Effros R M, Mason G R, Reid E, Graham L, Silverman P
Microvasc Res. 1985 Jan;29(1):45-55. doi: 10.1016/0026-2862(85)90005-6.
A perfused, in situ rabbit lung preparation was used to study the diffusion of tritiated water and labeled lipophilic solutes from the airways into the pulmonary vasculature. Following instillation into the airways, initial concentrations of labeled ethanol and butanol in the left atrial outflow usually exceeded those of 3H2O when the lungs were perfused at 37 degrees. In contrast, initial concentrations of [14C]acetone equaled 3H2O concentrations, and those of [14C]antipyrine were below 3H2O concentrations. Increasing the rate of perfusion increased concentrations of the labeled butanol and acetone but decreased that of antipyrine relative to 3H2O. This suggests that the tissues separating the gaseous and vascular compartments of the lung are more permeable to 3H2O than to antipyrine but less permeable to 3H2O than to the alcohols and acetone. Cooling slowed permeation of ethanol and antipyrine relative to 3H2O but seemed to slow diffusion of butanol less than that of 3H2O. These differences cannot be related to movement in the aqueous phase and suggest that cooling slows solute diffusion through lipid membranes. This phenomenon appears to be related to the activation energy of each molecule between the aqueous and lipid phases rather than a phase change in the membrane. 3H2O seems to diffuse through aqueous regions of the air-perfusate barrier.
采用灌注的原位兔肺制备方法，研究氚标记水和标记亲脂性溶质从气道向肺血管系统的扩散。将物质滴入气道后，当肺在37℃灌注时，左心房流出液中标记乙醇和丁醇的初始浓度通常超过氚标记水的浓度。相比之下，[14C]丙酮的初始浓度与氚标记水浓度相等，而[14C]安替比林的初始浓度低于氚标记水浓度。增加灌注速率会增加标记丁醇和丙酮的浓度，但相对于氚标记水，安替比林的浓度会降低。这表明分隔肺的气体和血管腔室的组织对氚标记水的通透性高于对安替比林的通透性，但对氚标记水的通透性低于对醇类和丙酮的通透性。冷却相对于氚标记水减缓了乙醇和安替比林的渗透，但似乎对丁醇扩散的减缓程度小于对氚标记水扩散的减缓程度。这些差异与水相中的移动无关，表明冷却减缓了溶质通过脂质膜的扩散。这种现象似乎与每个分子在水相和脂质相之间的活化能有关，而不是与膜中的相变有关。氚标记水似乎通过气-灌注屏障的水相区域扩散。
