1986 Fiscal Year Final Research Report Summary
Mode of Action of Anesthetics on Neuro-muscular Junction
| Project/Area Number |
60570714
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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 |
麻酔学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HASHIMOTO Yasuhiko Tohoku University, School of Medicine ・ Professor, 医学部, 助教授 (00004648)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Masato Tohoku University, Tohoku Univ. Hospital ・ Assistant, 医学部附属病院, 助手 (50169520)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Prejunctional effect / Anesthetics / Muscle relaxant / 麻酔薬 / 筋弛緩薬 / 連続刺激 / Ca拮抗薬 |
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| Research Abstract |
Pre- and postjumctional effects of anesthetics ( inhalationl&intravenous ),muscle relaxants and other related drugs during train-of-four stimulation were investigated in man. Since tubocurarine and related drungs produce rundown or fade of responses evoked by nerve stimulation apparently by blocking prejunctional acetylcholine receptors ( Bowman et al. Semin in Anesthesia,3:275-283,1984 ), (1)block of postjunctional receptors, an effect that is independent of stimulation frequency (2)block of prejunctional receptors resulting in an initial progressive diminution of acetylcholine release. The effects of anesthetics ( halothane, methoxyflurane, diethylether, thiamylal, propanidid, ketamine and althesin ) on train-of-four ratio ( <T_4> ratio ) were studred in surgical patients. All these agents alone did not change in <T_4> ratio. Diethylether methoxyflurane decreased in <T_4> ratio during partial tubocurarine blockade.
During neuromuscular blockade produced by succinylcholine, halothane>diethylether> methoxyflurane decreased <T_4> ratio, while other agents did not alter the ratio. Therefore, these 3 inhalational anesthetics block pre- and postjunctional acetylcholine choline receptors. Studies on anesthetized surgical patients in which the effects of non-deporalizing muscle relaxants ( alcuronium, tubocrarine, vecuronium and pancuronium ) were performed. All four non-deporalizing muscle relaxants produced train-of-four fade, but the degree of single twitch depression that accompanied the fade differed in each case. The degree of train-of-four fade was much more pronouned with alcuronium and following the order of tubocurarine, vecuronium and pancuronium. Therefore, alcuronium appears to have a relatively greater affinity to the prejunctional ( site involved in fade ) sites of the cholinoceptors.
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Research Products
(6 results)
