SR calcium handling and calcium after-transients in a rabbit model of heart failure

Abstract

in HF, diastolic calcium is increased and both SR calcium content and SR membrane calcium gradient are decreased in a stimulation rate-dependent manner. In HF, beta-adrenergic stimulation can partly restore the SR calcium content and SR membrane gradient at higher stimulation rates in a meta-stable condition; upon transition to low stimulation rates, the SR membrane can no longer maintain this high unbalanced SR calcium load at increased diastolic calcium, the magnitude of which is causally related to the occurrence of calcium after-transients.