Brain tonics for brain sprouts: how neurotrophic factors fertilize neurons.

BRAINSTORMS is a monthly section of The Journal of Clinical Psychiatry aimed at providing updates of novel concepts emerging from the neurosciences that have relevance to the practicing psychiatrist. From the Clinical Neuroscience Research Center in San Diego and the Department of Psychiatry at the University of California San Diego. Reprint requests to: Stephen M. Stahl, M.D., Ph.D., Editor, BRAINSTORMS, 8899 University Center Lane, Suite 130, San Diego, CA 92122. Brain Tonics Neurotrophic factors regulate both the survival and growth of various populations of neurons in the central and peripheral nervous systems. Recent research has generated a virtual explosion of information on dozens of different neurotrophic factors and their effects on various types of neurons (see Table). Some growth factors act not only on numerous populations of neurons, but also on non-neuronal cells as well. Furthermore, individual neurons do not necessarily respond only to a single neurotrophic factor. Sorting out the effects of different combinations of growth factors on various