Kroll B, Bautsch W, Bremer S, Wilke M, Tümmler B, Frömter E
Zentrum der Physiologie, Klinikum der J.W.-Goethe-Universität, Frankfurt, Federal Republic of Germany.
Am J Physiol. 1989 Oct;257(4 Pt 1):L284-8. doi: 10.1152/ajplung.1989.257.4.L284.
Poly(A)+RNA was prepared from primary cultures of human nasal polyp epithelia and from native bovine tracheal epithelia. Six to fifty nanograms mRNA were injected into prophase-arrested immature Xenopus laevis oocytes. One to four days later the oocytes were probed with electrophysiological techniques for induction of novel ion conductances. Oocytes injected with mRNA had lower membrane potentials (Vm) and resistances (Rm) than controls. By use of step changes in extracellular Na+ concentration and applying amiloride, a Na+ conductance could be identified in mRNA-injected oocytes, which was inhibited by submicromolar concentrations of amiloride with the same kinetics (Ki = 1.3 X 10(-7) mol/l) as in the original tissue. After complete inhibition of this conductance by 10(-5) mol/l amiloride, Vm and Rm approached the respective values of controls. The data indicate that oocytes express functional epithelial Na+ channels but apparently no other epithelial ion conductances from injected mRNA of respiratory epithelium.
从人鼻息肉上皮原代培养物和天然牛气管上皮中制备多聚腺苷酸加尾RNA（Poly(A)+RNA）。将6至50纳克的信使核糖核酸（mRNA）注射到处于减数分裂前期阻滞的未成熟非洲爪蟾卵母细胞中。1至4天后，用电生理技术检测卵母细胞，以诱导新的离子电导。注射了mRNA的卵母细胞比对照具有更低的膜电位（Vm）和电阻（Rm）。通过改变细胞外钠离子（Na+）浓度并应用氨氯吡咪，在注射了mRNA的卵母细胞中可鉴定出一种钠电导，其被亚微摩尔浓度的氨氯吡咪抑制，动力学与原始组织相同（抑制常数Ki = 1.3×10⁻⁷摩尔/升）。在用10⁻⁵摩尔/升氨氯吡咪完全抑制这种电导后，Vm和Rm接近对照的相应值。数据表明，卵母细胞表达功能性上皮钠通道，但从注射的呼吸道上皮mRNA中显然未表达其他上皮离子电导。
