Jin Zhen-Hua, Kikuchi Toshihiko, Tanaka Kohichi, Kobayashi Toshimitsu
Department of Otorhinolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan.
Tohoku J Exp Med. 2003 Jul;200(3):137-44. doi: 10.1620/tjem.200.137.
The immunohistochemical localization of glutamate transporter GLAST in the developing mouse cochlea was studied at different ages between 0 and 30 days after birth (DAB). In the adult mouse cochlea, intense GLAST-like immunoreactivity was found in the supporting cells adjacent to the inner hair cells of the organ of Corti, the type II and suprastrial fibrocytes of the cochlear lateral wall, the fibrocytes of the spiral limbus and the satellite cells surrounding the spiral ganglion cells. At 0 DAB, weak GLAST-like immunoreactivity was found in the supporting cells around the immature inner hair cells. Immature fibrocytes in the cochlea were also positively immunostained. At 3 DAB, weak immunostaining of GLAST appeared in the immature satellite cells in the spiral ganglion. The GLAST-like immunoreactivity in the supporting cells around the inner hair cells, in the fiborocytes in the spiral ligament and the spiral limbus and in the satellite cells in the spiral ganglion increased progressively during the second postnatal week, and reached the adult level at 15 DAB. This time course correlates with the electrophysiological onset and maturation of the mouse auditory function, which is mediated by glutamatergic neurotransmission. These results suggest that the expression of GLAST may be needed for the efficient removal and metabolism of the released glutamate in the cochlea and may play important roles in the onset and maturation of the auditory system.
研究了出生后0至30天（DAB）不同年龄段发育中小鼠耳蜗中谷氨酸转运体GLAST的免疫组织化学定位。在成年小鼠耳蜗中，在柯蒂氏器内毛细胞相邻的支持细胞、耳蜗外侧壁的II型和纹上纤维细胞、螺旋缘的纤维细胞以及围绕螺旋神经节细胞的卫星细胞中发现了强烈的GLAST样免疫反应性。在出生后0天，在未成熟内毛细胞周围的支持细胞中发现了弱的GLAST样免疫反应性。耳蜗中的未成熟纤维细胞也呈阳性免疫染色。在出生后3天，螺旋神经节中未成熟的卫星细胞出现了弱的GLAST免疫染色。内毛细胞周围支持细胞、螺旋韧带和螺旋缘纤维细胞以及螺旋神经节卫星细胞中的GLAST样免疫反应性在出生后第二周逐渐增加，并在出生后15天达到成年水平。这个时间进程与由谷氨酸能神经传递介导的小鼠听觉功能的电生理起始和成熟相关。这些结果表明，GLAST的表达可能是耳蜗中释放的谷氨酸有效清除和代谢所必需的，并且可能在听觉系统的起始和成熟中发挥重要作用。
