Changes in the countercurrent system in the renal papilla: Diuresis increases pH and HCO3- gradients between collecting duct and vasa recta

Gen Kuramochi, Ulrich Kersting, William H. Dantzler, Stefan Silbernagl

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

This study was designed to elucidate the acid-base balance local to the collecting duct urine (CD) and vasa recta blood (VR) in the rat renal papilla in diuresis. The pH changes were measured in both a furosemide-induced and a volume-load-induced diuresis, whereas the PCO2 (i.e., CO2 tension) and HCO3- concentration were measured only in a furosemide-induced diuresis. In an antidiuresis, the pH of the VR was more acidic than that of the systemic arterial blood (ΔpH = 0.44-0.73). Additionally, the pH of the ascending VR was significantly lower than that of the descending VR (ΔpH = 0.14-0.16). In diuresis, the pH of the CD decreased (ΔpH = 0.81-0.97), while the pH of the descending and the ascending VR increased; however, the increase was only significant in the ascending VR (ΔpH = 0.23-0.30). Consequently, the significant difference in the pH gradient between the descending and the ascending VR was eliminated. The PCO2 values in the CD and the ascending VR were not different from those in antidiuresis, while the HCO3- concentration in the CD and the ascending VR, respectively, decreased and increased significantly. Thus, in diuresis, the decrease in the pH of the CD and the increase in the pH of the ascending VR result, respectively, from the decrease and the increase in the HCO3- concentration, with no changes in the PCO2 values.

Original languageEnglish (US)
Pages (from-to)1062-1068
Number of pages7
JournalPflugers Archiv European Journal of Physiology
Volume432
Issue number6
DOIs
StatePublished - 1996

Keywords

  • Acid-base state
  • Collecting duct urine
  • Countercurrent system
  • Diuresis
  • Renal papilla
  • Vasa recta blood

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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