Yasuhiro Nakagami (#), Hiroshi Saito and Norio Matsuki (*)
Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Tokyo 113, Japan
(#) Research Fellow of the Japan Society for the Promotion of Science.
(*) To whom correspondence should be addressed.
Abstract: Neurotrophic effects in vitro have been generally related
to promotion of differentiation, maturation and survival, but little is
known about the effect on neuronal circuit formation. The organotypic culture
system would be an available technique to investigate neuronal circuit formation
and neuronal cell-cell interactions. As we reported previously, an optical
recording system is a useful technique to comprehend neuronal activities
and circuit from multi-points simultaneously. In this study, we investigated
whether continuous application of basic fibroblast growth factor (bFGF or
FGF-2) and brain-derived neurotrophic factor (BDNF) inhibited neuronal cell
death induced by serum-deprivation in organotypic culture using propidium
iodide staining, and we analyzed effects of bFGF and BDNF on the formation
of neuronal circuits using the optical recording system. Continuous application
of bFGF or BDNF significantly protected the slices from neuronal death.
Optical recording also demonstrated that addition of 10 ng/ml bFGF or 50
ng/ml BDNF enhanced optical signals in all hippocampal areas significantly.
These data strongly suggest that bFGF and BDNF promote the formation of
neuronal circuits as well as survival and that optical recording of organotypic
hippocampal slices would be a useful technique that enables us to analyze
neuronal circuit formation easily.
Keywords: Basic fibroblast growth factor, Brain-derived neurotrophic
factor, Hippocampus, Organotypic culture, Optical recording