title: Cardioprotective effects of nicorandil.
abstract: The effects of nicorandil, a nicotinamide nitrate with K(+)-channel-opening activity, was investigated in several models of ischemia-reperfusion injury in conscious and anesthetized dogs or isolated buffer-perfused rat hearts. In several models of reversible ischemic injury (stunned myocardium) in dogs, nicorandil resulted in an enhanced recovery of regional systolic shortening during reperfusion after a single episode of coronary artery occlusion (10-15 min). These beneficial actions of nicorandil were not shared by the nitrovasodilator sodium nitroprusside but were mimicked by the selective K(+)-channel opener EMD 52692. In a model of irreversible ischemia-reperfusion injury (i.e., 2 h of coronary occlusion followed by reperfusion) in anesthetized dogs, nicorandil produced a marked reduction of myocardial infarct size. An equihypotensive dose of the calcium antagonist nifedipine had no significant effect; however, EMD 52692 produced the same reduction in infarct size as had nicorandil. In isolated, perfused rat hearts subjected to 20 min of low-flow (1.0 ml/min) global ischemia followed by 30 min of reperfusion, nicorandil (7 microM) resulted in a significant improvement in the recovery of isovolumic left ventricular minute work during reperfusion compared with untreated hearts. Finally, the results of in vitro experiments indicated that nicorandil (10(-6) to 10(-3) M) produced a concentration-dependent inhibition of superoxide anion free radical production by human and canine neutrophils. The K(+)-channel opener EMD 52692 also inhibited superoxide production in canine neutrophils. These results indicate that nicorandil is a highly efficacious myocardial protective agent in several animal models of reversible or irreversible ischemia-reperfusion injury.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004095:Dihydropyridines / Q000494:pharmacology; D004285:Dogs; D005260:Female; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009203:Myocardial Infarction / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D009543:Nifedipine / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D013481:Superoxides / Q000032:analysis
chemical_list: D001578:Benzopyrans; D004095:Dihydropyridines; D015221:Potassium Channels; D013481:Superoxides; D009536:Niacinamide; D020108:Nicorandil; C061050:bimakalim; D009543:Nifedipine