| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
The expression of the genes for brain-derived neurotrophic factor (BDNF) and somatostatin (SRIF) was investigated in the brain of the macaque monkey during the aging process (2years, 10years, and>30years). BDNF mRNA declined (20-50% for 4.0kb transcript, and 40-70% for the 1.6kb transcript) in the various cerebral subdivisions. In the hippocampus, the level of the 1.6kb mRNA at > 30 years old declined to 60% of the level at 2 years old. SRIF mRNA significantly decreased (60%-70%) in the hippocampus and in several carebral subdivisions. The expression of SRIF mRNA has been shown to be enhanced by BDNF,suggesting the decrease in gene expression of BDNF may cause the levels of SRIF mRNA to decline in the primate brain during aging. (Brain Res.1997)
2.TrkB is a receptor for neurotrophins such as BDNF.The trkB gene give rise to the full length protein (TK+) and the truncated form (TK-) that lacks the tyrosin kinase domain. The TK+ immunoreactive structures were investigated in the monkey hippocampal formation between embryonic day 140 and adult stage. TK+ immunoreactivity was observed from the embryonic period to the adult stage in the granule cells of the dentate gyrus, the pyramidal cells of Ammon's horn and of the subiculum, indicating that TK+ may participate in the formation and the maintenance of the monkey hippocampus.(Neurosci. Res. 1997) By the western blot analysis, TK+ was detected at the same levels from embryonic 120 days to adult period in the developing monkey cerebral cortices. In contrast, the expression of TK- increased after the new-born stage, suggesting that TK- plays an important role as a negative effector of TK+ in the primate brain, reducing responsiveness to BDNF during development.(Soc. Neurosci. Abs., 1997)
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