TY - JOUR
T1 - Red blood cell regulation of microvascular tone through adenosine triphosphate
AU - Dietrich, Hans H.
AU - Ellsworth, Mary L.
AU - Sprague, Randy S.
AU - Dacey, Ralph G.
PY - 2000/4
Y1 - 2000/4
N2 - The matching of blood flow with metabolic need requires a mechanism for sensing the needs of the tissue and communicating that need to the arterioles, the ultimate controllers of tissue perfusion. Despite significant strides in our understanding of blood flow regulation, the identity of the O2 sensor has remained elusive. Recently, the red blood cell, the Hb- containing O2 carrier, has been implicated as a potential O2 sensor and contributor to this vascular control by virtue of its concomitant carriage of millimolar amounts of ATP, which it is able to release when exposed to a low- O2 environment. To evaluate this possibility, we exposed perfused cerebral arterioles to low extraluminal O2 in the absence and presence of red blood cells or 6% dextran and determined both vessel diameter and ATP in the vessel effluent. Only when the vessels were perfused with red blood cells did the vessels dilate in response to low extraluminal O2. In addition, this response was accompanied by a significant increase in vessel effluent ATP. These findings support the hypothesis that the red blood cell itself serves a role in determining O2 supply to tissue.
AB - The matching of blood flow with metabolic need requires a mechanism for sensing the needs of the tissue and communicating that need to the arterioles, the ultimate controllers of tissue perfusion. Despite significant strides in our understanding of blood flow regulation, the identity of the O2 sensor has remained elusive. Recently, the red blood cell, the Hb- containing O2 carrier, has been implicated as a potential O2 sensor and contributor to this vascular control by virtue of its concomitant carriage of millimolar amounts of ATP, which it is able to release when exposed to a low- O2 environment. To evaluate this possibility, we exposed perfused cerebral arterioles to low extraluminal O2 in the absence and presence of red blood cells or 6% dextran and determined both vessel diameter and ATP in the vessel effluent. Only when the vessels were perfused with red blood cells did the vessels dilate in response to low extraluminal O2. In addition, this response was accompanied by a significant increase in vessel effluent ATP. These findings support the hypothesis that the red blood cell itself serves a role in determining O2 supply to tissue.
KW - Cerebral arterioles
KW - Microvascular regulatory mechanism
KW - Oxygen tension
KW - Rat
UR - http://www.scopus.com/inward/record.url?scp=0034051945&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.2000.278.4.h1294
DO - 10.1152/ajpheart.2000.278.4.h1294
M3 - Article
C2 - 10749727
AN - SCOPUS:0034051945
VL - 278
SP - H1294-H1298
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 4 47-4
ER -