AGT and heart failure: However, there are significant technical challenges in studying AngII-induced intraneuronal signaling in vivo in animal models of hypertension and heart failure such as: (1) limited number of neurons within a specific cardiovascular control brain region of interest to perform a particular assay; (2) separating intraneuronal signaling events from other pathways activated in neighboring cells including glia and endothelial cells; and (3) separating the signaling mechanisms of other peptides and hormones associated with these diseases from those directly induced by AngII.