K+ efflux in deoxygenated sickle cells in the presence or absence of DIOA, a specific inhibitor of the [K+, Cl-] cotransport system.
The ouabain bumetanide resistant (OBR) K+ efflux was investigated in deoxygenated sickle cells in comparison to oxygenated ones, by using a specific inhibitor of the [K+, Cl-] co-transport system, [(DihydroIndenyl)Oxy] Alkanoic acid (DIOA). A DIOA sensitive and a DIOA resistant K+ efflux were measured in deoxygenated sickle cells. The DIOA sensitive K+ efflux shared the properties of the [K+, Cl-] co-transport system, being stimulated by decreased pH and hypoosmolarity. This DIOA sensitive K+ efflux represented 70% of the total K+ efflux at pH 7.0 and at low pO2 (10-15 mmHg). Thus, a small reduction in Ph effectively stimulated the [K+, Cl-] co-transport system in deoxygenated condition, and this may contribute significantly to the sickle cell dehydration. We conclude that at pH lower than 7.4, the [K+, Cl-] co-transport system is permanently activated in sickle cells and leads to sickle cell dehydration in both oxygenated and deoxygenated conditions.
Olivieri
O
O
INSERM U91, Hôpital Henri Mondor, Créteil, France.
Vitoux
D
D
Bachir
D
D
Beuzard
Y
Y
D000328:Adult; D000755:Anemia, Sickle Cell / Q000097:blood*; D001692:Biological Transport / Q000187:drug effects; D002264:Carboxylic Acids / Q000494:pharmacology*; D002352:Carrier Proteins / Q000097:blood*; D002712:Chlorides / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007192:Indenes / Q000494:pharmacology*; D009994:Osmolar Concentration; D010100:Oxygen / Q000097:blood; D011188:Potassium / Q000097:blood*; D012964:Sodium / Q000097:blood; D028021:Sodium-Potassium-Chloride Symporters
C059990:((dihydroindenyl)oxy)alkanoic acid; D002264:Carboxylic Acids; D002352:Carrier Proteins; D002712:Chlorides; D007192:Indenes; D028021:Sodium-Potassium-Chloride Symporters; D012964:Sodium; D011188:Potassium; D010100:Oxygen