The relaxant effect of dobutamine on porcine coronary arterial ring segments.
The purpose of this study was to assess the direct effects of dobutamine on porcine coronary arteries and to investigate the mechanism of its action. Rings of coronary arteries from pigs were suspended in baths containing Krebs solution, and isometric tension was measured. The response to dobutamine (10(-8)-10(-3) M) was investigated in porcine coronary arterial rings contracted by KCl. The roles of endothelium, nitric oxide (NO), cyclic GMP (cGMP), prostaglandins and the adrenergic beta1, beta2-receptor on dobutamine-induced relaxation were also studied. Dobutamine inhibited the vasocontractivity to KCl and CaCl2, and relaxed porcine coronary artery. The relaxing response to dobutamine in coronary artery was significantly reduced by blockage of the adrenergic beta1-receptor, but not by removal of endothelium, blockage of the adrenergic beta2-receptor, inhibitors of nitric oxide synthase, guanylate cyclase and prostaglandin synthase. Our results suggest that dobutamine induces relaxation of isolated porcine coronary arteries via the adrenergic P1-receptor.
Xu
Pei-Han
PH
Department of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, PR China.
Cheng
Qiang
Q
Li
Hong-Fang
HF
Yu
Ye
Y
Yan
Xiang
X
Wang
Rui
R
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D004280:Dobutamine / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000502:physiology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013552:Swine
D000318:Adrenergic beta-Agonists; D011453:Prostaglandins; D009569:Nitric Oxide; D004280:Dobutamine; D011189:Potassium Chloride; D001120:Arginine; D002118:Calcium