THE EFFECTS OF VALATILE ANESTHETICS ON VASCULAR SMOOTH MUSCLE

本研究旨在研究挥发性麻醉药对犬离体肠系膜动脉和静脉的影响。方法：用戊巴比妥钠(25 mg/kg)静脉麻醉的杂种犬(7~20 kg)离体肠系膜动、静脉为实验动物。剥离血管周围脂肪和结缔组织后，将动脉和静脉切成环状，悬浮在充满Krebs-Ringer液(20ml)的器官浴池中进行等长张力测量。本文观察了氟烷、异氟烷和七氟烷对去甲肾上腺素(NE，10^&lt；-8&gt；-10^&lt；-3&gt；M)、酪胺(Tyr，10^&lt；-8&gt；-10^&gt；-3&gt；M)和电场刺激(ES；9V，2ms，1-32 Hz)引起的张力发展的影响。将挥发性麻醉剂从雾化器输送到O2-CO2混合气体充气浴液中。麻醉气体分析仪连续监测生成的气体混合物中的浓度。结果：在所用浓度(1，2MAC)下，氟烷、异氟醚和七氟醚对血管环基础张力无明显影响。但氟烷、异氟醚和七氟醚均可减弱ES引起的静脉环最大收缩。氟烷、异氟醚和七氟醚不能抑制Tyr诱发的动脉和静脉收缩。氟烷和异氟醚可减弱去甲肾上腺素对肠系膜静脉的最大收缩作用，但七氟醚无此作用。结论：(1)氟烷、异氟烷和七氟烷可抑制肠系膜静脉交感神经末梢钙依赖性去甲肾上腺素的释放。(2)氟烷和异氟醚抑制α-肾上腺素受体介导的肠系膜静脉血管收缩。

This study was designed to investigate the effects of volatile anesthetics on isolated canine mesenteric artery and vein. Method ; The experiments were performed on isolated mesenteric arteries and veins from mongrel dogs (7-20kg) anesthetized with sodium pentobarbital (25mg/kg, IV.). After the perivascular fat and connective tissue were dissected away, artery and vein were cut into rings which were suspended into organ bath chamber filled with Krebs-Ringer solution (20ml) for isometric tension measurements. Effects of halothane, isoflurane and sevoflurane on tension development induced by norepinephrine (NE,10^<-8>-10^<-3>M), tyramine (Tyr, 10^<-8>-10^<-3>M) and electrical field stimulation (ES ; 9V,2ms, 1-32Hz) were investigated. Volatile anesthetics were delivered from a vaporizer into the O_2 -CO_2 mixture aerating bathing media. The concentration in the resulting gas mixture was monitored continuously by an anesthetic gas analyzer. Results ; In concentration (1,2MAC) used, halothane, isoflurane and sevoflurane did not effect basal tension of blood vessel rings. However, halothane, isoflurane and sevoflurane attenuated ES induced maximum contraction of vein rings by same extend. Halothane, isoflurane and sevoflurane did not inhibited Tyr induced contraction in both artery and vein. Halothane and isoflurane but not sevoflurane, attenuated maximum contraction by NE in mesenteric vein. Conclution ; These results suggested that (1) halothane, isoflurane and sevoflurane may inhibit Ca^<2+>-dependent NE release from sympathetic nerve endings of mesenteric vein. (2) halothane and isoflurane inhibit alpha-adrenoceptor mediated vascular smooth muscle contraction of mesenteric vein.