Whitlon D S
Waisman Center, University of Wisconsin, Madison 53705.
J Neurocytol. 1993 Dec;22(12):1030-8. doi: 10.1007/BF01235747.
The reticular lamina of the mammalian cochlea is formed by the tightly joined apical surfaces of hair cells and supporting cells. This lamina creates a barrier separating endolymph and perilymph, two fluids of different composition. The preservation of this fluid barrier is a requirement of cochlear function. This study aimed to determine whether the calcium-dependent, cell adhesion molecule, E-cadherin was appropriately placed both temporally and spatially to contribute to the formation and maintenance of the reticular lamina. Cochleas aged E15 to P31 were stained immunocytochemically for E-cadherin. In the P31 organ of Corti, E-cadherin is localized to the apical intercellular junctions of supporting cells, but is absent from supporting cell-hair cell borders. During development, E-cadherin is present only on the apices and lateral edges of those cells which will eventually lie adjacent to fluid spaces--pillar, outer hair and Deiters cells. The molecule disappears from the lateral cell membranes at about the time in development that fluid spaces form. These data suggest that E-cadherin plays a role in maintaining the reticular lamina by mediating inter-supporting cell adhesion and raise the possibility that fluid space opening in the organ of Corti is facilitated by the down-regulation or redistribution of E-cadherin.
哺乳动物耳蜗的网状板由毛细胞和支持细胞紧密相连的顶端表面形成。该板形成了一个将内淋巴和外淋巴（两种成分不同的液体）分隔开的屏障。维持这种液体屏障是耳蜗功能的必要条件。本研究旨在确定钙依赖性细胞粘附分子E-钙粘蛋白在时间和空间上的定位是否适当，以有助于网状板的形成和维持。对E15至P31年龄段的耳蜗进行E-钙粘蛋白免疫细胞化学染色。在P31的柯蒂氏器中，E-钙粘蛋白定位于支持细胞的顶端细胞间连接，但在支持细胞与毛细胞的边界处不存在。在发育过程中，E-钙粘蛋白仅存在于那些最终与液体空间相邻的细胞（柱细胞、外毛细胞和Dieters细胞）的顶端和侧边缘。在发育过程中，当液体空间形成时，该分子从侧细胞膜消失。这些数据表明，E-钙粘蛋白通过介导支持细胞间的粘附在维持网状板中发挥作用，并增加了柯蒂氏器中液体空间开放是由E-钙粘蛋白的下调或重新分布所促进的可能性。
