Garrick R A, Patel B C, Chinard F P
Am J Physiol. 1982 Jan;242(1):C74-80. doi: 10.1152/ajpcell.1982.242.1.C74.
Studies of permeability coefficients of biological barriers to members of homologous series can provide information of value in assessing barrier characteristics. To this end, we have determined the linear diffusion coefficients of tracer water (THO), [14C]antipyrine, [14C]acetamide, and n-[14C]alcohols over the range of 10-37 degrees C for dog erythrocytes (D), hemoglobin (D2), and plasma (D1). Permeability coefficients (Po) calculated with the series-parallel pathway model are higher than Po for water at 37 degrees C for all the alcohols except hexanol. Po for acetamide and antipyrine are considerably lower than Po for water at 37 degrees C. The apparent activation energies (Ea) for Po of acetamide and the C1, C2, and C3 alcohols are 10.5 kcal.mol-1, similar to the values obtained with epithelial or lipid bilayers. The Ea's for the larger alcohols are 2-4 kcal.mol-1. The Ea for Po of water is 5.3 kcal.mol-1, similar to the Ea for self-diffusion of water; Ea for antipyrine is 25 kcal.mol-1. We interpret these results to indicate heterogeneity of membrane-solute interactions or of membrane pathways in the erythrocyte for lipid-soluble molecules that is related to both lipid solubility and solute size, as we have suggested in an earlier study and confirmed experimentally in the present one.
对同源系列成员通过生物屏障的渗透系数进行研究，可为评估屏障特性提供有价值的信息。为此，我们测定了示踪水（THO）、[14C]安替比林、[14C]乙酰胺和正-[14C]醇在10 - 37摄氏度范围内对犬红细胞（D）、血红蛋白（D2）和血浆（D1）的线性扩散系数。用串联 - 并联途径模型计算的渗透系数（Po），对于除己醇以外的所有醇类，在37摄氏度时均高于水的Po。乙酰胺和安替比林的Po在37摄氏度时显著低于水的Po。乙酰胺以及C1、C2和C3醇的Po的表观活化能（Ea）为10.5千卡·摩尔-1，与上皮或脂质双层获得的值相似。较大醇类的Ea为2 - 4千卡·摩尔-1。水的Po的Ea为5.3千卡·摩尔-1，与水的自扩散Ea相似；安替比林的Ea为25千卡·摩尔-1。我们对这些结果的解释是，红细胞中膜 - 溶质相互作用或膜途径对于脂溶性分子存在异质性，这与脂溶性和溶质大小都有关，正如我们在早期研究中所提出并在本研究中通过实验证实的那样。
