Dell' Orbo C, Gioglio L, Quacci D
Laboratory of Human Morphology, University of Pavia, Varese, Italy.
J Electron Microsc (Tokyo). 1995 Aug;44(4):165-73.
Paracoronal secretory cells can be observed outside the sensorial area of the fungiform papilla of Rana esculenta. The morphology of these cells, the type of secretion and their function have, to date, only been incidentally described. By scanning electron microscopy (SEM), the paracoronal cells appear as swallow's-nest-shaped formations with openings 10-15 microns in diameter. The walls of paracoronal cells are characterized by laminar processes subdividing the interior hollow. The cavity of these formations is occupied by amorphous material as demonstrated by light microscopy (LM) pictures. The secretory material fills 7/8 of the upper part of the cytoplasm and appears rather transparent. The secretory material is PAS-negative, unlike the secretory granules contained in laminar processes. By transmission electron microscopy (TEM), they appear as clear ovoid structures, the nucleus of which is situated in the deeper part of the cell, enveloped by a thin cytoplasmic layer and characterized by secretory apparatus and the presence of secretory granules of middle electron-opacity. The apical part of these cells presents large mucous droplets. These cells adhere both to ciliated and parietal cells. Following cytochalasin-B treatment, cells do not show any considerable ultrastructural modification, while after terbutaline treatment the profiles of secreted paracoronal cells increase greatly. Histochemical properties of their secretory products are similar to those of parietal cells and their particular anatomical localization may exclude the direct implication of these cells in taste transduction.
在食用蛙菌状乳头的感觉区域之外可以观察到冠状旁分泌细胞。迄今为止，这些细胞的形态、分泌类型及其功能仅被偶然描述过。通过扫描电子显微镜（SEM）观察，冠状旁细胞呈现出燕窝状结构，其开口直径为10 - 15微米。冠状旁细胞的壁具有分层突起，将内部中空部分细分。如光学显微镜（LM）图片所示，这些结构的腔内充满无定形物质。分泌物质填充了细胞质上部的7/8，看起来相当透明。与分层突起中所含的分泌颗粒不同，分泌物质对过碘酸希夫反应（PAS）呈阴性。通过透射电子显微镜（TEM）观察，它们呈现为透明的卵圆形结构，其细胞核位于细胞的较深部分，被一层薄的细胞质层包裹，其特征是具有分泌 apparatus 和中等电子密度的分泌颗粒。这些细胞的顶端部分呈现出大的黏液滴。这些细胞既与纤毛细胞又与壁细胞相连。用细胞松弛素 - B处理后，细胞未显示出任何明显的超微结构改变，而用特布他林处理后，分泌的冠状旁细胞轮廓大大增加。其分泌产物的组织化学性质与壁细胞相似，并且它们特殊的解剖学定位可能排除了这些细胞在味觉转导中的直接作用。
