Diminished inotropic responsiveness to ouabain in aged rat myocardium.
Population
Hearts (isometric trabeculae carneae) from young adult and senescent rats
Comparison
Ouabain and paired pacing vs Young adult vs senescent rat myocardium
Design
Preclinical
Authors
Discussion
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Overview
May limit digitalis efficacy in older adults; leaves open post-binding calcium-handling defects as a research target.
Structured PICO
P
Population
Hearts (isometric trabeculae carneae) from young adult and senescent rats
I
Intervention
Ouabain (concentration range 2 x 10^-6 to 6 x 10^-5 M) and paired pacing
C
Comparator
Young adult vs senescent rat myocardium
O
Outcome
Developed tension (DT), maximal rate of tension development (dT/dt), and inhibition of (Na + K)-ATPasesurrogate
Aged rat myocardium exhibits diminished inotropic responsiveness to ouabain compared to young adult myocardium, likely due to an alteration in a step linking ouabain binding to increased myoplasmic calcium levels rather than enzyme inhibition.
Cite This Study
Gerstenblith et al. (1979) studied this question.