The goal of the proposed research is to identify all the neurotrophic or neuronal cell survival factors active during development of the inner ear. Neurotrophic factors are essential for survival and development of most if not all neurons. They have thus far been studied individually relative to a given population of neurons. At this point, few studies have probed the issue of whether multiple factors may be active on the same group of cells either at the same time or at different time points during development. This is a potentially important avenue of investigation that will be pursued in the present project. This laboratory has previously shown that neurons of the inner ear can respond to nerve growth factor (NGF), one member of a family of neurotrophic factors. This new project will focus on other members of this family of molecules. The initial studies will focus on when during embryonic development binding sites for the other members of the NGF family appear on the neurons of the inner ear. The presence of binding sites for a molecule is necessary for a nerve cell to be able to respond to that molecule. Subsequent studies will determine when the factors themselves appear during development. Although binding sites are a prerequisite for a response, the factor itself must be present in the embryo in order to elicit and effect. This project will yield a more complete picture of the multiple influences responsible for development of a neuron. ***//
