Mena M A, Pardo B, Paino C L, De Yebenes J G
Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain.
Neuroreport. 1993 Apr;4(4):438-40. doi: 10.1097/00001756-199304000-00025.
Levodopa, a dopamine (DA) precursor administered to patients with Parkinson's disease (PD), produces at 25-200 x 10(-6) M concentrations a dose-dependent reduction of 3H-DA uptake in foetal rat midbrain cultures. Also, a decrease in the number of viable cells and tyrosine hydroxylase (TH) positive neurones, plus disruption of the overall neuritic network are observed concurrently with an elevation of quinone levels in the culture medium. Ascorbic acid (AA), which abolished the quinone overproduction, partially prevented these effects. Though levodopa neurotoxicity in vivo is as yet unproven, AA may reduce vulnerability of endogenous or grafted DA neurones in patients with PD.
