Merigo Flavia, Benati Donatella, Cecchini Maria Paola, Cristofoletti Mirko, Osculati Francesco, Sbarbati Andrea
Human Anatomy and Histology Section, Morphological-Biomedical Sciences Department, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy.
Cell Tissue Res. 2009 Jun;336(3):411-21. doi: 10.1007/s00441-009-0789-7. Epub 2009 May 1.
The chemical composition of the luminal content is now accepted to have a profound influence on the performance of chemosensory receptors. Gustatory and intestinal chemoreceptors have in common their expression of molecules involved in taste sensing and signal transduction pathways. The recent finding that enterocytes of the duodenal epithelium are capable of expressing luminal pancreatic amylase suggests that taste cells of the gustatory epithelium might, in the same way, express salivary amylase in the oral cavity. Therefore, we investigated amylase expression in rat circumvallate papillae by using analyses involving immunohistochemistry, Western blot, and reverse transcription with the polymerase chain reaction. In addition, we used double-labeling confocal laser microscopy to compare amylase immunolabeling with that of the following markers: protein gene product 9.5 (PGP 9.5) and chromogranin A (CgA) for endocrine cells, alpha-gustducin and phospholipase C beta 2 (PLC beta 2) as taste-signaling molecules, and cystic fibrosis transmembrane regulator (CFTR) and Clara-cell-specific secretory protein of 10-kDa (CC10) as secretory markers. The results showed that amylase was present in some taste bud cells; its immunoreactivity was observed in subsets of cells that expressed CgA, alpha-gustducin, PLC beta 2, CFTR, or CC10. PGP 9.5 immunoreactivity was never colocalized with amylase. The data suggest that amylase-positive cells constitute an additional subset of taste receptor cells also associated with chemoreceptorial and/or secretory molecules, confirming the occurrence of various pathways in taste buds.
现在人们已经认识到，管腔内容物的化学成分对化学感应受体的功能有深远影响。味觉和肠道化学感受器共同表达参与味觉感知和信号转导途径的分子。最近发现十二指肠上皮的肠细胞能够表达管腔中的胰腺淀粉酶，这表明味觉上皮的味觉细胞可能同样在口腔中表达唾液淀粉酶。因此，我们通过免疫组织化学、蛋白质印迹以及聚合酶链反应逆转录等分析方法，研究了大鼠轮廓乳头中淀粉酶的表达情况。此外，我们使用双标记共聚焦激光显微镜，将淀粉酶免疫标记与以下标志物的免疫标记进行比较：用于内分泌细胞的蛋白质基因产物9.5（PGP 9.5）和嗜铬粒蛋白A（CgA）、作为味觉信号分子的α-味导素和磷脂酶Cβ2（PLCβ2），以及作为分泌标志物的囊性纤维化跨膜调节因子（CFTR）和10 kDa的克拉拉细胞特异性分泌蛋白（CC10）。结果显示，淀粉酶存在于一些味蕾细胞中；在表达CgA、α-味导素、PLCβ2、CFTR或CC10的细胞亚群中观察到了其免疫反应性。PGP 9.5免疫反应性从未与淀粉酶共定位。这些数据表明，淀粉酶阳性细胞构成了味觉受体细胞的一个额外亚群，也与化学感受和/或分泌分子相关，证实了味蕾中存在多种途径。
