Role of Nitric Oxide on Minimum Alveolar Anesthetic Concentration

方法：将14只Sprague-Dawley大鼠分为7-硝基茚唑（7-NI；选择性神经元型一氧化氮合酶抑制剂）组和对照组。测定7-NI （100 mg/kg）或载具注射前后氟烷的最低肺泡麻醉浓度（MAC）。利用NADPH-diaphorase组织化学方法，我们还研究了蓝斑（LC）和脊髓（SC）的nNOS活性。结果：7-NI使SC和LC的MAC降低约50%，同时抑制约25%的nNOS染色。方法：将13只sd大鼠分为右美托咪定（DEX）组（50μg/kg, 50μg/kg/d，连续给药3、2周）和3个对照组（载药组）。我们采用NADPH-diaphorase组织化学方法研究了氟烷MAC和LC和SC的nNOS活性。结果：大剂量注射DEX可使MAC降低约50%，但未改变NADPH-diaphorase的组织化学。另一方面，持续给药DEX并没有降低MAC，然而，3天DEX组腰椎SC LC和IV-V椎板的nNOS活性降低，但2周DEX组没有。结论：一氧化氮（NO）在MAC的决定中起重要作用，但NO不是唯一的因素。

"Effects of 7-Nitro Indazole on Halothane Minimum Alveolar Anesthetic Concentration"Methods : Fourteen Sprague-Dawley rats were divided into 7-Nitro indazole (7-NI ; selective neuronal nitric oxide synthase inhibitor) group and control group. We measured minimum alveolar anesthetic concentration (MAC) of halothane before and after injection of 7-NI (100 mg/kg) or vehicle. Using NADPH-diaphorase histochemistry, we also investigated the nNOS activity of the locus ceruleus (LC) and the spinal cord (SC).Results : 7-NI reduced the MAC about 50 %, which was accompanied by about 25 % suppression of nNOS staining in SC and LC."Halothane Minimum Alveolar Anesthetic Concentration and NADPH-diaphorase histochemistry after Dexmedetomidine injection"Methods : Thirteen-six Sprague-Dawley rats were divided into three Dexmedetomidine (DEX) groups (50μg/kg bolus, 50μg/kg/day ; three-day and two-week continuous administration) and three control groups (vehicle). We investigated halothane MAC and the nNOS activity of the LC and the SC using NADPH-diaphorase histochemistry.Results : Bolus injection of DEX reduced the MAC about 50 %, however, did not change the NADPH-diaphorase histochemistry. On the other hand, continuous administration of DEX did not reduce the MAC, however, nNOS activity of the LC and IV-V laminae of the lumbar SC decreased in the three-day DEX group, but not the two-week DEX group.Conclusion : Nitric oxide (NO) plays an important role in decision of MAC, however, NO is not only one factor.