AGTR1 and metabolic syndrome: However, the present study has been focused on dopaminergic neurons, as MetS has been associated with a higher risk of PD [6], and there is an important effect of RAS dysregulation on dopaminergic neuron vulnerability [15,17] and AT1 gene overexpression identifies the most vulnerable dopaminergic neurons located in the ventral substantia nigra in humans, while less vulnerable dopaminergic neurons in the dorsal substantia nigra showed very low levels of AT1 gene expression [14].