D2-MSN dysfunction in PD condition is mainly manifested by glutamate-mediated excitotoxicity and abnormal function of D2R (Chen et al., 2004; Garcia et al., 2010; Wei et al., 2013), leading to excessive activation of indirect pathways and dysfunction of the basal ganglia (Surmeier et al., 2007). This evidence concerns the gene MSN and Parkinson disease.