Figure 9

HA acts on early dopamine neural precursors but differentiated dopamine neurons are resistant. Sagittal sections of the VM from vehicle- and HA-treated rat embryos that were injected at different developmental stages, and analyzed two days later. Sections were stained to detect neurons (β-III Tubulin+) and dopaminergic phenotype (TH+); nuclei were detected with Hoechst. The decreasing effect of HA injection on dopaminergic phenotype is evident only when injected at early developmental stages (E10-E12 or E12-E14) but not at later developmental stages (E14-E16 or E16-E18). For the vehicle-injected E10-E12 embryos, only a few TH + neurons were found in the isthmic region and these neurons were absent in HA-injected organisms. Scale bars are indicated in the figure.