Stop-flow studies of solute uptake in rat lungs. J Appl Physiol (1985) 1998 Sep;85(3):986-92
Date
09/08/1998Pubmed ID
9729574DOI
10.1152/jappl.1998.85.3.986Scopus ID
2-s2.0-0031666140 (requires institutional sign-in at Scopus site) 5 CitationsAbstract
Stop-flow studies were used to characterize solute uptake in isolated rat lungs. These lungs were perfused at 8 or 34 ml/min for 10-28 s with solutions containing 125I-albumin and two or more of the following diffusible indicators: [3H]mannitol, [14C]urea, 3HOH, 201Tl+, or 86Rb+. After this loading period, flow was stopped for 10-300 s and then resumed to flush out the perfusate that remained in the pulmonary vasculature during the stop interval. Concentrations of 201Tl+ and 86Rb+ in the venous outflow decreased after the stop interval, indicating uptake from exchange vessels during the stop interval. The amount of these K+ analogs lost from the circulation during the stop interval was greater when the intervals were longer. However, losses of 201T1+ at 90 s approached those at 300 s. Because extraction continued after the vasculature had been flushed, vascular levels had presumably fallen to negligible levels during the stop interval. By 90 s of stop flow the vascular volume that was cleared of 201T1+ averaged 0.657 +/- 0.034 (SE) ml in the experiments perfused at 8 ml/min and 0.629 +/- 0.108 ml in those perfused at 34 ml/min. Increases in perfusate K+ decreased the cleared volumes of 201T1+ and 86Rb+. Uptake of [3H]mannitol, [14C]urea, and 3HOH during the stop intervals was observed only when the lungs were loaded at high flow for short intervals. Decreases in 201T1+ and 86Rb+ concentrations in the pulmonary outflow can be used to identify the fraction of the collected samples that were within exchange vessels of the lung during the stop interval and may help determine the distribution of solute and water exchange along the pulmonary vasculature.
Author List
Effros RM, Schapira R, Presberg K, Ozker K, Jacobs ERAuthors
Elizabeth R. Jacobs MD Emeritus Professor in the Medicine department at Medical College of WisconsinKenneth W. Presberg MD Professor in the Medicine department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsDeuterium Oxide
Extravascular Lung Water
Lung
Mannitol
Models, Biological
Organ Size
Pulmonary Circulation
Pulmonary Diffusing Capacity
Radiopharmaceuticals
Rats
Rubidium Radioisotopes
Serum Albumin, Radio-Iodinated
Solutions
Thallium Radioisotopes
Urea
