Clarification of pathophysiologic machanisms of anaphylactic shock and its treatment

1.对IgE介导的变态反应模型犬的左心室舒缩功能进行了评价。在过敏反应的早期阶段，左室舒张功能，即等容松弛功能受到的损害较小，而左室收缩功能在过敏开始后的早期阶段被相对较好地保存。2.为了验证过敏反应中一氧化氮(NO)的产生，我们用放置在腹部浅筋膜和腹直肌筋膜之间的非敏感电极检测了过敏兔周围组织中的NO。在过敏兔体内可以检测到NO的产生。3.我们研究了一氧化氮合酶(NOS)抑制剂是否能改善与过敏反应相关的心血管抑郁。致过敏性循环抑制后，一组给予一氧化氮合酶抑制剂(I组，n=6)，另一组给予生理盐水(II组，n=5)。I组平均动脉压和右房压显著高于II组，红细胞压积显著低于II组，心输出量在两组间无差异。综上所述，一氧化氮合酶抑制剂能减轻犬的低血压，但不能改善变态反应犬的心脏抑制。4.L-NAME组动物的存活率低于生理盐水对照组。在致过敏反应后给予L精氨酸可提高L预处理动物的存活率。与对照组相比，用L-NAME预处理的动物的心输出量显著降低，尽管静脉回流增加。在L-NAME预处理的动物中，肺阻力显著增加，精氨酸的应用减轻了支气管痉挛。综上所述，这些结果，以及L名字处理的动物的低存活率，表明NO的产生可能有利于体内过敏反应中的心脏抑制和支气管痉挛。

1.We assessed LV diastolic and systolic function in IgE-mediated anaphylaxis in dogs. LV diastolic funciton, i.e., isovolumic relaxation, is little impaired in anaphylaxis, and LV systolic function is relatively well preserved during the carly stage following the onset of anaphylaxis.2.To verify production of nitric oxide (NO) in anaphylaxis, we measured NO in peripheral tissue in anaphylactic rabbits using an NO-sensitive electrode, which was placed between the superficial abdominal fascia and the rectus abdominis fascia. NO production can be detected in anaphylactic rabbits.3.We investigated whether a No synthase (NOS) inhibitor improves cardiovascular depression associated with anaphylaxis. After induction of anaphylactic circulatory depression, one group received an NOS inhibitor (Group I,n=6), and the other received saline solution (Group II,n=5). Mean arterial pressure and right atrial pressure were significantly higher in Group I than in Group II.Hematocrit was significantly lower in Group I than in Group II.Cardiac output did not differ between the groups. In conclusion, NOS inhibitor attenuates hypotension, but does not improve cardiac depression in anaphylaxis in dogs.4.Animals pretreated with L-NAME showed lower survival rates than control animals pretreated with normal saline. The survival rate in L-NAME-pretreated animals was increased by the administration of L-arginine after initiation of anaphylaxis. Cardiac output fell significantly in animals pretreated with L-NAME compared with controls, although venous return was increased. In animals pretreated with L-NAME,pulmonary resistance was significantly increased, and administration of arginine attenuated the bronchospasm. In conclusion, these results, along with the low survival rates in the L-NAME-treated animals, suggest that NO production may be beneficial to cardiac depression and bronchospasm in anaphylaxis in vivo.