Figure 2.

Assessment of dopamine neuron sample enrichment and purity by qPCR. The graph column title, “Sections,” refers to midbrain sections that have not been altered in terms of cellular content and therefore contain dopamine neurons and many other cell types. They constitute an appropriate reference for the estimation of enrichment and purity of a population of cells isolated from midbrain sections. Increased expression of the dopaminergic genes: DAT (a), TH (b), Vmat2 (c), and NURR1 (d), in SN and VTA laser-microdissected samples relative to whole midbrain sections is indicative of dopamine neuron enrichment. A significant reduction in expression of the GABA gene, GAD65 (e), and the lack of detection of the genes encoding for vesicular glutamate transporter 2 (Vglut2), and the glial gene, Gfap (data not shown), within the SN and VTA suggests isolation of a relatively pure population of dopamine neurons. The Ct for each gene was normalized to the Ct for the 18S rRNA reference gene, and data are presented as mean fold change in expression relative to sections ± SEM. Asterisks indicate significant difference to whole midbrain sections. *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001; n = 3.