Division of Oral Histology and Neurobiology, Department of Biosciences, Science of Health Improvement, Kyushu Dental College, Kokurakita-ku, Kitakyushu, Japan.
Cell Tissue Res. 2011 Aug;345(2):243-52. doi: 10.1007/s00441-011-1210-x. Epub 2011 Jul 8.
Taste receptors and their downstream signaling molecules are activated by sugars and sweeteners in the gut and participate in the regulation of glucose transport into enterocytes. The glucose transporter families GLUT and SGLT are responsible for the absorption of glucose, GLUT4 and SGLT1 being expressed preferentially in T1R3-positive taste cells. However, the expression patterns of the other glucose transporters in mouse gustatory tissues have not yet been elucidated. Therefore, we have examined the expression patterns of the glucose transporters (GLUT1-4 and SGLT1-3) in mouse gustatory tissues. Reverse transcription/polymerase chain reaction assays have revealed that GLUT1, 3, and 4 and SGLT1 mRNAs are expressed in the circumvallate papillae. Immunohistochemical analysis has shown that SGLT1 is expressed in a subset of the epithelial cells: from the basal cell layer to the prickle cell layer and in intragemmal and extragemmal epithelium cells in the circumvallate, foliate, and fungiform papillae. GLUT1, GLUT3, and GLUT4 are expressed in the prickle cell layers and/or basal cell layers in these papillae. Moreover, GLUT1, but not GLUT3 or GLUT4, is expressed in a subset of intragemmal and extragemmal epithelium cells in these papillae. Double-labeling experiments have demonstrated that GLUT1-positive taste bud cells coexpress gustducin and inositol 1,4,5-triphosphate receptor type III. These results suggest that SGLT1 and GLUT1 play a role in glucose-sensing and/or transport in mouse taste buds.
味觉感受器及其下游信号分子可被肠道中的糖和甜味剂激活，并参与调节葡萄糖向肠上皮细胞的转运。葡萄糖转运体家族 GLUT 和 SGLT 负责葡萄糖的吸收，GLUT4 和 SGLT1 优先表达于 T1R3 阳性味觉细胞。然而，其他葡萄糖转运体在小鼠味觉组织中的表达模式尚未阐明。因此，我们检测了葡萄糖转运体（GLUT1-4 和 SGLT1-3）在小鼠味觉组织中的表达模式。反转录/聚合酶链反应（RT-PCR）分析显示，GLUT1、3 和 4 以及 SGLT1 mRNA 均在环状乳突中表达。免疫组织化学分析表明，SGLT1 表达于一部分上皮细胞：从基底细胞层到刺状细胞层，以及在环状、叶状和菌状乳突的内上皮细胞和外上皮细胞中。GLUT1、GLUT3 和 GLUT4 表达于这些乳突的刺状细胞层和/或基底细胞层。此外，GLUT1 而非 GLUT3 或 GLUT4 表达于这些乳突的内上皮细胞和外上皮细胞中的一部分。双标记实验表明，GLUT1 阳性味觉感受器细胞共表达 Gustducin 和肌醇 1,4,5-三磷酸受体 III。这些结果表明，SGLT1 和 GLUT1 在小鼠味觉感受器中参与葡萄糖感应和/或转运。
