Guggino W B, Windhager E E, Boulpaep E L, Giebisch G
J Membr Biol. 1982;67(2):143-54. doi: 10.1007/BF01868657.
Individual resistances of the apical cell membrane Ra, the basolateral cell membrane, Rbl, and the paracellular shunt, Rs, were determined in the Necturus proximal tubule using a set of three electrical parameters. Four electrical parameters were measured: the transepithelial resistance, (Rte), the apical and basolateral cell membrane resistance in parallel, (Rz free-flow tubules), the basolateral cell membrane resistance in oil-filled tubules, (Rz oil-filled), and the ratio of apical and basolateral cell membrane resistance (Ra/Rbl). Rte was determined from an analysis of the spatial decay of luminal voltage following luminal current injection. Rz free-flow and Rz oil-filled were measured by the analysis of the spatial decay of intracellular voltage deflections following cellular current injection in free flow and oil-filled tubules, respectively. Ra/Rbl was estimated from the ratio of voltage deflections across the apical and basolateral cell membranes following transepithelial current injection. In addition, the magnitude of cellular and luminal cable interactions was evaluated, by comparing the spatial decay of voltage deflections in the cell and in the lumen following intracellular current injection. The combined cell membrane resistance (Ra + Rbl) is between one to two orders of magnitude greater than the paracellular resistance. This result supports the view that the Necturus proximal tubule is a leaky epithelium.
利用一组三个电学参数，在美西螈近端小管中测定了顶端细胞膜电阻（Ra）、基底外侧细胞膜电阻（Rbl）和细胞旁分流电阻（Rs）。测量了四个电学参数：跨上皮电阻（Rte）、顶端和基底外侧细胞膜并联电阻（Rz，自由流动小管）、充满油的小管中的基底外侧细胞膜电阻（Rz，充满油）以及顶端和基底外侧细胞膜电阻之比（Ra/Rbl）。Rte通过分析注入管腔电流后管腔电压的空间衰减来确定。Rz自由流动和Rz充满油分别通过分析在自由流动和充满油的小管中注入细胞电流后细胞内电压偏转的空间衰减来测量。Ra/Rbl通过跨上皮电流注入后顶端和基底外侧细胞膜上电压偏转之比来估计。此外，通过比较注入细胞电流后细胞和管腔中电压偏转的空间衰减，评估了细胞和管腔电缆相互作用的大小。细胞膜总电阻（Ra + Rbl）比细胞旁电阻大1至2个数量级。这一结果支持了美西螈近端小管是一种漏性上皮的观点。
