Cysteine oxidation and redox signaling in dopaminergic neurons physiology and in Parkinson’s disease

•Oxidative stress is a recurring and fundamental pathogenic mechanism in PD.•Dopamine neurons in the SNpc are oxidized in physiological conditions.•Redox signaling is particularly important for dopamine neurons’ physiology.•Moderate oxidation may ensure redox signaling specificity and may be protective.•Physiological oxidation may be an example of antagonistic pleiotropy in aging.