Cell volume and metabolic dependence of NEM-activated K+-Cl- flux in human red blood cells.
The effects of incubation in anisosmotic media and of metabolic depletion on ouabain-resistant (OR) Cl--dependent K+ influxes stimulated by N-ethylmaleimide (NEM) were studied in human red blood cells using Rb+ as K+ analogue. The NEM-stimulated but not the basal Rb+-Cl- influx measured in phosphate-buffered anisosmotic media was found to be cell volume dependent. When cellular ATP, [ATP]c, was lowered to less than 0.10 of its initial level by exposure to nonmetabolizable 2-deoxy-D-glucose, the NEM-stimulated but not the basal Cl--dependent Rb+ influxes were abolished. Metabolically depleted red blood cells subsequently repleted by incubation in glucose plus inosine regained the NEM-inducible Rb+ (K+) transport activity. The difference in the time course of ATP breakdown and Rb+ influx inhibition suggests that energization of the NEM-stimulated Rb+ flux by metabolism may involve factors additional to ATP.
D000255:Adenosine Triphosphate / Q000097:blood; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000097:blood* / Q000502:physiology; D004911:Erythrocyte Volume; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology*; D006801:Humans; D006973:Hypertension / Q000097:blood; D066298:In Vitro Techniques; D009994:Osmolar Concentration; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000097:blood*; D012413:Rubidium / Q000097:blood
D002712:Chlorides; D010042:Ouabain; D000255:Adenosine Triphosphate; D012413:Rubidium; D005033:Ethylmaleimide; D011188:Potassium