Fig. 5. Loss of TH(+) interneurons in the OB of Arx-deficient mice. (A-J) Parasagittal sections of E16.5 (A-D) and P0 (E-J) brains of wild-type (A,C,E,G,I) and Arx-deficient (B,D,F,H,J) mice were labeled with anti-TH antibody (red), anti-GABA antibody (green) and counterstained with DAPI (blue). In wild-type mice, TH immunoreactivity was observed in periglomerular cells (PG) in the olfactory bulb (OB) (A,E,I). However, no TH(+) cells were detected in the OB or the rostral migratory stream (RMS) of mutant mice (B,F,J). In contrast, differentiation of TH(+) cells in the substantia nigra (SN) was not affected (D). TH signals in the caudate putamen (CPu) are derived from axon terminals of dopaminergic neurons in the SN (E,F,I,J). (K,L) In situ hybridization analysis of Nurr1 expression on OB coronal sections of P0 wild-type (K) and mutant (L) mice. In the wild-type mouse (K), Nurr1(+) cells were observed in the glomerular layer (GL) and granule cell layer (GCL), whereas no Nurr1-positive cells were observed in mutant OB (L). MCL, mitral cell layer; OE, olfactory epithelium; ONL, olfactory nerve layer. Scale bars: in B, 400 µm for A,B; in D, 200 µm for C,D; in J, 800 µm for E-J; in L, 100 µm for K,L.