Mode of Action of Anesthetics on Neuro-muscular Junction

研究了麻醉药物（吸入和静脉注射）、肌肉松弛剂和其他相关药物在四次训练刺激过程中的作用。由于管库碱及相关药物明显通过阻断结前乙酰胆碱受体而使神经刺激引起的反应下降或减弱（Bowman等）。麻醉中的Semin，3:275-283,1984),(1)突触后受体的阻断，与刺激频率无关；(2)突触前受体的阻断导致乙酰胆碱释放的初始进行性减少。研究了麻醉药物（氟烷、甲氧基氟醚、二乙醚、硫胺醛、丙胺酮、氯胺酮和醛松）对手术患者四列比（<T_4>比）的影响。所有这些药物单独使用均未改变<T_4>比值。二乙醚甲氧基氟醚<T_4>比值在部分导管阻断期间下降。琥珀胆碱阻断神经肌肉时，氟烷>二乙醚>甲氧基氟醚降低<T_4>比值，而其他药物对该比值无影响。因此，这3种吸入性麻醉剂阻断了交界前和交界后的乙酰胆碱受体。非去离性肌肉松弛剂（阿库溴铵、图克拉碱、维库溴铵和潘库溴铵）对麻醉手术患者的影响研究。所有四种非去分离性肌肉松弛剂都产生了四组衰退，但每种情况下伴随衰退的单个抽搐抑制程度不同。阿库溴铵的四列褪色程度更明显，并遵循管库溴铵、维库溴铵和潘库溴铵的顺序。因此，alcuronium似乎对胆碱受体的前膜（与褪色有关的部位）具有相对更大的亲和力。

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.