Figure 3.

Putative involvement of PON1 in susceptibility to Parkinson's disease. In Parkinson's disease, due to death of degeneration in the substantial nigra there is an imbalance between acetylcholine and dopamine (1 and 2). Free radical species (3) that generate peroxide and organophosphate oxons both attack and inhibit acetylcholinesterase (4), thereby increasing acetylcholine and aggravating the imbalance. PON1, thorough its peroxidase (5) and triesterase (6) actions, blocks these effects and prevents the worsening of the imbalance. Of note, the oxonase activity of PON1 is highly dependent on the most common polymorphisms. Subjects with different phenotypes may thereby be more or less susceptible to damage to acetylcholine.