DISTRIBUTION OF THE NEUROTROPHINS BRAIN-DERIVED NEUROTROPHIC FACTOR, NEUROTROPHIN-3, AND NEUROTROPHIN-4 5 IN THE POSTNATAL RAT-BRAIN - AN IMMUNOCYTOCHEMICAL STUDY/

The neurotrophin family of trophic factors influences survival and fun ction of neurons in both the peripheral and central nervous systems. C ritical information regarding physiological function of these factors may be gained by examining their localization in the brain. Here we re port the immunocytochemical characterization of antisera directed agai nst brain-derived neurotrophic factor, neurotrophin-3, and neurotrophi n 4/5. These antisera provide important tools to localize the bioactiv e neurotrophin proteins. Correspondence between protein distribution a nd previously determined messenger RNA expression was observed in some brain regions, such as hippocampus and cortex. However, neurotrophin proteins were also detected in neurons which have no apparent correspo nding messenger RNA, indicating that the proteins may be transported f rom the sites of synthesis in certain populations. Immunocytochemical double-labelling analysis also indicated that a sub-population of neur otrophin-positive cells were labelled with an astrocyte marker (glial fibrillary acidic protein) as well, demonstrating that trophic molecul es are localized to glial cells as well as neurons in vivo. Thus, the use of antisera specific for individual neurotrophic factors has indic ated potential cellular sites of action. (C) 1998 IBRO. Published by E lsevier Science Ltd.