Arterioles' contribution to oxygen supply to the skeletal muscles at rest

We tested the hypothesis that oxygen is supplied to the resting skeletal muscle by arterioles rather than by capillaries. This hypothesis was evaluated in rats and rabbits by combining different approaches (1) determination of the intravascular oxygen tension (PO2) in arterioles of different diamete...

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Bibliographic Details
Published in:European journal of applied physiology 2006-06, Vol.97 (3), p.327-331
Main Authors: Shibata, Masahiro, Ichioka, Shigeru, Togawa, Tatsuo, Kamiya, Akira
Format: Article
Language:English
Subjects:
Animals
Arterioles - anatomy & histology
Arterioles - metabolism
Capillaries - anatomy & histology
Capillaries - metabolism
Diffusion
Microscopy, Video
Muscle Contraction
Muscle, Skeletal - blood supply
Muscle, Skeletal - metabolism
Oxygen
Oxygen - blood
Oxygen - metabolism
Oxygen Consumption
Partial Pressure
Rabbits
Rats
Rats, Wistar
Regional Blood Flow
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Summary:We tested the hypothesis that oxygen is supplied to the resting skeletal muscle by arterioles rather than by capillaries. This hypothesis was evaluated in rats and rabbits by combining different approaches (1) determination of the intravascular oxygen tension (PO2) in arterioles of different diameters, (2) measurement of the perfused capillary number in response to changes in tissue PO2, and (3) estimation of the optimum capillary number to provide oxygen efficiently to the surrounding tissue. The intravascular PO2 values of arterioles along the vessels decreased downstream, suggesting that a significant amount of oxygen diffuses from the arterioles to the surrounding tissue. The perfused capillary number decreased as the tissue PO2 level was elevated, and this mutual relationship displayed a nonlinear correlation. The results suggest that a boundary PO2 level affecting the capillary recruitment exists for tissue PO2 of less than 40 mmHg with the capillary blood-flow stops above that PO2 level. At a high PO2 level, therefore, the oxygen is supplied from the arterioles. Furthermore, an estimation of optimum capillary number reveals that the capillary arrangement is constructed to achieve sufficient oxygen supply to the muscle during exercise, rather than at rest. These results suggest that oxygen is supplied from arterioles to the resting skeletal muscle, whereas the oxygen is supplied from the capillaries during exercise.
ISSN:1439-6319
1439-6327
DOI:10.1007/s00421-006-0200-2