Myocardial nucleoside and carbohydrate metabolism and hemodynamics during partial occlusion and reperfusion of pig coronary artery

de Jong, J.W.; Verdouw, P.D.; Remme, W.J.

Journal of Molecular and Cellular Cardiology 9(4): 297-312

1977


ISSN/ISBN: 0022-2828
PMID: 864716
DOI: 10.1016/s0022-2828(77)80036-9
Accession: 005952494

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Abstract
The effect of local ischemia on myocardial metabolism and hemodynamics was studied in open-chested pigs. Coronary artery flow was reduced by 74% with a screw clamp for 1 h, after which period the clamp was released. Arterial and local coronary venous samples were taken repeatedly during control, occlusion and reperfusion. During control, the myocardium extracted lactate (20%) and inosine (24%). No or minor arteriovenous differences were measured for glucose, K, Pi and hypoxanthine. During ischemia, the heart consumed glucose (about 25%); lactate and inosine extraction decreased to minimal values of -126% and -642%, respectively. Hypoxanthine, K and Pi showed relatively small changes in arteriovenous difference. Extraction patterns approached control values during release. Myocardial O2 uptake decreased by 68% after occlusion. Immediately following release, uptake returned to control value, but subsequently fell again by 20-30%. Extensive and long-lasting reactive hyperemia was observed during reperfusion. However, flow debt was only partially repaid. Throughout the experiment heart rate increased; cardiac output and mean aortic pressure decreased. During occlusion, the peak derivative of left ventricular pressure decreased about 24%; peripheral resistance and left ventricular end-diastolic pressure increased 20-30%. These changes were only partially reversed during reperfusion. In addition to changes in lactate metabolism, myocardial inosine production was a good marker for myocardial ischemia in the pig, because it correlated well with carbohydrate extraction and ventricular function, and the occlusion-induced changes were relatively large.