Cytokines and the function of the mature nervous system.

In addition to the role that cytokines (growth factors, interleukins, instructive factors) play in regulating neuronal survival, growth and gene expression during development, recent evidence suggests that these intercellular signals can also control similar functions in the normal, as well as the injured, adult nervous system. Some of this evidence is summarized here, with particular emphasis on the potential role of cytokines in synaptic function and plasticity.