Zuwała K
Department of Comparative Anatomy, Jagiellonian University, Kraków, Poland.
J Submicrosc Cytol Pathol. 2002 Jan;34(1):17-25.
From the 38th developmental stage of the tadpole of Rana esculenta the process of tongue formation consists in the fast growth of the lining of the oral cavity floor anteriorly and faucially. This process is accompanied by the development of taste organs on the dorsal side of the tongue. At developmental stages 39-42 taste disc anlages are covered by a layer of ordinary epithelial cells. At these stages, in some cells of a taste disc single synaptic-like vesicles with an electron-dense core appear. Apart from that, as early as at stage 42 differentiation of the cells of a taste disc can be observed at the ultrastructural level. It is only at the 44th stage that all cell types characteristic for the mature TD can be distinguished in TEM (i.e., taste cells, basal cells and three kinds of associate cells: mucous, wing and sustentacular). Starting from that stage changes in the cell membrane can be observed indicating the presence of afferent synaptic junctions. The antibody used in the experiment was raised against neuron-specific enolase (NSE). At each of the developmental stages investigated (38, 42, 45) nerve fibres within the connective tissue beneath the epithelium of a taste disc anlage were immunopositive for NSE. From stage 42 onwards neural elements present in the basal part of the epithelium of a taste disc anlage were also NSE-positive. Basal cells did not show immuno-reactivity for NSE at any of the developmental stages investigated.
从食用蛙蝌蚪的第38个发育阶段开始，舌头形成过程包括口腔底部内衬向前和向面部快速生长。这个过程伴随着舌背侧味觉器官的发育。在发育阶段39 - 42，味觉盘原基被一层普通上皮细胞覆盖。在这些阶段，在味觉盘的一些细胞中出现了带有电子致密核心的单个突触样小泡。除此之外，早在第42阶段，就可以在超微结构水平观察到味觉盘细胞的分化。只有在第44阶段，在透射电子显微镜（TEM）下才能区分成熟味觉盘特有的所有细胞类型（即味觉细胞、基底细胞和三种辅助细胞：黏液细胞、翼状细胞和支持细胞）。从那个阶段开始，可以观察到细胞膜的变化，表明存在传入突触连接。实验中使用的抗体是针对神经元特异性烯醇化酶（NSE）产生的。在所研究的每个发育阶段（38、42、45），味觉盘原基上皮下方结缔组织内的神经纤维对NSE呈免疫阳性。从第42阶段起，味觉盘原基上皮基部存在的神经成分也呈NSE阳性。在所研究的任何发育阶段，基底细胞对NSE均无免疫反应性。
