左旋四氢巴马汀对大鼠甲基苯丙胺辨别行为的影响

EFFECT OF l-TETRAHYDROPALMATINE ON DISCRIMINATION OF METHAMPHETAMINE IN RATS

研究左旋四氢巴马汀 (l-THP)对药物精神依赖性的影响。方法··:用固定比率食物强化方法使大鼠对甲基苯丙胺 (MA)形成稳定的辨别效应。以多巴胺受体拮抗剂Sch -23390和螺哌隆拮抗MA效应 ,观察辨别效应的变化 ;以l-THP替代及对抗MA效应 ,并观察其对大鼠MA辨别行为重建的影响。结果·· :大鼠对MA形成稳定的辨别 ;0.001mg·kg-1Sch -23390及0.01mg·kg-1螺哌隆均拮抗训练剂量MA的辨别效应 ;5mg.kg-1l-THP不能替代训练剂量MA ,但能阻断其辨别效应 ;l-THP明显降低大鼠MA辨别行为重建时的踏杆正确率 (P<0.05)。结论·· :MA可使大鼠形成稳定的辨别效应 ,而且DA受体参与调控MA的这种效应 ;l-THP能阻断MA辨别行为 ,影响MA辨别行为的重建 ,表明其可降低MA精神依赖性的形成。

Objective: To study the effects of l-tetrahydropalmatine (l-THP) on psychic dependence of drugs. Method: To train the rats to discriminate methamphetamine (MA) from saline by food reinforcer under fixed-ratio schedule. After acquisition of discrimination, D1 antagonist Sch-23390, D2 antagonist spiperone and l-THP were used respectively to antagonize this effect, and l-THP also substituted for MA, to observe their effects on MA discrimination. Then extinction and reestablishment of MA discrimination were conducted. Result: The rats acquired discrimination of MA from saline and the effect was antagonized by 0.001 mg·kg-1 Sch-23390 and 0.1 mg·kg-1 spiperone. The 5 mg·kg-1 l-THP failed to substitute but blocked the effect of MA discrimination. l-THP reduced significantly the percentage of correct lever-pressing of the rats when MA discrimination was reestablished (P<0.01). Conclusion: The rats can steadily discriminate MA from saline and DA receptors are involvd in this effect. The influence of establishment and reestablishment of MA discrimination by l-THP suggests that l-THP could inhibit the psychic dependence of MA.