ISSN:
1432-1912
Keywords:
Digoxin treatment
;
Dog heart Na+, K+-ATPase
;
Sodium pump
;
(3H)-ouabain binding
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary In order to determine whether a prolonged inhibition of cardiac Na+, K+-ATPase causes a compensatory or adaptive change in this enzyme, the relationships among serum digoxin concentration, binding of digoxin to the enzyme and cardiac Na+, K+-ATPase and sodium pump activity were studied in dogs chronically treated with digoxin. Digoxin was injected intravenously twice daily up to 4 weeks. Two hours after the injection of a single non-toxic dose of digoxin, Na+, K+-ATPase and sodium pump activities were inhibited quantitatively in a manner corresponding to the binding of digoxin to the enzyme. The magnitude of sodium pump inhibition was reduced 12 h after the digoxin injection, with simultaneous decreases in serum digoxin concentration and the binding of digoxin to the enzyme. After 1 or 4 weeks of digoxin treatment with non-toxic doses, the relationships among serum digoxin concentration, binding of digoxin to cardiac Na+, K+-ATPase and the degree of cardiac Na+, K+-ATPase or sodium pump inhibition remained unchanged. The magnitude of the inhibition was related to serum digoxin concentrations and digoxin binding to cardiac Na+, K+-ATPase, in a manner similar to that observed after a single digoxin injection. After 4 weeks of digoxin treatment with toxic doses, these relationships were also unaffected. It was concluded that prolonged digoxin treatment fails to alter the inhibition of myocardial Na+, K+-ATPase by this agent.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00501262
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