EFFECTS OF ISCHEMIC PRECONDITIONING ON CONTRACTILE AND METABOLIC FUNCTION DURING HYPOPERFUSION IN DOGS

Citation
T. Minamino et al., EFFECTS OF ISCHEMIC PRECONDITIONING ON CONTRACTILE AND METABOLIC FUNCTION DURING HYPOPERFUSION IN DOGS, American journal of physiology. Heart and circulatory physiology, 43(2), 1998, pp. 684-693
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physiology
ISSN journal
0363-6135
Volume
43
Issue
2
Year of publication
1998
Pages
684 - 693
Database
ISI
SICI code
0363-6135(1998)43:2<684:EOIPOC>2.0.ZU;2-R
Abstract
We examined the effects of ischemic preconditioning (IP) on metabolic and contractile function during coronary hypoperfusion in dogs. After the left anterior descending coronary artery (LAD) was occluded for 5 min (IP) and reperfused for 10 min, coronary blood Bow (CBF) of the LA D was decreased to 33% of the control. IP 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 durin g hypoperfusion compared with those in the control group, although IP did not change the endocardial-to-epicardial blood flow rai;io of the regional myocardium during hypoperfusion. IP increased (P < 0.115) the adenosine levels in coronary venous blood during hypoperfusion. IP in creased (P < 0.05) myocardial ecto-5'-nucleotidase activity. Administr ation of 8-sulophenyltheophylline or alpha,beta-methyleneadenosine 6'- diphosphate blunted the IP-induced changes in metabolic and contractil e parameters during hypoperfusion. These results suggest that IP reduc ed the severity of anaerobic myo-cardial metabolism of ischemic hearts by increasing the adenosine levels via an extracellular pathway.