TY - JOUR
T1 - Adenosine is not responsible for local metabolic control of coronary blood flow in dogs during exercise
AU - Tune, Johnathan D.
AU - Richmond, Keith Neu
AU - Gorman, Mark W.
AU - Olsson, Ray A.
AU - Feigl, Eric O.
PY - 2000/1
Y1 - 2000/1
N2 - The purpose of this investigation was to quantitatively evaluate the role of adenosine in coronary exercise hyperemia. Dogs (n = 10) were chronically instrumented with catheters in the aorta and coronary sinus, and a flow probe on the circumflex coronary artery. Cardiac interstitial adenosine concentration was estimated from arterial and coronary venous plasma concentrations using a previously tested mathematical model. Coronary blood flow, myocardial oxygen consumption, heart rate, and aortic pressure were measured at rest and during graded treadmill exercise with and without adenosine receptor blockade with either 8-phenyltheophylline (8-PT) or 8-p- sulfophenyltheophylline (8-PST). In control vehicle dogs, exercise increased myocardial oxygen consumption 4.2-fold, coronary blood flow 3.8-fold, and heart rate 2.5-fold, whereas mean aortic pressure was unchanged. Coronary venous plasma adenosine concentration was little changed with exercise, and the estimated interstitial adenosine concentration remained well below the threshold for coronary vasodilation. Adenosine receptor blockade did not significantly alter myocardial oxygen consumption or coronary blood flow at rest or during exercise. Coronary venous and estimated interstitial adenosine concentration did not increase to overcome the receptor blockade with either 8-PT or 8-PST as would be predicted if adenosine were part of a high-gain, negative-feedback, local metabolic control mechanism. These results demonstrate that adenosine is not responsible for local metabolic control of coronary blood flow in dogs during exercise.
AB - The purpose of this investigation was to quantitatively evaluate the role of adenosine in coronary exercise hyperemia. Dogs (n = 10) were chronically instrumented with catheters in the aorta and coronary sinus, and a flow probe on the circumflex coronary artery. Cardiac interstitial adenosine concentration was estimated from arterial and coronary venous plasma concentrations using a previously tested mathematical model. Coronary blood flow, myocardial oxygen consumption, heart rate, and aortic pressure were measured at rest and during graded treadmill exercise with and without adenosine receptor blockade with either 8-phenyltheophylline (8-PT) or 8-p- sulfophenyltheophylline (8-PST). In control vehicle dogs, exercise increased myocardial oxygen consumption 4.2-fold, coronary blood flow 3.8-fold, and heart rate 2.5-fold, whereas mean aortic pressure was unchanged. Coronary venous plasma adenosine concentration was little changed with exercise, and the estimated interstitial adenosine concentration remained well below the threshold for coronary vasodilation. Adenosine receptor blockade did not significantly alter myocardial oxygen consumption or coronary blood flow at rest or during exercise. Coronary venous and estimated interstitial adenosine concentration did not increase to overcome the receptor blockade with either 8-PT or 8-PST as would be predicted if adenosine were part of a high-gain, negative-feedback, local metabolic control mechanism. These results demonstrate that adenosine is not responsible for local metabolic control of coronary blood flow in dogs during exercise.
KW - 8-phenyltheophylline
KW - 8-sulfophenyltheophylline
KW - Myocardial blood flow
UR - http://www.scopus.com/inward/record.url?scp=0033952435&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.2000.278.1.h74
DO - 10.1152/ajpheart.2000.278.1.h74
M3 - Article
C2 - 10644586
AN - SCOPUS:0033952435
SN - 0363-6135
VL - 278
SP - H74-H84
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 1 47-1
ER -