Rate of Decrease of PO2 from an Arteriole with Arrested Flow
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When flow to a region is arrested, the amount of oxygen contained within the stationary blood decreases at a rate dependent on the oxygen utilization of the surrounding tissue. We used phosphorescence quenching microscopy to measure arteriolar PO2 in the mesentery of male Sprague-Dawley rats. Flow was quickly stopped (< 1 s) by occluding the microvessels using an inflatable Saran bag attached to the microscope objective. The rate of decline in PO2 following occlusion yielded a calculated initial flux of oxygen out of the vessel lumen of 8.0 × 10−7 ml O2 cm−2 sec−1. An upper limit on the oxygen consumption of the arteriolar wall was calculated by assuming that all of the oxygen in the lumen was consumed by the wall at the initial rate. This value was 2.5 × 10−3 ml O2 cm−3 sec−1 and is an overestimate since the oxygen consumption of the nearby parenchymal cells was neglected. The calculated maximum oxygen consumption of the wall is more than an order of magnitude smaller than that reported previously for arterioles in the rat mesentery (6.5 × 10−2 ml O2 cm−3 sec−1). We conclude that oxygen consumption of the arteriolar wall is similar to previous values for other vascular tissues.
KeywordsOxygen Consumption Heart Circ Intravital Microscopy Oxygen Gradient Oxygen Removal
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- 5.H. Kerger, I. P. Torres Filho, M. Rivas, R. M. Winslow, and M. Intaglietta, Systemic and subcutaneous microvascular oxygen tension in conscious Syrian golden hamsters, Am. J. Physiol. 267, H802–H810 (1995).Google Scholar
- 7.A. Seiyama, S. Tanaka, H. Kosaka, and T. Shiga, O2 transfer from single microvessels to acinar cells in secretin-stimulated pancreas of rat, Am. J. Physiol. Heart Circ. Physiol. 270, H1704–H1711 (1996).Google Scholar
- 9.H. Kobayashi, and N. Takizawa, Oxygen saturation and pH changes in cremaster microvessels of the rat, Am. J. Physiol. Heart Circ. Physiol. 270, H1453–H1461 (1996).Google Scholar
- 10.M. L. Ellsworth, C. G. Ellis, A. S. Popel, and R. N. Pittman, Role of microvessels in oxygen supply to tissue, News Physiol. Sci. 9, 119–123 (1994).Google Scholar
- 14.T. W. Secomb, and R. Hsu, Simulation of oxygen transport in skeletal muscle: diffusive exchange between arterioles and capillaries, Am. J. Physiol. Heart Circ. Physiol. 267, H1214–H1221 (1994).Google Scholar
- 17.R. N. Pittman, Influence of microvascular architecture on oxygen exchange in skeletal muscle, Microcirc. 2, 1–18 (1995).Google Scholar
- 18.A. R. Vadapalli, R. N. Pittman, and A. S. Popel, Estimating oxygen transport resistance of the microvascular wall, Am. J. Physiol. Heart Circ. Physiol. 279, 657–671 (2000).Google Scholar