F. Debernardi et al., THE POSTNODAL PIECE (PNP) OF THE CHICK-EMBRYO AS A MODEL SYSTEM FOR STUDYING ORGAN DIFFERENTIATION, Toxicology in vitro, 9(5), 1995, pp. 583
The postnodal piece of the chick embryo is prepared by cutting the bla
stoderm 0.6 mm behind Hensen's node at the primitive streak stage. The
explants with their area opaca can be maintained in flat culture (New
's method) for 24-30 hr. With this method the polarity and the connect
ions between various sheets are maintained, but the explants are stret
ched and difficult to handle for histology and immunostaining. Several
PNPs from which the area opaca had been trimmed were cultured on one
vitelline membrane (Niu and Deshpande's method) for up to 4 days witho
ut stretching effects. The polarity and connections between the embryo
nic sheets are hard to recognize, but explants can be easily processed
for histology and immunofluorescence. In both culture types the expla
nts can be easily treated, even with high molecular weight substances.
Although the hat culture was useful for the induction of somites and
of neural plates, we describe the advantages of culture without the ar
ea opaca of neural plates induced by tubulin mRNA or by TPA, which can
differentiate into neural tubes. We also demonstrated that TPA is a p
owerful neural inducer in the chick embryo and stimulates cell prolife
ration in ectoderm and endoderm.