GRK2 and heart failure: The mechanisms underlying these beneficial changes in rats with heart failure have not been fully elucidated; however, in heart failure, increased activity of the sympathetic nervous system leads to a detrimental downregulation and desensitisation of myocardial β1‐adrenoreceptors (β‐AR) and upregulation of a key negative regulator of β‐AR‐mediated signalling, G‐protein coupled receptor kinase 2 (GRK2) (Woo & Xiao, 2012).