Neurotrophin function in skin.

Neurotrophins, the NGF-related family of neurotrophic factors, regulate the innervation of skin by sensory and sympathetic neurons. For the sensory nervous system, sensory innervation of different modalities (nocioception, proprioception, mechanoreception) is regulated by different members of the neurotrophin gene family. This specificity reflects the expression, within different sensory neuronal subpopulations, of different members of the trk neurotrophin receptor gene family. Neurotrophins also act directly upon nonneural cells of the skin, including melanocytes and keratinocytes, regulating cell survival and proliferation. Effects on cell survival reflect a complex interplay between the actions of trk and 75-kDa neurotrophin receptors.