Effect of propranolol and nitroglycerin plus methoxamine on transmural creatine kinase activity after acute coronary occlusion.
Transmural creatine kinase activity was determined 5 hours after acute occlusion of the left anterior descending coronary artery in 27 open chest anesthetized dogs. In seven dogs, propranolol, 2 mg/kg, was given intravenously over a 10 minute period 10 minutes after occlusion. In 10 dogs, nitroglycerin, 300 microgram/min, was infused intravenously for 1 hour 10 minutes after occlusion. Methoxamine, 300 to 500 microgram, was administered to return blood pressure and heart rate to prenitroglycerin levels. In untreated dogs, there was a distinct transmural gradient of creatine kinase activity in the ischemic region from subepicardium to subendocardium: nonischemic subepicardium 1,187 +/- 50 international units (IU)/g versus ischemic subepicardium 1,054 +/- 46 IU/g and nonischemic subendocardium 1,170 +/- 53 IU/g versus ischemic subendocard;um 766 +/- 42 IU/g, respectively. Administration of propranolol did not affect the transmural creatine kinase gradient after 5 hours of occlusion. In contrast, nitroglycerin plus methoxamine significantly (P less than 0.05) decreased subendocardial creatine kinase depletion after 5 hours of occlusion (776 +/- 42 versus 978 +/- 47 IU/g). These findings demonstrate the unique capability of nitroglycerin plus methoxamine to protect the subendocardium during ischemic insult.
D000208:Acute Disease; D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism*; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D005260:Female; D006439:Hemodynamics; D007263:Infusions, Parenteral; D007275:Injections, Intravenous; D008297:Male; D008729:Methoxamine / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D009203:Myocardial Infarction / Q000201:enzymology* / Q000517:prevention & control; D009206:Myocardium / Q000201:enzymology*; D005996:Nitroglycerin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors
D011433:Propranolol; D003402:Creatine Kinase; D005996:Nitroglycerin; D008729:Methoxamine