眼镜蛇长链神经毒素Cobratoxin对丘脑束旁核神经元痛诱发放电的影响  

The Influence of Cobratoxin on Pain-evoked Discharge of Neurons in Thalamic Parafascicular Nucleus

作　　者：程勃超[1] 蒋星红[1] 朱奇[1] 龚珊[1] 秦正红[2] 周希平[3] 

机构地区：[1]苏州大学医学部神经生物学教研室,江苏苏州215123 [2]苏州大学医学部药理学教研室,江苏苏州215123 [3]苏州大学医学部生理学教研室

出　　处：《苏州大学学报（医学版）》2008年第3期375-378,420,共5页Suzhou University Journal of Medical Science

摘　　要：目的以大鼠丘脑束旁核(Pf)神经元痛诱发放电为指标,来验证眼镜蛇长链神经毒素(Cobratoxin)的镇痛作用。方法用玻璃微电极细胞外记录Pf神经元的单位放电,用电脉冲刺激坐骨神经作为伤害性刺激,诱发伤害性反应,观察侧脑室注射不同剂量Cobratoxin后痛诱发放电的变化。用侧脑室注射生理盐水作为阴性对照,侧脑室注射吗啡作为阳性对照。结果(1)侧脑室注射大剂量Cobratoxin(4.5μg/kg)后,Pf神经元的痛放电频率明显降低;(2)侧脑室注射中剂量(1.12μg/kg)和小剂量(0.56μg/kg)Cobratoxin后,Pf神经元的痛放电频率也降低,但降低的幅度依次递减。(3)侧脑室注射3种剂量Cobratoxin对Pf神经元痛放电频率的抑制时间比吗啡的长。结论Cobratoxin对丘脑Pf神经元的痛诱发放电有明显的抑制作用,提示Cobratoxin有镇痛作用,这种镇痛作用有一定的剂量依赖性。Objective To verify the analgesic effect of Cobratoxin through observation on the pain-evoked discharge of neurons in thalamic parafascicular nucleus （Pf） Methods Trains of electric impulses applied to the sciatic nerve were used as noxious stimuli to evoke nociceptive response. The pain-evoked unit discharge was recorded extracellularly with glass microelectrode from Pf nucleus. The changes of discharge frequency were examined after intracerebroventricular （icy） injection of different doses of Cobratoxin. Normal saline and morphine were used as negative and positive control, respectively. Results （1） The frequency of pain-evoked discharge of thalanfic Pf neurons was obviously depressed after icv injection of large dose of Cobratoxin.（2） Frequency of pain-evoked discharge was also depressed after icy injection of medium and low dose of Cobratoxin, but the extent of depression was reduced in turn.（3） The time course of depression induced by Cobratoxin was longer than that by morphine. Conclusion Cobratoxin has an dose-dependent analgesic effect.

关 键 词：眼镜蛇长链神经毒素 束旁核 单位放电 镇痛 

分 类 号：R338.2[医药卫生—人体生理学] R338.8[医药卫生—基础医学]