title: Myocardial sodium pump activity in endotoxin shock.
abstract: The effect of endotoxin administration on the integrity of sodium pump was studied in canine heart myocardium. Sodium pump activity was determined based on the 86Rb+ uptake by ventricular muscle strips. The results show that 4 hr following endotoxin administration the ouabain-sensitive 86Rb+ uptake was inhibited by 44-70%, and the inhibition was noncompetitive with 86Rb+ ions and was independent of Na+ concentrations. The sensitivity of sodium pump toward verapamil inhibition was unaffected by endotoxin administration, suggesting that the endotoxin-induced decrease in sodium pump activity is not mediated through alteration in either calcium or slow sodium channel. The sensitivity of 86Rb+ uptake to ouabain inhibition was decreased approximately sixfold in endotoxin-injected dogs. These data suggest that sodium pump is greatly impaired in dog hearts 4 hr after endotoxin administration. The impairment in sodium pump might have physiological significance in the development of myocardial dysfunction during endotoxic shock.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004285:Dogs; D005260:Female; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010766:Phosphorylation; D012413:Rubidium / Q000378:metabolism; D012772:Shock, Septic / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
chemical_list: D010042:Ouabain; D012964:Sodium; D014700:Verapamil; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D002118:Calcium