Effects of intravenous anesthetics on Ca2+ sensitivity in canine tracheal smooth muscle.
Effects of intravenous anesthetics on Ca2+ sensitivity in canine tracheal smooth muscle.
复制标题
静脉麻醉药对犬气管平滑肌 Ca2+敏感性的影响。
DOI：
10.1097/00000542-200001000-00024
复制
发表时间：
2000
期刊：
影响因子：
8.8
通讯作者：
Warner,DO
中科院分区：
文献类型：
--
作者：
Hanazaki,M;Jones,KA;Warner,DO
背景：氟烷和其他挥发性麻醉剂部分地通过减少刺激M受体时特定细胞内钙浓度(钙敏感性)所产生的力量来松弛气道平滑肌。本研究评价了氯胺酮、异丙酚和咪达唑仑，以确定挥发性麻醉药对这一信号转导通路的抑制作用是否为其他类型麻醉药的共性。氯胺酮、异丙酚和咪达唑仑的浓度分别为200M、270M和100M，在乙酰胆碱提供的M受体刺激或不存在的情况下，用钙刺激通透性肌肉。结果：与以往研究结果一致，氟烷(0.75 mM)可降低M受体刺激时的钙敏感性。结论：高浓度静脉麻醉药直接松弛犬气管平滑肌，不影响其对钙的敏感性。抑制激动剂诱导的犬气管光滑对钙敏感性的增加不是麻醉药的常见特性，而是挥发性药物所独有的。(关键词：呼吸道；支气管扩张剂；G蛋白；细胞内钙浓度。)
Background: Halothane and other volatile anesthetics relax airway smooth muscle in part by decreasing the amount of force produced for a particular intracellular calcium concentration (the Ca2 sensitivity) during muscarinic receptor stimulation. In this study, ketamine, propofol, and midazolam were evaluated to determine whether the inhibitory effect of volatile anesthetics on this signal transduction pathway is a general property of other types of anesthetic drugs.Methods: A-escin permeabilized canine tracheal smooth muscle preparation was used. Ketamine, propofol, and midazolam, in concentrations producing near-maximal relaxation in intact airway smooth muscle (200 M, 270 M, and 100 M, respectively), were applied to permeabilized muscles stimulated with calcium in either the absence or the presence of muscarinic receptor stimulation provided by acetylcholine. The effect of halothane also was evaluated.Results: Confirming previous studies, halothane (0.75 mM) decreased calcium sensitivity during muscarinic receptor stimulation. None of the intravenous anesthetics studied affected Ca2 sensitivity, either in the absence or the presence of muscarinic receptor stimulation.Conclusions: Intravenous anesthetics in high concentrations directly relax canine tracheal smooth muscle without affecting Ca2 sensitivity. The inhibition of agonist-induced increases in Ca2 sensitivity of canine tracheal smooth is not a common property of anesthetics, but is unique to volatile agents.(Key words: Airways; bronchodilators; G proteins; intracellular calcium concentration.)