Neural crest and placodal contributions in the development of the glossopharyngeal‐vagal complex in the chick

Abstract

By using the method of quail-to-chick transplantation of neural crest in one series (VNG) and placodal ectoderm in a second series (VPG) we were able to determine the relative contribution of cranial neural crest and placodal ectoderm to the formation of the Glossopharyngeal-vagal complex. In chimeric embryos, quail cells originating from cranial neural crest grafts of postotic levels end up in the root ganglia, while quail cells originating from placodal ectoderm of postotic levels end up in the trunk ganglia. The results clearly indicate that the caudal levels of the medulla and rostral cervical segments represent the site, and the neural crest the source, for the neurons of the root ganglia. The neurons form a homogenous population of the small-cell type. This clearly rules out any contribution to the root ganglia from placodal ectoderm. On the basis of our experiments, it is also concluded the the neurons of the trunk ganglia are purely placodal in origin and are composed of a populatin of cells of the large-cell type. Our experiments also provide convincing evidence for a neural crest origin for Schwann cell and ganglionic Satellite cells.

Cocaine- and amphetamine-regulated transcript in the rat vagus nerve: A putative mediator of cholecystokinin-induced satiety

“…41 for review). Such discrepancies may reflect the different embryological origins and different functions of these classes of neurons (45,46) and suggest that signaling in these two systems can be pharmacologically dissociated. Based on the sparse distribution of CARTp-ir DRG cell bodies described here, it seems likely that the dense plexuses of CARTp-ir fibers in the dorsal horn and trigeminal tract observed by ourselves and others (4) receive contributions also from CART-expressing populations other than primary afferent neurons.…”

Expression of Hox 2.1 protein in restricted populations of neural crest cells and pharyngeal ectoderm

“…It has been shown that the inferior ganglia of the cranial nerves V, VII, IX, and X (the nodose ganglion), are formed from two sources of cells; the epibranchial (ectodermal) placode, which contributes the neurons, and the neural crest, which produces supporting cells (Narayanan and Narayanan, 1980;D'Amico-Martel and Noden, 1983;reviewed by Le Douarin et al, 1984). Also, according to D'Amico-Martel and Noden (1983), the nodose placode releases neuroblasts to the ganglion primordium during stages 19 and 20 in the chick em- Lateral view of the stage 19 (4 days) chick embryo stained with EIC8 which specifically recognizes neurons and the circumpharyngeal crest, a subpopulation of the vagal crest cells.…”

THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl

“…(glossopharyngeal) and 10 th (vagus) cranial nerves as is the case in the chick (Hamburger, 1961;Noden, 1975: Narayanan & Narayanan, 1980and Le Douarin, 1982.…”

“…14), These sites are occupied by the proximal ganglionic primordia of the 9 ,h (glossopharyngeal), and 10 M (vagus) cranial nerves among other vertebrates (Noden, 1975(Noden, & 1978Narayanan & Narayanan, 1980), suggesting that the neural crest cells mesectoderm, may contribute to the formation of the proximal ganglia of these crania] nerves.…”