AGTR1 and Parkinson disease: In several recent studies, we used 6-OHDA and MPTP models of parkinsonism to study the possible role of the brain RAS in dopaminergic degeneration: the results suggest that enhanced levels of AII, via AT1 receptors, exacerbate dopaminergic cell death and may play a synergistic role in the pathogenesis and progression of PD.