Aim of the work was to study effect of
nicorandil [N-(2-nitrooxiethyl)
nicotinamide,
SG75] on blood pressure (BP), heart rate (HR) and rhythm disturbances during regional
ischemia and reperfusion of the heart in rats in vivo and its ability to limit acute
myocardial infarction (MI).
Nicorandil was obtained by nitrating
nicotinamide ethanol using produced by industry
ethylnicotinate. MI in Wistar rats was modeled by 40-min occlusion of anterior descending coronary artery (ADCA) and subsequent 60-min reperfusion.
Nicorandil (3,2 mmol/kg) was administered intravenously before occlusion. Nitroglycerine was used as preparation of comparison; it was administered in the same dose. MI area and zone at risk (ZR) were measured by computer planimetry after staining of left ventricular sections with 2, 3, 5-triphenyltetrazolium
chloride. Lowering of mean BP under influence of
nicorandil during ADCA occlusion and subsequent reperfusion were deeper and longer than under influence of nitroglycerine. Contrary to nitroglycerine administration of
nicorandil did not cause decrease of HR. Administration of both drugs postponed origination of rhythm disturbances during
ischemia but did not affect their duration. MI dimension assessed by MI/ZR ratio after administration of
nicorandil and nitroglycerine was significantly lowered down to 22 +/- 4 and 32 +/- 3%, respectively, compared with 47 +/- 3% in control. The results obtained evidence that in this model of ischemic and
reperfusion damage of the heart vasodilating properties of
nicorandil combined with decrease of postischemic loss of cardiomyocytes in ZR are comparable with effects of nitroglycerine.