2006 Fiscal Year Final Research Report Summary
Effects of oxygen consumption by arteriolar walls on oxygen transport to tissue under physiological condition
| Project/Area Number |
17300143
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Biomedical engineering/Biological material science
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
SHIBATA Masahiro The University of Tokyo, Graduate School of Medicine, Lecturer, 大学院医学系研究科, 講師 (60158954)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IRAMINA Keiji Kyushu University, Graduate School of Information Science, Professor, 大学院システム情報研究院, 教授 (20211758)
ICHIOKA Shigeru Saitama Medical School, Faculty of Medicine, Associate Professor, 医学部, 助教授 (60306272)
KAMIYA Akira Nihon University, Graduate School of Global Business, Professor, 大学院グローバルビジネス研究科, 教授 (50014072)
|
|---|
| Project Period (FY) |
2005 – 2006
|
| Keywords | microcirculation / arterioles / oxygen consumption / vasodilation / nitric oxide / skeletal muscle |
|---|
| Research Abstract |
To examine the formation of pO_2 gradients in arterioles, the oxygen consumption rates of arteriolar walls were determined under physiological conditions. A phosphorescence quenching technique was used to quantify the intra- and perivascular pO_2 values in rat cremaster arterioles. Using the measured pO_2 values, and a theoretical model, the O_2 consumption rates of the arteriolar walls were then estimated. We found that the O_2 consumption rate of functional arterioles was 100 times greater than that seen in in vitro experiments, and the O_2 consumption rate of the arteriolar walls in resting skeletal muscle was significantly higher than that during vasodilation. Furthermore, the O_2 consumption rate was the highest in the 1A arterioles, which are located upstream where the blood pressure is highest. These findings suggest that the high O_2 consumption rates of arteriolar walls depend on the workload of the smooth muscle, rather than the endothelium. These results confirm the strong involvement of O_2 consumption by the arteriolar wall itself in the formation of pO_2 gradients in arterioles. Furthermore, an important physiological function of arterioles was demonstrated: large amounts of O_2 are consumed by the vessel walls in resting skeletal muscle arterioles, enabling the arterioles to restrict blood perfusion into skeletal muscle. Consequently, an adequate blood supply to the other organs is ensured, even with a limited systemic blood flow. During exercise, on the other hand the arteriolar O_2 consumption decreases as a result of the relaxation of the vascular smooth muscle, thereby efficiently supplying O_2 to the skeletal muscle.
|
