Levitt D G, Bond J H, Levitt M D
Am J Physiol. 1980 Jul;239(1):G23-9. doi: 10.1152/ajpgi.1980.239.1.G23.
The purpose of this study was to determine if the observed rate of passive absorption of inert gases from the canine small bowel could be predicted by the use of an anatomical model of the mucosa and measurements of villus blood flow and the diffusive barrier to absorption. Villus blood flow was measured with microspheres and the diffusive barrier separating bulk luminal contents and blood was estimated from CO absorption. The model predicts initial uptake of the inert gases (H2, He, CH4, and 133Xe) in blood at the villus tip, subsequent countercurrent exchange in the villus, and longitudinal diffusion of the gases down the villus to a subvillus blood flow. Observed absorption rates for each of these four gases were reasonably accurately predicted by the model at both basal villus blood flow and at low villus blood flow induced by hypotension. We suggest that this model can be used to predict passive absorption kinetics over a range of villus blood flows and to predict the influence of a variety of parameters on the rate of passive absorption of diffusible substances.
本研究的目的是确定能否通过使用黏膜解剖模型、测量绒毛血流以及吸收的扩散屏障，来预测犬小肠中惰性气体的被动吸收速率。用微球测量绒毛血流，并根据一氧化碳吸收估算分隔大量管腔内容物和血液的扩散屏障。该模型预测了惰性气体（氢气、氦气、甲烷和氙-133）在绒毛尖端血液中的初始摄取、随后在绒毛中的逆流交换以及气体沿绒毛向下扩散至绒毛下血流的情况。在基础绒毛血流和低血压诱导的低绒毛血流条件下，该模型对这四种气体中每种气体的观察吸收速率都进行了合理准确的预测。我们认为，该模型可用于预测一系列绒毛血流情况下的被动吸收动力学，并预测各种参数对可扩散物质被动吸收速率的影响。
