These experiments will probe neurotransmitter plasticity in cholinergic neurons. The longterm goals of this research are to understand the cell lineage decisions involved in aspects of neural crest cell differentiation. The preliminary results have shown that cholinergic neurons derived from the ciliary ganglion can acquire adrenergic properties when transplanted into the trunk somites. This research will extend and further characterize this observation and will examine the phenotypic plasticity of other types of neurons. The experimental paradigm utilizes a new cell marking technique for selectively labeling neurons by retrograde transport of flourescent latex microspheres. After labeling, the neurons will then be microinjected onto neural crest pathways in different regions of the embryo using an injection technique developed in this laboratory. In this way, it is possible to introduce cells into either normal or ectopic sites at a variety of developmental stages.
