Resistance of descending vasa recta to the transport of water
- PMID: 1699435
- DOI: 10.1152/ajprenal.1990.259.4.F688
Resistance of descending vasa recta to the transport of water
Abstract
The effect of varying intracapillary oncotic pressure on the rate of transcapillary volume flux in microperfused descending vasa recta (DVR) was studied during furosemide diuresis in the Munich-Wistar rat. At the papillary base, plasma protein concentration and hydraulic pressure were 5.7 +/- 0.1 g/dl and 11.7 +/- 0.7 mmHg in nonperfused DVR, respectively, and 5.6 +/- 0.1 g/dl and 9.4 +/- 0.4 mmHg in nonperfused ascending vasa recta (AVR), respectively. These results demonstrate that the papillary microcirculation does not remove water from the interstitium during furosemide diuresis and defines Starling forces in the pericapillary interstitium. Osmolality and urea concentration were 380 +/- 11 mosmol/kgH2O and 56 +/- 5 mM in DVR plasma at the papillary base, respectively, and 386 +/- 10 mosmol/kgH2O and 62 +/- 5 mM in DVR plasma at the tip, respectively. These results demonstrate abolition of corticomedullary small solute gradients. DVR were perfused at a rate of 10 nl/min with a buffer solution containing small-solute concentrations that matched those of plasma in nonperfused DVR. The buffer solution also contained 2 x 10(6) mol wt fluorescein isothiocyanate-labeled dextran (FITC-Dx, 5 mg/ml) and either 0.1 or 5.0 g/dl albumin. Microperfused DVR were punctured a second time downstream of the perfusion site for sample collection or servo-nulling pressure measurement. The rate of transmembrane volume flux, determined from the change in FITC-Dx concentration from perfusate to collectate, was 0.99 +/- 0.29 nl.min-1.mm-1 when perfusate contained 0.1 g/dl albumin and 0.00 +/- 0.23 nl.min-1.mm-1 with 5.0 g/dl albumin (P less than 0.01). Intracapillary hydraulic pressures were 21.7 and 20.4 mmHg during microperfusion of DVR with 0.1 and 5.0 g/dl albumin, respectively. These results demonstrate that transcapillary driving forces of 20 mmHg (5 g/dl albumin) influence transcapillary water movement across the DVR endothelium. For an average capillary diameter of 12.9 microns, DVR hydraulic conductivity is calculated to be greater than 1.4 x 10(-6) cm.s-1.mmHg-1.
Similar articles
-
Molecular sieving of albumin by the ascending vasa recta wall.J Clin Invest. 1992 Jul;90(1):30-4. doi: 10.1172/JCI115852. J Clin Invest. 1992. PMID: 1634618 Free PMC article.
-
Effect of sodium chloride gradients on water flux in rat descending vasa recta.J Clin Invest. 1991 Jan;87(1):12-9. doi: 10.1172/JCI114960. J Clin Invest. 1991. PMID: 1985089 Free PMC article.
-
Resistance of ascending vasa recta to transport of water.Am J Physiol. 1991 Mar;260(3 Pt 2):F303-10. doi: 10.1152/ajprenal.1991.260.3.F303. Am J Physiol. 1991. PMID: 1705755
-
The renal medullary microcirculation.Front Biosci. 2000 Jun 1;5:E36-52. doi: 10.2741/edwards. Front Biosci. 2000. PMID: 10833463 Review.
-
Renal medullary microcirculation: architecture and exchange.Microcirculation. 1995 Aug;2(2):125-39. doi: 10.3109/10739689509146761. Microcirculation. 1995. PMID: 7497165 Review.
Cited by
-
A mathematical model of the rat kidney: K+-induced natriuresis.Am J Physiol Renal Physiol. 2017 Jun 1;312(6):F925-F950. doi: 10.1152/ajprenal.00536.2016. Epub 2017 Feb 8. Am J Physiol Renal Physiol. 2017. PMID: 28179254 Free PMC article.
-
Transport of sodium and urea in outer medullary descending vasa recta.J Clin Invest. 1994 Jan;93(1):212-22. doi: 10.1172/JCI116948. J Clin Invest. 1994. PMID: 8282790 Free PMC article.
-
Molecular sieving of albumin by the ascending vasa recta wall.J Clin Invest. 1992 Jul;90(1):30-4. doi: 10.1172/JCI115852. J Clin Invest. 1992. PMID: 1634618 Free PMC article.
-
High microvascular endothelial water permeability in mouse lung measured by a pleural surface fluorescence method.Biophys J. 1998 Apr;74(4):2121-8. doi: 10.1016/S0006-3495(98)77919-6. Biophys J. 1998. PMID: 9545071 Free PMC article.
-
Effect of sodium chloride gradients on water flux in rat descending vasa recta.J Clin Invest. 1991 Jan;87(1):12-9. doi: 10.1172/JCI114960. J Clin Invest. 1991. PMID: 1985089 Free PMC article.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Miscellaneous