IMMUNOHISTOCHEMICAL VISUALIZATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR IN THE RAT-BRAIN

A purified polyclonal antibody preparation was made against recombinan t human brain-derived neurotrophic factor (BDNF) in guinea pig and cha racterized for use in immunoassays and immunohistochemistry. The anti- BDNF antibodies specifically recognized BDNF in Western blots and immu noprecipitation. There was no crossreactivity with the other known mam malian members of the neurotrophin family, nerve growth factor, neurot rophin-3 and neurotrophin-4/5. In immunohistochemical analysis, the an ti-BDNF recognized exogenous BDNF injected into the brain of rats, whe reas no signal was obtained with the other neurotrophins. Preabsorptio n with native BDNF abolished the immunoreactivity in brain sections. T hese studies identify the anti-BDNF as a tool for immunocytochemistry and the development of an immunoassay. Immunohistochemical analysis re vealed widespread neuronal localization of BDNF in many brain areas. B DNF was localized in ail subpopulations of hippocampal neurons. The di stribution in the hippocampus suggests localization in the cytoplasm o f cell bodies and dendrites.