Journal
PHARMACOLOGICAL REPORTS
Volume 61, Issue 1, Pages 183-190Publisher
SPRINGER HEIDELBERG
DOI: 10.1016/S1734-1140(09)70020-9
Keywords
adenosine triphosphate; vasodilation; hypoxia; hamster; microcirculation
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Funding
- National Institutes of Health [HL64180, HL089094]
- American Diabetes Association [R-133]
- American Heart Association Fellowship
- NATIONAL HEART, LUNG, AND BLOOD INSTITUTE [R33HL089094, R01HL064180] Funding Source: NIH RePORTER
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In skeletal muscle, oxygen (O-2) delivery to appropriately meet metabolic need requires mechanisms for detection of the magnitude of O-2 demand and the regulation of O-2 delivery. Erythrocytes, when exposed to a decrease in O-2 tension, release both O-2 and the vasodilator adenosine triphosphate (ATP). The aims of this study were to establish that erythrocytes release ATP in response to reduced O-2 tension and determine if erythrocytes are necessary for the dilation of isolated skeletal muscle arterioles exposed to reduced extraluminal O-2 tension. Rabbit erythrocytes exposed to reduced O-2 tension in a tonometer (n = 5, pO(2) = 27 +/- 3, p < 0.01) released ATP in response to reduced O-2 tension. ATP release increased in proportion to the decrease in O-2 tension. The contribution of erythrocytes to the response of skeletal muscle arterioles to reduced extraluminal O-2 tension was determined using isolated hamster cheek pouch retractor muscle arterioles perfused with buffer (n = 11, mean diameter 52 +/- 3 mu m) in the absence and presence of rabbit erythrocytes. Without erythrocytes, arterioles did not dilate when exposed to reduced extraluminal O-2 tension (pO(2) = 32 +/- 4 mmHg). In contrast, when rabbit erythrocytes were present in the perfusate (hematocrit 15%), the same decrease in O-2 tension resulted in a 20 +/- 4% dilation (p < 0.01). These results provide support for the hypothesis that erythrocytes, via their ability to release O-2 along with ATP in response to exposure to reduced O-2 tension, can participate in the matching of O-2 delivery with metabolic need in skeletal muscle.
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