Fig. 1. The aphakia (ak) mice have no detectable Pitx3 and a markedly reduced midbrain dopaminergic system. (A-D) Adjacent coronal midbrain sections containing the SN in P50 wild-type (A,C) and ak (B,D) mice immunostained for TH (A,B) and Pitx3 (C,D). Rostrocaudal positions are indicated as millimeters relative to bregma in the lower right corner. (E) High-power view of the SN shown in C, highlighting the nuclear staining. By contrast, none of the weak background staining in D was nuclear. (F-K) Equivalent rostral-to-caudal coronal midbrain sections of P100 wild-type (F,H,J) and ak (G,I,K) mice immunostained for TH. (L) Stereological analysis of TH-positive cells of the left SN and VTA in wild-type and ak mice. The data are represented as the means±s.e.m. (n=4). (M) Density of Nissl-stained cell bodies in the left SN and VTA of wild-type and ak mice (n=4). A statistically significant decrease in TH-positive cell bodies and density of Nissl-stained cell bodies was detected in the SN and VTA of ak mice compared with controls (P<0.01, t-test). (N,O) Coronal sections through the right SN (N) and VTA (O) of a P50 wild-type mouse immunostained for TH (fluorescein-labeled, green) and Pitx3 (rhodamine-labeled, red) analyzed by confocal microscopy. Scale bars: in A, 125 µm for A-D; in F, 250 µm for F-K; in E, 30 µm for E; in N and O, 30 µm.