Further evidence that enterochromaffin cells are not derived from the neural crest

Abstract

Recently, a previous finding that the enterochromaffin cells of chick embryos are not derived from the neural crest has been contested, and so further evidence has been sought. Presumptive gut, i.e. endoderm and adherent mesoderm, of embryos between the short headprocess stage and the 25-somite stage was grown on the chorio-allantoic membranes of host embryos. Whether the presumptive gut was excised before or after the probable time of arrival of neural crest cells in the gut, enterochromaffin cells occurred in the intestine in the grafts. The presence or absence of enteric ganglia indicated the presence or absence, respectively, of neural crest cells. Enterochromaffin cells were plentiful even if the donor had been at a stage preceding that at which cells of the neural crest start to migrate, or preceding that at which the crests themselves first appear. In a second experiment, presumptive gut of embryos at 10-to 21-somite stages was excised so as to exclude the portion underlying the somites. Enteric ganglia were lacking in the intestine of these grafts, but enterochromaffin cells were invariably present. These experiments show that the precursors of enterochromaffin cells are present in the more lateral part of the presumptive gut before the neural crest precursors of enteric ganglia reach the region; and that they are present in the presumptive gut long before any crest cells could have arrived there. This evidence supports the view that enterochromaffin cells are not derived from the neural crest in chick embryos.