In the striatum, BoNT-A is thought to act in two main directions: ACh release of the tonically active cholinergic interneurons is blocked [1,4,5]; and the concentrations of the dopamine D2 receptor is reduced as shown in hemi-PD rats with D2 receptor upregulation, as in BoNT-A-injected normal rats [38,39]. The gene discussed is DRD2; the disease is Parkinson disease.