Effects of nicorandil and nipradilol on ischemic myocardium in perfused rat heart.
We examined the effect of nicorandil and nipradilol on the ischemic myocardium in the isolated perfused rat heart. The heart was perfused by the working heart technique with an afterload pressure of 60 mm Hg and with a left atrial filling pressure of 9 mm Hg. Ischemia was induced for 20 min by lowering the afterload pressure. The afterload pressure was raised to 60 mm Hg again during reperfusion. Ischemia decreased the pressure-rate product, coronary flow, adenosine triphosphate level and creatine phosphate level, and increased the lactate level. Reperfusion could not restore the pressure-rate product nor the adenosine triphosphate level completely. Nicorandil (5 x 10(-5) and 1.5 x 10(-4) M) or nipradilol (10(-5), 5 x 10(-5) and 1.5 x 10(-4) M) was introduced 5 min before ischemia. Nipradilol preserved the levels of adenosine triphosphate and creatine phosphate after 20 min of ischemia and increased the extent of recovery of the pressure-rate product during reperfusion, whereas nicorandil did not. Nipradilol, but not nicorandil, can protect the myocardium against ischemic damage.
Haneda
T
T
First Department of Internal Medicine, Asahikawa Medical College, Japan.
Ichihara
K
K
Onodera
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism; D008297:Male; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D010725:Phosphocreatine / Q000378:metabolism; D011412:Propanolamines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D007773:Lactates; D011412:Propanolamines; D010725:Phosphocreatine; D009536:Niacinamide; D020108:Nicorandil; D000255:Adenosine Triphosphate; C036089:nipradilol