Edelman A, Anagnostopoulos T
Am J Physiol. 1978 Aug;235(2):F89-95. doi: 10.1152/ajprenal.1978.235.2.F89.
In the perfused Necturus kidney, the ratio of transepithelial sodium-to-chloride permeabilities (PNa/PCl) was estimated from dilution potentials at 1:7. The ratio of transepithelial permeabilities PHCO3/cl was estimated from bi-ionic potentials at 1:4 and that of Plact/PCl at 1:12. The permeability sequence, therefore, is PCl greater than PHCO3 greater than than PNa or PnaCl greater than PNaHCO3. The latter is similar to the situation in the rat. However, because of the low Na permeability, passive NaCl absorption by solvent drag is probably less important in Necturus than in the rat. The measurement of transepithelial input conductance during replacement of extracellular chloride by either bicarbonate or lactate shows that the former reduces the transmural conductance to 31% of control values as compared with 40% for the latter. Such discrepancies between permeability and conductance sequences are consistent either with an interference of the test anion with chloride permeation or with the presence of positive fixed changes within the shunt pathway.
在灌注的美西螈肾脏中，跨上皮钠与氯通透性之比（PNa/PCl）是根据1:7时的稀释电位估算的。跨上皮通透性PHCO3/cl之比是根据1:4时的双离子电位估算的，而Plact/PCl之比是根据1:12时的双离子电位估算的。因此，通透性顺序为PCl大于PHCO3大于PNa或PnaCl大于PNaHCO3。后者与大鼠的情况相似。然而，由于钠通透性较低，在美西螈中，通过溶剂拖曳进行的被动氯化钠吸收可能比在大鼠中不太重要。在用碳酸氢盐或乳酸盐替代细胞外氯的过程中对跨上皮输入电导的测量表明，与后者的40%相比，前者可将跨膜电导降低至对照值的31%。通透性和电导顺序之间的这种差异，要么与测试阴离子对氯通透的干扰一致，要么与分流途径内存在正的固定电荷一致。
