Circulation Research, Vol 71, 558-566, Copyright © 1992 by American Heart Association

ARTICLES

Superoxide dismutase enhances ischemia-induced reactive hyperemic flow and adenosine release in dogs. A role of 5'-nucleotidase activity

M Kitakaze, M Hori, S Takashima, K Iwai, H Sato, M Inoue, A Kitabatake and T Kamada
First Department of Medicine, Osaka University School of Medicine, Japan.

To test the hypothesis that 5'-nucleotidase activity during ischemia is attenuated by oxygen-derived free radicals, we measured ischemia- induced reactive hyperemic flow, adenosine release, and 5'-nucleotidase activity in dogs (n = 62). A 1-minute occlusion of the coronary artery caused reactive hyperemic flow (307 +/- 5 versus 92 +/- 1 ml.100 g- 1.min-1 at baseline) with increased release of adenosine (14.4 +/- 1.4 versus 0.4 +/- 0.1 nmol.100 g-1.min-1 at baseline). Superoxide dismutase augmented (p less than 0.001) both peak coronary blood flow (333 +/- 6 ml.100 g-1.min-1) and repayment (436 +/- 12 versus 320 +/- 7 ml/100 g in the untreated group). Adenosine release during reperfusion was augmented (22.7 +/- 1.9 nmol.100 g-1.min-1, p less than 0.001), and 8-phenyltheophylline completely abolished the enhanced reactive hyperemia. Enzymatic assay of 5'-nucleotidase activity revealed that the administration of superoxide dismutase increases ecto-5'- nucleotidase activity in ischemic myocardium. When an inhibitor of ecto- 5'-nucleotidase, alpha, beta-methyleneadenosine 5'-diphosphate, was administered, the effects of superoxide dismutase were completely abolished. Thus, we conclude that 1) the augmentation of reactive hyperemic flow caused by superoxide dismutase is attributed to the enhanced release of adenosine and 2) the enhanced release of adenosine over the untreated controls is attributed to the protection of ecto-5'- nucleotidase activity during ischemia.

This article has been cited by other articles:

				T. Yada, H. Shimokawa, K. Morikawa, A. Takaki, Y. Shinozaki, H. Mori, M. Goto, Y. Ogasawara, and F. Kajiya Role of Cu,Zn-SOD in the synthesis of endogenous vasodilator hydrogen peroxide during reactive hyperemia in mouse mesenteric microcirculation in vivo Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H441 - H448. [Abstract] [Full Text] [PDF]

				H. Asanuma, T. Minamino, S. Sanada, S. Takashima, H. Ogita, A. Ogai, M. Asakura, Y. Liao, Y. Asano, Y. Shintani, et al. {beta}-Adrenoceptor Blocker Carvedilol Provides Cardioprotection via an Adenosine-Dependent Mechanism in Ischemic Canine Hearts Circulation, June 8, 2004; 109(22): 2773 - 2779. [Abstract] [Full Text] [PDF]

				G. A. Lutty, C. Merges, and D. S. McLeod 5' Nucleotidase and Adenosine during Retinal Vasculogenesis and Oxygen-Induced Retinopathy Invest. Ophthalmol. Vis. Sci., January 1, 2000; 41(1): 218 - 229. [Abstract] [Full Text]