Matsunami Tatsuya, Suzuki Toshihiro, Hisa Yasuo, Takata Kuniaki, Takamatsu Tetsuro, Oyamada Masahito
Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Cell Commun Adhes. 2006 Jan-Apr;13(1-2):93-102. doi: 10.1080/15419060600631805.
To elucidate the role of the spiral limbus in glucose transport in the cochlea, we analyzed the expression and localization of GLUT1, connexin26, connexin30, and occludin in the spiral limbus of the rat cochlea. GLUT1 and occludin were detected in blood vessels. GLUT1, connexin26, connexin30, and occludin were also expressed in fibrocytes just basal to the supralimbal lining cells. Connexin26 and connexin30 were present among not only these GLUT1-positive fibrocytes but also GLUT1-negative fibrocytes. In vivo glucose imaging using 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (6-NBDG, MW 342) together with Evans Blue Albumin (EBA, MW 68,000) showed that 6-NBDG was rapidly distributed throughout the spiral limbus, whereas EBA was localized only in the vessels. Moreover, the gap junctional uncoupler heptanol inhibited the distribution of 6-NBDG. These findings suggest that gap junctions play an important role in glucose transport in the spiral limbus, i.e., that gap junctions mediate glucose transport from GLUT1-positive fibrocytes to GLUT1-negative fibrocytes in the spiral limbus.
为阐明螺旋缘在耳蜗葡萄糖转运中的作用，我们分析了大鼠耳蜗螺旋缘中葡萄糖转运蛋白1（GLUT1）、连接蛋白26、连接蛋白30和闭合蛋白的表达及定位。在血管中检测到了GLUT1和闭合蛋白。在缘上衬细胞下方的纤维细胞中也表达了GLUT1、连接蛋白26、连接蛋白30和闭合蛋白。连接蛋白26和连接蛋白30不仅存在于这些GLUT1阳性纤维细胞中，也存在于GLUT1阴性纤维细胞中。使用6-[N-(7-硝基苯并-2-恶唑-1,3-二氮杂-4-基)氨基]-6-脱氧葡萄糖（6-NBDG，分子量342）和伊文思蓝白蛋白（EBA，分子量68,000）进行的体内葡萄糖成像显示，6-NBDG迅速分布于整个螺旋缘，而EBA仅定位于血管中。此外，缝隙连接解偶联剂庚醇抑制了6-NBDG的分布。这些发现表明，缝隙连接在螺旋缘的葡萄糖转运中起重要作用，即缝隙连接介导葡萄糖从螺旋缘中GLUT1阳性纤维细胞向GLUT1阴性纤维细胞的转运。
