NO2- uptake and HCO3- excretion in the intestine of the European flounder (Platichthys flesus)

M. Grosell, F. B. Jensen

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

Ion transport across isolated intestinal segments from the European flounder (Platichthys flesus) was studied with the primary aim of evaluating the mechanisms of nitrite (NO2-) uptake and HCO3- excretion. A double-radiolabelling technique was applied to monitor unidirectional Cl- and Na+ influx. Furthermore, net fluxes of NO2-, HCO3-, Cl-, Na+ and water were recorded. NO2- uptake was inhibited by mucosal application of bumetanide (10-4 mol l-1) but not DIDS (10-3 mol l-1), suggesting that NO2- is transported across the intestine via the Na+/K+/2Cl- cotransporter rather than via a Cl-/HCO3-exchanger. In addition to transport via the Na+/K+/2Cl- cotransporter, NO2- uptake may also occur through the Na+/Cl- cotransporter and by conductive transport. NO2- and Cl- influx rates seemed to reflect their mucosal concentrations, and NO2- did not influence unidirectional influx or net flux of Cl-. HCO3- efflux was significantly reduced in the presence of 10-3 mol l-1 DIDS in the mucosal solution. This may indicate the presence of an apical Cl-/HCO3- exchanger in the intestinal epithelium, which would not comply with the current model of HCO3- excretion in the intestine of marine teleost fish. An alternative model of HCO3- excretion across the intestinal epithelium is proposed.

Original languageEnglish (US)
Pages (from-to)2103-2110
Number of pages8
JournalJournal of Experimental Biology
Volume202
Issue number15
StatePublished - Aug 1 1999
Externally publishedYes

Keywords

  • Base excretion
  • Bumetanide
  • Cl/HCO exchange
  • DIDS
  • Flounder
  • Ion transport
  • Marine teleost
  • Na/K/2Cl cotransport
  • Nitrite
  • NO
  • Platichthys flesus

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Fingerprint Dive into the research topics of 'NO<sub>2</sub><sup>-</sup> uptake and HCO<sub>3</sub><sup>-</sup> excretion in the intestine of the European flounder (Platichthys flesus)'. Together they form a unique fingerprint.

  • Cite this