豚鼠膜迷路积水模型耳蜗Ca^(2+)-ATP酶的变化

Changes of Ca 2+ ATPase in the cochlea of guinea pig during labyrinthine hydrop

目的了解Ｃａ２＋ＡＴＰ酶在耳蜗活动位点及膜迷路积水后耳蜗Ｃａ２＋ＡＴＰ酶的变化。方法选成年健康、Ｐｒｅｙｅｒ反射正常豚鼠１４只，左耳装圆窗电极后阻塞内淋巴，经声反应阈（ＣＡＰ阈值）证明膜迷路积水形成；右侧为对照耳。用枸橼酸铅细胞组化法测定Ｃａ２＋ＡＴＰ酶，在透射电镜下Ｃａ２＋ＡＴＰ酶以磷酸铅黑色颗粒显示。结果对照耳Ｃａ２＋ＡＴＰ酶活动部位在蜗管前庭膜内淋巴侧、内外毛细胞皮板及静纤毛、血管纹中间细胞指突膜等处；实验性膜迷路积水后，声反应阈提高，前庭膜、内外毛细胞等处之Ｃａ２＋ＡＴＰ酶颗粒明显减少。结论膜迷路积水后声反应阈提高，前庭膜、内外毛细胞等处Ｃａ２＋ＡＴＰ酶活性明显下降，两者呈负相关。

Objective To investigate the localization of Ca 2+ ATPase (Ca 2+ pump) in the cochlea and its change in labyrinthine hydrops.Methods The left endolymphatic sac was ablated to induce endolymphatic hydrops in fourteen healthy guinea pigs after the sliver ball electrode was placed on the round window. The Ca 2+ ATPase was studied by the lead citrate reaction in the control and hydropic ears. The reaction product was lead phosphate particles as an expression of Ca 2+ ATPase activity under the electron microscope.Results The Ca 2+ ATPase activity was found mainly on the endolymphatic surface of the Reissner's membrane, the stereocilia and cuticular plate of inner and outer hair cells, as well as along the infolding plasma membrane of the strial intermediate cells.The Ca 2+ ATPase activity was significantly decreased during endolymphatic hydrops in the above mentioned locations. Conclusion The response thresholds of filtered click were increased and the Ca 2+ ATPase significantly decreased in the cochlea during labyrinthine hydrops. These results suggest that correlation exists between the CAP threshold and the activity of Ca 2+ ATPase in the model of labyrinthine hydrops.