脑干和脊髓在异氟烷抑制伤害性逃避反射中的作用

目的 探讨脑干和脊髓在吸入麻醉剂异氟烷抑制伤害性逃避反射中的作用.方法 30只成年SD大鼠随机平分为血管钳钳夹大鼠后爪组和血管钳钳夹大鼠口鼻组,分别以血管钳钳夹大鼠后爪或大鼠口鼻(即分别钳夹大鼠脊神经支配区及由脑干发出的颅神经支配区)作为伤害性刺激,测定异氟烷的最低肺泡有效浓度(minimum alveolar concentration,MAC),并测定所有大鼠抑制角膜反射的MAC值,观察所得MAC值的相互关系.结果 血管钳钳夹大鼠后爪和大鼠口鼻组,异氟烷的MAC分别为1.44% ±0.09%和1.29%±0.11%(P＜0.05).MAC角膜与MAC口鼻有很好的相关性(r＝0.95,P＜0.05),而与MAC后爪相关性较弱(r=0.61,P＜0.05).结论 脑干和脊髓都是吸入全麻药的作用部位,但脊髓敏感度低于脑干.

Effects of Brain Stem and Spinal Cord by Isoflurane Inhibiting Nociceptive Reflex

OBJECTIVE: To explore the effect positions of the volatile anesthetic inhibiting the nociceptive reflex in the central nervous system. METHODS: Thirty adult SD rats were randomly and equally divided into two groups that the lip and hind paw of rats were held by clamp. The minimum alveolar concentration (MAC) was determined by clamping two places: one was to clamp the hind paw of rats, of which the nervous reflex is controlled via the spinal cord; the another group was to clamp the lip of rats, of which the nervous reflex is controlled through the brain stem. RESULTS: The isoflurane MAC was 1.44% +/- 0.09% in clamping the hind paw group, while 1.29% +/- 0.11% for clamping the lip group (P < 0.05). CONCLUSION: Both brain stem and spinal cord are the effect positions of volatile anesthetics (especially isoflurane).