Yeh T, Van den Abbeele T, Marianovski R, Herman P, Tran Ba Huy P
Laboratoire d'ORL Expérimentale, Université Paris, France.
Hear Res. 1995 Oct;90(1-2):79-88. doi: 10.1016/0378-5955(95)00149-3.
Ionic channels located on the luminal side of strial marginal cells (MCs) of gerbil in culture were investigated using the patch-clamp technique. Two types of channels were identified. The most frequently recorded single-channel activity corresponded to a non-selective cation (NSC) channel with a conductance of 23.7 +/- 0.2 pS (n = 18) in symmetrical NaCl conditions. The channel was activated by internal Ca2+ and inhibited by internal adenine nucleotides and flufenamic acid. Spontaneous activity of NSC channels was found in 16% of the cell-attached patches and with a very high density (9 +/- 2 levels/patch, n = 28) in 100% of the excised patches. An outwardly rectifying chloride (ORC) channel was also identified in 14% of the patches but only after excision. The channel exhibited at 0 mV a unit conductance of 26.8 +/- 1.3 pS (n = 8) and a strong outward rectification in symmetrical NaCl conditions, and the open probability increased with depolarization. The luminal NSC channel and the ORC channel evidenced in this study might participate in the production of endolymph. Although extrapolation of the presents results to the in vivo situation should be made with caution, this study suggests that culture of strial MCs may be a suitable model for investigation of endolymph physiology.
运用膜片钳技术对体外培养的沙鼠血管纹边缘细胞（MCs）管腔侧的离子通道进行了研究。鉴定出两种类型的通道。在对称的NaCl条件下，最常记录到的单通道活性对应于一种非选择性阳离子（NSC）通道，其电导为23.7±0.2 pS（n = 18）。该通道被细胞内Ca2+激活，被细胞内腺嘌呤核苷酸和氟芬那酸抑制。在16%的细胞贴附膜片中发现了NSC通道的自发活性，在100%的切除膜片中其密度非常高（9±2个水平/膜片，n = 28）。在14%的膜片中也鉴定出了外向整流性氯离子（ORC）通道，但仅在切除后。在对称的NaCl条件下，该通道在0 mV时的单位电导为26.8±1.3 pS（n = 8），并表现出强烈的外向整流性，且开放概率随去极化增加。本研究中证实的管腔NSC通道和ORC通道可能参与内淋巴的产生。尽管将目前的结果外推至体内情况时应谨慎，但本研究表明，血管纹MCs的培养可能是研究内淋巴生理学的合适模型。
