Effects of nicorandil and other antianginal drugs on myocardial pH in the ischemic dog heart.
The effects of nicorandil and other antianginal drugs on the pH of ischemic myocardium were examined in dogs anesthetized with pentobarbital. The myocardial pH was measured with a micro glass pH electrode placed in the inner layers of the area of myocardium perfused by the left anterior descending coronary artery (LAD). The myocardium (LAD area) was made ischemic by partially occluding the LAD so that only about one-third of the normal blood flow was allowed to perfuse the tissue. The period of LAD occlusion was 90 min. By 30 min, the partial occlusion had produced a decrease in myocardial pH (about 0.5 U) which lasted until the end of occlusion. The acidosis in the myocardium induced by LAD partial occlusion was metabolic acidosis. The experimental drugs were injected intravenously 30 min after the LAD was occluded. Nicorandil (50 micrograms/kg), nitroglycerin (20 micrograms/kg), and diltiazem (100 micrograms/kg) moderately restored the myocardial H+ concentrations induced by LAD occlusion; propranolol (1 mg/kg) and sotalol (5 mg/kg) markedly restored these concentrations. It was concluded that all five experimental drugs improved ischemic myocardium; nicorandil, nitroglycerin, and diltiazem only moderately counteracted the increased myocardial H+ concentrations produced by LAD occlusion, whereas propranolol and sotalol markedly returned myocardial pH close to normal levels.
D000138:Acidosis / Q000378:metabolism; D000818:Animals; D003327:Coronary Disease / Q000378:metabolism*; D004110:Diltiazem / Q000494:pharmacology; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D005996:Nitroglycerin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013015:Sotalol / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D009536:Niacinamide; D020108:Nicorandil; D011433:Propranolol; D013015:Sotalol; D004110:Diltiazem; D005996:Nitroglycerin