| Project/Area Number |
03807004
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
神経解剖学
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| Research Institution | Jichi Medical School |
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Principal Investigator |
ARAKI Masasuke Jichi Medical School, Anatomy, Lecturer, 医学部, 講師 (00118449)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | pineal / Retinopotency / Cell differentiation / Rat / Quail / Potassium / Cell Culture / Neuron-specific antigens / 網膜 / 視細胞 / 神経発生 / ノルエピネフリン |
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| Research Abstract |
Both neural retina and pineal originate from the diencephalon and develop in a same fashion by protruding the rudiment. In a lower vertebrate the pineal has photoreceptor function. With all these similarities, the pineal has much smaller repertory in phenotypic expression of cell types than the retina. From our previous findings in rat pineal cells, we hypothesized that pineal cells in the higher vertebrates may have potency to differentiate into various neural cells and that such potency is not revealed in the tissue. We tried to elucidate the potency under the culture conditions and to know the mechanisms involved in the phenotypic expression of such potency.
Using neonatal rat pineals as materials, we found that differentiation of several different neural phenotypes are controled by different mechanisms : photoreceptor (rod) differentiation is completely suppressed by the presence of 1muM norepinephrine (NE) which acts on both alpha-and beta-adrenoceptors. Neuron-specific antigens (HPC-1 and MAP2) are strongly expressed when the concentration of KCI is raised to 35mM, suggesting that innervation of some other neurons is an important factor for the induction of neural cell differentiation. GABA neurons, which are also found in the culture, are affected neither by NE nor KCI. The reason for the absence of GABA cells in the tissue is so far unknown.
Pineal cells of the quail embryos also showed potency for neural cell differentiation. Among them, many cells show rod cell phenotype but only few cone cell phenotype. We have confirmed the existence of a certain factor in the medium of neural retinal culture. This factor seems to enable quail pineal cells to express the cone cell phenotype. We are now trying to purify the factor.
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