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Bidirectional Effects of Aminophylline on Myocardial Ischemia

Authors :
Michitoshi Inoue
Tetsuo Minamino
Toshikazu Morioka
Koichi Node
Masatsugu Hori
Hidezo Mori
Masafumi Kitakaze
Mitsuaki Chujo
Hiroshi Takeda
Yoshiro Shinozaki Be
Takenobu Kamada
Source :
Circulation. 92:1254-1260
Publication Year :
1995
Publisher :
Ovid Technologies (Wolters Kluwer Health), 1995.

Abstract

Background Aminophylline blocks adenosine receptors and increases levels of plasma catecholamines. We investigated the effect of aminophylline on myocardial ischemia by varying its severity and attempted to identify the mechanism by which aminophylline modulates myocardial ischemia in the canine model. Methods and Results In 41 open-chest dogs, the left anterior descending coronary artery was cannulated and perfused with blood through a bypass tube from the left carotid artery. When coronary blood flow (CBF) was reduced to 80% of the control, aminophylline increased fractional shortening (FS) from 11.0±0.4% to 18.5±1.7% ( P P 1 -adrenoceptor antagonist, blunted the aminophylline-induced improvement in contractile and metabolic function. Administration of 8-phenyltheophylline, a selective antagonist of adenosine receptors, did not increase FS, LER, or the Endo/Epi ratio when CBF was reduced to 80% of control. When CBF was reduced to 60% of control, aminophylline did not change the metabolic and contractile function. In contrast, when CBF was reduced to 33% of control, release of adenosine was increased markedly (243±19 pmol/mL) and aminophylline induced decreases in FS, LER, and Endo/Epi ratio similar to those observed with 8-phenyltheophylline. Conclusions Aminophylline had opposite effects on the ischemic myocardium depending on the severity of ischemia. It improved mild ischemia but worsened severe ischemia. The beneficial effect of aminophylline was attributable to α 1 -adrenoceptor stimulation, which improves endomyocardial flow in the ischemic myocardium. The deleterious effect was attributable to the aminophylline-induced blockade of adenosine receptors.

Details

ISSN :
15244539 and 00097322
Volume :
92
Database :
OpenAIRE
Journal :
Circulation
Accession number :
edsair.doi.dedup.....74d760e622710219eeb615cbbb1c34c5
Full Text :
https://doi.org/10.1161/01.cir.92.5.1254