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Figure 1. Patterning of ventral dopamine-containing spinal cord neurons. A: Whole-mounted spinal cord showing two longitudinal columns of cells immunoreactive for tyrosine hydroxylase in animals a day after hatching (3.2 d, st 41). Immunoreactivity can be detected soon after neural tube closure (1.2 d, st 26, Chen et al.,[1999]). Most of these cells are primary dopaminergic neurons (Binor and Heathcote,[2001]). B: Similar view of immunoreactive cells at 12 d (st 49) show that dopaminergic neurons and their pattern of organization (two columns of dispersed cells) are maintained as secondary neurons are added. C: Frozen cross-section of a posthatching embryo including the spinal cord, stained with glyoxylic acid, which causes catecholamines to fluoresce (Torre and Surgeon,[1976]). Arrows indicate cells in each column and show that they are in a ventral location, adjacent to the notochord. Scale bars = 10 mu m in A, 50 mu m in B,C. |
