星状神经节阻滞对兔血浆去甲肾上腺素浓度的影响

Effect of stellate ganglion block on the plasma concentration of noradrenaline in rabbits suffering from acute pain

目的 观察星状神经节阻滞 (SGB)对兔血浆去甲肾上腺素 (NE)浓度的影响 ,探讨其治疗疼痛的可能机制。方法 14只日本大耳白兔在严格无菌操作下暴露右侧星状神经节 ,置入并固定硬膜外导管 ,使其一端开口位于星状神经节附近 ,另一端自颈背部穿出。手术 1w后利用福尔马林皮下注射法建立急性疼痛模型 ,随机分为对照组 (A组 )和SGB组 (B组 ) ,每组 7只。致痛 6 0min后 ,B组经导管注入 0 .2 5 %布比卡因 (Bu) 0 .5ml,A组用等量的生理盐水 (NS)。观察致痛前 10min(T0 )、致痛后 10min (T1)、30min (T2 )、5 0min (T3 )和应用Bu或NS后 10min (T4)、30min (T5)、5 0min (T6)时血浆NE浓度的变化。结果 致痛前两组血浆NE无差别 (P >0 .0 5 ) ;与致痛前相比 ,致痛后两组NE均升高 ,且在T1时达高峰 ,在T2 、T3 时略有下降 (P <0 .0 1) ;两组间血浆NE无明显差别 (P >0 .0 5 )。与用NS前相比 ,用NS后A组血浆NE无统计学差异 (P >0 .0 5 ) ;与用Bu前相比 ,用Bu后B组血浆NE明显下降 (P <0 .0 5 )。结论 星状神经节阻滞降低血浆NE浓度 ,NE降低可能是其治疗疼痛性疾病的机制之一。

Objective To investigate the effect of stellate ganglion block(SGB) on the plasma concentration of noradrenaline(NE) in rabbits suffering from acute pain and the possible mechanism.Methods Fourteen healthy rabbits of both sexes weighing 2.5 2.8 kg were anesthetized with 20% urethane 1 g·kg -1 . Spontanous breathing was maintained. Right stellate ganglion was exposed aseptically. An epidural catheter was fixed with one end placed close to stellate ganglion and the other end outside the neck through a hole on the skin for administration of drugs. One week later 3% formalin 0.2ml was injected subcutaneously into plantar region of the right paw. Pain response was observed . 60 min after formalin injection 0.25% bupivacaine 0.5ml was injected through catheter (bupivacaine group n=7) while in control group (n=7) normal saline 0.5ml was injected. The effect of SGB was confirmed by ptosis and miosis. Blood samples were taken from edge vein of the ear 10 min before (T 0) and 10(T 1), 30(T 2), 50min(T 3) after subcutaneous injection of formalin and 10min(T 4), 30min(T 5), 50min(T 6) after bupivacaine or normal saline injection for determination of plasma NE concentration by radioimmunoassay.Results Plasma NE concentration increased significantly after subcutaneous formalin injection and peaked at T 1,then decreased slightly at T 2 and T 3. In group B, plasma NE concentration decreased significantly after bupivacaine injection, while in control group there was no significantly change in plasma NE concentration after normal saline injection.Conclusions SGB reduces the increased plasma NE concentration in rabbits suffering from acute pain. This may be the possible mechanism of analgesia provided by SGB.