Reinstatement of Morphine-Induced ConditionedPlace Preference in Mice by Priming Injections

[摘要] To construct a model of relapse of drugabuse in mice, the induction, we evaluated theextinction and reinstatement of morphine-inducedplace preference. In Experiment 1, weexamined the effects of morphine (0, 2, 3, 5, 10,20 and 40 mg/kg) in the conditioned placepreference (CPP) paradigm. Mice showed CPPwith 5, 10, 20 and 40 mg/kg. In Experiment 2,we evaluated the effects of two different extinctionprocedures. After conditioning with 40mg/kg of morphine, the mice underwent dailyextinction sessions of 60 or 15 min of duration.CPP was extinguished after seven and ninesessions, respectively. In Experiment 3, wetested the reinstating effects of several primingdoses of morphine. Mice were conditioned with40 mg/kg of morphine and underwent the daily15 min extinction sessions until CPP was nolonger evident. Then, the effects of morphine (0,2, 3, 5, 10, 20, 40 mg/kg, i.p.) were evaluated.CPP was reinstated by doses from 5 mg/kgupward. The results show that morphine priminginjections are effective in reactivating opiateseekingbehavior in mice, and thus, the CPPparadigm might be useful to investigate themechanisms underlying relapse of drug abuse.

[学科分类] 精神健康和精神病学