The influence of ouabain and alpha angelica lactone on calcium metabolism of dog cardiac microsomes

Mark L. Entman; Joseph W. Cook; Rubin Bressler

doi:10.1172/JCI105979

^{Department of Medicine, Duke University Medical Center, Durham, North Carolina 27706}

^{Department of Physiology and Pharmacology, Duke University Medical Center, Durham, North Carolina 27706}

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^{Department of Medicine, Duke University Medical Center, Durham, North Carolina 27706}

^{Department of Physiology and Pharmacology, Duke University Medical Center, Durham, North Carolina 27706}

Find articles by Cook, J. in: PubMed | Google Scholar

^{Department of Medicine, Duke University Medical Center, Durham, North Carolina 27706}

^{Department of Physiology and Pharmacology, Duke University Medical Center, Durham, North Carolina 27706}

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Published in Volume 48, Issue 2 on February 1, 1969
J Clin Invest. 1969;48(2):229–234. https://doi.org/10.1172/JCI105979.
© 1969 The American Society for Clinical Investigation

Published February 1, 1969 - Version history

The influence of ouabain and alpha angelica lactone on ⁴⁵calcium accumulation in cardiac microsomes was studied. Calcium binding (accumulation in the absence of excess oxalate or phosphate) was augmented by both ouabain and alpha angelica lactone in the presence of adenosine triphosphate (ATP) but unaffected in its absence. Calcium turnover (defined as the change in ⁴⁵Ca⁺⁺ bound to the microsomes after the specific activity is changed) was studied to determine if the augmented bound pool was freely exchangeable at equilibrium. Ouabain and alpha angelica lactone augmented calcium turnover in both the presence and absence of ATP. Calcium-stimulated ATPase was increased by both agents.

It is proposed that these two unsaturated lactones, with known cardiotonic activity, may exert their effects by providing an increased contraction-dependent calcium pool to be released upon systolic depolarization.