A catalyst function for MPTP in superoxide formation.

We demonstrate that 1-methyl-4-phenyl-1,2-dihydropyridine (MPDP) can be generated, in an alternate pathway, from the catalyst action of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) upon the iron redox equilibrium reaction. Superoxide and ferric iron are instantaneously produced after addition of MPTP to a solution of ferrous iron. This reaction is oxygen and pH dependent. Superoxide, through a iron dependent Haber-Weiss reaction with peroxide, can generate the cytotoxic hydroxyl radical. A small portion of the superoxide reacts with MPTP to produce the reactive species X. which, in the presence of Fe+3 can also generate MPDP.