells and the transitional cells were devoid of any basal membrane infolding. Surrounding the semicircular canal, very flattened and interdigitated mesothelial cells constituted a thin multilayer tissue which limited the perilymphatic space. The morphological aspect of the dark cells suggests that they may play a role in the secretion and/or in the reabsorption of endolymph, which bathes the apical pole of these cells. The undifferentiated and transitional cells can play a role in the maintenance of the endolymphatic ionic composition because of their apical tight junctions and desmosomes.
运用透射电子显微镜对蛙半规管的非感觉细胞（暗细胞、过渡细胞和未分化细胞）的超微结构进行了研究，旨在将这些上皮细胞的结构与其功能联系起来。所有非感觉细胞都通过紧密连接和桥粒相连；这表明从外淋巴到内淋巴的细胞旁离子转运很少。在暗细胞上皮中，顶端细胞间隙扩张；在基部，大量含有线粒体的基底外侧质膜内褶界定了电子透明空间。未分化细胞和过渡细胞没有任何基底膜内褶。围绕半规管，非常扁平且相互交错的间皮细胞构成了一层薄薄的多层组织，限制了外淋巴间隙。暗细胞的形态学特征表明它们可能在内淋巴的分泌和/或重吸收中发挥作用，内淋巴浸润这些细胞的顶端极。未分化细胞和过渡细胞因其顶端紧密连接和桥粒，可能在内淋巴离子组成的维持中发挥作用。
