| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥900,000 (Direct Cost: ¥900,000)
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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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