Sbarbati A, Crescimanno C, Benati D, Osculati F
Institute of Human Anatomy and Histology, University of Verona, Italy.
J Neurocytol. 1998 Sep;27(9):631-5. doi: 10.1023/a:1006933528084.
The solitary chemosensory cells are considered typical of aquatic vertebrates and have never been described in the oral cavity of terrestrial vertebrates. We describe elements with ultrastructural characteristics of the solitary chemosensory cell in the gustatory epithelium of rats in the first week of extrauterine life. These elements appeared isolated, located among keratinocytes, and wrapped by glial-like elements. They showed a bipolar shape with a round cell body, a thin apical process, and a thicker basal one. Nerve fibers contacted the cell body and the processes. The cells showed small dense granules mainly located near nerve contacts. Small bundles of tonofilaments were visible in the perinuclear cytoplasm. Similar elements were not found in rats after the first week of extrauterine life. The present study demonstrates in a mammal that the development of taste buds is preceded by the presence of epithelial elements with ultrastructural characteristics of the solitary chemosensory cells described in lower vertebrates. This finding suggests that the oral chemoreception in the suckling rats may be mediated by three different pathways (i.e., gustatory system, common chemical sense, and solitary chemosensory cell system).
孤立化学感受细胞被认为是水生脊椎动物所特有的，在陆生脊椎动物的口腔中从未被描述过。我们描述了出生后第一周大鼠味觉上皮中具有孤立化学感受细胞超微结构特征的细胞成分。这些细胞成分呈孤立状态，位于角质形成细胞之间，并被类神经胶质细胞成分包裹。它们呈双极形态，有一个圆形的细胞体、一个细小的顶端突起和一个较粗的基部突起。神经纤维与细胞体和突起相接触。这些细胞显示出小的致密颗粒，主要位于神经接触部位附近。在核周细胞质中可见小束张力丝。在出生后第一周后的大鼠中未发现类似的细胞成分。本研究表明，在哺乳动物中，味蕾的发育之前存在具有低等脊椎动物中所描述的孤立化学感受细胞超微结构特征的上皮细胞成分。这一发现表明，乳鼠的口腔化学感受可能由三种不同的途径介导（即味觉系统、普通化学感觉和孤立化学感受细胞系统）。
