Figure 3

Developmental regulation of Trk receptors in sympathetic ganglia. Transverse sections of St 29/30 (E6.5), St. 31 (E7), and St. 34 (E8) sympathetic ganglia were labeled for Islet-1 (red) and TrkA, TrkB, or TrkC (green). The number of Islet-1-positive cells that express TrkA increases between St. 29/30 (E6.5) and St. 31 (E7), and all of the neurons express TrkA at St. 34 (E8) (A, D, G). Islet-1 positive cells express TrkB and TrkC at St. 29/30 (E6.5) (B, C). TrkB and TrkC expression appeared dispersed at St. 31 (E7) (E, F), and expression was no longer detectable at St. 34 (E8) (H, I). Calibration bar: 20 μ.