In vivo evaluation of oxygen consumption by arteriolar walls in skeletal muscle.
To estimate the oxygen consumption rate of arteriolar walls we measured the intra-and perivascular partial oxygen tension (PO<inf>2</inf>) of arterioles in rat cremaster muscle, both at resting and vasodilating states by phosphorescence quenching technique. Using measured intra- and perivascular PO<inf>2</inf>values, oxygen consumption rates were determined based on Krogh-Erlang analysis. We found a significant drop in PO<inf>2</inf>in the arterioles after branching. We found that the vascular oxygen consumption rates of functional arterioles were 100-1000 times greater than those seen in in vitro experiments. These results strongly support the hypothesis that arteriolar walls consume a significant amount of oxygen as compared with the surrounding tissue. Furthermore, the reduction of vascular tone of arteriolar walls may facilitate an efficient supply of oxygen to the surrounding tissue.
Shibata
M
M
Department of Biomedical Engineering, University of Tokyo, Bunkyo-ku Tokyo 113-0033, Japan. shibatam@m.u-tokyo.ac.jp.