Erythrocyte and the Regulation of Human Skeletal Muscle Blood Flow and Oxygen Delivery
- 29 November 2002
- journal article
- clinical trial
- Published by Ovid Technologies (Wolters Kluwer Health) in Circulation Research
- Vol. 91 (11), 1046-1055
- https://doi.org/10.1161/01.res.0000044939.73286.e2
Abstract
Blood flow to contracting skeletal muscle is tightly coupled to the oxygenation state of hemoglobin. To investigate if ATP could be a signal by which the erythrocyte contributes to the regulation of skeletal muscle blood flow and oxygen (O2) delivery, we measured circulating ATP in 8 young subjects during incremental one-legged knee-extensor exercise under conditions of normoxia, hypoxia, hyperoxia, and CO+normoxia, which produced reciprocal alterations in arterial O2 content and thigh blood flow (TBF), but equal thigh O2 delivery and thigh O2 uptake. With increasing exercise intensity, TBF, thigh vascular conductance (TVC), and femoral venous plasma [ATP] augmented significantly (PPP=0.14) to be elevated compared with normoxia, whereas with hyperoxia they tended to be reduced. In CO+normoxia, where femoral venous O2Hb and (O2+CO)Hb were augmented compared with hypoxia despite equal arterial deoxygenation, TBF and TVC were elevated, whereas venous [ATP] was markedly reduced. At peak exercise, venous [ATP] in exercising and nonexercising limbs was tightly correlated to alterations in venous (O2+CO)Hb (r2=0.93 to 0.96; P2 sensor, contributing to the regulation of skeletal muscle blood flow and O2 delivery, by releasing ATP depending on the number of unoccupied O2 binding sites in the hemoglobin molecule.Keywords
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