Using reverse transcription in combination with the polymerase chain reaction, the developmental expression of neurotrophins in organotypic slice cultures of rat hippocampus was investigated. Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) mRNA levels after different time periods in vitro were compared with equivalent developmental stages in vivo. Our results show that neurotrophin expression occurs in hippocampal slice cultures with a similar time course as observed in the developing hippocampus in vivo. Thus, the development of neurotrophin expression in the hippocampus does not seem to be dependent on specific extrinsic afferents.
