Hayashi / Poster

Neuronal distribution and BDNF immunoreactive cells in the cerebral cortex of a fetal chimpanzee

Motoharu Hayashi, Mariko Itoh, Keiko Shimizu, Fusako Mitsunaga, and Koji Ohira , Department of Cellular and Molecular Biology, Primate Research Institute of Kyoto University

     Brain-derived neurotrophic factor (BDNF) is one of the neurotrophic molecules (Neurotrophins) in the mammalian central nervous system. BDNF has been reported to be involved not only in the survival and differentiation of neuronal cells during development, but also in the maintenance of neuronal cells in adulthood. In the present study, we examined the distribution and morphology of neuronal cells and BDNF-immunoreactive cells in the prefrontal and the cingulate cortices of an embryonic chimpanzee. A brain from a chimpanzee (still-birth, male, 1.5kg) at embryonic 224 days was immersed in 4% paraformaldehyde and 0.5% gluraraldehyde in 0.1M phosphate buffer, pH 7.4 and stored in 30% sucrose. The sections (20 Žľm for the frontal cortex, 10 Žľm for the cingulate cortex) were cut with a cryostat (MICRON). The sections were incubated in the anti-BDNF antibody (Santa Cruz, diluted 1:800). The immunoreactive sites were visualized by the ABC method. Adjacent sections were stained with Cresyl Violet. They are then dehydrated in ethanol, cleared in xylene, and covered with coverstips. In the frontal and cingulate cortices, six layers of neuronal cells were observed. At this stage, high numbers of cells were found in layer I and the white matter. In both the frontal and cingulate cortices, the pyramidal cells were BDNF-immunopositive. BDNF-immunoreactivity was also observed in the dendrites of the pyramidal cells, indicating that BDNF is secreted from the dendrites. These findings suggest that BDNF may be involved in the development of the cerebral cortex of the chimpanzee.

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