Smith D V, Akeson R A, Shipley M T
Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, Ohio 45267-0528.
J Comp Neurol. 1993 Oct 22;336(4):493-506. doi: 10.1002/cne.903360403.
The expression of the neural cell adhesion molecule (NCAM) and distinct carbohydrate groups by cells of the taste buds of the rat vallate papilla was investigated by immunohistochemical and biochemical techniques. We employed antibodies against 1) the extracellular (mAb 3F4) and cytoplasmic (mAb 5B8) portions of the NCAM polypeptide, 2) the highly sialylated form of NCAM (mAb 5A5), 3) carbohydrate epitopes associated with glycosylated NCAM forms in the rat (mAb 2B8) or frog (mAb 9-OE) olfactory system, and also 4) the Lewisb blood group carbohydrate epitope (mAb CO431). NCAM mRNA was demonstrated by polymerase chain reaction (PCR) in samples of the vallate papilla, suggesting the presence of NCAM in cells of the taste buds. Antibodies against NCAM (mAbs 3F4 and 5B8) recognized a subset (about 20%) of cells within the vallate taste buds; fibers of the glossopharyngeal nerve, including those innervating the gustatory epithelium, were NCAM immunoreactive. Taste bud cells did not express polysialic acid (mAb 5A5), but mAb 5A5 immunoreactivity was observed on fibers of the IXth nerve, including a few that entered the taste buds. All or nearly all of the cells within the vallate taste buds were immunoreactive to mAb 2B8, whereas mAbs 9-OE and CO431 reacted with subsets of cells. The carbohydrates recognized by mAbs 2B8 and 9-OE were also abundantly expressed in the ducts and acini of the lingual salivary glands. Bilateral crush of the IXth nerve resulted in the loss of expression of all of these molecules from the gustatory epithelium. If cells of the taste bud express NCAM during their final stage(s) of differentiation, then NCAM could play a role(s) in the growth of gustatory axons toward their target epithelial cells and in the recognition between the nerve fibers and mature taste receptor cells, or among the taste bud cells themselves.
运用免疫组织化学和生化技术，研究大鼠轮廓乳头味蕾细胞中神经细胞黏附分子（NCAM）及其不同碳水化合物基团的表达情况。我们使用了针对以下几种物质的抗体：1）NCAM多肽的细胞外部分（单克隆抗体3F4）和细胞质部分（单克隆抗体5B8）；2）高度唾液酸化形式的NCAM（单克隆抗体5A5）；3）与大鼠（单克隆抗体2B8）或青蛙（单克隆抗体9 - OE）嗅觉系统中糖基化NCAM形式相关的碳水化合物表位；4）Lewisb血型碳水化合物表位（单克隆抗体CO431）。通过聚合酶链反应（PCR）在轮廓乳头样本中证实了NCAM mRNA的存在，这表明味蕾细胞中存在NCAM。针对NCAM的抗体（单克隆抗体3F4和5B8）识别出轮廓味蕾内的一部分细胞（约20%）；舌咽神经的纤维，包括那些支配味觉上皮的纤维，呈NCAM免疫反应性。味蕾细胞不表达多唾液酸（单克隆抗体5A5），但在第九神经的纤维上观察到单克隆抗体5A5免疫反应性，包括一些进入味蕾的纤维。轮廓味蕾内所有或几乎所有细胞对单克隆抗体2B8呈免疫反应性，而单克隆抗体9 - OE和CO431与部分细胞发生反应。单克隆抗体2B8和9 - OE识别的碳水化合物在舌唾液腺的导管和腺泡中也大量表达。双侧切断第九神经导致味觉上皮中所有这些分子的表达缺失。如果味蕾细胞在其分化的最后阶段表达NCAM，那么NCAM可能在味觉轴突向其靶上皮细胞的生长过程中以及在神经纤维与成熟味觉受体细胞之间或味蕾细胞自身之间的识别过程中发挥作用。
