ISSN:
1432-1912
Keywords:
Cardiac metabolism
;
Ischemia
;
Isosorbide dinitrate
;
Nicorandil
;
Oxygen-debt
;
Oxygen-repayment
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary This study was designed to investigate the effects of nicorandil in comparison to isosorbide dinitrate (ISDN) on hemodynamics, on myocardial metabolism and on effectiveness in the preservation of ischemically stressed myocardium. Repeated ischemia (3 min) was produced in anaesthetized open-chest mongrel dogs by proximal, intermittent left anterior descending artery occlusion with subsequent reperfusion. In each experiment 2–3 control occlusions were compared to 2–3 occlusions under nicorandil or ISDN. Application of both nicorandil (0.64 μmol·kg−1 body weight, i.v.) and ISDN (1.27 μmol·kg−1 body weight, i.v.) led to a significant afterload reduction and to a decrease of the coronary vascular resistance. The efficiency of the compounds in the protection of ischemic myocardium was examined by quantification of oxygen-debt and oxygen-repayment in the occlusion and reperfusion periods. Compared to control, premedication with nicorandil led to a significant increase of oxygen-debt, whereas ISDN reduced it significantly. Oxygen-repayment remained unchanged. The influence of the drugs on the metabolism of glucose, lactate and free fatty acids (FFA) was examined under basic conditions, in ischemia and during reperfusion. For all substrates, extraction, extraction ratio and oxygen extraction ratio were calculated. Under basic conditions, glucose metabolism was significantly enhanced in both groups but FFA metabolism was inhibited only by ISDN. In ischemia, FFA metabolism was enhanced by nicorandil and depressed by ISDN. Data obtained in this study suggest that nicorandil may even aggravate the metabolic and energetic situation of ischemic myocardium and, on the other hand, clearly support the well documented protective effects of ISDN.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00496379
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