Relationship between luminal Na+/H+ exchange and luminal K+ conductance in diluting segment of frog kidney.
Experiments were performed in the isolated perfused kidney of K+ adapted Rana pipiens to investigate the relationship between luminal K+ conductance and H+ transport in cells of the diluting segment. Inhibition of luminal Na+/H+ exchange by amiloride or by omission of luminal Na+ blocked luminal K+ conductance. Acidification of the kidney perfusate by elevation of pCO2 also reduced luminal K+ conductance. This effect could be prevented by furosemide. Since the steepest transcellular Na+ potential difference, directed from the lumen into the cell, is found when luminal Na+/Cl-/K+ cotransport is inhibited by furosemide, we conclude that luminal Na+/H+ exchange is most efficient at these conditions and thus could attenuate intracellular acidification.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008954:Models, Biological; D011188:Potassium / Q000378:metabolism*; D011894:Rana pipiens; D012964:Sodium / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers; D000584:Amiloride; D012964:Sodium; D011188:Potassium