A high-salt diet reduced cardiac norepinephrine reuptake by 26%, and additional aldosterone infusion augmented this effect to a 36% reduction in rats.
Does aldosterone and/or high sodium intake reduce cardiac norepinephrine reuptake in rat models?
Aldosterone exacerbates the reduction in cardiac norepinephrine reuptake induced by a high-salt diet, suggesting a synergistic mechanism for sympathetic overstimulation in heart failure.
Effect estimate: 36% reduction
Impairment of the cardiac norepinephrine (NE) reuptake by the neuronal NE transporter contributes to enhanced cardiac NE net release in congestive heart failure. Elevated plasma levels of aldosterone (AL) promote sympathetic overstimulation in failing hearts by unclear mechanisms. Our aim was to evaluate if elevated AL and/or alterations in Na(+) intake regulate cardiac NE reuptake. To test the effects of AL and Na(+) on cardiac NE reuptake, Wistar rats were fed a normal-salt (NS) diet (0.2% NaCl), a low-salt (LS) diet (0.015% NaCl), or a high-salt (HS) diet (8% NaCl). Another group of animals received AL infusion alone (0.75 μg/h) or AL infusion plus HS diet. Specific cardiac (3)HNE uptake via the NE transporter in a Langendorff preparation and AL plasma levels were measured at different time points between 5 and 42 days of treatment. To compare these findings from healthy animals with a disease model, Dahl salt-sensitive rats were investigated as a model of congestive heart failure with endogenously elevated AL. In summary, neither exogenous nor endogenous elevations of AL alone were sufficient to reduce cardiac NE reuptake. Only the HS diet induced a reduction of NE reuptake by 26%; additional infusion of AL augmented this effect to a further reduction of NE reuptake by 36%. In concordance, Dahl salt-sensitive rats treated with a HS diet displayed elevated AL and a marked reduction of NE reuptake. We conclude that exogenous or endogenous AL elevations alone do not reduce cardiac NE reuptake, but AL serves as an additional factor that negatively regulates cardiac NE reuptake in concert with HS intake.
Kreußer et al. (Sat,) conducted a other in Congestive heart failure model. Aldosterone infusion plus high-salt diet vs. Normal-salt diet, low-salt diet, or aldosterone infusion alone was evaluated on Cardiac norepinephrine (NE) reuptake (36% reduction). A high-salt diet reduced cardiac norepinephrine reuptake by 26%, and additional aldosterone infusion augmented this effect to a 36% reduction in rats.