1990 Fiscal Year Final Research Report Summary
The Effects of Anesthetics on Neurotransmission
| Project/Area Number |
01480377
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
麻酔学
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| Research Institution | Kyoto University |
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Principal Investigator |
MORI Kenjiro Kyoto University, Medicine, Professor, 医学部, 教授 (20025620)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAO Shin-ichi Kyoto University, Medicine, Assistant, 医学部, 助手 (10207714)
MURAKAWA Masahiro Kyoto University, Medicine, Assistant, 医学部, 助手 (90182112)
ARAI Toshiyuki Kyoto University, Medicine, Lecturer, 医学部, 講師 (80175950)
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| Project Period (FY) |
1989 – 1990
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| Keywords | neurotransmitter / halothane / pentobarbital / lidocaine / diazepam / GABA / aspartate / glumatate |
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| Research Abstract |
The effects of anesthetics on neurotransmission were investigated using following materials ; 1) whole brain, 2) brain tissues, and 3) cerebral synaptic membranes.
1) Whole brain : The effects of halothane on the contents of putative transmitter amino acids in whole rat brain were investigated. Gamma-Aminobutyric Acid (GABA), Aspartate (Asp), and Glutamate (Glu) were objected and their concentrations were measured by the gas chromatography-mass spectrometry. The results showed that the brain contents of these amino acids increased by high concentrations of halothane, which indicated the facilitation of their synthesis by halothane or the suppression of their catabolism by halothane. The additional study using ^<13>C-glucose revealed that the synthesis of these amino acids was suppressed by high concentrations of halothane in whole mouse brain. Therefore, it was documented that halothane suppresses the catabolism of putative transmitter amino acids, which may be the mechanism of halothan
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e anesthesia.
2) Brain tissues : The effects of pentobarbital on the release of putative transmitter amino acids were investigated in rat brain tissues in vivo with the microdialysis technique. The concentrations of the amino acids were measured by the high-performance liquid chromatography. The results showed tht pentobarbital suppressed the release of Asp and Glu when the tissues were perfused with KCl solution. These indicated that pentobarbital suppresses the release of excitatory transmitter amino acids, which may be the mechanism of pentobarbital anesthesia.
3) Cerebral synaptic membranes : The effects of pentobarbital, halothane, and lidocaine on the binding of diazepam to rat cerebral synaptic membranes were investigated using ^3H-diazepam. The results showed that both pentobarbital and halothane enhanced the binding and that lidocaine enhancd the binding in low concentrations and suppressed that in high concentrations. These may explain the suppressive effects of general anesthetics and low concentrations of local anesthetics on the central nervous system. Less
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