title: Lack of interaction of spironolactone with ouabain guinea pig isolated heart muscle preparations.
abstract: The effect of spironolactone on ouabain action was studied in experiments on guinea pig isolated heart muscle preparations. There was no effect of spironolactone on the ouabain-induced positive inotropic or toxic effects in isolated papillary muscles. This was accompanied by a lack of spironolactone effect on myocardial ouabain uptake. Only rather high spironolactone concentrations (1 X 10(-4) M) led to a reduced cardiac ouabain uptake (about 10%). The subcellular distribution pattern of ouabain, however, remained unchanged under these conditions. Studies on ouabain binding to a cardiac NaK-ATPase supported the conclusion that a direct interaction of spironolactone and cardiac glycosides at the myocardium could be ruled out.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D004347:Drug Interactions; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D010042:Ouabain / Q000378:metabolism / Q000494:pharmacology*; D010210:Papillary Muscles / Q000187:drug effects; D013148:Spironolactone / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D013148:Spironolactone; D010042:Ouabain; D000251:Adenosine Triphosphatases