TY - JOUR
T1 - Evaluation of bioavailability of nitric oxide in coronary circulation by direct measurement of plasma nitric oxide concentration
AU - Neishi, Yoji
AU - Mochizuki, Seiichi
AU - Miyasaka, Takehiro
AU - Kawamoto, Takahiro
AU - Kume, Teruyoshi
AU - Sukmawan, Renan
AU - Tsukiji, Miwako
AU - Ogasawara, Yasuo
AU - Kajiya, Fumihiko
AU - Akasaka, Takashi
AU - Yoshida, Kiyoshi
AU - Goto, Masami
PY - 2005/8/9
Y1 - 2005/8/9
N2 - Although bioavailabillty of NO in the coronary circulation is commonly evaluated by acetylcholine (ACh)-induced vasodilation, a change in plasma NO concentration and its relation to the flow response after injection of ACh are still unknown. Thus, we directly measured the concentration of NO in the coronary sinus by using a catheter-type NO sensor for coronary sinus. An NO-sensitive sensor was located and fixed in a 4-Fr catheter with a soft tip for protection of vascular wall. After calibration with an NO-saturated pure water, the catheter-type NO sensor was located in the coronary sinus in anesthetized dogs. The coronary flow velocity (CFV) was measured with a Doppler guide wire. Intracoronary injection of ACh (0.4 and 1.0 μg/kg) increased plasma NO concentration in a dose-dependent manner (3-10 nM). Although ACh increased CFV by 95%, there was no significant difference between the two ACh doses. After ACh, the peak value of plasma NO concentration was observed significantly later than CFV. NG-methyl-L-arginine (NO synthase inhibitor) decreased basal NO concentration by 3 nM and suppressed the ACh-induced NO synthesis with no significant change in average peak velocity. We conclude that production of NO in the coronary circulation can be evaluated in the coronary sinus. Although ACh increases both CFV and NO concentration, CFV dose not reflect NO concentration in terms of magnitude and time course. Direct measurement of plasma NO concentration by the catheter-type NO sensor is useful to evaluate bioavailabillty of NO in the coronary circulation.
AB - Although bioavailabillty of NO in the coronary circulation is commonly evaluated by acetylcholine (ACh)-induced vasodilation, a change in plasma NO concentration and its relation to the flow response after injection of ACh are still unknown. Thus, we directly measured the concentration of NO in the coronary sinus by using a catheter-type NO sensor for coronary sinus. An NO-sensitive sensor was located and fixed in a 4-Fr catheter with a soft tip for protection of vascular wall. After calibration with an NO-saturated pure water, the catheter-type NO sensor was located in the coronary sinus in anesthetized dogs. The coronary flow velocity (CFV) was measured with a Doppler guide wire. Intracoronary injection of ACh (0.4 and 1.0 μg/kg) increased plasma NO concentration in a dose-dependent manner (3-10 nM). Although ACh increased CFV by 95%, there was no significant difference between the two ACh doses. After ACh, the peak value of plasma NO concentration was observed significantly later than CFV. NG-methyl-L-arginine (NO synthase inhibitor) decreased basal NO concentration by 3 nM and suppressed the ACh-induced NO synthesis with no significant change in average peak velocity. We conclude that production of NO in the coronary circulation can be evaluated in the coronary sinus. Although ACh increases both CFV and NO concentration, CFV dose not reflect NO concentration in terms of magnitude and time course. Direct measurement of plasma NO concentration by the catheter-type NO sensor is useful to evaluate bioavailabillty of NO in the coronary circulation.
KW - Acetylcholine
KW - Coronary blood flow
KW - Endothelial function
KW - Nitric oxide synthase
KW - Nitric oxide-selective sensor
UR - http://www.scopus.com/inward/record.url?scp=23844457911&partnerID=8YFLogxK
U2 - 10.1073/pnas.0501392102
DO - 10.1073/pnas.0501392102
M3 - Article
C2 - 16051703
AN - SCOPUS:23844457911
VL - 102
SP - 11456
EP - 11461
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 32
ER -