GRK2 and hydrops fetalis: Of note, elevated GRK2-dependent α2AR dysfunction during HF might also occur in other peripheral sympathetic nerve terminals of the heart (Figure 2) and of other organs, thus contributing to the increased NE release and spillover, as well as to the presynaptic α2AR dysfunction in ANS neurons observed in chronic HF (see above) (Lang et al., 1997; Aggarwal et al., 2001).