Kuhn B, Vater M
Institut für Zoologie, Universität Regensburg, FRG.
Hear Res. 1995 Apr;84(1-2):139-56. doi: 10.1016/0378-5955(95)00021-u.
The composition of cytoskeletal elements in hair cells and non-sensory cells was studied in paraformaldehyde fixed cochleae of the horseshoe bat and the gerbil using phallotoxins and antibodies directed against actin, alpha-tubulin and fodrin. In both species, cryostat sections of the organ of Corti were studied using confocal fluorescence microscopy; in the bat, ultrathin sections were investigated using actin-immunoelectron and classical electron microscopy. F-actin was found in stereocilia and cuticular plates of inner and outer hair cells (IHCs and OHCs) of both species. In fixed material from both species, no F-actin staining was detected in the cytoplasm or along the lateral cell membrane of OHCs, whereas in freshly isolated OHCs of the gerbil, a faint F-actin staining was detected along the lateral wall. In the bat, the patterns of F-actin staining were confirmed with actin-immunoelectron microscopy. The alpha-tubulin antibody strongly labeled IHCs of both species. They contained a complex network of microtubules especially in the neck portion. In the bat, OHCs showed no distinct alpha-tubulin reactivity, as would be expected given the scarcity of microtubules observed at the ultrastructural level. In the gerbil, alpha-tubulin reactivity was found throughout the OHC body with highest intensity in the cell apex. In Deiters cells, pillar cells and Boettcher cells of both species, F-actin and microtubules were colocalized at contact zones with the basilar membrane. In Deiters cups, F-actin staining was most pronounced in the basal turn of the bat cochlea. In the gerbil, a distinct baso-apical gradient was found in immunostaining properties and morphology of the Deiters cells. Intense fodrin reactivity was found in the cuticular plates and along the lateral cell membrane of both types of hair cells of the bat. Cytoplasmic fodrin staining was localized within the IHCs of the bat. In the gerbil, intense fodrin staining was only found in cuticular plates of hair cells and staining of the lateral cell membrane of hair cells was faint. A faint fodrin staining was also seen in Deiters cells of both species. The basic arrangement of the cytoskeletal elements in the batś organ of Corti is similar to that of other mammals, however, certain features suggest the presence of subtle differences in micromechanical properties: there is an increased concentration of microtubules in the neck portion of IHCs, an increase in the amount of F-actin within the Deiters cups and a reduced amount of microtubules in the OHCs.
利用鬼笔环肽和针对肌动蛋白、α-微管蛋白和血影蛋白的抗体，对马蹄蝠和沙鼠经多聚甲醛固定的耳蜗中的毛细胞和非感觉细胞的细胞骨架成分进行了研究。在这两个物种中，使用共聚焦荧光显微镜对柯蒂氏器的冰冻切片进行了研究；在蝙蝠中，使用肌动蛋白免疫电子显微镜和经典电子显微镜对超薄切片进行了研究。在两个物种的内毛细胞（IHCs）和外毛细胞（OHCs）的静纤毛和表皮板中均发现了F-肌动蛋白。在两个物种的固定材料中，未在OHCs的细胞质或沿外侧细胞膜检测到F-肌动蛋白染色，而在新鲜分离的沙鼠OHCs中，沿侧壁检测到微弱的F-肌动蛋白染色。在蝙蝠中，通过肌动蛋白免疫电子显微镜证实了F-肌动蛋白染色模式。α-微管蛋白抗体强烈标记了两个物种的IHCs。它们含有复杂的微管网络，尤其是在颈部。在蝙蝠中，OHCs未显示出明显的α-微管蛋白反应性，这与在超微结构水平观察到的微管稀少情况相符。在沙鼠中，在整个OHC体中均发现了α-微管蛋白反应性，在细胞顶端强度最高。在两个物种的Dieters细胞、柱细胞和Boettcher细胞中，F-肌动蛋白和微管在与基底膜的接触区域共定位。在Dieters杯状结构中，F-肌动蛋白染色在蝙蝠耳蜗的基部转弯处最为明显。在沙鼠中，在Dieters细胞的免疫染色特性和形态中发现了明显的基底-顶端梯度。在蝙蝠的两种毛细胞的表皮板和沿外侧细胞膜发现了强烈的血影蛋白反应性。细胞质血影蛋白染色定位于蝙蝠的IHCs内。在沙鼠中，仅在毛细胞的表皮板中发现了强烈的血影蛋白染色，而毛细胞外侧细胞膜的染色较弱。在两个物种的Dieters细胞中也可见微弱的血影蛋白染色。蝙蝠柯蒂氏器中细胞骨架成分的基本排列与其他哺乳动物相似，然而，某些特征表明在微机械性能方面存在细微差异：IHCs颈部的微管浓度增加，Dieters杯状结构内的F-肌动蛋白量增加，OHCs中的微管量减少。
