Nitric oxide formation contributes to beta-adrenergic dilation of epicardial coronary arteries in response to intravenous administration of dobutamine in dogs.
To examine the role of nitric oxide in the beta-adrenergic vasodilation of epicardial coronary arteries in dogs, 12 dogs were instrumented for measurement of left anterior descending coronary artery diameter by transthoracic echocardiography before and after dobutamine (5 microg/kg/min IV) with and without intracoronary infusion of NG-monomethyl-L-arginine (L-NMMA) (1 mg/kg). In all 12 dogs, the diameter of left anterior descending coronary artery increased significantly from 2.35 +/- 0.25 mm to 2.59 +/- 0.24 mm (P<0.001) after dobutamine administration. In 6 of the 12 dogs, the percent change in left anterior descending coronary artery diameter induced by dobutamine decreased significantly from 12.5% +/- 8.6% to -1.5% +/- 5.4% (P<0.05) after the administration of intracoronary L-NMMA (1 mg/kg for 5 min) to block nitric oxide synthesis from L-arginine. The study demonstrated that nitric oxide formation contributes to the beta-adrenergic dilatory response of epicardial coronary arteries to dobutamine in dogs.
Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Haoyi
H
Yang
Youbin
Y
Deng
Xiaojun
X
Bi
Qing
Q
Chang
Jiao
J
Bai
Min
M
Pan
Huijuan
H
Xiang
Hongyun
H
Liu
Xiulan
X
Li
Yani
Y
Liu
Chunlei
C
Li
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D003331:Coronary Vessels / Q000502:physiology*; D004280:Dobutamine / Q000494:pharmacology*; D004285:Dogs; D004452:Echocardiography; D005260:Female; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*; D019323:omega-N-Methylarginine / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D004280:Dobutamine