Fig. 3. Effects of limb bud deletion and NT3 treatment on trkC+ sensory neurons. Transverse sections of E10 DRG from control (A–C) and NT3-treated (D–F) embryos are stained for trkC. A, In normal lumbar DRG of control embryos, trkC+ neurons (arrows) were mainly confined to the ventrolateral (VL) region of each ganglion. B, In lumbar DRG on the limb-deleted side, few trkC+ neurons (arrows) survived, and the VL aspect of the DRG was reduced (compare with A). C, In thoracic DRG of control embryos, few trkC+ neurons (arrows) were normally detected. As in lumbar segments, these neurons were localized primarily to the VL region.D, In normal lumbar DRG, NT3 treatment (10 μg/d) increased the number of trkC+ neurons (arrows) within the VL region (compare with A). E, In lumbar DRG on the limb-deleted side, NT3 treatment rescued the trkC+ population and maintained the normal size of the VL region (compare with A and B). F, In thoracic DRG, NT3 treatment increased the trkC+ population (arrows) and expanded the VL region of the DRG. In each panel, the orientation is the same: dorsal is up and lateral is to the left. VL indicates the ventrolateral region of the ganglion, and DM indicates the dorsomedial region. In this figure and in Figures 4 and 5, the lumbar ganglia shown are from LS3 and the thoracic ganglia shown are from T5 or T6. The ganglia shown are the same ganglia that were used for cell counts (Fig. 6). Scale bar, 50 μm.