Effects of ischemic preconditioning on contractile and metabolic function during hypoperfusion in dogs.
We examined the effects of ischemic preconditioning (i.p.) on metabolic and contractile function during coronary hypoperfusion in dogs. After the left anterior descending coronary artery (LAD) was occluded for 5 min (i.p.) and reperfused for 10 min, coronary blood flow (CBF) of the LAD was decreased to 33% of the control. I.p. increased (P < 0.05) lactate extraction ratio and the pH of coronary venous blood and decreased (P < 0.05) myocardial oxygen consumption and fractional shortening during hypoperfusion compared with those in the control group, although i.p. did not change the endocardial-to-epicardial blood flow ratio of the regional myocardium during hypoperfusion. I.p. increased (P < 0.05) the adenosine levels in coronary venous blood during hypoperfusion. I.p. increased (P < 0.05) myocardial ecto-5'-nucleotidase activity. Administration of 8-sulfophenyltheophylline or alpha, beta-methyleneadenosine 5'-diphosphate blunted the i.p.-induced changes in metabolic and contractile parameters during hypoperfusion. These results suggest that i.p. reduced the severity of anaerobic myocardial metabolism of ischemic hearts by increasing the adenosine levels via an extracellular pathway.
Minamino
T
T
First Department of Medicine, Osaka University School of Medicine, Japan.
Kitakaze
M
M
Sato
H
H
Funaya
H
H
Ueda
Y
Y
Asanuma
H
H
Kuzuya
T
T
Hori
M
M
D015720:5'-Nucleotidase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D003331:Coronary Vessels; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D019157:Ischemic Preconditioning, Myocardial; D019344:Lactic Acid / Q000097:blood; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D058915:Purinergic P1 Receptor Antagonists; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology
D004791:Enzyme Inhibitors; D058915:Purinergic P1 Receptor Antagonists; C523965:alpha,beta-methyleneadenosine 5'-diphosphate; D019344:Lactic Acid; D000244:Adenosine Diphosphate; C031433:8-(4-sulfophenyl)theophylline; D013806:Theophylline; D015720:5'-Nucleotidase; D000241:Adenosine