ABSTRACT
The neurotrophins are a family of secreted proteins that promote growth, differentiation, and survival of neurons (1, 2). They also regulate the extent of innervation of the target tissues. This family includes nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3), and neurotrophin-5 (NT5; also known as neurotrophin-4 or neurotrophin-4/5). Although the members of this family have similar functions, they exert their effects on different but overlapping neuronal populations. This is the result of patterns of expression that differ both temporally and spatially.
