RT Journal Article SR Electronic T1 STUDIES ON THE INOTROPIC ACTION OF ALDOSTERONE ON ISOLATED CARDIAC TISSUE PREPARATIONS; INCLUDING THE EFFECTS OF pH, OUABAIN AND SC-8109 JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 71 OP 78 VO 135 IS 1 A1 Ralph D. Tanz YR 1962 UL http://jpet.aspetjournals.org/content/135/1/71.abstract AB The inotropic action of aldosterone on various in vitro cardiac preparations was investigated. The results obtained are presented as evidence that the addition of dl-aldosterone ( 1 x 10-5 µg/ml) to the perfusate has the ability to produce a positive inotropic action on the cat papillary and whole isolated heart preparations. Furthermore, the observed positive inotropic action is the result of a direct effect upon the myocardium. Ancillary studies showed that a reduction in the NaHCO3 concentration lowers the pH of the perfusate and apparently increases the sensitivity of cardiac tissue to aldosterone, as well as providing a more stable preparation. In addition, the renal-aldosterone antagonist, SC-8109, is also able to produce a positive inotropic action but our data suggest that it does not antagonize the cardiotonic action of aldosterone, nor the cardiotoxic action of ouabain.