Greenwell J R
Pflugers Arch. 1977 Jan 17;367(3):265-70. doi: 10.1007/BF00581364.
In the anaethetised cat the electrical potential difference between the lumen of the main collecting duct of the pancreas and blood in the jugular vein was measured. The duct was perfused with isotonic solutions of monovalent ions and the recorded potential corrected for the liquid junction potentials. The data were fitted to the Shinagawa extension of the Goldman constant field equation and the relative permeabilities of the duct epithelium to the ions were determined. The duct showed negligible selectivity between the monovalent cations Li:Na:K:Rb:Cs = 1.08:1.10:1.09:1.12 in contrast to the definite selectivity sequence for the anions F:Br:Cl:I:HCO3 = 0.44:1.38:1.08:2.05:0.60. This halide selectivity sequence is the Eisenman sequence I and is indicative of the selectivity being due to weak positive charges on membrane bound sites surrounding a highly hydrated channel. It is argued that these highly hydrated channels may be identified with the "tight junctions" between cells and the selectivity properties of the pancreatic duct are determined by flow of ions through these areas rather than flow through the epithelial cells.
在麻醉的猫身上，测量了胰腺主集合管管腔与颈静脉血液之间的电位差。用单价离子的等渗溶液灌注导管，并对记录的电位进行液体接界电位校正。将数据拟合到高盛恒定场方程的品川扩展式，确定导管上皮对离子的相对渗透率。与阴离子F:Br:Cl:I:HCO3 = 0.44:1.38:1.08:2.05:0.60的明确选择性顺序相反，导管对单价阳离子Li:Na:K:Rb:Cs = 1.08:1.10:1.09:1.12的选择性可忽略不计。这种卤化物选择性顺序是艾森曼序列I，表明这种选择性是由于高度水合通道周围膜结合位点上的弱正电荷所致。有人认为，这些高度水合的通道可能与细胞间的“紧密连接”有关，胰腺导管的选择性特性是由离子通过这些区域的流动而不是通过上皮细胞的流动决定的。
