A model for aganglionosis in the chicken embryo.

We investigated the ability of neural crest (NC) cells to colonize hindgut, which had remained aneuronal due to bowel transection in ovo at an early stage. The fact that the bowel remained aneuronal proved that the "sacral" NC does not provide precursor cells for enteric neurons in the hindgut. HNK-1 immunostaining of aneuronal hindgut revealed cell-free, ganglionic structures at the site of the myenteric plexus and a sub-population of mesenchymal cells in the submucosa. We cocultured this particular type of aneuronal bowel with the vagal neural anlage of either quail or chick embryos on the chick chorioallantoic membrane. After 1 week coculture, it appeared that NC cell colonisation of the hindgut had taken place, although there was a difference between the quail-chick and chick-chick model. Quail NC cells had given rise to submucous plexuses and some myenteric plexuses. Chick NC cells had only colonised the submucous region. These findings indicate that the cell-free ganglionic structures hamper neural crest cell colonization in the myenteric region.