An experimental and ultrastructural study on the development of the avian choroid plexus.
The choroid plexus consists of the choroidal epithelium, a derivative of the neural tube, and the choroidal stroma, which originates from the embryonic head mesenchyme. This study deals with epithelio-mesenchymal interactions of these two components leading to the formation of the organ. Grafting experiments of the prospective components have been performed using the quail-chicken marker technique. Prospective choroidal epithelium of quail embryos, forced to interact with mesenchyme of the body wall of chicken embryos, gives rise to a choroid plexus showing normal morphogenesis and differentiation. The choroidal epithelium induces the differentiation of organ-typical fenestrated capillaries, which are highly permeable to intravenously injected horseradish peroxidase. The choroidal epithelium of the grafts constitutes a blood-cerebrospinal fluid barrier. On top of the choroidal epithelium, there are epiplexus cells displaying a typical ultrastructure. The experimental results show that these cells do not originate from the transplanted neural epithelium. Prospective choroidal stroma of chicken embryos does not exert a choroid plexus-inducing influence upon a quail embryo's neural epithelium isolated from parts of the brain that normally do not develop a choroid plexus. The experiments show that the choroidal epithelial cells are determined at least three days before the first organ anlage is detectable.
Wilting
J
J
Institut für Anatomie, Ruhr-Universität Bochum, Abteilung für Entwicklungsbiologie, Federal Republic of Germany.
Christ
B
B
D000818:Animals; D002454:Cell Differentiation; D002642:Chick Embryo / Q000166:cytology*; D002831:Choroid Plexus / Q000166:cytology / Q000196:embryology*; D008855:Microscopy, Electron, Scanning; D011784:Quail / Q000196:embryology*