The long-term goal of the proposed research is to establish an alternate source of donor neurons in vitro which can be used in neural transplants to improve the symptoms of some neurodegenerative diseases such as Parkinsonism. This study is essential because of problems associated with the use of human fetal tissue in neural transplants. Most of the neurological disorders are due to neuronal degeneration, but the mechanisms of the degeneration are not understood. Our specific aims are: (a) to test the usefulness of differentiated adrenergic neuroblastoma (NB) and hybrid (NB X glioma) cells in neural transplants; (b) to establish and characterize immortalized clones of dopamine cells derived from rat fetal CNS; (c) to test the usefulness of differentiated immortalized dopamine cells in neural transplants; and (d) to elucidate the changes in cell signaling pathways during neuronal degeneration in vitro. The rat fetal CNS cells will be immortalized by plasmid vectors carrying immortalizing genes from such viruses as SV40, polyoma, and adenoma type 5. The immortalized dopamine clone, which is not tumorigenic, will be used in neural transplants. The experimental conditions which induce terminal differentiation in NB cells, hybrid cells and immortalized dopamine cells will be established. Each of these differentiated cell types will be transplanted separately into rats which have unilateral 6-hydroxydopamine (6-OHDA)-induced lesions of the nigrostriatal dopamine pathway. The structural (dendritic processes) and functional (TH and DA) characteristics of grafted nerve cells will be determined by histochemical and immunochemical techniques, and they will be correlated with the degree of improvement in spontaneous and amphetamine-induced rotation in lesioned, transplanted animals. The functional efficacy of each cell type will be compared with that of fetal mesencephalic DA cell implants. The alterations in protein kinase A (PKA) and PKC mediated cellular events during spontaneous and 6-OHDA-induced degeneration of nerve cells in vitro will be studied. These studies may lead to the development and availability of high quality donor cells for neural transplants, and may help to develop human donor neural cells suitable for transplantation into patients with neurological disorders such as Parkinson's disease. Future studies may also focus on how PKA and PKC interact with each other in regulating the expression of certain protooncogenes in neuronal degeneration.