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Fotros A, Casey KF, Larcher K, Verhaeghe JAJ, Cox SML, Gravel P, Reader AJ, Dagher A, Benkelfat C, Leyton M. Cocaine cue-induced dopamine release in amygdala and hippocampus: a high-resolution PET [¹⁸F]fallypride study in cocaine dependent participants. Neuropsychopharmacology 2013; 38:1780-8. [PMID: 23546387 PMCID: PMC3717549 DOI: 10.1038/npp.2013.77] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 03/23/2013] [Accepted: 03/27/2013] [Indexed: 11/09/2022]
Abstract
Drug-related cues are potent triggers for relapse in people with cocaine dependence. Dopamine (DA) release within a limbic network of striatum, amygdala and hippocampus has been implicated in animal studies, but in humans it has only been possible to measure effects in the striatum. The objective here was to measure drug cue-induced DA release in the amygdala and hippocampus using high-resolution PET with [(18)F]fallypride. Twelve cocaine-dependent volunteers (mean age: 39.6 ± 8.0 years; years of cocaine use: 15.9 ± 7.4) underwent two [(18)F]fallypride high-resolution research tomography-PET scans, one with exposure to neutral cues and one with cocaine cues. [(18)F]Fallypride non-displaceable-binding potential (BPND) values were derived for five regions of interest (ROI; amygdala, hippocampus, ventral limbic striatum, associative striatum, and sensorimotor striatum). Subjective responses to the cues were measured with visual analog scales and grouped using principal component analysis. Drug cue exposure significantly decreased BPND values in all five ROI in subjects who had a high-, but not low-, craving response (limbic striatum: p=0.019, associative striatum: p=0.008, sensorimotor striatum: p=0.004, amygdala: p=0.040, and right hippocampus: p=0.025). Individual differences in the cue-induced craving response predicted the magnitude of [(18)F]fallypride responses within the striatum (ventral limbic: r=0.581, p=0.048; associative: r=0.589, p=0.044; sensorimotor: r=0.675, p=0.016). To our knowledge this study provides the first evidence of drug cue-induced DA release in the amygdala and hippocampus in humans. The preferential induction of DA release among high-craving responders suggests that these aspects of the limbic reward network might contribute to drug-seeking behavior.
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Affiliation(s)
- Aryandokht Fotros
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada,Department of Psychiatry, McGill University, Montréal, QC, Canada
| | - Kevin F Casey
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada,Department of Psychiatry, McGill University, Montréal, QC, Canada
| | - Kevin Larcher
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | | | - Sylvia ML Cox
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Paul Gravel
- Department of Biomedical Engineering, McGill University, Montréal, QC, Canada
| | - Andrew J Reader
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada,Department of Biomedical Engineering, McGill University, Montréal, QC, Canada
| | - Alain Dagher
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Chawki Benkelfat
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada,Department of Psychiatry, McGill University, Montréal, QC, Canada
| | - Marco Leyton
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada,Department of Psychiatry, McGill University, Montréal, QC, Canada,Center for Studies in Behavioral Neurobiology, Concordia University, Montréal, QC, Canada,Department of Psychiatry, McGill University, 1033 Pine Avenue West, Montreal, QC, Canada H3A 1A1, Tel: +514 398 5804, Fax: +514 398 4866, E-mail:
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Xi ZX, Li X, Li J, Peng XQ, Song R, Gaál J, Gardner EL. Blockade of dopamine D3 receptors in the nucleus accumbens and central amygdala inhibits incubation of cocaine craving in rats. Addict Biol 2013; 18:665-77. [PMID: 22913325 DOI: 10.1111/j.1369-1600.2012.00486.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cue-induced drug seeking progressively increases over time of withdrawal from drug self-administration in rats, a phenomenon called 'incubation of craving'. The underlying mechanisms have been linked to increased expression of brain-derived neurotrophic factor and GluR2-lacking AMPA receptors in the mesolimbic dopamine (DA) system and also to increased extracellular signal-regulated kinase activation in the central amygdala (CeA). However, it remains unclear whether any DA mechanism is also involved in incubation of craving. Recent research demonstrates that cue-induced cocaine seeking appears to parallel increased DA D3 , but not D1 or D2 , receptor expression in the nucleus accumbens (NAc) of rats over time of withdrawal, suggesting possible involvement of D3 receptors (D3 Rs) in incubation of cocaine craving. Here, we report that systemic or local administration of SB-277011A, a highly selective D3 R antagonist, into the NAc (core and shell) or the CeA, but not the dorsal striatum or basolateral amygdala, significantly inhibits expression of incubation of cocaine craving in rats after 2-30 days of withdrawal from previous cocaine self-administration but had no effect on sucrose-seeking behavior in rats after 10-30 days of withdrawal. These data suggest that DA D3 Rs in both the NAc and the CeA play an important role in incubation of cocaine craving in rats and support the potential utility of D3 R antagonists in the treatment of cocaine addiction.
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Affiliation(s)
- Zheng-Xiong Xi
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
| | - Xia Li
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
| | - Jie Li
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
| | - Xiao-Qing Peng
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
| | - Rui Song
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
| | | | - Eliot L. Gardner
- Intramural Research Program; National Institute on Drug Abuse; Baltimore; MD; USA
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53
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AMPA receptor endocytosis in the amygdala is involved in the disrupted reconsolidation of Methamphetamine-associated contextual memory. Neurobiol Learn Mem 2013; 103:72-81. [DOI: 10.1016/j.nlm.2013.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 03/27/2013] [Accepted: 04/09/2013] [Indexed: 11/24/2022]
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Stamatakis AM, Sparta DR, Jennings JH, McElligott ZA, Decot H, Stuber GD. Amygdala and bed nucleus of the stria terminalis circuitry: Implications for addiction-related behaviors. Neuropharmacology 2013; 76 Pt B:320-8. [PMID: 23752096 DOI: 10.1016/j.neuropharm.2013.05.046] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 02/07/2023]
Abstract
Complex motivated behavioral processes, such as those that can go awry following substance abuse and other neuropsychiatric disorders, are mediated by a distributive network of neurons that reside throughout the brain. Neural circuits within the amygdala regions, such as the basolateral amygdala (BLA), and downstream targets such as the bed nucleus of the stria terminalis (BNST), are critical neuroanatomical structures for orchestrating emotional behavioral responses that may influence motivated actions such as the reinstatement of drug seeking behavior. Here, we review the functional neurocircuitry of the BLA and the BNST, and discuss how these circuits may guide maladaptive behavioral processes such as those seen in addiction. Thus, further study of the functional connectivity within these brain regions and others may provide insight for the development of new treatment strategies for substance use disorders. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Alice M Stamatakis
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Yang FY, Lee YS, Cherng CG, Cheng LY, Chang WT, Chuang JY, Kao GS, Yu L. D-cycloserine, sarcosine and D-serine diminish the expression of cocaine-induced conditioned place preference. J Psychopharmacol 2013; 27:550-8. [PMID: 21106609 DOI: 10.1177/0269881110388333] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Reactivation of cocaine-associated memories plays a critical role in reinstating the cocaine-seeking behavior and causing relapse. Cocaine-induced conditioned place preference (CPP) was used as a behavioral paradigm indicative of cocaine-associated memory and repeated cocaine-free preference tests served as a behavioral procedure to retrieve such a memory in this study. Since D-cycloserine was reported to eradicate drug-associated memories, two other N-methyl-D-aspartate (NMDA) receptor agonists were assessed for their efficacy on facilitating the extinction of cocaine-induced CPP. Although D-cycloserine (30 mg/kg) abolished cocaine (10 mg/kg)-induced CPP, sarcosine (300 and 600 mg/kg) and D-serine (600 mg/kg) diminished the expression of such a cocaine memory. Sarcosine (600 mg/kg) and D-serine (600 mg/kg) did not affect the storage of this cocaine memory. It was of interest to note that D-cycloserine facilitated the extinction of cocaine-induced CPP in a fast and early-onset manner, while sarcosine and D-serine decreased cocaine-induced CPP expression in a delay-onset manner. D-cycloserine (30 mg/kg), D-serine (600 mg/kg) and sarcosine (600 mg/kg) did not affect the consolidation of cocaine (5 mg/kg)-induced CPP. Finally, sarcosine (at 600 mg/kg/day for 3 consecutive days) and D-serine (at 600 mg/kg/day for 3 consecutive days) did not produce observable aversive effect associated with their administration in a conditioned place aversion paradigm. Likewise, a similar dosing regimen of sarcosine or D-serine did not cause evident activity-impairing effect. In addition to D-cycloserine treatment, our results indicate that long-term treatment with D-serine and sarcosine may afford a therapeutic advance in suppressing the expression of cocaine-associated memory.
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Affiliation(s)
- Fu-Yung Yang
- Institute of Behavioral Medicine, National Cheng Kung University College of Medicine, Tainan, Republic of China
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Abstract
Drug addiction is a chronic relapsing disorder for which research has been dedicated to understand the various factors that contribute to development, loss of control, and persistence of compulsive addictive behaviors. In this review, we provide a broad overview of various theories of addiction, drugs of abuse, and the neurobiology involved across the addiction cycle. Specific focus is devoted to the role of the mesolimbic pathway in acute drug reinforcement and occasional drug use, the mesocortical pathway and associated areas (e.g., the dorsal striatum) in escalation/dependence, and the involvement of these pathways and associated circuits in mediating conditioned responses, drug craving, and loss of behavioral control thought to underlie withdrawal and relapse. With a better understanding of the neurobiological factors that underlie drug addiction, continued preclinical and clinical research will aid in the development of novel therapeutic interventions that can serve as effective long-term treatment strategies for drug-dependent individuals.
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Affiliation(s)
- Matthew W Feltenstein
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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57
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Torregrossa MM, Taylor JR. Learning to forget: manipulating extinction and reconsolidation processes to treat addiction. Psychopharmacology (Berl) 2013; 226:659-72. [PMID: 22638814 PMCID: PMC3466391 DOI: 10.1007/s00213-012-2750-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 05/13/2012] [Indexed: 11/29/2022]
Abstract
Finding effective long-lasting treatments for drug addiction has been an elusive goal. Consequently, researchers are beginning to investigate novel treatment strategies including manipulations of drug-associated memories. When environmental stimuli (cues) become associated with drug use, they become powerful motivators of continued drug use and relapse after abstinence. Reducing the strength of these cue-drug memories could decrease the number of factors that induce craving and relapse to aid in the treatment of addiction. Enhancing the consolidation of extinction learning and/or disrupting cue-drug memory reconsolidation are two strategies that have been proposed to reduce the strength of cues in motivating drug-seeking and drug-taking behavior. Here, we review the latest basic and clinical research elucidating the mechanisms underlying consolidation of extinction and reconsolidation of cue-drug memories in the hopes of developing pharmacological tools that exploit these signaling systems to treat addiction.
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Affiliation(s)
| | - Jane R. Taylor
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT,Department of Psychology, Yale University, New Haven, CT
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58
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Karlsson RM, Kircher DM, Shaham Y, O’Donnell P. Exaggerated cue-induced reinstatement of cocaine seeking but not incubation of cocaine craving in a developmental rat model of schizophrenia. Psychopharmacology (Berl) 2013; 226:45-51. [PMID: 23010798 PMCID: PMC3553299 DOI: 10.1007/s00213-012-2882-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 09/12/2012] [Indexed: 01/09/2023]
Abstract
RATIONALE Patients with schizophrenia exhibit high comorbidity for substance abuse, but the biological underpinnings of this dual-diagnosis condition are still unclear. Previous studies have shown that rats with a neonatal ventral hippocampal lesion (NVHL), a widely used developmental animal model of schizophrenia, exhibit increased cocaine and methamphetamine self-administration and cocaine-induced reinstatement. OBJECTIVE Here, we assessed whether a NVHL would also potentiate cue-induced reinstatement of cocaine seeking and the time-dependent increases in cue-induced cocaine seeking after withdrawal (incubation of cocaine craving) in adult rats. METHODS Rats were trained to self-administer cocaine (3 or 6 h/day with 0.75 mg kg(-1) infusion(-1) paired with a tone-light cue) for 10 days, followed by extinction training (3 h/day) and cue-induced reinstatement of cocaine seeking. Other rats were tested for incubation of cocaine craving, assessed in extinction tests 1 and 30 days after the last self-administration session. RESULTS Although there was no significant difference in cocaine intake between NVHL and sham controls, NVHL rats took significantly longer to reach an a priori set extinction criterion and exhibited enhanced cue-induced reinstatement. However, while cue-induced cocaine seeking was higher after 30 days than after 1 day of withdrawal (incubation of cocaine craving), the NVHL had no effect on this incubation. CONCLUSION These data confirm previous reports on enhanced resistance to extinction after NVHL and demonstrate that NVHL rats exhibit enhanced cue-induced reinstatement of cocaine seeking after extinction, a measure of drug relapse.
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Affiliation(s)
- Rose-Marie Karlsson
- Department of Anatomy and Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, USA
| | - Daniel M. Kircher
- Department of Anatomy and Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, USA
| | - Yavin Shaham
- Neurobiology of Relapse Section, National Institute of Drug Abuse, National Institute of Health, Baltimore, MD, USA
| | - Patricio O’Donnell
- Department of Anatomy and Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, USA,Department of Psychiatry, University of Maryland, School of Medicine, Baltimore, MD, USA,Corresponding Author: Patricio O’Donnell, MD., Ph.D., Department of Anatomy and Neurobiology, University of Maryland, School of Medicine, 20 Penn St, HSFII, Room S251, Baltimore, MD, 21201, 410-706-6412,
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59
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Repeated orexin 1 receptor antagonism effects on cocaine seeking in rats. Neuropharmacology 2012; 63:1201-7. [PMID: 22971541 DOI: 10.1016/j.neuropharm.2012.07.044] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/16/2012] [Accepted: 07/25/2012] [Indexed: 11/22/2022]
Abstract
The orexin/hypocretin system has been implicated in multiple phases of drug addiction. Acute orexin receptor blockade with the orexin-1 receptor (OX1R) antagonist, SB-334867, has been found to reduce cocaine seeking after cocaine self-administration. As repeated drug dosing can have differential effects and is more clinically relevant than acute dosing, in the current study we examined the effects of repeated SB-334867 on cocaine self-administration, extinction, and reinstatement to cocaine seeking in Sprague-Dawley rats. We found that repeated SB-334867 (10 mg/kg/day) had no effect on established cocaine self-administration. Repeated SB-334867 (both 10 and 20 mg/kg) attenuated cocaine seeking during extinction; however, this effect was only observed when animals had no prior experience with SB-334867 and when SB-334867 was administered prior to, but not after, daily extinction sessions. Notably, daily treatment with SB-334867 (10 mg/kg) during extinction increased subsequent cue-induced reinstatement, whereas repeated SB-334867 (20 mg/kg) administration during extinction enabled acute SB-334867 to reduce cue-induced reinstatement. Repeated SB-334867 treatment (10 or 20 mg/kg) failed to affect reinstatement induced by priming injections of cocaine (10 mg/kg). These results show that repeated inhibition of OX1R-mediated signaling exerts a lasting and specific role in mediating environmentally activated cocaine seeking.
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LeBlanc KH, Ostlund SB, Maidment NT. Pavlovian-to-instrumental transfer in cocaine seeking rats. Behav Neurosci 2012; 126:681-9. [PMID: 22866668 DOI: 10.1037/a0029534] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Drug-associated cues are believed to be important mediators of addiction and drug relapse. Although such cues may influence drug-seeking behavior through multiple routes, it is their putative incentive motivational properties-their ability to elicit "craving"-that interests many addiction researchers. The Pavlovian-to-instrumental transfer paradigm is commonly used to assay cue-evoked incentive motivation in situations involving natural rewards, but has not been widely applied to the study of drug self-administration. We used this paradigm to determine whether cues paired with intravenous cocaine could promote performance of an independently trained task in which rats self-administered cocaine by completing a chain of two different lever press actions, a procedure used to parse behavior into cocaine seeking (first action) and cocaine taking (second action). Rats showed significant transfer, increasing task performance during cocaine-paired cues. This effect was observed for both seeking and taking actions, although a trend toward greater cocaine taking was observed, a result that is consistent with studies using natural rewards. Our results demonstrate that cocaine-paired cues can provoke the pursuit of cocaine through a Pavlovian motivational process. This phenomenon may provide a useful new tool for modeling drug relapse, particularly as a method for targeting the response-invigorating effects of stimulus-drug learning.
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Affiliation(s)
- Kimberly H LeBlanc
- Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90024, USA.
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61
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Nic Dhonnchadha BÁ, Lovascio BF, Shrestha N, Lin A, Leite-Morris KA, Man HY, Kaplan GB, Kantak KM. Changes in expression of c-Fos protein following cocaine-cue extinction learning. Behav Brain Res 2012; 234:100-6. [PMID: 22721675 DOI: 10.1016/j.bbr.2012.06.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 06/07/2012] [Accepted: 06/12/2012] [Indexed: 01/15/2023]
Abstract
Extinguishing abnormally strengthened learned responses to cues associated with drugs of abuse remains a key tactic for alleviating addiction. To assist in developing pharmacotherapies to augment exposure therapy for relapse prevention, investigation into neurobiological underpinnings of drug-cue extinction learning is needed. We used regional analyses of c-Fos and GluR2 protein expression to delineate neural activity and plasticity that may be associated with cocaine-cue extinction learning. Rats were trained to self-administer cocaine paired with a light cue, and later underwent a single 2h extinction session for which cocaine was withheld but response-contingent cues were presented (cocaine-cue extinction). Control groups consisted of rats yoked to animals self-administering cocaine and receiving saline non-contingently followed by an extinction session, or rats trained to self-administer cocaine followed by a no-extinction session for which levers were retracted, and cocaine and cues were withheld. Among 11 brain sites examined, extinction training increased c-Fos expression in basolateral amygdala and prelimbic prefrontal cortex of cocaine-cue extinguished rats relative to both control conditions. In dorsal subiculum and infralimbic prefrontal cortex, extinction training increased c-Fos expression in both cocaine-cue and saline-cue extinguished rats relative to the no-extinction control condition. GluR2 protein expression was not altered in any site examined after extinction or control training. Findings suggest that basolateral amygdala and prelimbic prefrontal cortex neurons are activated during acquisition of cocaine-cue extinction learning, a process that is independent of changes in GluR2 abundance. Other sites are implicated in processing the significance of cues that are present early in extinction training.
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Di Clemente A, Franchi C, Orrù A, Arnt J, Cervo L. Bifeprunox: a partial agonist at dopamine D2 and serotonin 1A receptors, influences nicotine-seeking behaviour in response to drug-associated stimuli in rats. Addict Biol 2012; 17:274-86. [PMID: 21521422 DOI: 10.1111/j.1369-1600.2011.00319.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Environmental stimuli repeatedly associated with the self-administered drugs may acquire motivational importance. Because dopamine (DA) D(2) /D(3) partial agonists and D(3) antagonists interfere with the ability of drug-associated cues to induce drug-seeking behaviour, the present study investigated whether bifeprunox, 7-[4-([1,1'biphenyl]-3-ylmethyl)-1-piperazinyl]-2(3H)-benzoxazolone mesylate), a high-affinity partial agonist of the D(2) subfamily of DA receptors and of serotonin(1A) receptors, influences reinstatement of drug-associated cue-induced nicotine-seeking behaviour. The study also explored whether bifeprunox reduced motivated behaviour by evaluating its effects on reinstatement induced by stimuli conditioned to sucrose. To verify whether bifeprunox interferes with the primary reinforcing properties of either drug or sucrose, we compared its effects on nicotine self-administration and on sucrose-reinforced behaviour. Different groups of experimentally naïve, food-restricted Wistar rats were trained to associate a discriminative stimulus with response-contingent availability of nicotine or sucrose and tested for reinstatement after extinction of nicotine or sucrose-reinforced behaviour. Bifeprunox (4-16 µg/kg, s.c.) dose-dependently attenuated the response-reinstating effects of nicotine-associated cues. Higher doses (64-250 µg/kg, s.c.) reduced spontaneous locomotor activity and suppressed operant responding induced by sucrose-associated cues and by the primary reinforcing properties of nicotine or sucrose. Provided they can be extrapolated to abstinent human addicts, these results suggest the potential therapeutic use of partial DA D(2) receptor agonist to prevent cue-controlled nicotine-seeking and relapse. The profile of action of high doses of bifeprunox remains to be examined for potential sedation or anhedonia effects.
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Affiliation(s)
- Angelo Di Clemente
- Experimental Psychopharmacology, Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via Giuseppe La Masa 19, Milan, Italy
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63
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mGluR5 receptors in the basolateral amygdala and nucleus accumbens regulate cue-induced reinstatement of ethanol-seeking behavior. Pharmacol Biochem Behav 2012; 101:329-35. [PMID: 22296815 DOI: 10.1016/j.pbb.2012.01.014] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/25/2023]
Abstract
Pharmacological blockade of the type 5 metabotropic glutamate receptor (mGluR5) attenuates cue-induced reinstatement of ethanol-seeking behavior, yet the brain regions involved in these effects are not yet known. The purpose of the present study was to determine if local blockade of mGluR5 receptors in the basolateral amygdala (BLA) and/or the nucleus accumbens (NAc), two brain regions known to be involved in stimulus-reward associations, attenuate the reinstatement of ethanol-seeking behavior induced by ethanol-paired cues. As a control for possible non-specific effects, the effects of mGluR5 blockade in these regions on cue-induced reinstatement of sucrose-seeking were also assessed. Male Wistar rats were implanted with bilateral microinjection cannulae aimed at the BLA or NAc. Following recovery, animals were trained to self-administer ethanol (10% w/v) or 45 mg sucrose pellets on an FR1 schedule of reinforcement in 30 min daily sessions using a sucrose fading procedure. Following stabilization of responding, animals underwent extinction training. Next, animals received infusions of vehicle or the selective mGluR5 antagonist MTEP (3 μg/μl) into the BLA or NAc prior to cue-induced reinstatement testing sessions. mGluR5 blockade eliminated cue-induced reinstatement of alcohol - but not sucrose-seeking behavior. Results from this study indicate that mGluR5 receptors in the BLA and NAc mediate cue-induced reinstatement of ethanol-seeking behavior, and provide two potential neuroanatomical sites of action where systemically administered mGluR5 antagonists attenuate cue-induced reinstatement. These data are consistent with previous findings that cue-induced reinstatement of ethanol-seeking increases neuronal activity and glutamatergic transmission in these two regions.
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Milton AL, Everitt BJ. The persistence of maladaptive memory: addiction, drug memories and anti-relapse treatments. Neurosci Biobehav Rev 2012; 36:1119-39. [PMID: 22285426 DOI: 10.1016/j.neubiorev.2012.01.002] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/09/2012] [Accepted: 01/15/2012] [Indexed: 01/15/2023]
Abstract
Addiction is a chronic, relapsing disorder, characterised by the long-term propensity of addicted individuals to relapse. A major factor that obstructs the attainment of abstinence is the persistence of maladaptive drug-associated memories, which can maintain drug-seeking and taking behaviour and promote unconscious relapse of these habits. Thus, addiction can be conceptualised as a disorder of aberrant learning of the formation of strong instrumental memories linking actions to drug-seeking and taking outcomes that ultimately are expressed as persistent stimulus-response habits; of previously neutral environmental stimuli that become associated with drug highs (and/or withdrawal states) through pavlovian conditioning, and of the subsequent interactions between pavlovian and instrumental memories to influence relapse behaviour. Understanding the psychological, neurobiological and molecular basis of these drug memories may produce new methods of pro-abstinence, anti-relapse treatments for addiction.
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Affiliation(s)
- Amy L Milton
- Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Downing Site, Cambridge CB2 3EB, UK.
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Effect of amphetamine place conditioning on excitatory synaptic events in the basolateral amygdala ex vivo. Neuroscience 2012; 206:7-16. [PMID: 22280974 DOI: 10.1016/j.neuroscience.2012.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 12/20/2011] [Accepted: 01/11/2012] [Indexed: 11/21/2022]
Abstract
The basolateral amygdala (BLA) plays an important role in the formation of associations between context and drug. BLA activity and BLA-dependent drug-seeking behavior are driven by excitatory inputs. Drug-seeking behavior driven by context involves participation of the BLA, and plasticity of excitatory inputs to the BLA may contribute to this behavior. In this study, amphetamine conditioned place preference (AMPH CPP) was used to model the formation of context-drug associations. Learning-induced changes of excitatory synapses within the BLA were examined. Male Sprague-Dawley rats were assigned to one of three groups, the experimental group (AMPH CPP) or one of two control groups (saline or AMPH delayed pairing). Approximately 24 h after testing their preference, spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs, respectively) in BLA pyramidal neurons were investigated using whole-cell patch-clamp recordings. There were no between-groups differences in the amplitude or frequency of sEPSCs or mEPSCs. In a higher osmolarity solution to increase release, there was a significantly greater frequency of the mEPSCs in neurons from AMPH CPP animals compared with controls. This was observed with no change detected in the probability of glutamate release. Together, these data demonstrate no evidence for increased synaptic strength, but are consistent with an increase in the number of synapses in the BLA after AMPH CPP. These findings may underlie increased excitatory drive of the BLA after AMPH CPP, and contribute to the animals' preference for the AMPH-paired compartment.
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Santini E, Klann E. Dysregulated mTORC1-Dependent Translational Control: From Brain Disorders to Psychoactive Drugs. Front Behav Neurosci 2011; 5:76. [PMID: 22073033 PMCID: PMC3210466 DOI: 10.3389/fnbeh.2011.00076] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/21/2011] [Indexed: 01/09/2023] Open
Abstract
In the last decade, a plethora of studies utilizing pharmacological, biochemical, and genetic approaches have shown that precise translational control is required for long-lasting synaptic plasticity and the formation of long-term memory. Moreover, more recent studies indicate that alterations in translational control are a common pathophysiological feature of human neurological disorders, including developmental disorders, neuropsychiatric disorders, and neurodegenerative diseases. Finally, translational control mechanisms are susceptible to modification by psychoactive drugs. Taken together, these findings point to a central role for translational control in the regulation of synaptic function and behavior.
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Affiliation(s)
- Emanuela Santini
- Center for Neural Science, New York University New York, NY, USA
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67
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Wells AM, Lasseter HC, Xie X, Cowhey KE, Reittinger AM, Fuchs RA. Interaction between the basolateral amygdala and dorsal hippocampus is critical for cocaine memory reconsolidation and subsequent drug context-induced cocaine-seeking behavior in rats. Learn Mem 2011; 18:693-702. [PMID: 22005750 DOI: 10.1101/lm.2273111] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Contextual stimulus control over instrumental drug-seeking behavior relies on the reconsolidation of context-response-drug associative memories into long-term memory storage following retrieval-induced destabilization. According to previous studies, the basolateral amygdala (BLA) and dorsal hippocampus (DH) regulate cocaine-related memory reconsolidation; however, it is not known whether these brain regions interact or independently control this phenomenon. To investigate this question, rats were trained to lever press for cocaine reinforcement in a distinct environmental context followed by extinction training in a different context. Rats were then briefly re-exposed to the cocaine-paired context to destabilize cocaine-related memories, or they were exposed to an unpaired context. Immediately thereafter, the rats received unilateral microinfusions of anisomycin (ANI) into the BLA plus baclofen/muscimol (B/M) into the contralateral (BLA/DH disconnection) or ipsilateral DH, or they received contralateral or ipsilateral microinfusions of vehicle. They then remained in their home cages overnight or for 21 d, followed by additional extinction training and a test of cocaine-seeking behavior (nonreinforced active lever responding). BLA/DH disconnection following re-exposure to the cocaine-paired context, but not the unpaired context, impaired subsequent drug context-induced cocaine-seeking behavior relative to vehicle or ipsilateral ANI + B/M treatment. Prolonged home cage stay elicited a time-dependent increase, or incubation, of drug-context-induced cocaine-seeking behavior, and BLA/DH disconnection inhibited this incubation effect despite some recovery of cocaine-seeking behavior. Thus, the BLA and DH interact to regulate the reconsolidation of cocaine-related associative memories, thereby facilitating the ability of drug-paired contexts to trigger cocaine-seeking behavior and contributing to the incubation of cocaine-seeking behavior.
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Affiliation(s)
- Audrey M Wells
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina 27599-3270, USA
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68
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Gabriele A, See RE. Lesions and reversible inactivation of the dorsolateral caudate-putamen impair cocaine-primed reinstatement to cocaine-seeking in rats. Brain Res 2011; 1417:27-35. [PMID: 21890120 PMCID: PMC3183406 DOI: 10.1016/j.brainres.2011.08.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/10/2011] [Accepted: 08/12/2011] [Indexed: 11/16/2022]
Abstract
Recent evidence suggests that cocaine addiction may involve progressive drug-induced neuroplasticity of the dorsal striatum. Here, we examined the effects of a) dorsolateral caudate putamen (dlCPu) lesions on cocaine self-administration, extinction of responding, and subsequent reinstatement to cocaine-seeking, and b) reversible inactivation of the dlCPu with GABA receptor agonists (baclofen and muscimol) immediately prior to reinstatement testing. Male, Sprague-Dawley rats self-administered cocaine (0.2mg/50μl infusion, i.v.) along an FR1 schedule in daily 2h sessions for 10days, whereby lever presses resulted in cocaine infusions and presentation of a paired light-tone stimulus complex. After 14days of abstinence, animals were returned to the self-administration chamber and lever responding was recorded, but had no programmed consequences (relapse test). Animals then underwent daily extinction, followed by reinstatement tests in the presence of the conditioned cues, after a cocaine priming injection (10mg/kg), or cues+cocaine prime. Lesions of the dlCPu failed to affect responding during self-administration, extinction, relapse, or cued-induced reinstatement. However, lesioned animals showed reduced cocaine-seeking during cocaine-primed reinstatement as compared to sham controls. Furthermore, reversible inactivation of the dlCPu significantly impaired both cocaine-primed and cocaine-primed+cue-induced reinstatement. These results demonstrate the critical involvement of the dlCPu in cocaine-primed reinstatement, perhaps via chronic drug-induced changes in the interoceptive effects of cocaine that impact drug-seeking.
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Affiliation(s)
- Amanda Gabriele
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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69
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Krishnan B, Genzer KM, Pollandt SW, Liu J, Gallagher JP, Shinnick-Gallagher P. Dopamine-induced plasticity, phospholipase D (PLD) activity and cocaine-cue behavior depend on PLD-linked metabotropic glutamate receptors in amygdala. PLoS One 2011; 6:e25639. [PMID: 21980514 PMCID: PMC3181343 DOI: 10.1371/journal.pone.0025639] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 09/08/2011] [Indexed: 01/14/2023] Open
Abstract
Cocaine-cue associations induce synaptic plasticity with long lasting molecular and cellular changes in the amygdala, a site crucial for cue-associated memory mechanisms. The underlying neuroadaptations can include marked alterations in signaling via dopamine (DA) receptors (DRs) and metabotropic glutamate (Glu) receptors (mGluRs). Previously, we reported that DR antagonists blocked forms of synaptic plasticity in amygdala slices of Sprague-Dawley rats withdrawn from repeated cocaine administration. In the present study, we investigated synaptic plasticity induced by exogenous DA and its dependence on mGluR signaling and a potential role for phospholipase D (PLD) as a downstream element linked to mGluR and DR signaling. Utilizing a modified conditioned place preference (CPP) paradigm as a functional behavioral measure, we studied the neurophysiological effects after two-weeks to the last cocaine conditioning. We recorded, electrophysiologically, a DR-induced synaptic potentiation in the basolateral to lateral capsula central amygdala (BLA-lcCeA) synaptic pathway that was blocked by antagonists of group I mGluRs, particularly, the PLD-linked mGluR. In addition, we observed 2–2.5 fold increase in PLD expression and 3.7-fold increase in basal PLD enzyme activity. The enhanced PLD activity could be further stimulated (9.3 fold) by a DA D1-like (D1/5R) receptor agonist, and decreased to control levels by mGluR1 and PLD-linked mGluR antagonists. Diminished CPP was observed by infusion of a PLD-linked mGluR antagonist, PCCG-13, in the amygdala 15 minutes prior to testing, two weeks after the last cocaine injection. These results imply a functional interaction between D1/5Rs, group I mGluRs via PLD in the amygdala synaptic plasticity associated with cocaine-cues.
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MESH Headings
- Amygdala/drug effects
- Amygdala/enzymology
- Amygdala/metabolism
- Amygdala/physiology
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Benzazepines/pharmacology
- Cocaine/pharmacology
- Conditioning, Psychological/drug effects
- Conditioning, Psychological/physiology
- Cues
- Cyclopropanes/pharmacology
- Dopamine/pharmacology
- Gene Expression Regulation, Enzymologic/drug effects
- Glycine/analogs & derivatives
- Glycine/pharmacology
- Isoenzymes/metabolism
- Long-Term Potentiation/drug effects
- Male
- Memory/drug effects
- Memory/physiology
- Neuronal Plasticity/drug effects
- Phospholipase D/metabolism
- Raclopride/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D5/agonists
- Receptors, Dopamine D5/metabolism
- Receptors, Metabotropic Glutamate/antagonists & inhibitors
- Receptors, Metabotropic Glutamate/metabolism
- Substance Withdrawal Syndrome/metabolism
- Substance Withdrawal Syndrome/physiopathology
- Synapses/drug effects
- Synapses/metabolism
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Balaji Krishnan
- Department of Pharmacology and Toxicology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America.
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70
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Schmidt K, Krishnan B, Xia Y, Sun A, Orozco-Cabal L, Pollandt S, Centeno M, Genzer K, Gallagher JP, Shinnick-Gallagher P, Liu J. Cocaine withdrawal reduces group I mGluR-mediated long-term potentiation via decreased GABAergic transmission in the amygdala. Eur J Neurosci 2011; 34:177-89. [PMID: 21749491 DOI: 10.1111/j.1460-9568.2011.07769.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cocaine relapse can occur when cocaine-associated environmental cues induce craving. Conditioned place preference (CPP) is a behavioral paradigm modeling the association between cocaine exposure and environmental cues. The amygdala is involved in cocaine cue associations with the basolateral amygdala (BLA) and central amygdala (CeA) acting differentially in cue-induced relapse. Activation of metabotropic glutamate receptors induces synaptic plasticity, the mechanism of which is thought to underlie learning, memory and drug-cue associations. The goal of this study was to examine the neural alterations in responses to group I metabotropic glutamate receptor (mGluR) agonists in the BLA to lateral capsula of CeA (BLA-CeLc) pathway in slices from rats exposed to cocaine-CPP conditioning and withdrawn for 14 days. mGluR1, but not mGluR5, agonist-induced long-term potentiation (mGluR1-LTP) in the BLA-CeLc pathway was reduced in rats withdrawal from cocaine for 2 and 14 days, and exhibited an altered concentration response to picrotoxin. Cocaine withdrawal also reduced γ-aminobutyric acid (GABA)ergic synaptic inhibition in CeLc neurons. Blocking cannabinoid receptor 1 (CB(1) ) reduced mGluR1-LTP in the saline-treated but not cocaine-withdrawn group. Response to CB(1) but not CB(2) agonist was altered after cocaine. Additionally, increasing endocannabinoid (eCB) levels abolished mGluR1-LTP in the saline but not cocaine-withdrawn group. However, CB(1) and CB(2) protein levels were increased in the amygdala of cocaine-withdrawn rats while mGluR1 and mGluR5 remained unchanged. These data suggested that the mechanisms underlying the diminished mGluR1-LTP in cocaine-withdrawn rats involve an altered GABAergic synaptic inhibition mediated by modulation of downstream eCB signaling. These changes may ultimately result in potentiated responses to environmental cues that would bias behavior toward drug-seeking.
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Affiliation(s)
- Kady Schmidt
- Department of Pharmacology and Toxicology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
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71
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Steketee JD, Kalivas PW. Drug wanting: behavioral sensitization and relapse to drug-seeking behavior. Pharmacol Rev 2011; 63:348-65. [PMID: 21490129 DOI: 10.1124/pr.109.001933] [Citation(s) in RCA: 451] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeated exposure to drugs of abuse enhances the motor-stimulant response to these drugs, a phenomenon termed behavioral sensitization. Animals that are extinguished from self-administration training readily relapse to drug, conditioned cue, or stress priming. The involvement of sensitization in reinstated drug-seeking behavior remains controversial. This review describes sensitization and reinstated drug seeking as behavioral events, and the neural circuitry, neurochemistry, and neuropharmacology underlying both behavioral models will be described, compared, and contrasted. It seems that although sensitization and reinstatement involve overlapping circuitry and neurotransmitter and receptor systems, the role of sensitization in reinstatement remains ill-defined. Nevertheless, it is argued that sensitization remains a useful model for determining the neural basis of addiction, and an example is provided in which data from sensitization studies led to potential pharmacotherapies that have been tested in animal models of relapse and in human addicts.
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Affiliation(s)
- Jeffery D Steketee
- Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Avenue, Memphis, TN 38163, USA.
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72
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Gass JT, Sinclair CM, Cleva RM, Widholm JJ, Olive MF. Alcohol-seeking behavior is associated with increased glutamate transmission in basolateral amygdala and nucleus accumbens as measured by glutamate-oxidase-coated biosensors. Addict Biol 2011; 16:215-28. [PMID: 21054692 DOI: 10.1111/j.1369-1600.2010.00262.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Relapse is one of the most problematic aspects in the treatment of alcoholism and is often triggered by alcohol-associated environmental cues. Evidence indicates that glutamate neurotransmission plays a critical role in cue-induced relapse-like behavior, as inhibition of glutamate neurotransmission can prevent reinstatement of alcohol-seeking behavior. However, few studies have examined specific changes in extracellular glutamate levels in discrete brain regions produced by exposure to alcohol-associated cues. The purpose of this study was to use glutamate oxidase (GluOx)-coated biosensors to monitor changes in extracellular glutamate in specific brain regions during cue-induced reinstatement of alcohol-seeking behavior. Male Wistar rats were implanted with indwelling jugular vein catheters and intracerebral guide cannula aimed at the basolateral amygdala (BLA) or nucleus accumbens (NAc) core, and then trained to self-administer alcohol intravenously. A separate group of animals were trained to self-administer food pellets. Each reinforcer was accompanied by the presentation of a light/tone stimulus. Following stabilization of responding for alcohol or food reinforcement, and subsequent extinction training, animals were implanted with pre-calibrated biosensors and then underwent a 1-hour cue-induced reinstatement testing period. As determined by GluOx-coated biosensors, extracellular levels of glutamate were increased in the BLA and NAc core during cue-induced reinstatement of alcohol-seeking behavior. The cumulative change in extracellular glutamate in both regions was significantly greater for cue-induced reinstatement of alcohol-seeking behavior versus that of food-seeking behavior. These results indicate that increases in glutamate transmission in the BLA and NAc core may be a neurochemical substrate of cue-evoked alcohol-seeking behavior.
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Affiliation(s)
- Justin T Gass
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA.
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73
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Casini A, Vivacqua G, Pontieri FE, Kimura H, Bellier JP, D’Este L, Renda TG. Choline acetyltransferase of the common type immunoreactivity in the rat brain following different heroin treatments: A pilot study. J Chem Neuroanat 2011; 41:111-21. [DOI: 10.1016/j.jchemneu.2010.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 11/26/2022]
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74
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Ziółkowska B, Kiełbiński M, Gieryk A, Soria G, Maldonado R, Przewłocki R. Regulation of the immediate-early genes arc and zif268 in a mouse operant model of cocaine seeking reinstatement. J Neural Transm (Vienna) 2011; 118:877-87. [PMID: 21318636 DOI: 10.1007/s00702-011-0583-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 01/09/2011] [Indexed: 01/27/2023]
Abstract
Reinstatement of extinguished operant responding for drug is an appropriate model of relapse to drug abuse. Due to the difficulty of implementing in mice the procedure of instrumental intravenous self-administration, mechanisms of reinstatement have so far been studied almost exclusively in rats. A mouse model of reinstatement of cocaine seeking has recently been characterized (Soria et al. 2008). The aim of the present study was to assess regional brain activation, as measured by induction of the immediate early genes (IEG) arc and zif268, during priming- or cue-elicited reinstatement of cocaine seeking using this new mouse model and the in situ hybridization technique. We have demonstrated that cue-elicited reinstatement of cocaine seeking was associated with induction of the IEG in the medial prefrontal cortex (prelimbic and infralimbic) and basolateral amygdala. Priming-induced reinstatement produced a more widespread up-regulation of those genes in forebrain regions including medial prefrontal, orbitofrontal and motor cortex, dorsal striatum and basolateral amygdala. These patterns of IEG expression are in agreement with previous results obtained in rats and thus indicate that the new mouse model of reinstatement is functionally equivalent to rat models. That comparability adds to the usefulness of the mouse model as a tool for addressing neurobiological mechanisms of addiction.
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Affiliation(s)
- Barbara Ziółkowska
- Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
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75
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Cognitive enhancers for facilitating drug cue extinction: insights from animal models. Pharmacol Biochem Behav 2011; 99:229-44. [PMID: 21295059 DOI: 10.1016/j.pbb.2011.01.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/23/2010] [Accepted: 01/24/2011] [Indexed: 12/30/2022]
Abstract
Given the success of cue exposure (extinction) therapy combined with a cognitive enhancer for reducing anxiety, it is anticipated that this approach will prove more efficacious than exposure therapy alone in preventing relapse in individuals with substance use disorders. Several factors may undermine the efficacy of exposure therapy for substance use disorders, but we suspect that neurocognitive impairments associated with chronic drug use are an important contributing factor. Numerous insights on these issues are gained from research using animal models of addiction. In this review, the relationship between brain sites whose learning, memory and executive functions are impaired by chronic drug use and brain sites that are important for effective drug cue extinction learning is explored first. This is followed by an overview of animal research showing improved treatment outcome for drug addiction (e.g. alcohol, amphetamine, cocaine, heroin) when explicit extinction training is conducted in combination with acute dosing of a cognitive-enhancing drug. The mechanism by which cognitive enhancers are thought to exert their benefits is by facilitating consolidation of drug cue extinction memory after activation of glutamatergic receptors. Based on the encouraging work in animals, factors that may be important for the treatment of drug addiction are considered.
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76
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Buffalari DM, See RE. Inactivation of the bed nucleus of the stria terminalis in an animal model of relapse: effects on conditioned cue-induced reinstatement and its enhancement by yohimbine. Psychopharmacology (Berl) 2011; 213:19-27. [PMID: 20827461 PMCID: PMC3132192 DOI: 10.1007/s00213-010-2008-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/21/2010] [Indexed: 02/03/2023]
Abstract
RATIONALE Drug-associated cues and stress increase craving and lead to greater risk of relapse in abstinent drug users. Animal models of reinstatement of drug seeking have been utilized to study the neural circuitry by which either drug-associated cues or stress exposure elicit drug seeking. Recent evidence has shown a strong enhancing effect of yohimbine stress on subsequent cue-elicited reinstatement; however, there has been no examination of the neural substrates of this interactive effect. OBJECTIVES The current study examined whether inactivation of the bed nucleus of the stria terminalis (BNST), an area previously implicated in stress activation of drug seeking, would affect reinstatement of cocaine seeking caused by conditioned cues, yohimbine stress, or the combination of these factors. METHODS Male rats experienced daily IV cocaine self-administration, followed by extinction of lever responding in the absence of cocaine-paired cues. Reinstatement of responding was measured during presentation of cocaine-paired cues, following pretreatment with the pharmacological stressor, yohimbine (2.5 mg/kg, IP), or the combination of cues and yohimbine. RESULTS All three conditions led to reinstatement of cocaine seeking, with the highest responding seen after the combination of cues and yohimbine. Reversible inactivation of the BNST using the gamma-aminobutyric acid receptor agonists, baclofen + muscimol, significantly reduced all three forms of reinstatement. CONCLUSION These results demonstrate a role for the BNST in cocaine seeking elicited by cocaine-paired cues, and suggest the BNST as a key mediator for the interaction of stress and cues for the reinstatement of cocaine seeking.
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Affiliation(s)
- Deanne M. Buffalari
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ronald E. See
- Department of Neurosciences, Medical University of South Carolina, BSB416B, 173 Ashley Avenue, Charleston, SC 29425, USA
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77
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Polston JE, Rubbinaccio HY, Morra JT, Sell EM, Glick SD. Music and methamphetamine: conditioned cue-induced increases in locomotor activity and dopamine release in rats. Pharmacol Biochem Behav 2010; 98:54-61. [PMID: 21145911 DOI: 10.1016/j.pbb.2010.11.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 10/25/2010] [Accepted: 11/29/2010] [Indexed: 11/18/2022]
Abstract
Associations between drugs of abuse and cues facilitate the acquisition and maintenance of addictive behaviors. Although significant research has been done to elucidate the role that simple discriminative or discrete conditioned stimuli (e.g., a tone or a light) play in addiction, less is known about complex environmental cues. The purpose of the present study was to examine the role of a musical conditioned stimulus by assessing locomotor activity and in vivo microdialysis. Two groups of rats were given non-contingent injections of methamphetamine (1.0 mg/kg) or vehicle and placed in standard conditioning chambers. During these conditioning sessions both groups were exposed to a continuous conditioned stimulus, in the form of a musical selection ("Four" by Miles Davis) played repeatedly for 90 min. After seven consecutive conditioning days subjects were given one day of rest, and subsequently tested for locomotor activity or dopamine release in the absence of drugs while the musical conditioned stimulus was continually present. The brain regions examined included the basolateral amygdala, nucleus accumbens, and prefrontal cortex. The results show that music is an effective contextual conditioned stimulus, significantly increasing locomotor activity after repeated association with methamphetamine. Furthermore, this musical conditioned stimulus significantly increased extracellular dopamine levels in the basolateral amygdala and nucleus accumbens. These findings support other evidence showing the importance of these brain regions in conditioned learning paradigms, and demonstrate that music is an effective conditioned stimulus warranting further investigation.
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Affiliation(s)
- J E Polston
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA.
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78
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Nucleus accumbens core mammalian target of rapamycin signaling pathway is critical for cue-induced reinstatement of cocaine seeking in rats. J Neurosci 2010; 30:12632-41. [PMID: 20861369 DOI: 10.1523/jneurosci.1264-10.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Relapse to drug seeking was studied using a rodent model of reinstatement induced by exposure to drug-related cues. The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase that regulates cell growth and survival by controlling translation in response to nutrients and growth factors, has been demonstrated to be involved in neuronal adaptations that underlie drug addiction and learning and memory. We investigated the potential role of the mTOR signaling pathway in relapse to cocaine seeking by using the cue-induced reinstatement model in self-administering rats. We found that exposure to a cocaine-related cue induced reinstatement to cocaine seeking and increased phosphorylation of p70s6 kinase (p70s6k) and ribosomal protein s6 (rps6), measures of mTOR activity, in the nucleus accumbens (NAc) core but not shell. Furthermore, inhibition of NAc core but not shell p70s6k and rps6 phosphorylation by rapamycin decreased cue-induced reinstatement of cocaine seeking. Finally, stimulation of NAc core p70s6k and rps6 phosphorylation by NMDA enhanced cue-induced reinstatement, an effect reversed by rapamycin pretreatment. Additionally, rapamycin infusion into the NAc core or shell did not alter ongoing cocaine self-administration or cue-induced reinstatement of sucrose seeking. These findings indicate that cue-induced reinstatement of cocaine seeking is mediated by activation of the mTOR signaling pathway in the NAc core.
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79
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Gabriele A, See RE. Reversible inactivation of the basolateral amygdala, but not the dorsolateral caudate putamen, attenuates consolidation of cocaine-cue associative learning in a reinstatement model of drug-seeking. Eur J Neurosci 2010; 32:1024-9. [PMID: 20796021 PMCID: PMC3001041 DOI: 10.1111/j.1460-9568.2010.07394.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Previous research has shown that the basolateral amygdala (BLA) mediates stimulus-reward learning, including drug-cue associations, whereas the dorsolateral caudate putamen (dlCPu) primarily mediates stimulus-response (habit) learning. Recent evidence has indicated that the dlCPu may be critical in cocaine-seeking following extended self-administration, but it remains unknown whether the dlCPu plays a role in the early formation of drug-cue associations. The current study used a model of Pavlovian learning to compare the roles of the BLA and dlCPu in the consolidation of cocaine-cue associations that maintain cocaine-seeking during cue-induced reinstatement. Male Sprague-Dawley rats self-administered cocaine (0.2 mg/ 50μL infusion, i.v.) in the absence of cues for 6 days (2 h/day). Immediately following a single 1-h classical conditioning session in which passive cocaine infusions were paired with a light/tone cue, animals received bilateral infusions of the GABA receptor agonists, baclofen/muscimol (1.0/0.1 mm), or vehicle into the BLA or dlCPu. Following additional cocaine self-administration (5 days) and subsequent extinction (no cocaine or cues, 7 days), the ability of the previously cocaine-paired cues to reinstate cocaine-seeking was assessed. Inactivation of the BLA, but not the dlCPu, immediately following the classical conditioning session impaired the consolidation of cocaine-cue associations as seen by decreased cue-induced reinstatement. These results extend previous findings that the BLA mediates the consolidation of learned associations that drive cocaine-seeking during subsequent reinstatement and indicate that the dlCPu does not play a role during initial stimulus-drug associative learning.
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Affiliation(s)
- Amanda Gabriele
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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80
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Context-driven cocaine-seeking in abstinent rats increases activity-regulated gene expression in the basolateral amygdala and dorsal hippocampus differentially following short and long periods of abstinence. Neuroscience 2010; 170:570-9. [PMID: 20654701 DOI: 10.1016/j.neuroscience.2010.07.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 07/02/2010] [Accepted: 07/14/2010] [Indexed: 01/29/2023]
Abstract
In this study, the expression patterns of zif268 and activity-regulated cytoskeleton-associated gene (arc) were investigated in the basolateral amygdala (BLA) and dorsal hippocampal (dHPC) subregions during context-induced drug-seeking following 22 h or 15 d abstinence from cocaine self-administration. Arc and zif/268 mRNA in BLA and dHPC increased after re-exposure to the cocaine-paired chamber at both timepoints; however, only the BLA increases (with one exception-see below) were differentially affected by the presence or absence of the cocaine-paired lever in the chamber. Following 22 h of abstinence, arc mRNA was significantly increased in the BLA of cocaine-treated rats re-exposed to the chamber only with levers extended, whereas following 15 d of abstinence, arc mRNA in the BLA was increased in cocaine-treated rats returned to the chamber with or without levers extended. In contrast, zif268 mRNA in the BLA was greater in cocaine-treated rats returned to the chamber with levers extended vs. levers retracted only after 15 d of abstinence. In the dentate gyrus (DG) following 22 h of abstinence, zif268 mRNA was greater in rats returned to the chamber where levers were absent regardless of drug treatment whereas arc mRNA was increased in CA1 (cell bodies and dendrites) and CA3 only in cocaine-treated groups. Following 15 d of abstinence, arc mRNA was significantly greater in CA1 and CA3 of both cocaine-treated groups returned to the chamber than in those placed into a familiar, non-salient alternate environment; however, only in CA1 cell bodies the cocaine context-induced increases significantly greater than in yoked-saline controls. In contrast, zif/268 mRNA in all dHPC regions was significantly greater in both cocaine-treated groups returned to the cocaine context than in the cocaine-treated group returned to an alternative environment or saline-treated groups. These data suggest that the temporal dynamics of arc and zif268 gene expression in the BLA and dHPC encode different key elements of drug context-induced cocaine-seeking.
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81
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Thiel KJ, Wenzel JM, Pentkowski NS, Hobbs RJ, Alleweireldt AT, Neisewander JL. Stimulation of dopamine D2/D3 but not D1 receptors in the central amygdala decreases cocaine-seeking behavior. Behav Brain Res 2010; 214:386-94. [PMID: 20600343 DOI: 10.1016/j.bbr.2010.06.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 05/24/2010] [Accepted: 06/09/2010] [Indexed: 10/19/2022]
Abstract
Alterations in dopamine output within the various subnuclei of the amygdala have previously been implicated in cocaine reinforcement, as well as cocaine-seeking behavior. To elucidate the potential for increased stimulation of D1- and D2-like receptors (D1Rs and D2Rs, respectively) specifically in the central nucleus of the amygdala (CeA) to modulate cue- and cocaine-elicited reinstatement of cocaine-seeking behavior, we infused either the D1R agonist, SKF-38393 (0-4.0 microg/side) or the D2R agonist, 7-OH-DPAT (0-4.0 microg/side) into the CeA immediately prior to tests for cue and cocaine-primed reinstatement. We also examined the effects of 7-OH-DPAT on cocaine self-administration as a positive behavioral control. 7-OH-DPAT decreased cue-and cocaine-primed reinstatement, and reduced the number of cocaine infusions obtained during self-administration; SKF-38393 produced no discernable effects. The results suggest that enhanced stimulation of D2Rs, but not D1Rs, in the CeA is sufficient to inhibit expression of the incentive motivational effects of cocaine priming and cocaine-paired cues. Together with previous findings that D1R blockade attenuates reinstatement of cocaine-seeking behavior, the results suggest that D1R stimulation may be necessary, but not sufficient, to modulate the incentive motivational effects of cues and cocaine priming.
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Affiliation(s)
- Kenneth J Thiel
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104, United States
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82
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Interaction of the rostral basolateral amygdala and prelimbic prefrontal cortex in regulating reinstatement of cocaine-seeking behavior. Pharmacol Biochem Behav 2010; 96:347-53. [PMID: 20600250 DOI: 10.1016/j.pbb.2010.06.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 05/25/2010] [Accepted: 06/12/2010] [Indexed: 11/21/2022]
Abstract
Previous findings in rats suggest that the rostral basolateral amygdala (rBLA) and prelimbic prefrontal cortex (plPFC) are likely components of cue reinstatement circuitry based on bilateral inactivation of each site alone. In the present investigation, we examined whether the rBLA and plPFC interact to regulate reinstatement of cocaine-seeking behavior elicited by reexposure to a combination of discrete and contextual cocaine-paired cues. After establishing stable baseline responding under a second-order schedule of cocaine reinforcement and cue presentation, rats underwent response-extinction training in which cocaine and cocaine-paired cues were withheld. To test the interaction, rats with asymmetric cannulae placements in the rBLA and plPFC received vehicle or lidocaine infusions prior to reinstatement testing during which cocaine-paired cues were presented, in the absence of cocaine availability, under a second-order schedule. Asymmetric inactivation of the rBLA and plPFC significantly attenuated reinstatement of cocaine-seeking behavior relative to vehicle treatment. As expected, inactivation of the rBLA or plPFC in rats with unilateral cannulae placements did not disrupt reinstatement relative to vehicle treatment. Findings propose critical intrahemispheric interaction between the rBLA and plPFC in regulating reinstatement of cocaine-seeking behavior elicited by reexposure to drug-paired cues.
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83
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Sun W, Xue Y, Huang Z, Steketee JD. Regulation of cocaine-reinstated drug-seeking behavior by kappa-opioid receptors in the ventral tegmental area of rats. Psychopharmacology (Berl) 2010; 210:179-88. [PMID: 20232055 PMCID: PMC2866003 DOI: 10.1007/s00213-010-1812-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 02/21/2010] [Indexed: 11/29/2022]
Abstract
RATIONALE Relapse is one of the main challenges facing the current treatment of cocaine addiction. Understanding its neurobiological mechanism is a critical step toward developing effective anti-relapse therapies. OBJECTIVES Emerging evidence indicates that glutamate-mediated activation of dopamine (DA) neurons in the ventral tegmental area (VTA) may be critically involved in cocaine-induced relapse to drug-seeking behavior. Activity of VTA DA neurons is modulated by multiple neurotransmitter systems including opioids, serotonin, dopamine, and acetylcholine. Recent studies demonstrated that activation of kappa-opioid receptors (kappaORs) in the rat VTA directly inhibits the activity of a subpopulation of DA neurons projecting to the prefrontal cortex (PFC) and amygdala. Because we previously showed that blockade of DA receptors in the dorsal PFC inhibits cocaine-induced reinstatement of extinguished cocaine-seeking behavior suggesting a critical role of the VTA-PFC DA circuit in this process, we tested the hypothesis that activation of kappaORs in the VTA will block cocaine-induced reinstatement in rats. METHODS Rats were trained to self-administer intravenous cocaine (0.125 mg/infusion) under a modified fixed-ratio five schedule. After extinction of the learned behavior, the effects of activation of VTA kappaORs on cocaine-induced reinstatement were studied. RESULTS The kappaOR agonist U50 488 (0-5.6 microg/side) microinjected into the VTA dose-dependently decreased cocaine-induced reinstatement. The effects could not be explained by either a disruption of operant behavior or diffusion of the drug to the areas surrounding the VTA. Moreover, the effect was reversed by norbinaltorphimine. CONCLUSIONS The VTA DA neurons expressing functional kappaORs are critically involved in cocaine-induced reinstatement in rats.
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Affiliation(s)
- Wenlin Sun
- Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Avenue, Crowe 115, Memphis, TN 38163, USA.
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84
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Myers KM, Carlezon WA. Extinction of drug- and withdrawal-paired cues in animal models: relevance to the treatment of addiction. Neurosci Biobehav Rev 2010; 35:285-302. [PMID: 20109490 DOI: 10.1016/j.neubiorev.2010.01.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 01/14/2010] [Accepted: 01/20/2010] [Indexed: 12/22/2022]
Abstract
Conditioned drug craving and withdrawal elicited by cues paired with drug use or acute withdrawal are among the many factors contributing to compulsive drug taking. Understanding how to stop these cues from having these effects is a major goal of addiction research. Extinction is a form of learning in which associations between cues and the events they predict are weakened by exposure to the cues in the absence of those events. Evidence from animal models suggests that conditioned responses to drug cues can be extinguished, although the degree to which this occurs in humans is controversial. Investigations into the neurobiological substrates of extinction of conditioned drug craving and withdrawal may facilitate the successful use of drug cue extinction within clinical contexts. While this work is still in the early stages, there are indications that extinction of drug- and withdrawal-paired cues shares neural mechanisms with extinction of conditioned fear. Using the fear extinction literature as a template, it is possible to organize the observations on drug cue extinction into a cohesive framework.
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Affiliation(s)
- Karyn M Myers
- Behavioral Genetics Laboratory, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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85
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Schwartz DL, Mitchell AD, Lahna DL, Luber HS, Huckans MS, Mitchell SH, Hoffman WF. Global and local morphometric differences in recently abstinent methamphetamine-dependent individuals. Neuroimage 2010; 50:1392-401. [PMID: 20096794 DOI: 10.1016/j.neuroimage.2010.01.056] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 01/01/2010] [Accepted: 01/14/2010] [Indexed: 11/18/2022] Open
Abstract
Methamphetamine (MA) is associated with behavioral and cognitive deficits that may be related to macrostructural abnormalities. Quantitative anatomical comparisons between controls and methamphetamine-dependent individuals have produced conflicting results. We examined local and global differences in brain structure in 61 abstinent methamphetamine-dependent individuals and 44 controls with voxel-based morphometry and tissue segmentation. We related regional differences in gray matter density and whole brain segmentation volumes to performance on a behavioral measure of impulsivity and group membership using multiple linear regression. Within the MA group, we related cortical and subcortical gray matter density to length of abstinence. Controls had greater density relative to MA in bilateral insula and left middle frontal gyrus. Impulsivity was higher in the MA group and, within all subjects, impulsivity was positively correlated with gray matter density in posterior cingulate cortex and ventral striatum and negatively correlated in left superior frontal gyrus. Length of abstinence from MA was associated with greater amygdalar density. Earlier age of first use of MA (in subjects who initiated use before age 21) was associated with smaller intracranial volume. The findings are consistent with multiple possible mechanisms including neuroadaptations due to addictive behavior, neuroinflammation as well as dopaminergic and serotonergic neurotoxicity.
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Affiliation(s)
- Daniel L Schwartz
- Research Service, Portland Veterans Affairs Medical Center, Portland, OR, USA.
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86
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Buffalari DM, See RE. Amygdala mechanisms of Pavlovian psychostimulant conditioning and relapse. Curr Top Behav Neurosci 2010; 3:73-99. [PMID: 21161750 DOI: 10.1007/7854_2009_18] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Psychostimulant addiction often consists of periods of sustained drug abstinence disrupted by periods of relapse and renewed heavy drug use. Prevention of relapse remains the greatest challenge to the successful treatment of drug addiction. Drug-associated cues are a primary trigger for relapse, as they can elicit intense craving for the drug. These cues become associated with the drug reward through Pavlovian learning processes that develop over multiple drug-cue pairings. The amygdala (AMY) is critical for such drug-related learning. Intrinsic and extrinsic circuitry position the AMY to integrate cue and drug-related information and influence drug-seeking and drug-taking behaviors. Animal models of conditioned drug reward, drug use, and relapse have confirmed the necessary role of the AMY for drug conditioned cues to control motivated behavior. Neurons within the AMY are responsive to the primary effects of psychostimulants, and more critically, they also respond to the presentation of drug-associated cues. The mechanisms by which conditioned cues come to influence drug-seeking behavior likely involve long-term plasticity and neuroadaptations within the AMY. A greater understanding of the associative learning mechanisms that depend upon the AMY and related limbic and cortical structures, and the process by which drug cues come to gain control over behavior that maintains the addictive state, will facilitate the development of more effective addiction treatments.
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Affiliation(s)
- Deanne M Buffalari
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA.
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87
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Neuroplastic alterations in the limbic system following cocaine or alcohol exposure. Curr Top Behav Neurosci 2010; 3:3-27. [PMID: 21161748 DOI: 10.1007/7854_2009_23] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuroplastic changes in the CNS are thought to be a fundamental component of learning and memory. While pioneering studies in the hippocampus and cerebellum have detailed many of the basic mechanisms that can lead to alterations in synaptic transmission based on previous activity, only more recently has synaptic plasticity been monitored after behavioral manipulation or drug exposure. In this chapter, we review evidence that drugs of abuse are powerful modulators of synaptic plasticity. Both the dopaminergic neurons of the ventral tegmental area as well medium spiny neurons in nucleus accumbens show enhanced excitatory synaptic strength following passive or active exposure to drugs such as cocaine and alcohol. In the VTA, both the enhancement of excitatory synaptic strength and the acquisition of drug-related behaviors depend on signaling through the N-methyl-D: -aspartate receptors (NMDARs) which are mechanistically thought to lead to increased synaptic insertion of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). Synaptic insertion of AMPARs by drugs of abuse can be long lasting, depending on the route of administration, number of drug exposures, or whether the drugs are received passively or self-administered.
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88
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Lovaglio J, Lin JY, Roman C, Reilly S. Basolateral amygdala and morphine-induced taste avoidance in the rat. Physiol Behav 2009; 99:419-23. [PMID: 20015452 DOI: 10.1016/j.physbeh.2009.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 11/02/2009] [Accepted: 12/07/2009] [Indexed: 11/26/2022]
Abstract
The present experiment examined the influence of excitotoxic lesions of the basolateral amygdala (BLA) on morphine-induced saccharin avoidance. Neurologically intact subjects rapidly learned to avoid drinking the taste conditioned stimulus (CS), an effect that was sustained throughout the experiment. Although the BLA-lesioned (BLAX) rats showed CS avoidance over the first few trials, the effect was not sustained. That is, by the end of the experiment, the BLAX rats were drinking the same amount of saccharin after seven saccharin-morphine trials as they did on the first trial (i.e., prior to the morphine injections). Potential interpretations of the results are discussed including a disruption of the mechanism that governs drug-induced taste avoidance in normal subjects and the more rapid development of tolerance in BLAX rats.
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Affiliation(s)
- Jamie Lovaglio
- University of Illinois at Chicago, Biologic Resources Laboratory, 1840 West Taylor St, Chicago, IL 60612, USA
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89
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Feil J, Zangen A. Brain stimulation in the study and treatment of addiction. Neurosci Biobehav Rev 2009; 34:559-74. [PMID: 19914283 DOI: 10.1016/j.neubiorev.2009.11.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 10/26/2009] [Accepted: 11/07/2009] [Indexed: 01/19/2023]
Abstract
Addiction is a devastating and chronically relapsing disorder. Repeated drug administration induces neuroadaptations associated with abnormal dopaminergic activity in the mesocorticolimbic circuitry, resulting in altered cortical neurotransmission and excitability. Electrical stimulation of specific brain regions can be used in animal models and humans to induce local activation or disruption of specific circuitries or alter neuronal excitability and cause neuroadaptations. Non-surgical stimulation of specific brain regions in human addicts can be achieved by transcranial magnetic stimulation (TMS). TMS is used for transient stimulation or disruption of neural activity in specific cortical regions, which can be used to assess cortical excitability, and to induce changes in cortical excitability. Moreover, it is suggested that repeated stimulation can cause long-lasting neuroadaptations. Therefore, TMS paradigms were used in some studies to assess the presence of altered cortical excitability associated with chronic drug consumption, while other studies have begun to assess the therapeutic potential of repetitive TMS. Similarly, transcranial direct current stimulation (tDCS) is used to modulate neuronal resting membrane potential in humans and alter cortical excitability. The current review describes how these brain stimulation techniques have recently been used for the study and treatment of addiction in animal models and humans.
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Affiliation(s)
- Jodie Feil
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
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90
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Mashhoon Y, Tsikitas LA, Kantak KM. Dissociable effects of cocaine-seeking behavior following D1 receptor activation and blockade within the caudal and rostral basolateral amygdala in rats. Eur J Neurosci 2009; 29:1641-53. [PMID: 19419427 DOI: 10.1111/j.1460-9568.2009.06705.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Research with dopamine D(1) receptor antagonists or neuronal inactivating agents suggests that there is dissociable regulation of cocaine-seeking behavior by the rostral and caudal basolateral amygdala. In the present study, discrete infusions of the D(1) receptor agonist SKF 81297 (0.0-0.8 microg per side) were compared with those of the D(1) receptor antagonist SCH 23390 (0.0-2.0 microg per side) to demonstrate directly the importance of D(1) receptor mechanisms within the rostral and caudal basolateral amygdala for their functional heterogeneity in regulating cocaine-seeking behavior. Under a second-order schedule, cocaine-seeking behavior was studied during maintenance (cocaine and cocaine cues present) and reinstatement (only cocaine cues present). Food-maintained responding was used to examine the specificity of maximal behaviorally effective doses of SKF 81297 and SCH 23390. The results demonstrated that the D(1) agonist (0.4 or 0.8 microg) increased and the D(1) antagonist (1.0 microg) decreased cocaine-seeking behavior during maintenance when infused into the caudal but not the rostral basolateral amygdala. Cocaine intake was not affected by the agonist, and was decreased by the antagonist. During reinstatement, the D(1) agonist (0.4 microg) increased and the D(1) antagonist (1.0 microg) decreased cocaine-seeking behavior when infused into the rostral but not the caudal basolateral amygdala. In tests for behavioral specificity, the above effective doses of SKF 81297 and SCH 23390 used in self-administration experiments did not alter food-maintained responding. However, the 2.0-microg dose of SCH 23390 suppressed drug-maintained and food-maintained responding after infusion into both subregions. Collectively, these findings indicate dissociable sensitivity to D(1) receptor ligands within the caudal and rostral basolateral amygdala for altering cocaine-seeking behavior under different conditions that model phases of addiction.
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Affiliation(s)
- Yasmin Mashhoon
- Laboratory of Behavioral Neuroscience, Department of Psychology, Boston University, Boston, MA, USA
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91
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Smith RJ, Tahsili-Fahadan P, Aston-Jones G. Orexin/hypocretin is necessary for context-driven cocaine-seeking. Neuropharmacology 2009; 58:179-84. [PMID: 19591850 DOI: 10.1016/j.neuropharm.2009.06.042] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 06/29/2009] [Indexed: 01/22/2023]
Abstract
Orexin/hypocretin signaling at the orexin 1 receptor (OX(1)R) has recently been implicated in addiction and relapse. We examined the role of the orexin system in cocaine-seeking elicited by a drug-associated context following abstinence or extinction from chronic cocaine self-administration. Male Sprague-Dawley rats self-administered cocaine in 2-h sessions for 10 days, followed by extinction training or extended abstinence in the home cage. The OX(1)R antagonist SB-334867 (SB; 10, 20, or 30 mg/kg, i.p.) was administered prior to re-exposure to the cocaine self-administration environment. We found that pretreatment with SB significantly attenuated cocaine-seeking when rats were placed back into the self-administration environment following either 1 day or 2 weeks of abstinence (no extinction), or following extinction of cocaine-seeking in an alternative environment (distinct from the training environment). These results indicate that orexin signaling at OX(1)R is critical for conditioned cocaine-seeking elicited by a drug-associated context, following either extinction or abstinence.
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Affiliation(s)
- Rachel J Smith
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Ave., 403 Basic Science Bldg., Charleston, SC 29425-5100, USA
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92
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Nic Dhonnchadha B, Fox R, Stutz S, Rice KC, Cunningham K. Blockade of the serotonin 5-HT2A receptor suppresses cue-evoked reinstatement of cocaine-seeking behavior in a rat self-administration model. Behav Neurosci 2009; 123:382-96. [PMID: 19331461 PMCID: PMC3830454 DOI: 10.1037/a0014592] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The serotonin 5-HT2A receptor (5-HT-sub(2A)R) may play a role in reinstatement of drug-seeking. This study investigated the ability of a selective 5-HT-sub(2A)R antagonist to suppress reinstatement evoked by exposure to cues conditioned to cocaine self-administration. Cocaine self-administration (0.75 mg/kg/0.1 mL/6 s infusion; FR 4) was trained in naïve, free-fed rats to allow interpretation of results independent from changes related to food deprivation stress. Pretreatment with the selective 5-HT-sub(2A)R antagonist M100907 (volinanserin) failed to reduce rates of operant responding for cocaine infusions. On the other hand, M100907 (0.001-0.8 mg/kg ip) significantly suppressed the cue-induced reinstatement of cocaine-seeking behavior following extinction; effective M100907 doses did not alter operant responding for cues previously associated with sucrose self-administration. Importantly, a greater magnitude of active lever presses on the initial extinction session (high extinction responders) predicted the maximal susceptibility to M100907-induced suppression of cue-evoked reinstatement. The findings indicate that blockade of the 5-HT-sub(2A)R attenuates the incentive-motivational effects of cocaine-paired cues, particularly in high extinction responders, and suggests that M100907 may afford a therapeutic advance in suppression of cue-evoked craving and/or relapse.
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Affiliation(s)
- B.Á. Nic Dhonnchadha
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - R.G. Fox
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - S.J. Stutz
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - K. C. Rice
- Chemical Biology Research Branch, Drug Design and Synthesis Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - K.A. Cunningham
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
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93
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Liu X, Palmatier MI, Caggiula AR, Sved AF, Donny EC, Gharib M, Booth S. Naltrexone attenuation of conditioned but not primary reinforcement of nicotine in rats. Psychopharmacology (Berl) 2009; 202:589-98. [PMID: 18807246 PMCID: PMC2811405 DOI: 10.1007/s00213-008-1335-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 09/04/2008] [Indexed: 12/01/2022]
Abstract
RATIONALE Opioid neurotransmission has been implicated in reinforcement-related processes for several drugs of abuse, including opiates, stimulants, and alcohol. However, less is known about its role in the motivational effects of nicotine and nicotine-associated environmental cues. OBJECTIVE This study investigated whether pretreatment with naltrexone, an opioid receptor antagonist, alters conditioned incentive salience of nicotine cues under two conditions: cue-induced reinstatement of nicotine-seeking after extinction and cue-maintained responding during extinction. The effect of naltrexone on nicotine self-administration during the maintenance phase was also examined. MATERIALS AND METHODS Male Sprague-Dawley rats were trained in daily 1-h sessions to self-administer nicotine (0.03 mg/kg/infusion, i.v.) on a fixed-ratio 5 schedule and associate a conditioned stimulus (CS) with each nicotine delivery. Once responding was extinguished by saline substitution for nicotine and omission of the CS, the reinstatement tests were conducted following subcutaneous administration of naltrexone (0, 0.25, 1, 2 mg/kg). In separate groups of rats, naltrexone (0, 2 mg/kg) was chronically given before each extinction sessions, where responses on the active lever resulted in presentations of the CS without nicotine infusion (saline substitution). Self-administration/naltrexone tests were conducted in different groups of rats receiving similar nicotine self-administration training. RESULTS Naltrexone significantly attenuated the CS-reinstated responding on the active, previously nicotine-reinforced lever in the reinstatement tests and the CS-maintained active lever responding during the extinction tests. In contrast, neither acute nor chronic naltrexone produced an effect on nicotine self-administration behavior. CONCLUSIONS These results indicate that activation of opioid receptors is implicated in mediation of the conditioned incentive properties of nicotine cues but not in the maintenance of nicotine self-administration. Therefore, these findings suggest that opioid receptor antagonists might have clinical potential for prevention of smoking relapse associated with exposure to environmental cues.
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Affiliation(s)
- Xiu Liu
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216, USA.
| | | | - Anthony R. Caggiula
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alan F. Sved
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Eric C. Donny
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Maysa Gharib
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Sheri Booth
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA
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94
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Lee JLC, Gardner RJ, Butler VJ, Everitt BJ. D-cycloserine potentiates the reconsolidation of cocaine-associated memories. Learn Mem 2009; 16:82-5. [PMID: 19144966 PMCID: PMC2632849 DOI: 10.1101/lm.1186609] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 10/23/2008] [Indexed: 11/24/2022]
Abstract
Conditioned cue-induced relapse to drug seeking is a major challenge to the treatment of drug addiction. It has been proposed that D-cycloserine might be useful in the prevention of relapse by reducing the conditioned reinforcing properties of drug-associated stimuli through facilitation of extinction. Here we show that intrabasolateral amygdala infusions of D-cycloserine in fact potentiate the reconsolidation of stimulus-cocaine memories to increase cue-induced relapse to drug seeking in rats with an extensive drug self-administration history. This elevation of cocaine seeking was correlated with an increase in the expression of the reconsolidation-associated gene zif268.
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Affiliation(s)
- Jonathan L C Lee
- Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, United Kingdom.
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95
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Nic Dhonnchadha BA, Cunningham KA. Serotonergic mechanisms in addiction-related memories. Behav Brain Res 2008; 195:39-53. [PMID: 18639587 PMCID: PMC2630382 DOI: 10.1016/j.bbr.2008.06.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 06/10/2008] [Accepted: 06/10/2008] [Indexed: 11/22/2022]
Abstract
Drug-associated memories are a hallmark of addiction and a contributing factor in the continued use and relapse to drugs of abuse. Repeated association of drugs of abuse with conditioned stimuli leads to long-lasting behavioral responses that reflect reward-controlled learning and participate in the establishment of addiction. A greater understanding of the mechanisms underlying the formation and retrieval of drug-associated memories may shed light on potential therapeutic approaches to effectively intervene with drug use-associated memory. There is evidence to support the involvement of serotonin (5-HT) neurotransmission in learning and memory formation through the families of the 5-HT(1) receptor (5-HT(1)R) and 5-HT(2)R which have also been shown to play a modulatory role in the behavioral effects induced by many psychostimulants. While there is a paucity of studies examining the effects of selective 5-HT(1A)R ligands, the available dataset suggests that 5-HT(1B)R agonists may inhibit retrieval of cocaine-associated memories. The 5-HT(2A)R and 5-HT(2C)R appear to be integral in the strong conditioned associations made between cocaine and environmental cues with 5-HT(2A)R antagonists and 5-HT(2C)R agonists possessing potency in blocking retrieval of cocaine-associated memories following cocaine self-administration procedures. The complex anatomical connectivity between 5-HT neurons and other neuronal phenotypes in limbic-corticostriatal brain structures, the heterogeneity of 5-HT receptors (5-HT(X)R) and the conflicting results of behavioral experiments which employ non-specific 5-HT(X)R ligands contribute to the complexity of interpreting the involvement of 5-HT systems in addictive-related memory processes. This review briefly traces the history of 5-HT involvement in retrieval of drug-cue associations and future targets of serotonergic manipulation that may reduce the impact that drug cues have on addictive behavior and relapse.
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Affiliation(s)
- Bríd A Nic Dhonnchadha
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
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96
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Alvarez-Jaimes L, Polis I, Parsons LH. Attenuation of cue-induced heroin-seeking behavior by cannabinoid CB1 antagonist infusions into the nucleus accumbens core and prefrontal cortex, but not basolateral amygdala. Neuropsychopharmacology 2008; 33:2483-93. [PMID: 18059440 DOI: 10.1038/sj.npp.1301630] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As with other drugs of abuse, heroin use is characterized by a high incidence of relapse following detoxification that can be triggered by exposure to conditioned stimuli previously associated with drug availability. Recent findings suggest that cannabinoid CB(1) receptors modulate the motivational properties of heroin-conditioned stimuli that induce relapse behavior. However, the neural substrates through which CB(1) receptors modulate cue-induced heroin seeking have not been elucidated. In this study, we evaluated alterations in cue-induced reinstatement of heroin-seeking behavior produced by infusions of the CB(1) receptor antagonist SR 141716A (0, 0.3 and 3 microg per side) delivered into the prefrontal cortex (PFC), nucleus accumbens (NAC), and basolateral amygdala (BLA) of rats. Results show that following extinction of operant behavior the presentation of a discriminative stimulus conditioned to heroin availability reinstated nonreinforced lever pressing to levels comparable to preextinction levels. Intra-PFC SR 141716A dose-dependently reduced cue-induced reinstatement of heroin seeking, with a significant reduction following the 3 microg per side dose. In the NAC, both SR 141716A doses induced a significant reduction in cue-induced reinstatement, with the highest dose completely blocking the effect of the cue. In contrast, intra-BLA SR 141716A did not alter cue-induced reinstatement of responding while systemic administration of this antagonist (3 mg/kg, i.p.) significantly blocked cue-induced reinstatement in all three-placement groups (BLA, PFC, and NAC). These findings provide new insights into the neural mechanisms through which CB(1) receptors modulate the motivational properties of heroin-associated cues inducing relapse.
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Affiliation(s)
- Lily Alvarez-Jaimes
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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97
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Milton AL, Lee JLC, Butler VJ, Gardner R, Everitt BJ. Intra-amygdala and systemic antagonism of NMDA receptors prevents the reconsolidation of drug-associated memory and impairs subsequently both novel and previously acquired drug-seeking behaviors. J Neurosci 2008; 28:8230-7. [PMID: 18701685 PMCID: PMC6670560 DOI: 10.1523/jneurosci.1723-08.2008] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The amygdala has long been considered a primary locus in mediating the effects of previously drug-associated stimuli on subsequent drug-seeking behavior, and the NMDA subtype of glutamate receptor within the amygdala is important for the consolidation of associations between environmental conditioned stimuli and the effects of addictive drugs. Here we demonstrate that amygdala NMDA receptors are also necessary for the reconsolidation of drug-associated memories. Using a behavioral task that specifically measures the conditioned reinforcing properties of a previously drug-paired stimulus, we show that infusion of the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid (D-APV) into the basolateral amygdala before a memory reactivation session disrupted the drug-associated memory and abolished subsequent instrumental responding for conditioned reinforcement. This effect was memory reactivation dependent, and the memory deficit persisted for at least 4 weeks. In contrast, infusion of d-APV immediately after the memory reactivation session had no effect on subsequent responding for conditioned reinforcement, indicating that NMDA receptors have a temporally limited role in the reconsolidation process. Furthermore, in molecular studies, we show that the reconsolidation-impairing effect of D-APV is correlated with downstream reductions in expression of the plasticity-related immediate early gene, zif268. We also demonstrate that systemic antagonism of NMDA receptors with MK-801 [(+)-5-methyl-10,11-dihydro-SH-dibenzo[a,d]cyclohepten-5,10-imine maleate] before memory reactivation subsequently reduced previously acquired instrumental drug-seeking behavior that depends on drug-associated cues acting as conditioned reinforcers. These data suggest that drugs modulating glutamatergic transmission at the NMDA receptor may be useful in the future treatment of relapse prevention in drug addiction through memory reconsolidation blockade.
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Affiliation(s)
- Amy L Milton
- Department of Experimental Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Site, Cambridge CB2 3EB, United Kingdom.
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98
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Zavala AR, Browning JR, Dickey ED, Biswas S, Neisewander JL. Region-specific involvement of AMPA/Kainate receptors in Fos protein expression induced by cocaine-conditioned cues. Eur Neuropsychopharmacol 2008; 18:600-11. [PMID: 18539009 PMCID: PMC4798851 DOI: 10.1016/j.euroneuro.2008.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/04/2008] [Accepted: 04/15/2008] [Indexed: 11/18/2022]
Abstract
This study investigated the effects of the AMPA/Kainate receptor antagonist, NBQX, on cue-elicited cocaine-seeking behavior and concomitant changes in Fos protein expression. After cocaine self-administration training, rats underwent 24 days of abstinence during which they were exposed daily either to the self-administration environment with response-contingent cues previously paired with cocaine infusions available (Extinction group) or to an alternate environment (No Extinction group). Subsequently, rats were tested for cocaine-seeking behavior (i.e., operant responses without cocaine reinforcement) elicited by the cocaine-associated cues after pretreatment with either vehicle or NBQX (10 mg/kg, IP). NBQX markedly attenuated cue-elicited cocaine-seeking behavior relative to vehicle pretreatment in the No Extinction group and also decreased cue-elicited Fos protein expression in a region-specific manner in the anterior cingulate and orbitofrontal cortices, basolateral amygdala, nucleus accumbens core, and dorsal caudate-putamen, suggesting involvement of AMPA glutamate systems in specific subregions of the neuronal circuitry activated by cocaine cues.
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Affiliation(s)
- Arturo R Zavala
- Department of Psychology, Arizona State University, Box 871104, Tempe, AZ 85287-1104, United States
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99
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Taylor JR, Olausson P, Quinn JJ, Torregrossa MM. Targeting extinction and reconsolidation mechanisms to combat the impact of drug cues on addiction. Neuropharmacology 2008; 56 Suppl 1:186-95. [PMID: 18708077 DOI: 10.1016/j.neuropharm.2008.07.027] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/11/2008] [Accepted: 07/20/2008] [Indexed: 02/01/2023]
Abstract
Drug addiction is a progressive and compulsive disorder, where recurrent craving and relapse to drug-seeking occur even after long periods of abstinence. A major contributing factor to relapse is drug-associated cues. Here we review behavioral and pharmacological studies outlining novel methods of effective and persistent reductions in cue-induced relapse behavior in animal models. We focus on extinction and reconsolidation of cue-drug associations as the memory processes that are the most likely targets for interventions. Extinction involves the formation of new inhibitory memories rather than memory erasure; thus, it should be possible to facilitate the extinction of cue-drug memories to reduce relapse. We propose that context-dependency of extinction might be altered by mnemonic agents, thereby enhancing the efficacy of cue-exposure therapy as treatment strategy. In contrast, interfering with memory reconsolidation processes can disrupt the integrity or strength of specific cue-drug memories. Reconsolidation is argued to be a distinct process that occurs over a brief time period after memory is reactivated/retrieved - when the memory becomes labile and vulnerable to disruption. Reconsolidation is thought to be an independent, perhaps opposing, process to extinction and disruption of reconsolidation has recently been shown to directly affect subsequent cue-drug memory retrieval in an animal model of relapse. We hypothesize that a combined approach aimed at both enhancing the consolidation of cue-drug extinction and interfering with the reconsolidation of cue-drug memories will have a greater potential for persistently inhibiting cue-induced relapse than either treatment alone.
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Affiliation(s)
- Jane R Taylor
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University School of Medicine, S307 Connecticut Mental Health Center, Ribicoff Research Laboratories, 34 Park Street, New Haven, CT 06508, USA.
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100
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Schroeder JP, Spanos M, Stevenson JR, Besheer J, Salling M, Hodge CW. Cue-induced reinstatement of alcohol-seeking behavior is associated with increased ERK1/2 phosphorylation in specific limbic brain regions: blockade by the mGluR5 antagonist MPEP. Neuropharmacology 2008; 55:546-54. [PMID: 18619984 DOI: 10.1016/j.neuropharm.2008.06.057] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/24/2008] [Accepted: 06/25/2008] [Indexed: 01/15/2023]
Abstract
Relapse to alcohol use after periods of abstinence is a hallmark behavioral pathology of alcoholism and a major clinical problem. Emerging evidence indicates that metabotropic glutamate receptor 5 (mGluR5) antagonists attenuate relapse to alcohol-seeking behavior but the molecular mechanisms of this potential therapeutic effect remain unexplored. The extracellular signal-regulated kinase (ERK1/2) pathway is downstream of mGluR5 and has been implicated in addiction. We sought to determine if cue-induced reinstatement of alcohol-seeking behavior, and its reduction by an mGluR5 antagonist, is associated with changes in ERK1/2 activation in reward-related limbic brain regions. Selectively-bred alcohol-preferring (P) rats were trained to lever press on a concurrent schedule of alcohol (15% v/v) vs. water reinforcement. Following 9 days of extinction, rats were given an additional extinction trial or injected with the mGluR5 antagonist MPEP (0, 1, 3, or 10mg/kg) and tested for cue-induced reinstatement. Brains were removed 90-min later from the rats in the extinction and MPEP (0 or 10mg/kg) conditions for analysis of p-ERK1/2, total ERK1/2, and p-ERK5 immunoreactivity (IR). Cue-induced reinstatement of alcohol-seeking behavior was associated with a three to five-fold increase in p-ERK1/2 IR in the basolateral amygdala and nucleus accumbens shell. MPEP administration blocked both the relapse-like behavior and increase in p-ERK1/2 IR. p-ERK1/2 IR in the central amygdala and NAcb core was dissociated with the relapse-like behavior and the pharmacological effect of mGluR5 blockade. No changes in total ERK or p-ERK5 were observed. These results suggest that exposure to cues previously associated with alcohol self-administration is sufficient to produce concomitant increases in relapse-like behavior and ERK1/2 activation in specific limbic brain regions. Pharmacological compounds, such as mGluR5 antagonists, that reduce cue-induced ERK1/2 activation may be useful for treatment of relapse in alcoholics that is triggered by exposure to environmental events.
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Affiliation(s)
- Jason P Schroeder
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Thurston-Bowles Building; CB #7178, Chapel Hill, NC 27599, USA
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