皮质酮对吗啡条件性位置偏爱及条件性精神运动获得的影响

目的 :研究皮质酮作用下吗啡条件性位置偏爱 (CPP)及条件性精神运动的变化趋势及其可能机制 ,为探讨应激、环境线索诱发复吸的机制提供基础。方法 :32只♂SD大鼠分成 4组。训练 2d ,1次药物匹配训练 (吗啡 2mg·kg- 1 ,皮质酮 5mg·kg- 1 ,ip ,提前 2 0min注射 ) ,1次生理盐水训练。观察训练前后大鼠在伴药侧停留的时间 ,急性给药后的运动及条件性精神运动的变化。结果 :(1)吗啡组训练后在伴药侧停留的时间显著长于对照组 (P <0 0 1) ,皮质酮吗啡组、皮质酮组与对照组比较差异无显著性 (P >0 0 5 ) ;(2 )在 5 0、6 0min时皮质酮吗啡组的急性精神运动显著大于吗啡组和对照组 (P <0 0 1) ;(3)皮质酮吗啡组大鼠的条件性精神运动显著大于对照组、吗啡组 (P <0 0 1,P <0 0 5 )。结论 :5mg·kg- 1 的皮质酮显著抑制吗啡CPP的获得 ,但促进吗啡条件性精神运动的获得以及急性精神运动。CPP与条件性精神运动获得的机制可能存在差异

EFFECTS OF CORTICOSTERONE ON MORPHINE- INDUCED CONDITIONED PLACE PREFERENCE AND CONDITIONED LOCOMOTION ACTIVITY

Objective: To investigate the effect of corticosterone on morphine-induced CPP and conditioned locomotion activity in order to provide the foundation for exploring the mechanism of stress- and cue-induced relapse. Methods: 32 male SD rats were divided into 4 groups, and trained once a day for two days with drug (morphine, corticosterone) and saline in an alternate sequence. Corticosterone (5 mg·kg -1 ,ip) was administrated 20 minutes prior to morphine (2 mg·kg -1 ip) training. Time spent on drug-paired compartment was recorded, and locomotor activity was recorded immediately after morphine administration and saline challenge. Results: (1) Compared with control group, rats treated with morphine spent more time in drug-paired compartment after training(P<0 01); no difference between control group and corticosterone/morphine-treated rats (P> 0 05); (2) In the last twenty minutes, corticosterone increased the acute psychomotor activity of morphine-treated rats(P<0 05); (3) Corticosterone increased the conditioned psychomotor activity of morphine-treated rats(P<0 01). Conclusion: Corticosterone (5 mg·kg -1 ip) inhibited the acquisition of morphine-induced CPP, but facilitated the acquisition of morphine-induced conditioned locomotor activity and acute psychomotor activity. The mechanism of CPP may be different from that of conditioned locomotor activity.