AJP - Heart and Circulatory Physiology, Vol 270, Issue 2 427-H434, Copyright © 1996 by American Physiological Society

ARTICLES

Role of adenosine in regulation of coronary flow in dogs with inhibited synthesis of endothelium-derived nitric oxide

T. Matsunaga, K. Okumura, R. Tsunoda, S. Tayama, T. Tabuchi and H. Yasue
Division of Cardiology, Kumamoto University School of Medicine, Japan.

Endothelium-derived nitric oxide (NO) regulates coronary blood flow, but it is unclear how NO synthesis inhibition affects myocardial metabolism. In pentobarbital sodium-anesthetized dogs, myocardial oxygen metabolism, adenosine release, lactate extraction rate (LER), and systolic ventricular wall thickening (SWT) at baseline and during atrial pacing were estimated before and after intracoronary NG-nitro-L-arginine methyl ester (L-NAME) infusion. Coronary blood flow and PO2 in the anterior interventricular vein at baseline were both significantly decreased by L-NAME (3 x 10(-4) M in the coronary blood). Coronary flow was increased during pacing, which was not affected by L-NAME. Myocardial adenosine release remained unchanged during pacing before L-NAME, but it was significantly increased after L-NAME infusion. Neither LER nor SWT changed during pacing performed before and after L-NAME. The experiment was also performed in dogs pretreated with 8-phenyltheophyl-line. After L-NAME, pacing-induced increase in coronary flow was suppressed, and both LER and SWT were significantly decreased during pacing. In conclusion, when NO synthesis is inhibited, adenosine release is increased in response to the increase in myocardial oxygen demand. With this compensatory adenosine release, coronary flow is increased and ventricular function is unaffected.

This article has been cited by other articles:

				R. R. Martinez, S. Setty, P. Zong, J. D. Tune, and H. F. Downey Nitric oxide contributes to right coronary vasodilation during systemic hypoxia Am J Physiol Heart Circ Physiol, March 1, 2005; 288(3): H1139 - H1146. [Abstract] [Full Text] [PDF]

				J. D. Tune, M. W. Gorman, and E. O. Feigl Matching coronary blood flow to myocardial oxygen consumption J Appl Physiol, July 1, 2004; 97(1): 404 - 415. [Abstract] [Full Text] [PDF]

				D. Merkus, D. B. Haitsma, T.-Y. Fung, Y. J. Assen, P. D. Verdouw, and D. J. Duncker Coronary blood flow regulation in exercising swine involves parallel rather than redundant vasodilator pathways Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H424 - H433. [Abstract] [Full Text] [PDF]

				J. D. Tune, K. N. Richmond, M. W. Gorman, and E. O. Feigl Control of Coronary Blood Flow during Exercise Experimental Biology and Medicine, April 1, 2002; 227(4): 238 - 250. [Abstract] [Full Text] [PDF]

				J. D. Tune, K. N. Richmond, M. W. Gorman, and E. O. Feigl KATP+ channels, nitric oxide, and adenosine are not required for local metabolic coronary vasodilation Am J Physiol Heart Circ Physiol, February 1, 2001; 280(2): H868 - H875. [Abstract] [Full Text] [PDF]

				T. Tanikawa, H. Kanatsuka, R. Koshida, M. Tanaka, A. Sugimura, T. Kumagai, M. Miura, T. Komaru, and K. Shirato Role of pertussis toxin-sensitive G protein in metabolic vasodilation of coronary microcirculation Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H1819 - H1829. [Abstract] [Full Text] [PDF]

				J. M. Canty Jr. Nitric Oxide and Short-Term Hibernation : Friend or Foe? Circ. Res., July 21, 2000; 87(2): 85 - 87. [Full Text] [PDF]

				J. D. Tune, K. N. Richmond, M. W. Gorman, and E. O. Feigl Role of Nitric Oxide and Adenosine in Control of Coronary Blood Flow in Exercising Dogs Circulation, June 27, 2000; 101(25): 2942 - 2948. [Abstract] [Full Text] [PDF]

				T. W. Hein and L. Kuo cAMP-Independent Dilation of Coronary Arterioles to Adenosine : Role of Nitric Oxide, G Proteins, and KATP Channels Circ. Res., October 1, 1999; 85(7): 634 - 642. [Abstract] [Full Text] [PDF]

				L. E. Davis, A. R. Hohimer, and M. J. Morton Myocardial blood flow and coronary reserve in chronically anemic fetal lambs Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R306 - R313. [Abstract] [Full Text] [PDF]

				R. O. Cannon III Role of nitric oxide in cardiovascular disease: focus on the endothelium Clin. Chem., August 1, 1998; 44(8): 1809 - 1819. [Abstract] [Full Text] [PDF]

				T. Minamino, M. Kitakaze, K. Node, H. Funaya, and M. Hori Inhibition of Nitric Oxide Synthesis Increases Adenosine Production via an Extracellular Pathway Through Activation of Protein Kinase C Circulation, September 2, 1997; 96(5): 1586 - 1592. [Abstract] [Full Text]

				M. Takamura, R. Parent, and M. Lavallee Enhanced contribution of NO to exercise-induced coronary responses after alpha -adrenergic receptor blockade Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H508 - H515. [Abstract] [Full Text] [PDF]