| Project/Area Number |
15591643
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Faculty of Medicine, University of Miyazaki (2004)
宮崎医科大学 (2003) |
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Principal Investigator |
KASABA Toshiharu University of Miyazaki, Faculty of Medicine Department of Anesthesiology, Associate Professor, 医学部, 助教授 (80145599)
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| Co-Investigator(Kenkyū-buntansha) |
NARUO Hiroaki Faculty of Medicine, University of Miyazaki, Department of Anesthesiology, Instructor, 医学部, 助手 (10274797)
HAMAKAWA Toshiro Faculty of Medicine, University of Miyazaki, Department of Anesthesiology, Assistant Professor (50253836)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Lymnaea stagnalis / local anesthetics / lidocaine / tetrodotoxin / neurotoxicty / 水棲かたつむり / 培養細胞 / 細胞内ナトリウム |
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| Research Abstract |
To know whether the increase in intracellular Ca^<2+> concentration by lidocaine produces neurotoxicity, we compared morphological changes and Ca^<2+> concentration using fura-2 imaging in the culture neuron of Lymnaea stagnalis.
We used BAPTA-AM, a Ca^<2+> chelator, to prevent the increase of the intracellular Ca^<2+> concentration and Calcimycin A23187,a Ca^<2+> ionophore, to identify the relationship between increased intracellular Ca^<2+> concentration and neuronal damage without lidocaine. Morphological changes were confirmed using trypan blue to stain the cells.
Increasing the dose of lidocaine increased the intracellular Ca^<2+> concentration ; however, there was no morphological damage to the cells in lidocaine at 3x10^<-3> M. Lidocaine at 3x10^<-2> M increased the intracellular Ca^<2+> concentration in both the saline (from 238±63 to 1038±156 nM) and the Ca^<2+>-free medium (from 211±97 to 1046±169 nM) and produced morphological damage and shrinkage with a rugged surface. By the addition of BAPTA-AM, lidocaine at 3x10^<-2> M moderately increased the intracellular Ca^<2+> concentration (from 150±97 to 428±246 nM) and produced morphological damage. These morphologically changed cells were stained to dark blue with trypan blue dye. Ca^<2+> ionophore resulted in an extreme increase of the intracellular Ca^<2+> concentration ; however, no morphological damage was observed.
These results indicated that the morphological damage was induced by lidocaine itself rather than by the increase in the intracellular Ca^<2+> concentration. Controlling the increase in the intracellular Ca^<2+> concentration is not enough to prevent the neurotoxicity of lidocaine.
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