Fig. 1. Ahd2 expression marks a specific mdDA subpopulation in the adult brain. (A) Coronal sections from the rostral (R) to caudal (C) mdDA area containing neurons in the SNc (A-D) and VTA (E-L). (Left panels) The cell bodies of these mdDA neurons were identified by Th mRNA expression. (Right panels) Analysis of Ahd2 expression on adjacent sections. (B) Combined in situ hybridization for Ahd2 mRNA (purple) and an immunohistochemical staining for TH protein (brown) on adult coronal sections. The boxed areas indicated in A and D are displayed at a higher magnification in the panels B and C, and E and F, respectively. (C) Adult coronal sections of the SNc (A-C,G-I) and VTA (D-F,J-L). (B,E) Ahd2 protein distribution (red). MdDA neurons were identified by the expression of TH protein (green; A,D). Overlays demonstrate the co-expression of the TH and Ahd2 proteins in a subpopulation of mdDA neurons located in the SNc and VTA (C,F-L). The boxed areas indicated in G and J are displayed at a higher magnification in H and I, and K and L, respectively. mdDA, meso-diencephalic dopaminergic; SNc. substantia nigra pars compacta; VTA, ventral tegmental area.