Objective To investigate the localization of Ca2+-ATPase (Ca2+ pump) in the cochlear and its change after endolymphatic hydrops, and to study the relationship between compound action potential (CAP) threshold and the Ca2+-ATPase activety.Methods The left endolymphatic sac was ablated to induce endolymphatic hydrops in fourteen healthy guinea pigs with normal action potential thresholds measured after a sliver ball electrode placed on the round window. Ca2+-ATPase activity was studied cytochemically using a lead citrate reaction in control and hydropic ears. The reaction product was lead phosphate particles as an expression of Ca2+-ATPase activity, observed with an eletron microscope. Results Ca2+-ATPase activity is mainly found on the endolymphatic surface of Reissner's membrane, the stereocilia and cuticular plate of inner and outer hair cells, and along the infolded plasma membrane of strial marginal cells. CAP thresholds of filtered click are increased and Ca2+-ATPase activity significantly decreased after endolymphatic hydrops in the mentioned locations.Conclusions CAP thresholds are increased and Ca2+-ATPase activity are significantly decreased in the cochlea after endolymphatic hydrops. These results suggest that there is a negative correlation between them.%目的了解Ca2+-ATP酶(即钙泵)在耳蜗活动位点及内淋巴积水后的变化,测复合动作电位(CAP)与Ca2+-ATP酶的活性关系. 方法健康豚鼠14只,左耳圆窗装电极后测CAP阈值正常者阻塞内淋巴囊,使诱发内淋巴积水.对照耳和积水耳进入细胞组化试验.对Ca2+-ATP酶活性用枸橼酸铅反应进行细胞化学研究,在电镜下以磷酸颗粒表示Ca2+-ATP酶活性.结果 Ca2+-ATP酶活跃在蜗管前庭膜内淋巴侧、内外毛细胞之皮板及静纤毛、血管纹边缘细胞内浆膜等处;内淋巴积水后,滤波短声复合动作电位阈值增高,前庭膜、内外毛细胞等处之Ca2+-ATP颗粒明显减少. 结论内淋巴积水后CAP阈值提高,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.
展开▼
