ADORA2A and congestive heart failure: Indeed, in chronic heart failure in particular, adrenal GRK2 upregulation has already been established as an absolutely essential process for the induction and maintenance of the chronic sympathetic nervous system hyperactivity that accompanies and aggravates this disease thanks to the GRK2-dependent termination/blockade of the sympatho-inhibitory α2AR signaling in the chromaffin cells of the adrenal medulla [19,22,25,26].