Role of erythrocyte in regulating local O2 delivery mediated by hemoglobin oxygenation.
The release of ATP from red blood cells (RBC) in response to low O2 levels is linked to ATP production and the oxygenation state of hemoglobin. Because O2 is unloaded from the RBC, the concentration of deoxygenated hemoglobin increases, displacing phosphofructokinase from the cytoplasmic domain of band 3. We hypothesize that the ATP molecules produced through this glycolytic stimulation at the membrane surface result in the release of ATP from the RBC. Rat whole blood exposed to 5 min of low PO2 in vitro increased plasma [ATP] by 1.0 miccroM (+45%). This increase was reduced to 0.1 microM (+12%, P < 0.05) after citrate incubation and reversed after fluoride treatment (both glycolytic inhibitors) by -0.2 microM (-23%, P < 0.05). Plasma [ATP] of control RBC decreased -0.3 microM (-12%) when 8% CO (P < 0.05) was added to the chamber. Because CO and O2 bind competitively to heme, these results support our hypothesis that the release of ATP from RBC is linked to ATP production through the oxygenation state of the hemoglobin molecule.
Jagger
J E
JE
Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada N6A 5C1.
Bateman
R M
RM
Ellsworth
M L
ML
Ellis
C G
CG
D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000097:blood*; D000818:Animals; D001158:Arteries; D002245:Carbon Dioxide / Q000378:metabolism; D002248:Carbon Monoxide / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005459:Fluorides / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects / Q000502:physiology; D006454:Hemoglobins / Q000187:drug effects / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D008297:Male; D008955:Models, Cardiovascular; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D014680:Veins
D006454:Hemoglobins; D002245:Carbon Dioxide; D019343:Citric Acid; D002248:Carbon Monoxide; D000255:Adenosine Triphosphate; D006493:Heparin; D005459:Fluorides; D010100:Oxygen