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Bidirectional Effects of Aminophylline on Myocardial Ischemia
- 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.
- Subjects :
- Adenosine
Myocardial Ischemia
Ischemia
Anterior Descending Coronary Artery
Dogs
Theophylline
Coronary Circulation
Receptors, Adrenergic, alpha-1
Physiology (medical)
medicine
Prazosin
Animals
Lactic Acid
business.industry
Myocardium
Receptors, Purinergic P1
Reproducibility of Results
Heart
Blood flow
medicine.disease
Aminophylline
Myocardial Contraction
Adenosine receptor
Purinergic P1 Receptor Antagonists
Anesthesia
Lactates
medicine.symptom
Cardiology and Cardiovascular Medicine
business
Vasoconstriction
medicine.drug
Subjects
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