Relative amnesic potency of five inhalational anesthetics follows the Meyer-Overton rule
Relative amnesic potency of five inhalational anesthetics follows the Meyer-Overton rule
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DOI：
10.1097/00000542-200408000-00023
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发表时间：
2004-08-01
期刊：
影响因子：
8.8
通讯作者：
Gorski, LA
中科院分区：
文献类型：
--
作者：
Alkire, MT;Gorski, LA
背景：吸入麻醉药的最小肺泡浓度（MAC）约为0.3时，会抑制学习能力。然而，阈值健忘剂量和相对效力的代理之间没有很好地建立。作者确定了健忘症的效力在大鼠四种常见的挥发物和nitrox.Methods：经过机构审查委员会批准，成年Sprague-Dawley大鼠接受抑制性回避训练暴露在空气或各种亚麻醉剂量的地氟烷，七氟烷，异氟烷，氟烷，或一氧化二氮（4-21大鼠/剂量）。训练动物在开始的“安全”隔室中保持连续100秒，每次它们进入相邻的“电击”隔室时给予足部电击（0.3 mA）。在24 h时评估记忆。麻醉对痛阈的影响分别determined.Results：学习：只有相对较高剂量的七氟烷，氟烷，地氟烷增加了任务收购所需的冲击次数。内存：在0.2%异氟醚、0.3%七氟醚和氟烷、0.44%地氟醚和20%氧化亚氮的相对低吸入浓度下，发现保留性能显著降低（P < 0.05）。药效为一氧化二氮大于或等于地氟烷>七氟烷大于或等于异氟烷，远大于氟烷（按等级排序的ED 50值为%MAC）。驱油效能与油气分配系数相关（r =-0.956，P < 0.007）。0.08%的氟烷能显著提高固位力（P < 0.01）。所有药物在较高doses.Conclusions镇痛效力不同的代理，一氧化二氮是最有效的，氟烷是最有效的MAC。遗忘阈值范围为0.06至0.3 MAC。效力和油：气分配系数之间的相关性表明疏水性在介导健忘症中的基本作用，类似于其与MAC的关联。一些代理（例如，氟烷）可以在通常在出现期间遇到的剂量下增强厌恶性记忆保持。
Background: Doses of volatile anesthetics around 0.3 minimum alveolar concentration (MAC) inhibit learning. However, threshold amnesic doses and relative potencies between agents are not well established. The authors determined amnesic potency in rats for four common volatiles and nitrous oxide.Methods: After institutional review board approval, adult Sprague-Dawley rats received inhibitory avoidance training during exposure to either air or various subanesthetic doses of desflurane, sevoflurane, isoflurane, halothane, or nitrous oxide (4-21 rats/dose). Animals were trained to remain in a starting "safe" compartment for 100 consecutive seconds by administering a foot shock (0.3 mA) each time they entered an adjacent "shock" compartment. Memory was assessed at 24 h. Anesthetic effects on pain thresholds were separately determined.Results: Learning: Only relatively higher doses of sevoflurane, halothane, and desflurane increased the number of shocks required for task acquisition. Memory: Significantly decreased retention performance (P < 0.05) was found at relatively low inspired concentrations of 0.2% isoflurane, 0.3% sevoflurane and halothane, 0.44% desflurane, and 20% nitrous oxide. Amnesic potency was nitrous oxide greater than or equal to desflurane > sevoflurane greater than or equal to isoflurane much greater than halothane, (rank-ordered ED50 values as %MAC). Amnesic potency correlated with oil:gas partition coefficients (r = -0.956, P < 0.007). Halothane, only at 0.08%, enhanced retention (P < 0.01). All agents were analgesic at higher doses.Conclusions: Amnesic potency differs between agents; nitrous oxide is most potent and halothane is least potent relative to MAC. The amnesic threshold ranges from 0.06 to 0.3 MAC. The correlation between potency and oil:gas partition coefficients suggests a fundamental role for hydrophobicity in mediating amnesia, similar to its association with MAC. Some agents (e.g., halothane) may enhance aversive memory retention at doses typically encountered during emergence.