| Project/Area Number |
08671755
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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 | Miyazaki Medical College |
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Principal Investigator |
TAKASAKI Mayumi Miyazaki Medical College, Department of Anesthesiology, Professor, 医学部, 教授 (30094212)
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| Co-Investigator(Kenkyū-buntansha) |
KATSUKI Hiroshi Miyazaki Medical College, Department of Anesthesiology, Instructor, 医学部, 助手 (80194786)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | bupvacaine / ropivacaine / enantiomer / intracellular concentration / 細胞内濃度 / レボブピバカイン / 神経細胞内濃度 |
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| Research Abstract |
Background : Levobupivacaine and ropivacaine are both single S(-)-enantiomers that have less cardiotoxic and convulsant effects than racemic bupivacaine. The anesthetic action of S(-)-bupivacaine, R(+)-bupivacaine and ropivacaine was directly compared in vitro by studying their effects on action potential and the maximum value of dV/dt (dV/dt max) in crayfish giant axon. To clarify the difference of intracellular anesthetic concentration, the intracellular ionized anesthetic concentration was measured.
Methods : Desheathed crayfish axons were perfused with 1 mM of each anesthetic agent at a stimulation frequency of either 0.1 or 5 Hz. Intracellular anesthetic concentration was measured using local anesthetic-sensitive microelectrodes.
Results : At 0.1-Hz stimulation, no differences were observed in either model. In crayfish giant axon at 5 Hz stimulation, the order of magnitude of the mean percentage decrease in dV/dt max was S(-)-bupivacaine > R(+)-bupivacaine> ropivacaine. Intracellular local anesthetic concentration did not differ among three agents.
Conclusion : Compared with ropivacaine, S(-)-bupivacaine has potent phasic blocking effect in crayfish giant axon. The equivalent intracellular local anesthetic concentration among three agents suggests that intracellular protonated local anesthetic concentration are not directly correlated with blocking effects.
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