Determination of pathways for sodium movement across corneal endothelial cell derived plasma membrane vesicles.
A bovine corneal endothelial cell plasma membrane vesicle preparation was used to investigate passive Na+ transport across the plasma membrane of these cells. Sodium accumulation rate into the vesicle was not dependent on the presence of HCO3- or a HCO3- gradient, but was stimulated by a trans-vesicle pH gradient. Amiloride, furosemide and DIDS all reduced the rate of Na+ accumulation. The data indicate the presence of at least two independent pathways for passive sodium movement across the vesicle: the first probably via a Na+/H+ exchanger and the second a furosemide inhibitable Na+ entry mechanism. No evidence was found for direct Na(+)-HCO3- coupled transport.
Wigham
C G
CG
Department of Optometry and Vision Sciences, University of Wales College of Cardiff, UK.
Kaila
D
D
Hodson
S A
SA
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism*; D004727:Endothelium / Q000378:metabolism; D005665:Furosemide / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000187:drug effects; D013347:Subcellular Fractions / Q000378:metabolism
D017923:Sodium-Hydrogen Exchangers; D000584:Amiloride; D005665:Furosemide; D012964:Sodium; D011188:Potassium