Role and expression of neurotrophins and the trk family of tyrosine kinase receptors in neural growth and rescue after injury.

Molecular cloning of genes for the neurotrophin family and the identification of their high-affinity receptors have recently contributed to our understanding of neurotrophic interactions in the vertebrate nervous system. From their primary sites of synthesis, novel neuronal populations that may be sensitive to the neurotrophins have been identified. Protective roles for these factors following epileptic, ischemic, and hypoglycemic insults have been inferred. Documented neurotrophic actions on basal forebrain cholinergic neurons and mesencephalic dopaminergic neurons imply future clinical applications for the treatment of dementia of both Alzheimer's and Parkinson's disease. Studies on structure-function relationships of the neurotrophins hold promises for the development of specific receptor agonists and antagonists with possible basic science and clinical applications.