GABA_A受体拮抗药对小鼠痛阈的影响

目的　本研究旨在探讨印防已毒素和荷包牡丹碱对小鼠CO2 激光痛阈的影响。方法　NIH小鼠 10 5只 ,随机分为七组 ,每组 15只。对照组 ,注射 0 9%生理盐水 10ml/kg(NS组 ) ;印防己毒素组 ,注射印防己毒素 0 5mg/kg(PTX1组 ) ,1 0mg/kg(PTX2组 )、2 0mg/kg(PTX3组 ) ;荷包牡丹碱组 ,注射荷包牡丹碱 0 5mg/kg(BIC1组 )、1 0mg/kg(BIC2组 )、2 0mg/kg(BIC3组 )。所有的药物均经腹腔注射。采用CO2 激光作为伤害性刺激 ,痛阈值以激光脉冲持续时间 (ms)表示。结果　与NS组比较 ,PTX1与BIC1组小鼠的痛阈没有明显差异 (P >0 0 5 )。PTX2组、PTX3组及BIC2组、BIC3组小鼠的激光脉冲持续时间较NS组延长 (P <0 0 1) ,PTX3组、BIC3组分别比PTX2组、BIC2组延长更明显 (P <0 0 5 )。结论　本研究表明 ,GABAA 受体拮抗药印防己毒素和荷包牡丹碱对CO2 激光刺激引起的疼痛有明显的镇痛作用 ,且呈剂量相关

Effects of GABA_A antagonist on the pain threshold of mice

Objective To observe the effects of GABA A antagonist on the pain threshold of mice.Methods One hundred and five NIH mice were divided randomly into seven groups each with fifteen.The control group received 0 9% saline(group NS).In the picrotoxin groups,a dose of picrotoxin 0 5mg/kg(group PTX1)?1 0mg/kg(group PTX2) or 2 0mg/kg(group PTX3) was injected.A dose of bicuculline 0 5mg/kg(group BIC1)?1 0mg/kg(group BIC2) or 2 0mg/kg(group BIC3) in the bicuculline groups was given.All drugs were administered intraperitoneally.Brief pulses of CO 2 laser radiation were used to determine laser duration as parameter of pain threshold.Results The differences of laser duration among the group PTX1,group BIC1 and group NS were not statistically significant.Laser duration of group PTX2,group PTX3,group BIC2 and group BIC3 was longer than that of control group( P< 0 01).Furthermore,compared with the laser duratin of group PTX2 and group BIC2,the laser duration of mice in group PTX3 and BIC3 was longer( P< 0 05).Conclusion GABA A antagonist has an analgesic effect on the pain induced by CO 2 laser in a dose dependent manner.