Offner F F, Dallos P, Cheatham M A
Hear Res. 1987;29(2-3):117-24. doi: 10.1016/0378-5955(87)90160-2.
The positive endocochlear potential (EP+) and high K+ concentration of the endolymph in the scala media of the mammalian cochlea are unusual. They have long been assumed to be due to a putative K-pump in the luminal membrane of the marginal cells of the stria vascularis, which were believed to have a negative internal potential. We show that the cell potential is more positive than the EP+, and that the ion pump is conventional Na,K-ATPase, probably in the basolateral membrane. The latter was determined from experiments in which the ionic environment of the strial cells was controlled by perfusion of the perilymphatic space of the cochlea, in the absence of vascular circulation. While the usual EP+ was maintained by normal perfusate, replacement of Na+ by choline resulted in a negative EP, showing that Na,K-ATPase is necessary for the production of EP+. Elimination of K+ as well as Na+ from the perfusate did not change the value of the negative EP, showing that no K-ATPase is involved.
哺乳动物耳蜗中阶内淋巴的内淋巴正电位（EP+）和高钾浓度非同寻常。长期以来，人们一直认为这是由于血管纹边缘细胞腔面膜中一种假定的钾泵所致，人们认为这些细胞具有负的内部电位。我们发现，细胞电位比EP+更正，并且离子泵是传统的钠钾ATP酶，可能位于基底外侧膜。后者是通过实验确定的，在实验中，在没有血管循环的情况下，通过灌注耳蜗的外淋巴间隙来控制血管纹细胞的离子环境。当正常灌注液维持通常的EP+时，用胆碱替代钠会导致负的EP，表明钠钾ATP酶是产生EP+所必需的。从灌注液中去除钾以及钠并没有改变负EP的值，表明没有钾ATP酶参与其中。
