Prevention by K+, Mg2+-aspartate of isoproterenol-induced metabolic changes in the myocardium.
Isoproterenol ISO), in a single dose of 7.5 mg/kg body weight, was found to produce alterations of cardiac metabolism in dogs. After 2 hours, high energy phosphate stores and glycogen were reduced, whereas the levels of lactate and pyruvate, the lactate/pyruvate ratio, and myofibrillar ATPase activity were elevated. Ca2+ accumulation by sarcoplasmic reticulum (SR) and mitochondria were increased (p less than 0.01). After 24 hours, a partial recovery in the parameters studied could be observed. Only myofibrillar ATPase activity and the Ca2+ uptake by SR and mitochondria were lowered. When K+, Mg2+-aspartate (K,Mg-ASP) was administered concurrently with ISO, myofibrillar ATPase and Ca2+ accumulation by SR did not differ from controls 2 hours after ISO application; also, the other parameters exhibited a tendency to improve (p less than 0.01), but did not reach control levels. At 24 hours after ISO application, we could observe a similar effect of K,Mg-ASP in the prevention of Ca2+ overload accompanying metabolic changes.
D000227:Adenine Nucleotides / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D050260:Carbohydrate Metabolism; D004285:Dogs; D006321:Heart / Q000187:drug effects; D007545:Isoproterenol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009210:Myofibrils / Q000201:enzymology / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D014475:Uncoupling Agents
D000227:Adenine Nucleotides; D014475:Uncoupling Agents; D010725:Phosphocreatine; D001224:Aspartic Acid; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium; D007545:Isoproterenol; D011188:Potassium; D002118:Calcium