左旋四氢巴马汀对吗啡辨别效应的影响

目的 :了解不同剂量的左旋四氢巴马汀 (l-THP)对成瘾药物精神依赖性的影响。方法 :用固定比强化方法使大鼠对吗啡形成稳定的辨别效应。用不同剂量的吗啡 (0 31、0 6 3、1 2 5、2 5 0mg·kg- 1 )替代训练剂量的吗啡 (2 5 0mg·kg- 1 ) ;以不同剂量的l-THP (1 2 5、2 5 0、5 0 0mg·kg- 1 )对抗吗啡的辨别效应 ,并与多巴胺受体拮抗剂Sch2 3390和雷可必利的效应对照。结果 :2 5 0mg·kg- 1 吗啡能使大鼠形成稳定的辨别行为 ;Sch2 3390、雷可必利以及不同剂量的l-THP均能拮抗吗啡的辨别效应 ,且l-THP的对抗效应呈剂量依赖性。结论 :在本实验系统中 ,2 5 0mg·kg- 1 吗啡即能产生稳定的辨别刺激 ;DA受体参与调控吗啡的这种效应 ;l-THP能阻断吗啡的辨别效应 ,表明它可降低吗啡精神依赖性的形成。

THE EFFECTS OF l-THP ON MORPHINE-INDUCED DISCRIMINATION

Objective: To explore the effects o f l-THP (l-tetrahydropalmatine) on drugs with psychic dependence producing poten tial. Methods:The rats were trained to discriminate morphine (2.50 mg·kg -1) from saline under fixed-ratio schedule and after the dis crimination established, morphine of different doses(0.31、0.63、1.25、2.50 mg·kg -1) was given to substitute for the training dose. Then, the rats we re administered with DA receptor antagonists Sch23390, raclopride and l-THP (1. 25、2.50、5.00 mg·kg -1), respectively to antagonize the effect. Results:The rats acquired morphine discrimination at the dose of 2 .50 mg·kg -1 and the effect was antagonized by Sch23390, raclopride a nd l -THP, and l-THP could dose-dependently antagonize the effects of morphine. Conclusion:The rats can steadily discriminate morphine from salin e and DA receptors are involved in this effect. The effect of l-THP on the discr iminative stimulus suggests that l-THP can inhibit the psychic dependence of mor phine.