title: Increased dopamine peroxidation in postmortem Parkinsonian brain.
abstract: We have previously reported the presence, in human midbrain, of an enzymatic activity which catalyzes the formation of dopaminochrome from dopamine (DA) and hydrogen peroxide. Here, we report, for the first time, an increased DA peroxidizing activity in the midbrain and basal ganglia of autoptic Parkinsonian brains. The crude activity was determined spectrophotometrically in extracts of paraffin-embedded slices obtained from autopsied brain. No addition of substrate was necessary since endogenous substrates such as DA and hydrogen peroxide were present in the samples. In Parkinson's patients' midbrain, this activity was substantially increased compared to normal midbrain. Moreover, the DA peroxidizing activity, which was absent in basal ganglia of normal people, was detectable in all our Parkinson's patients. These observations suggest that a peroxidizing pathway of DA may be present in human brain. The increased peroxidizing activity in Parkinson's patients generates the toxic compound dopaminochrome which may play a role in the pathogenesis of this disease.
authors.affiliation: Department of Diagnostics, University of Padua, Viale G. Colombo 3, Italy. angela.deiuliis@unipd.it
authors.forename: Angela
authors.initials: A
authors.lastname: De Iuliis
authors.forename: Alessandro P
authors.initials: AP
authors.lastname: Burlina
authors.forename: Roberta
authors.initials: R
authors.lastname: Boschetto
authors.forename: Pamela
authors.initials: P
authors.lastname: Zambenedetti
authors.forename: Paola
authors.initials: P
authors.lastname: Arslan
authors.forename: Lauro
authors.initials: L
authors.lastname: Galzigna
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001479:Basal Ganglia / Q000378:metabolism; D001921:Brain / Q000201:enzymology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D045563:Indolequinones; D007211:Indoles / Q000378:metabolism; D008297:Male; D008636:Mesencephalon / Q000378:metabolism; D008875:Middle Aged; D010084:Oxidation-Reduction; D010300:Parkinson Disease / Q000201:enzymology / Q000209:etiology / Q000378:metabolism*; D011180:Postmortem Changes
chemical_list: D045563:Indolequinones; D007211:Indoles; C091584:aminochrome 1; D006861:Hydrogen Peroxide; D004298:Dopamine