Ferrary E, Bernard C, Oudar O, Sterkers O, Amiel C
INSERM U.251, Faculté Xavier Bichat, Université Paris 7, France.
Acta Otolaryngol. 1992;112(2):294-8. doi: 10.1080/00016489.1992.11665421.
Secretion of endolymph is localized in some structures of the inner ear, namely the stria vascularis in the cochlea and the dark cells in the vestibule and in the lower vertebrate inner ear. In isolated semicircular canal it is possible to study separately the endolymphatic composition in the ampulla, which contains the dark cells, and in its non-ampullar part, which is devoid of these cells. Further, in vitro preparation of the semicircular canal provides access to both faces of the epithelium so that different agents can be applied separately to the apical or to the basolateral membranes of the epithelium. In this structure, the following results were obtained: i) in vitro, the semicircular canal secreted a K-rich, positively polarized fluid; ii) this fluid was secreted only in the ampulla of the semicircular canal; iii) the secretion of endolymph was dependent on basolateral Na+, K(+)-ATPase, inhibited by ouabain, and basolateral Na-K-Cl co-transporter, inhibited by bumetanide; iv) approximately 60% of luminal Na absorption occurred across a luminal Na channel inhibited by amiloride; v) the permeability of the paracellular pathway of the semicircular canal epithelium was 7.10(-7) cm/s. These results indicate that endolymph secretion involves basolateral Na+, K(+)-ATPase and Na-K-Cl co-transporter. An Na channel has been shown at the apical membrane.
内淋巴的分泌局限于内耳的某些结构，即耳蜗中的血管纹以及前庭和低等脊椎动物内耳中的暗细胞。在分离的半规管中，可以分别研究壶腹中（含有暗细胞）和非壶腹部分（不含这些细胞）的内淋巴成分。此外，半规管的体外制备可接触到上皮细胞的两面，这样不同的试剂就可以分别应用于上皮细胞的顶端或基底外侧膜。在这个结构中，获得了以下结果：i）在体外，半规管分泌富含钾的、呈正极化的液体；ii）这种液体仅在半规管的壶腹中分泌；iii）内淋巴的分泌依赖于基底外侧的Na + ，K(+)-ATP酶（被哇巴因抑制）和基底外侧的Na-K-Cl共转运体（被布美他尼抑制）；iv）约60%的管腔钠吸收通过被氨氯吡脒抑制的管腔钠通道发生；v）半规管上皮细胞旁细胞途径的通透性为7.10(-7) cm/s。这些结果表明，内淋巴分泌涉及基底外侧的Na + ，K(+)-ATP酶和Na-K-Cl共转运体。已在上皮细胞顶端膜发现一个钠通道。
