FXYD1 and Hypertension: Although it is tempting to suggest that the downregulation of Na/K pump function in WT mice is causally associated with aging-induced hypertension, and the protection afforded in the PLM3SA mouse suggests a causal role for phospholemman phosphorylation, it is also possible that the chronic downregulation of sympathetic outflow in the PLM3SA mouse is akin to a lifetime of β-blockade, and the changes in WT phospholemman are merely coincidental.