Fig. 1. Distribution of NGF, NT3, and BDNF mRNAs in sections from the dorsal hippocampus immunostained for calcium-binding proteins. All pairs of photomicrographs are from the same section except in C and D. A, B, Dark-field photomicrograph (A) illustrating NGF mRNA autoradiographic labeling in a PARV-immunoreacted section (B). NGF mRNA hybridization is observed in the dentate gyrus and in cells scattered throughout the hippocampal layers (small arrows). PARV-immunoreactivity is concentrated around the main cell layers.C, Dark-field image showing NT3 hybridization signals in the dentate granule cell layer and in the CA2 pyramidal layer.D, CALB-immunoreacted section showing immunolabeling in dentate granule cells and their axons, the mossy fibers (small arrows). Some nonpyramidal immunoreactive neurons are observed in several layers. E, F, A pair of photomicrographs of the same field showing BDNF mRNA hybridization (E) and CALR-immunostaining. F, BDNF transcripts are detected in the dentate granule cell layer and in the pyramidal cell layer. CALR-immunopositive nonpyramidal neurons are present in the different hippocampal layers. CA1, CA2, CA3, Hippocampal fields;DG, dentate gyrus; h, hilus; sg, stratum granulare; sm, stratum moleculare; so, stratum oriens; sp, stratum pyramidale; sr, stratum radiatum. Scale bar, 200 μm.