Speciation 98: Abstracts

In the presence of O₂ dopamine (1-amino-2-(3,4-dihydroxyphenyl)-ethane, DA) reacts spontaneously without the necessity of metal-ion catalysis under the production of stoichiometric amounts of, to form initially pink dopaminochrome, which is not stable and reacts further (without the consumption of dioxygen) to form the insoluble polymeric material known as "melanine". At the other hand it is shown (in vitro) that Fe(II) reacts in a Fenton type reaction with DA and the present H₂O₂ producing 5-hydroxydopamine (5-OHDA) and especially 6-hydroxydopamine (6-OHDA) which is shown to be able to release iron as Fe(II) from ferritine. The catalytic effects of some other transition-metal ions are presented and an explanation for the peculiarly toxic effects of manganese(II) is put forward¹. Based on these mutual interacting reactions a mechanism for the initiation and progress of Parkinson's Disease is suggested. A possible reason for the effect that nicotine has in the mitigation of Parkinson's Disease is discussed.

Acknowledgments: Thanks for financial support are due to the "Fonds zur Förderung der wissenschaftlichen Forschung un Österreich" (Project 11218) and the Österreichische Nationalbank" (Project: 5556)

References

1. W. Linert, E. Herlinger, R. F. Jameson, E. Kienzly, K. Jellinger and M.B.H. Youdim, Biochim. Biophys. Acta, 1996, 1316, 160.

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