APLNR and essential hypertension: 2001). Chronic sympathetic hyperactivity is present in a significant percentage of patients with essential hypertension, and is responsible for more than 90% of all hypertensive disorders (Carretero & Oparil, 2000). The causative mechanisms of elevated SNA remain unclear, although they probably involve both neural and humoral mechanisms. Studies have implicated the apelin‐apelin receptor (APJ) system in the increase of SNA and in the development of hypertension (Wu et al. 2014), although the underlying mechanism of action is undetermined.