TY - JOUR
T1 - Nonlinear regulation of capillary perfusion in relation to ambient pO2 changes in skeletal muscle
AU - Shibata, Masahiro
AU - Ichioka, Shigeru
AU - Ando, Joji
AU - Togawa, Tatsuo
AU - Kamiya, Akira
N1 - Funding Information:
Acknowledgements The authors wish to thank M. Tofflemire for his kind assistance.This work was supported by a Grant-in-Aid for Scientific Research (15300156) from Japan Society for the Promotion of Science (JSPS).
PY - 2005/6
Y1 - 2005/6
N2 - To study the process of O2 transport to tissue, we investigated how capillary perfusion is controlled in response to changes in tissue O2 levels in skeletal muscle. Capillary red blood cell (RBC) velocity and perfused capillary recruitment were measured in rabbit tenuissimus muscle at various ambient oxygen tensions (pO2) by intravital microscopy. Both RBC velocity and capillary recruitment significantly decreased as the pO2 level of the suffusate was increased, and the relationship between capillary perfusion, calculated from the velocity and recruitment data, and the pO2 level of the suffusate clearly yielded a nonlinear correlation that fitted a sigmoidal curve. Capillary perfusion dramatically decreases or increases above or below a suffusate pO2 level of around 40 Torr, where the O2 dissociation curve of hemoglobin changes slope. These findings support the hypothesis that microvasculature possesses an intrinsic, effective flow-control mechanism by sensing the metabolic demands of tissue, intimately related to the O2 saturation of hemoglobin.
AB - To study the process of O2 transport to tissue, we investigated how capillary perfusion is controlled in response to changes in tissue O2 levels in skeletal muscle. Capillary red blood cell (RBC) velocity and perfused capillary recruitment were measured in rabbit tenuissimus muscle at various ambient oxygen tensions (pO2) by intravital microscopy. Both RBC velocity and capillary recruitment significantly decreased as the pO2 level of the suffusate was increased, and the relationship between capillary perfusion, calculated from the velocity and recruitment data, and the pO2 level of the suffusate clearly yielded a nonlinear correlation that fitted a sigmoidal curve. Capillary perfusion dramatically decreases or increases above or below a suffusate pO2 level of around 40 Torr, where the O2 dissociation curve of hemoglobin changes slope. These findings support the hypothesis that microvasculature possesses an intrinsic, effective flow-control mechanism by sensing the metabolic demands of tissue, intimately related to the O2 saturation of hemoglobin.
KW - Capillary RBC velocity
KW - Capillary recruitment
KW - Hemoglobin dissociation curve
KW - Oxygen transport
KW - Rabbit skeletal muscle
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U2 - 10.1007/s00421-005-1315-6
DO - 10.1007/s00421-005-1315-6
M3 - Article
C2 - 15815940
AN - SCOPUS:20344397668
VL - 94
SP - 352
EP - 355
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
SN - 1439-6319
IS - 3
ER -