CFTR null mutation altered cAMP-sensitive and swelling-activated Cl- currents in primary cultures of mouse nephron

Am J Physiol Renal Physiol. 2003 Apr;284(4):F796-811. doi: 10.1152/ajprenal.00237.2002. Epub 2002 Dec 10.


The role of cystic fibrosis transmembrane conductance regulator (CFTR) in the control of Cl(-) currents was studied in mouse kidney. Whole cell clamp was used to analyze Cl(-) currents in primary cultures of proximal and distal convoluted and cortical collecting tubules from wild-type (WT) and cftr knockout (KO) mice. In WT mice, forskolin activated a linear Cl(-) current only in distal convoluted and cortical collecting tubule cells. This current was not recorded in KO mice. In both mice, Ca(2+)-dependent Cl(-) currents were recorded in all segments. In WT mice, volume-sensitive Cl(-) currents were implicated in regulatory volume decrease during hypotonicity. In KO mice, regulatory volume decrease and swelling-activated Cl(-) current were impaired but were restored by adenosine perfusion. Extracellular ATP also restored swelling-activated Cl(-) currents. The effect of ATP or adenosine was blocked by 8-cyclopentyl-1,3-diproxylxanthine. The ecto-ATPase inhibitor ARL-67156 inhibited the effect of hypotonicity and ATP. Finally, in KO mice, volume-sensitive Cl(-) currents are potentially functional, but the absence of CFTR precludes their activation by extracellular nucleosides. This observation strengthens the hypothesis that CFTR is a modulator of ATP release in epithelia.

MeSH terms

  • Adenosine / pharmacology
  • Animals
  • Calcium / pharmacology
  • Cell Size / drug effects
  • Cells, Cultured
  • Chloride Channels / metabolism*
  • Chlorides / metabolism*
  • Colforsin / pharmacology
  • Cyclic AMP / pharmacology*
  • Cystic Fibrosis Transmembrane Conductance Regulator / deficiency*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Enzyme Inhibitors / pharmacology
  • Hypotonic Solutions / pharmacology
  • Kidney Tubules / cytology
  • Kidney Tubules / drug effects
  • Kidney Tubules / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CFTR
  • Mice, Knockout
  • Mutation
  • Nephrons / cytology
  • Nephrons / drug effects
  • Nephrons / metabolism*
  • Patch-Clamp Techniques
  • Transfection


  • Chloride Channels
  • Chlorides
  • Enzyme Inhibitors
  • Hypotonic Solutions
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Colforsin
  • Cyclic AMP
  • Adenosine
  • Calcium