OXTR and Parkinson disease: We demonstrated that 1) both oxytocin level and SN oxytocin receptor expression are significantly disturbed in the MPTP‐induced PD model; 2) modulating brain oxytocin level or SN oxytocin receptor expression bi‐directionally changes the vulnerability of nigrostriatal DA neurons in the MPTP‐induced PD model; 3) oxytocin may protect nigrostriatal DA signal by reducing DA neuronal excitotoxicity via oxytocin receptors expressed in SN GABA neurons and GABA(B) receptors expressed in SNc DA neuron‐targeted glutamatergic terminals.