Brain RAS contains the same elements as the other tissue RAS. Besides Ang II and AT1R, all the other components of RAS such as AGT, renin, AT2R, ACE, Ang IV, Ang-(1-7), Mas, and new elements such as prorenin/renin receptor and Ang- (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) , have been identified in the central nervous system [7, 8] . However, the distribution of the new element ACE2 in the brain was at first controversial because original reports failed to identify the carboxypeptidase in this tissue [2, 3] . A few years later, ACE2 mRNA and protein were found in the brain by our group and others [9] [10] [11] . Using a selective antibody, we reported that ACE2 is widespread throughout the mouse brain, present in nuclei involved in the central regulation of cardiovascular function such as the subfornical organ, paraventricular nucleus (PVN), nucleus of the tractus solitarius (NTS), and rostral ventrolateral medulla (RVLM), as well as in noncardiovascular areas such as the motor cortex and raphe ( Fig. 1 ). Shortly after our observation, Lin et al. [12•] confirmed the presence of ACE2 mRNA and protein in the mouse brainstem and reported the interaction between ACE2 and AT1R in this region. These data suggest that ACE2 is actively involved in the brain RAS function.