DRD5 and early-onset autosomal dominant Alzheimer disease: Activation of DRD5 also protected dopaminergic neurons in a PD rat model (Chetrit et al., 2013), promoted neurogenesis in an Alzheimer’s disease mouse model (Shen et al., 2016) and regulated BDNF expression in the rodent brain (Perreault et al., 2013).