Selective Inhibition of Amygdala Neuronal Ensembles Encoding Nicotine-Associated Memories Inhibits Nicotine Preference and Relapse.

Nicotine craving and relapse often occurs after reactivation of nicotine reward memories. We recently developed a memory retrieval-reconsolidation interference procedure in which reactivating nicotine reward memories by acute exposure to nicotine (the unconditioned stimulus [UCS]) and then pharmacologically interfering with memory reconsolidation decreased relapse to nicotine seeking in rats and nicotine craving in smokers. Here, we investigated underlying mechanisms. In the first series of experiments, we trained rats for nicotine-induced conditioned place preference (CPP) or nicotine self-administration and ventricularly microinjected them with the protein synthesis inhibitor anisomycin immediately after UCS-induced memory retrieval. In the second series of experiments, we used tyramide-amplified immunohistochemistry-fluorescence in situ hybridization to examine neural ensembles in the basolateral amygdala (BLA) reactivated by nicotine conditioned stimulus- or UCS-induced memory retrieval. We then used the Daun02 chemogenetic inactivation procedure to selectively inhibit the nicotine UCS-reactivated BLA neuronal ensembles. Ventricular injections of the anisomycin immediately after nicotine UCS memory retrieval inhibited subsequent nicotine CPP and relapse to operant nicotine seeking after short or prolonged abstinence. More important, within BLA, distinct neuronal ensembles encoded pavlovian CPP and operant self-administration reward memories and nicotine (the UCS) injections in the home cage reactivated both neuronal ensembles. Daun02 chemogenetic inactivation of the nicotine-reactivated ensembles inhibited both nicotine CPP and relapse to nicotine seeking. Results demonstrate that the nicotine UCS-induced memory retrieval manipulation reactivates multiple nicotine reward memories that are encoded by distinct BLA neuronal ensembles that play a role in nicotine preference and relapse.

Xue YX ，Chen YY ，Zhang LB ，Zhang LQ ，Huang GD ，Sun SC ，Deng JH ，Luo YX ，Bao YP ，Wu P ，Han Y ，Hope BT ，Shaham Y ，Shi J ，Lu L ... -  《-》

Effect of Selective Inhibition of Reactivated Nicotine-Associated Memories With Propranolol on Nicotine Craving.

Xue YX ，Deng JH ，Chen YY ，Zhang LB ，Wu P ，Huang GD ，Luo YX ，Bao YP ，Wang YM ，Shaham Y ，Shi J ，Lu L ... -  《-》

Distinct Fos-Expressing Neuronal Ensembles in the Ventromedial Prefrontal Cortex Mediate Food Reward and Extinction Memories.

In operant learning, initial reward-associated memories are thought to be distinct from subsequent extinction-associated memories. Memories formed during operant learning are thought to be stored in "neuronal ensembles." Thus, we hypothesize that different neuronal ensembles encode reward- and extinction-associated memories. Here, we examined prefrontal cortex neuronal ensembles involved in the recall of reward and extinction memories of food self-administration. We first trained rats to lever press for palatable food pellets for 7 d (1 h/d) and then exposed them to 0, 2, or 7 daily extinction sessions in which lever presses were not reinforced. Twenty-four hours after the last training or extinction session, we exposed the rats to either a short 15 min extinction test session or left them in their homecage (a control condition). We found maximal Fos (a neuronal activity marker) immunoreactivity in the ventral medial prefrontal cortex of rats that previously received 2 extinction sessions, suggesting that neuronal ensembles in this area encode extinction memories. We then used the Daun02 inactivation procedure to selectively disrupt ventral medial prefrontal cortex neuronal ensembles that were activated during the 15 min extinction session following 0 (no extinction) or 2 prior extinction sessions to determine the effects of inactivating the putative food reward and extinction ensembles, respectively, on subsequent nonreinforced food seeking 2 d later. Inactivation of the food reward ensembles decreased food seeking, whereas inactivation of the extinction ensembles increased food seeking. Our results indicate that distinct neuronal ensembles encoding operant reward and extinction memories intermingle within the same cortical area. A current popular hypothesis is that neuronal ensembles in different prefrontal cortex areas control reward-associated versus extinction-associated memories: the dorsal medial prefrontal cortex (mPFC) promotes reward seeking, whereas the ventral mPFC inhibits reward seeking. In this paper, we use the Daun02 chemogenetic inactivation procedure to demonstrate that Fos-expressing neuronal ensembles mediating both food reward and extinction memories intermingle within the same ventral mPFC area.

Warren BL ，Mendoza MP ，Cruz FC ，Leao RM ，Caprioli D ，Rubio FJ ，Whitaker LR ，McPherson KB ，Bossert JM ，Shaham Y ，Hope BT ... -  《-》

Role of Central Amygdala Neuronal Ensembles in Incubation of Nicotine Craving.

The craving response to smoking-associated cues in humans or to intravenous nicotine-associated cues in adult rats progressively increases or incubates after withdrawal. Here, we further characterized incubation of nicotine craving in the rat model by determining whether this incubation is observed after adolescent-onset nicotine self-administration. We also used the neuronal activity marker Fos and the Daun02 chemogenetic inactivation procedure to identify cue-activated neuronal ensembles that mediate incubation of nicotine craving. We trained adolescent and adult male rats to self-administer nicotine (2 h/d for 12 d) and assessed cue-induced nicotine seeking in extinction tests (1 h) after 1, 7, 14, or 28 withdrawal days. In both adult and adolescent rats, nicotine seeking in the relapse tests followed an inverted U-shaped curve, with maximal responding on withdrawal day 14. Independent of the withdrawal day, nicotine seeking in the relapse tests was higher in adult than in adolescent rats. Analysis of Fos expression in different brain areas of adolescent and adult rats on withdrawal days 1 and 14 showed time-dependent increases in the number of Fos-positive neurons in central and basolateral amygdala, orbitofrontal cortex, ventral and dorsal medial prefrontal cortex, and nucleus accumbens core and shell. In adult Fos-lacZ transgenic rats, selective inactivation of nicotine-cue-activated Fos neurons in central amygdala, but not orbitofrontal cortex, decreased "incubated" nicotine seeking on withdrawal day 14. Our results demonstrate that incubation of nicotine craving occurs after adolescent-onset nicotine self-administration and that neuronal ensembles in central amygdala play a critical role in this incubation. The craving response to smoking-associated cues in humans or to intravenous nicotine-associated cues in adult rats progressively increases or incubates after withdrawal. It is currently unknown whether incubation of craving also occurs after adolescent-onset nicotine self-administration. The brain areas that mediate such incubation are also unknown. Here, we used a rat model of incubation of drug craving, the neuronal activity marker Fos, and the Daun02 chemogenetic inactivation method to demonstrate that incubation of nicotine craving is also observed after adolescent-onset nicotine self-administration and that neuronal ensembles in the central nucleus of the amygdala play a critical role in this incubation in adult rats.

Funk D ，Coen K ，Tamadon S ，Hope BT ，Shaham Y ，Lê AD ... -  《-》

β1-Adrenoceptor in the Central Amygdala Is Required for Unconditioned Stimulus-Induced Drug Memory Reconsolidation.

Drug memories become labile and reconsolidated after retrieval by presentation of environmental cues (conditioned stimulus) or drugs (unconditioned stimulus). Whether conditioned stimulus and unconditioned stimulus retrieval trigger different memory reconsolidation processes is not clear. Protein synthesis inhibitor or β-adrenergic receptor (β-AR) antagonist was systemically administrated or intra-central amygdala infused immediately after cocaine reexposure in cocaine-conditioned place preference or self-administration mice models. β-ARs were selectively knocked out in the central amygdala to further confirm the role of β-adrenergic receptor in cocaine reexposure-induced memory reconsolidation of cocaine-conditioned place preference. Cocaine reexposure triggered de novo protein synthesis dependent memory reconsolidation of cocaine-conditioned place preference. Cocaine-priming-induced reinstatement was also impaired with post cocaine retrieval manipulation, in contrast to the relapse behavior with post context retrieval manipulation. Cocaine retrieval, but not context retrieval, induced central amygdala activation. Protein synthesis inhibitor or β1-adrenergic receptor antagonist infused in the central amygdala after cocaine retrieval, but not context retrieval, inhibited memory reconsolidation and reinstatement. β1-adrenergic receptor knockout in the central amygdala suppressed cocaine retrieval-triggered memory reconsolidation and reinstatement of cocaine conditioned place preference. β1-adrenergic receptor antagonism after cocaine retrieval also impaired reconsolidation and reinstatement of cocaine self-administration. Cocaine reward memory triggered by unconditioned stimulus retrieval is distinct from conditioned stimulus retrieval. Unconditioned stimulus retrieval induced reconsolidation of cocaine reward memory depends on β1-adrenergic signaling in the central amygdala. Post unconditioned stimulus retrieval manipulation can prevent drug memory reconsolidation and relapse to cocaine, thus providing a potential strategy for the prevention of substance addiction. It is well known that drug memories become labile and reconsolidated upon retrieval by the presentation of conditioned stimulus (CS) or unconditioned stimulus (US). Whether CS and US retrieval trigger different memory reconsolidation processes is unknown. In this study, we found that US retrieval, but not CS retrieval, triggered memory reconsolidation of cocaine-conditioned place preference dependent on β1-AR and de novo protein synthesis in the central amygdala. Furthermore, cocaine priming-induced reinstatement was impaired with post US retrieval manipulation in contrast to the relapse behavior with post CS retrieval manipulation. In cocaine self-administration, β1-AR antagonism after US retrieval also impaired reconsolidation and reinstatement. Our study indicates that reconsolidation of cocaine reward memory triggered by US retrieval is distinct from CS retrieval. US retrieval induced reconsolidation of cocaine reward memory depends on β1-adrenergic signaling in the central amygdala.

Zhu H ，Zhou Y ，Liu Z ，Chen X ，Li Y ，Liu X ，Ma L ... -  《-》