Fig. 6.

Effect of α-synuclein overexpression on DA synthesis in MN9D cell lines. Cells lysates were prepared from equivalent cultures of MN9D cells incubated in the presence of 200 μm NSD-1015 for 30 min. a, More DOPA accumulated after blocking AADC activity with NSD-1015 in parental MN9D cells than in wild-type (WT) or A53T mutant α-synuclein lines, indicating that TH activity is dramatically reduced in cells that overexpress α-synuclein. b, In situ DA synthesis was significantly greater for parental MN9D cells than for WT or A53T α-synuclein clonal lines incubated withl-[1-¹⁴C]tyrosine and compared for their ability to generate ¹⁴CO₂ from the radioactive precursor. Data are from two to six independent experiments presented as the mean ± SEM for each condition. *p < 0.05; **p < 0.01; ***p < 0.001.