Enhancing effect of manganese on L-DOPA-induced apoptosis in PC12 cells: role of oxidative stress.
L-DOPA and manganese both induce oxidative stress-mediated apoptosis in catecholaminergic PC12 cells. In this study, exposure of PC12 cells to 0.2 mM MnCl2 or 10-20 microM L-DOPA neither affected cell viability, determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, nor induced apoptosis, tested by flow cytometry, fluorescence microscopy, and the TUNEL technique. L-DOPA (50 microM) induced decreases in both cell viability and apoptosis. When 0.2 mM MnCl2 was associated with 10, 20, or 50 microM L-DOPA, a concentration-dependent decrease in cell viability was observed. Apoptotic cell death also occurred. In addition, manganese inhibited L-DOPA effects on dopamine (DA) metabolism (i.e., increases in DA and its acidic metabolite levels in both cell lysate and incubation medium). The antioxidant N-acetyl-L-cysteine significantly inhibited decreases in cell viability, apoptosis, and changes in DA metabolism induced by the manganese association with L-DOPA. An increase in autoxidation of L-DOPA and of newly formed DA is suggested as a mechanism of manganese action. These data show that agents that induce oxidative stress-mediated apoptosis in catecholaminergic cells may act synergistically.
Migheli
R
R
Department of Pharmacology, University of Sassari, Italy.
Godani
C
C
Sciola
L
L
Delogu
M R
MR
Serra
P A
PA
Zangani
D
D
De Natale
G
G
Miele
E
E
Desole
M S
MS
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000096:biosynthesis; D015259:Dopamine Agents / Q000633:toxicity*; D004357:Drug Synergism; D005434:Flow Cytometry; D007980:Levodopa / Q000633:toxicity*; D020149:Manganese Poisoning; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats
D000975:Antioxidants; D015259:Dopamine Agents; D007980:Levodopa; D001205:Ascorbic Acid; D004298:Dopamine; D000111:Acetylcysteine