Objective The pathologic associative memories that develop between drug-paired contextual cues and rewarding stimuli or the drug withdrawal-associated aversive feeling may contribute to the high rate of relapse.Like other types of memories, drug-related memories also require a process of consolidation to stabilize the association of drugs and cues, during which reorganization occurs in both synapse and neural circuits level.A great body of evidence has elucidated some synaptic plasticities during consolidation of drug cue memories, but little is known about the plastic changes of neural circuits that support the drug cue memories of different ages.Methods We used a Pavlovian conditioned place preference (CPP) procedure to assess the morphine-associated cues.During the conditioning days, the rats were trained for 8 consecutive days with alternating injections of morphine (10 mg/kg, s.c.) or saline (1 ml/kg, s.c.) in the designated compartments.Tests for the expression of drug CPP in a drug-free state (15-min duration) were performed either 1 d (recent test, recent memory) or 21 d (remote test, remote memory) later.Results In experiment 1, we focus on the hippocampus and anterior cingulated cortex (ACC), which are required for the recent and remote spatial memory, respectively.We trained the rats to learned morphine CPP.Then the rats were divided into eight groups, four groups received the microinjections of sodium channel blocker lidocaine or vehicle into either hippocampus or ACC and then tested 1 day later; the other four groups received the same treatment 21 day later.We found inactivation of ACC blocked the expression of remote (21 d old), but spared recent (1 d old), CPP task.In contrast, inactivation of the dorsal hippocampus disrupted expression of recent CPP task.These indicated that hippocampus and ACC are required for the retrieval of recent and remote morphine cue memory, respectively.In experiment 2, we focused on the role of basolateral amygdala (BLA) and central amygdala (CeA) in the morphine cue memory of different ages.These two brain site has been show to involve in the consolidation, retrieval and reconsolidation of appetitive memory and aversive memory.The experiment design was similar to experiment 1.We found inactivation of BLA disrupted the expression of CPP, regardless of its age; whereas inactivation of CeA had no effect on expression of either recent or remote CPP task.In experiment 3, we aimed to determine the role of BLA and CeA in the process of system consolidation of morphine cue memory.Rats were trained to learn CPP, and then were divided into four groups.Two groups received lesions of BLA with quinolinic acid or sham lesions, and then tested for morphine CPP 3 days and 23 days after treatment.The other two groups received lesions of CeA or sham lesions, and then tested morphine CPP 1 days and 21 days after recovery from surgery.We found that lesions of the BLA 1 d after CPP training disrupt the expression of both recent and remote CPP task.In contrast, in the groups with CeA lesions, the expression of recent CPP task was intact, but the expression of remote CPP task was impaired.Experiment 2 and 3 indicated that BLA is required for the retrieval/storage of morphine cue memory, whereas CeA may contribute to the transition from recent to remote morphine cue memory.Previous studies have showed that synaptic consolidation occurs within a specific time window after learning (range from 30 min to 48 h), and interference of this process would disrupt the formation or persistence of long-term memory.To exclude the possibility that effect lesion of BLA and CeA on morphine rewarding memory was due to disrupt this process, two another experiments were designed.In experiment 4, four groups of rats received lesions or sham lesions in BLA and CeA, respectively.After recovery from the surgery, the rats received 8 sessions of CPP training, and were tested 1 d and 21 d later.We found that the rats with lesion of BLA did not show the CPP in both recent and remote test, and the rats with lesion of CeA showed a normal CPP in recent test, but a decreased CPP in remote test.In experiment 5, rats received 8 days of CPP training and 18 days of withdrawal.Then rats were given lesions or sham lesions in BLA or CeA, and tested 1 d and 21 after recovery from surgery.The results showed that lesion of BLA impaired the expression of both CPP test, in contrast, lesions of CeA has no effect on both CPP test.Experiment, 4 and 5 indicated that BLA is required for the expression/storage of morphine cue memory all the time, but the role of CeA in the morphine cue memory is time-limited, and specific for the transition from the recent to the remote memory.Conclusion Take together, our data provide evidence that the circuits supporting different ages of morphine cue memory are distinct.Hipocampus and BLA are essential for the expression of recent morphine cue memories, and ACC and BLA is critical for the expression of remote morphine cue memories.CeA may mediate the transition from the recent to the remote morphine memories.