Böhmer C, Wehner F
Max-Planck-Institut für molekulare Physiologie, Abteilung Epithelphysiologie, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.
FEBS Lett. 2001 Apr 6;494(1-2):125-8. doi: 10.1016/s0014-5793(01)02303-1.
The epithelial Na(+) channel (ENaC) is composed of the subunits alpha, beta, and gamma [Canessa et al., Nature 367 (1994) 463-467] and typically exhibits a high affinity to amiloride [Canessa et al., Nature 361 (1993) 467-470]. When expressed in Xenopus oocytes, conflicting results were reported concerning the osmo-sensitivity of the channel [Ji et al., Am. J. Physiol. 275 (1998) C1182-C1190; Hawayda and Subramanyam, J. Gen. Physiol. 112 (1998) 97-111; Rossier, J. Gen. Physiol. 112 (1998) 95-96]. Rat hepatocytes were the first system in which amiloride-sensitive sodium currents in response to hypertonic stress were reported [Wehner et al., J. Gen. Physiol. 105 (1995) 507-535; Wehner et al., Physiologist 40 (1997) A-4]. Moreover, all three ENaC subunits are expressed in these cells [Böhmer et al., Cell. Physiol. Biochem. 10 (2000) 187-194]. Here, we injected specific antisense oligonucleotides directed against alpha-rENaC into single rat hepatocytes in confluent primary culture and found an inhibition of hypertonicity-induced Na(+) currents by 70%. This is the first direct evidence for a role of the ENaC in cell volume regulation.
上皮钠离子通道（ENaC）由α、β和γ亚基组成[卡内萨等人，《自然》367（1994年）463 - 467页]，通常对氨氯吡脒表现出高亲和力[卡内萨等人，《自然》361（1993年）467 - 470页]。当在非洲爪蟾卵母细胞中表达时，关于该通道的渗透敏感性报道了相互矛盾的结果[季等人，《美国生理学杂志》275（1998年）C1182 - C1190页；哈韦达和苏布拉马尼亚姆，《普通生理学杂志》112（1998年）97 - 111页；罗西耶，《普通生理学杂志》112（1998年）95 - 96页]。大鼠肝细胞是第一个报道对高渗应激有氨氯吡脒敏感钠电流的系统[韦纳等人，《普通生理学杂志》105（1995年）507 - 535页；韦纳等人，《生理学家》40（1997年）A - 4页]。此外，所有三个ENaC亚基都在这些细胞中表达[伯默等人，《细胞生理学与生物化学》10（2000年）187 - 194页]。在此，我们将针对α - rENaC的特异性反义寡核苷酸注射到汇合原代培养的单个大鼠肝细胞中，发现高渗诱导的钠电流被抑制了70%。这是ENaC在细胞体积调节中起作用的首个直接证据。
