| Project/Area Number |
62540552
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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 |
動物発生・生理学
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| Research Institution | Saga Medical School |
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Principal Investigator |
TANAKA Shuitsu (1988) Saga Medical School ・ Research Assistant, 医学部, 教務員 (90202431)
小池 達郎 (1987) 佐賀医科大学, 医学部, 教授 (80128131)
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| Co-Investigator(Kenkyū-buntansha) |
TAKASHIMA Akihiko Saga Medical School ・ Research Assistant, 医学部, 教務員 (00154774)
KOIKE Tatsuro Saga Medical School ・ Professor, 医学部, 教授 (80128131)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Nerve growth factor / Pheochromocytoma / Neurite outgrowth / Receptor / Potassium / Neurotransmitter / GTP結合蛋白質 / 褐色細胞種 / GTPアナログ / Ca^<2+>イオン / カテコーラミン / Ca^<2+>チャンネル |
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| Research Abstract |
1. Response to NGF by PC12 cells is regulated by modulation of NGF receptors. Fractions of the binding and internalization of ^<125>I-NGF by the cells increased with an increase in extracellular potassium concentration. This high K^+ effect was also induced by treatment of the cells with veratridine. Neurite outgrowth of the cells in the presence of low concentrations of NGF was potentiated in high K^+ medium. The fractions of ^<125>I-NGF binding and internalization by the cells were also influenced by treatent of the cells with catecholamines.
2. A regulatory mechanism of dopamine release in PC12 cells. Pre-treatment of the cells with phorbol ester(TPA) resulted in enhanced dopamine release, which could be further stimulated by high K^+. This enhanced dopamine release was associated with concomitant reduction of the high K^+-induced increase in intracellular Ca^<2+> concentration. Moreover, in TPA-treated cells, the high K^+-evoked dopamine release was completely abolished by the prese
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nce of nicardipine, Cd^<2+>, or Co^<2+>, but only partially inhibited by the presence of verapamil. These findings suggest possible involvement of protein kinase C in regulating the efficiency of high K^+-evoked dopamine release through the modification of nicardipine-sensitive Ca^<2+> channels.
3. Enhancement of the NGF action by intracellular application of GTP analougues. Pre-treatment of PC12 cells with NGF induced an increase in the fraction of ^<35>S-GTP S bound to the cell membranes. The fractions of the cell-surface binding of ^<125>I-NGF were measured after introduction of some nucleotides into the cytoplasm by electric pulses. Introduction of GTP s or GTP into the cytoplasm caused an increase in the fraction of ^<125>I-NGF binding. Moreover, the number of cells which grew neurite increased when GTP s or GTP was introduced into theic cytoplasm before a treatment of the cell with NGF for 1-2 hours. These results indicate that GTP plays a role in the process of the binding of NGF to NGF receptors. Less
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