The role of ectoderm and mesoderm interaction in the distribution of muscle acetylcholine receptors and neuronal differentiation in Xenopus

During gastrulation, mesoderm comes into contact with ectoderm, providing an opportunity for the exchange of presumptive inductive signals. One may disrupt such an interaction with exogastrulation, a process in which mesoderm is made to move outward rather than into the embryo during gastrulation, and thus presumably the nervous system fails to develop. Whether or not, and how, this abnormal movement interferes with the development of the neuromuscular junction in the myotomes of Xenopus embryos were the objectives of this thesis. In particular, the distribution of acetylcholine receptors (AChRs) in the myotomal muscle and the fate of ectodermal cells in the exogastrulated embryos were investigated. Fluorescent toxin binding to AChRs, nerve specific staining, and cell cultures were used in the study. The results show that the exogastrulated embryos have fewer AChR aggregates and fewer differentiated neurons than the control embryos.