OXT and Parkinson disease: Since the reduction of PVN oxytocin neurons was reported in PD patients [16] and our previous study found the relative sex invariance in structure and function for oxytocinergic regulation of midbrain DA neurons,[23] we focused on investigating the changes of oxytocin signal in the MPTP‐induced PD model in male mice in this study.[28] It's difficult to selectively dissect the SNc, so we used the SN region for the molecular biology experiments.