TY - JOUR
T1 - Nitric oxide modulates right ventricular flow and oxygen consumption during norepinephrine infusion
AU - Setty, Srinath
AU - Tune, Johnathan D.
AU - Downey, H. Fred
PY - 2002
Y1 - 2002
N2 - This study was designed to test if nitric oxide (NO) contributes to norepinephrine-induced right coronary vasodilation and if NO blunts the norepinephrine-induced increase in myocardial oxygen consumption (MVO2) in the right ventricle. In five anesthetized, open-chest dogs, mean aortic pressure, heart rate, right ventricular rate of pressure development over time (dP/dt), right coronary blood flow, and right ventricular MVO2 were measured before and during graded intracoronary infusions of norepinephrine in the absence and presence of a NO synthase blocker, Nω-nitro-L-arginine methyl ester (L-NAME; 150 μg/min ic). During both conditions, right coronary blood flow and right ventricular MVO2 significantly increased with graded infusions of norepinephrine. L-NAME significantly blunted the coronary hyperemic response to norepinephrine, although L-NAME did not alter the relationship between right ventricular MVO2 and norepinephrine dose. However, when right ventricular function was indexed by heart rate × right ventricular maximum dP/dt × peak right ventricular systolic pressure, L-NAME significantly increased the oxygen cost of right ventricular function. These results indicate that NO contributes to norepinephrine-induced right coronary vasodilation and improves right ventricular oxygen utilization efficiency.
AB - This study was designed to test if nitric oxide (NO) contributes to norepinephrine-induced right coronary vasodilation and if NO blunts the norepinephrine-induced increase in myocardial oxygen consumption (MVO2) in the right ventricle. In five anesthetized, open-chest dogs, mean aortic pressure, heart rate, right ventricular rate of pressure development over time (dP/dt), right coronary blood flow, and right ventricular MVO2 were measured before and during graded intracoronary infusions of norepinephrine in the absence and presence of a NO synthase blocker, Nω-nitro-L-arginine methyl ester (L-NAME; 150 μg/min ic). During both conditions, right coronary blood flow and right ventricular MVO2 significantly increased with graded infusions of norepinephrine. L-NAME significantly blunted the coronary hyperemic response to norepinephrine, although L-NAME did not alter the relationship between right ventricular MVO2 and norepinephrine dose. However, when right ventricular function was indexed by heart rate × right ventricular maximum dP/dt × peak right ventricular systolic pressure, L-NAME significantly increased the oxygen cost of right ventricular function. These results indicate that NO contributes to norepinephrine-induced right coronary vasodilation and improves right ventricular oxygen utilization efficiency.
KW - N-nitro-L-arginine methyl ester
KW - Open-chest dogs
KW - Right coronary circulation
KW - Right ventricular oxygen utilization efficiency
UR - http://www.scopus.com/inward/record.url?scp=0036087586&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00398.2001
DO - 10.1152/ajpheart.00398.2001
M3 - Article
C2 - 11788420
AN - SCOPUS:0036087586
VL - 282
SP - H696-H703
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 2 51-2
ER -