Figure 1.

Expression pattern of the p75^NTR in the mouse hippocampus. A, Quantitative real-time PCR assays document the expression of p75^NTR in the developing hippocampus (HIP) and cerebellum (CER) as well as in hippocampal slice cultures (HIP slice). CNS tissues were obtained from animals 10 or 28 d of age. The slices had a corresponding age and were isolated from a P5 mouse brain allowed to mature in vitro for an additional 5 or 23 d, respectively. Note that, in each case, p75^NTR expression is developmentally downregulated. Gene expression data are shown as percentage relative p75^NTR transcript levels normalized to GAPDH mRNA. The error bars indicate the SD of the mean of three measurements. A total of four independent real-time PCR experiments were performed (3 using probe set p75^NTR-A and 1 with probe set p75^NTR-B), all giving similar results. B, Micrographs showing in situ hybridization for p75^NTR mRNA in the P21 mouse hippocampus. Note p75^NTR gene expression in the dentate gyrus and in both the CA1 and CA3 region [4′,6′-diamidino-2-phenylindole dihydrochloride (DAPI) staining in the bottom panels]. Sections incubated with the p75^NTR sense probe did not show specific staining (right panels). Scale bar, 1 mm. C, Micrographs showing the in situ hybridization for p75^NTR mRNA in hippocampal slice cultures derived from P5 mouse and cultivated for 15 d. Similar to the in vivo condition, p75^NTR mRNA was detected in the dentate gyrus as well as in CA1 and CA3. Sections incubated with the sense probe did not reveal specific staining (right panel). Scale bar, 1 mm. D, Left, Higher magnification of the CA1 area of a culture stained with the p75^NTR antisense probe showing a significant number of positive cells in all of the areas mentioned above. Right, A higher magnification shows several positive cells in the CA1 region. Scale bar, 500 and 100 μm, respectively. In situ hybridizations shown in B-D were performed on more than five occasions each with identical outcome.