Brain-Derived Neurotrophic Factor mRNA Expression in the Brain of the Teleost Fish, Anguilla anguilla, the European Eel

The spatial expression pattern of Brain-Derived Neurotrophic Factor (BDNF) mRNA in the brain of the European eel (Anguilla anguilla) was determined using non-radioactive in situ hybridization, and mapped and compared to that of other vertebrates. Riboprobes were prepared based on a partial cDNA coding sequence for A. anguilla BDNF that was amplified using degenerate primers, cloned and sequenced. As in other animal groups, in the eel, BDNF mRNA expression was seen in the telencephalon, hypothalamus, tectum, many primary and secondary sensory centers, and cranial motor nuclei. However, in contrast to mammals, BDNF mRNA expression was observed in some brain stem nuclei, such as the reticular formation, that contain cell bodies of neurons that project down the spinal cord. We suggest that these differences might relate to the continual growth of teleost fish.