Table 3.

Summary.

Neuromelanin synthesis can be a normal and harmless process that requires the formation of the endogenous neurotoxin aminochrome due to the existence of DT-diaphorase and glutathione transferase M2-2 prevent the neuro-toxic effects of aminochrome.

Astrocytes secrete glutathione transferase M2-2 through exosomes that penetrate dopaminergic neurons, releasing this enzyme inside the cytosol of these neurons.