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Ball KT, Slane M. Differential involvement of prelimbic and infralimbic medial prefrontal cortex in discrete cue-induced reinstatement of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) seeking in rats. Psychopharmacology (Berl) 2012; 224:377-85. [PMID: 22710489 PMCID: PMC4078904 DOI: 10.1007/s00213-012-2762-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 05/28/2012] [Indexed: 01/12/2023]
Abstract
RATIONALE The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) is a widely abused drug, particularly in adolescent and young adult populations. Although it was shown that MDMA-associated cues reinstate extinguished MDMA seeking in an animal relapse model, there is little information regarding the neural mechanisms underlying this behavior. OBJECTIVES Because the medial prefrontal cortex (mPFC) plays an important role in relapse to cocaine and methamphetamine seeking, we tested the effects of lidocaine inactivation of prelimbic (PL) and infralimbic (IL) subregions of mPFC on cue-induced relapse to MDMA seeking. METHODS Rats were trained to respond for MDMA infusions (0.50 mg/kg/infusion, i.v.) paired with a discrete cue in daily 2-h sessions. Responding was reinforced contingent on a modified fixed ratio 5 schedule of reinforcement. Cue-induced reinstatement tests were conducted after responding was extinguished in the absence of MDMA and the conditioned cues. Prior to reinstatement tests, rats received bilateral microinjections of either lidocaine (100 μg/0.5 μl/side) or physiological saline (0.5 μl/side) delivered to either PL or IL mPFC. RESULTS Microinjections of lidocaine into PL completely blocked reinstatement of MDMA-seeking behavior compared with saline microinjections into the same region. Lidocaine microinjections did not, however, have an effect on food-maintained responding, ruling out a nonspecific disruption of motor performance. Conversely, lidocaine inactivation of IL had no effect on reinstatement of MDMA seeking or food-maintained responding. CONCLUSIONS Our results provide direct support for PL activation in reinstatement of MDMA-seeking behavior. Moreover, akin to cocaine seeking, there appears to be differential involvement of PL and IL subregions in this behavior.
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Affiliation(s)
- Kevin T Ball
- Department of Psychology, Bloomsburg University of Pennsylvania, 400 E 2nd St, Bloomsburg, PA 17815, USA.
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152
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Rogala B, Li Y, Li S, Chen X, Kirouac GJ. Effects of a post-shock injection of the kappa opioid receptor antagonist norbinaltorphimine (norBNI) on fear and anxiety in rats. PLoS One 2012; 7:e49669. [PMID: 23166745 PMCID: PMC3498224 DOI: 10.1371/journal.pone.0049669] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 10/12/2012] [Indexed: 11/18/2022] Open
Abstract
Exposure of rats to footshocks leads to an enduring behavioral state involving generalized fear responses and avoidance. Recent evidence suggests that the expression of negative emotional behaviors produced by a stressor is in part mediated by dynorphin and its main receptor, the kappa opioid receptor (KOR). The purpose of this study was to determine if a subcutaneous injection of the long-acting KOR antagonist norbinaltorphimine (norBNI; 15.0 and 30.0 mg/kg) given 2 days after an acute exposure of rats to footshooks (5×2 s episodes of 1.5 mA delivered over 5 min) attenuates the expression of lasting fear and anxiety. We report that exposure of rats to acute footshock produced long-lasting (>4 weeks) fear (freezing) and anxiety (avoidance of an open area in the defensive withdrawal test). The 30 mg dose of norBNI attenuated the fear expressed when shock rats were placed in the shock context at Day 9 but not Day 27 post-shock. The same dose of norBNI had no effect on the expression of generalized fear produced when shock rats were placed in a novel chamber at Days 8 and 24. In contrast, the 30 mg dose of norBNI produced consistent anxiolytic effects in shock and nonshock rats. First, the 30 mg dose was found to decrease the latency to enter the open field in the defensive withdrawal test done 30 days after the shock exposure. Second, the same high dose also had anxiolytic effects in both nonshock and shock rats as evidence by a decrease in the mean time spent in the withdrawal box. The present study shows that systemic injection of the KOR antagonist norBNI had mixed effect on fear. In contrast, norBNI had an anxiolytic effect which included the attenuation of the enhanced avoidance of a novel area produced by a prior shock experience.
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Affiliation(s)
- Benjamin Rogala
- Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yonghui Li
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Sa Li
- Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Xiaoyu Chen
- Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Gilbert J. Kirouac
- Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Psychiatry, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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153
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Hearing MC, Zink AN, Wickman K. Cocaine-induced adaptations in metabotropic inhibitory signaling in the mesocorticolimbic system. Rev Neurosci 2012; 23:325-51. [PMID: 22944653 DOI: 10.1515/revneuro-2012-0045] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/11/2012] [Indexed: 12/17/2022]
Abstract
The addictive properties of psychostimulants such as cocaine are rooted in their ability to activate the mesocorticolimbic dopamine (DA) system. This system consists primarily of dopaminergic projections arising from the ventral tegmental area (VTA) and projecting to the limbic and cortical brain regions, such as the nucleus accumbens (NAc) and prefrontal cortex (PFC). While the basic anatomy and functional relevance of the mesocorticolimbic DA system is relatively well-established, a key challenge remaining in addiction research is to understand where and how molecular adaptations and corresponding changes in function of this system facilitate a pathological desire to seek and take drugs. Several lines of evidence indicate that inhibitory signaling, particularly signaling mediated by the Gi/o class of heterotrimeric GTP-binding proteins (G proteins), plays a key role in the acute and persistent effects of drugs of abuse. Moreover, recent evidence argues that these signaling pathways are targets of drug-induced adaptations. In this review we discuss inhibitory signaling pathways involving DA and the inhibitory neurotransmitter GABA in two brain regions - the VTA and PFC - that are central to the effects of acute and repeated cocaine exposure and represent sites of adaptations linked to addiction-related behaviors including sensitization, craving, and relapse.
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Affiliation(s)
- Matthew C Hearing
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
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154
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Cocaine-induced reinstatement of a conditioned place preference in developing rats: involvement of the d2 receptor. Brain Sci 2012; 2:573-88. [PMID: 24961261 PMCID: PMC4061817 DOI: 10.3390/brainsci2040573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 10/19/2012] [Accepted: 10/24/2012] [Indexed: 11/26/2022] Open
Abstract
Reinstatement of conditioned place preferences have been used to investigate physiological mechanisms mediating drug-seeking behavior in adolescent and adult rodents; however, it is still unclear how psychostimulant exposure during adolescence affects neuron communication and whether these changes would elicit enhanced drug-seeking behavior later in adulthood. The present study determined whether the effects of intra-ventral tegmental area (VTA) or intra-nucleus accumbens septi (NAcc) dopamine (DA) D2 receptor antagonist infusions would block (or potentiate) cocaine-induced reinstatement of conditioned place preferences. Adolescent rats (postnatal day (PND 28–39)) were trained to express a cocaine place preference. The involvement of D2 receptors on cocaine-induced reinstatement was determined by intra-VTA or intra-NAcc infusion of the DA D2 receptor antagonist sulpiride (100 μM) during a cocaine-primed reinstatement test (10 mg/kg cocaine, i.p.). Infusion of sulpiride into the VTA but not the NAcc blocked reinstatement of conditioned place preference. These data suggest intrinsic compensatory mechanisms in the mesolimbic DA pathway mediate responsivity to cocaine-induced reinstatement of a conditioned place preference during development.
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155
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Willcocks AL, McNally GP. The role of medial prefrontal cortex in extinction and reinstatement of alcohol-seeking in rats. Eur J Neurosci 2012; 37:259-68. [PMID: 23106416 DOI: 10.1111/ejn.12031] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/13/2012] [Accepted: 09/19/2012] [Indexed: 11/29/2022]
Abstract
The prelimbic (PL) and infralimbic (IL) medial prefrontal cortex (mPFC) are thought to play opposing roles in drug-seeking behaviour. Specifically, the PL promotes drug-seeking whereas the IL is necessary for the inhibition of drug-seeking during extinction. We studied the roles of the PL, IL and dorsal peduncular PFC (DP) in the expression of context-induced reinstatement, reacquisition and extinction of alcoholic beer-seeking. In context-induced reinstatement (renewal), animals were trained to nosepoke for alcoholic beer (context A), extinguished (context B) and then tested in context A and B. In reacquisition, animals received the same instrumental training and extinction without any contextual manipulation. On test, alcoholic beer was again available and responding was compared with naive controls. Just prior to the test, rats received bilateral infusion of baclofen/muscimol into the PL, IL or DP. Reversible inactivation of the PL attenuated ABA renewal but augmented reacquisition. Reversible inactivation of IL had no effect on the reinstatement or reacquisition of alcoholic beer-seeking and had no effect on extinction expression (ABB and AAA). IL inactivation did, however, increase the latencies with which animals responded on test but only when animals were tested in the extinction context. DP inactivation had no effect on reinstatement or reacquisition. These studies are inconsistent with the view that PL and IL exert opposing effects on drug-seeking. Rather, they support the view that PL is important for retrieval of drug-seeking contingency information and that the use of contextual information is enhanced with IL manipulation.
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Affiliation(s)
- Andrea L Willcocks
- School of Psychology, The University of New South Wales, Sydney, NSW 2052, Australia
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156
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El Rawas R, Klement S, Kummer KK, Fritz M, Dechant G, Saria A, Zernig G. Brain regions associated with the acquisition of conditioned place preference for cocaine vs. social interaction. Front Behav Neurosci 2012; 6:63. [PMID: 23015784 PMCID: PMC3449336 DOI: 10.3389/fnbeh.2012.00063] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Accepted: 09/04/2012] [Indexed: 11/13/2022] Open
Abstract
Positive social interaction could play an essential role in switching the preference of the substance dependent individual away from drug related activities. We have previously shown that conditioned place preference (CPP) for cocaine at the dose of 15 mg/kg and CPP for four 15-min episodes of social interaction were equally strong when rats were concurrently conditioned for place preference by pairing cocaine with one compartment and social interaction with the other. The aim of the present study was to investigate the differential activation of brain regions related to the reward circuitry after acquisition/expression of cocaine CPP or social interaction CPP. Our findings indicate that cocaine CPP and social interaction CPP activated almost the same brain regions. However, the granular insular cortex and the dorsal part of the agranular insular cortex were more activated after cocaine CPP, whereas the prelimbic cortex and the core subregion of the nucleus accumbens were more activated after social interaction CPP. These results suggest that the insular cortex appears to be potently activated after drug conditioning learning while activation of the prelimbic cortex-nucleus accumbens core projection seems to be preferentially involved in the conditioning to non-drug stimuli such as social interaction.
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Affiliation(s)
- Rana El Rawas
- Experimental Psychiatry Unit, Medical University Innsbruck Innsbruck, Austria
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157
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Psychostimulant abuse and neuroinflammation: emerging evidence of their interconnection. Neurotox Res 2012; 23:174-88. [PMID: 22714667 DOI: 10.1007/s12640-012-9334-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/09/2012] [Accepted: 05/22/2012] [Indexed: 12/31/2022]
Abstract
During the past two decades, there has been a tremendous expansion of knowledge regarding the neurobiological effects of substance abuse and how these effects impact behavior. At the same time, there has been a profound change in our understanding of the way in which the central nervous system responds to noxious stimuli. Most often referred to as the innate immune response (IIR), this defense mechanism is activated by a number of agents (toxic, microbial, ischemic) and has been implicated in the progression of a number of neurodegenerative diseases. We review evidence that psychostimulants of abuse (cocaine, methamphetamine, ecstasy) are associated with activation of the IIR. We first present background on what is currently known about the IIR including some of the cellular elements involved (microglia, astrocytes, vascular endothelial cells), key receptor pathways, and primary inflammatory cytokines (IL-1β, IL-6, TNF-α). We then present a variety of protein and gene expression data taken from animal studies that show increased expression of various components of the IIR following acute or repeated psychostimulant administration. Collectively the data indicate an association of psychostimulant use with IIR activation in the brain even at exposures not traditionally associated with neurotoxicity. Thus, the gradually escalating deleterious effects of psychostimulant use could in part involve neuroinflammatory mechanisms. Finally, we offer one hypothesis of a possible mechanism by which psychostimulants result in IIR activation and discuss the potential therapeutic implications of these findings for treatment of the recovering addict.
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158
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Role of projections from ventral medial prefrontal cortex to nucleus accumbens shell in context-induced reinstatement of heroin seeking. J Neurosci 2012; 32:4982-91. [PMID: 22492053 DOI: 10.1523/jneurosci.0005-12.2012] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In humans, exposure to contexts previously associated with heroin use can provoke relapse. In rats, exposure to heroin-paired contexts after extinction of drug-reinforced responding in different contexts reinstates heroin seeking. This effect is attenuated by inhibition of glutamate or dopamine transmission in nucleus accumbens shell, or inactivation of ventral medial prefrontal cortex (mPFC). Here, we used an anatomical asymmetrical disconnection procedure to demonstrate that an interaction between glutamatergic projections from ventral mPFC to accumbens shell and local dopamine D(1) postsynaptic receptors contributes to context-induced reinstatement of heroin seeking. We also combined the marker of neuronal activity, Fos, with the retrograde tracer Fluoro-Gold to assess activation in this pathway during context-induced reinstatement. Rats were trained to self-administer heroin for 12 d; drug infusions were paired with a discrete tone-light cue. Lever pressing was subsequently extinguished in a nondrug-associated context in the presence of the discrete cue. Rats were then tested in the heroin- or extinction-associated contexts under extinction conditions. Injections of muscimol + baclofen into ventral mPFC in one hemisphere and D(1)-family receptor antagonist SCH 23390 into the contralateral or ipsilateral accumbens shell decreased context-induced reinstatement. Unilateral injections of muscimol + baclofen into ventral mPFC or SCH 23390 into the accumbens shell had no effect. Context-induced reinstatement was associated with increased Fos expression in ventral mPFC neurons, including those projecting to accumbens shell, with higher double-labeling in the ipsilateral projection than in the contralateral projection. Our results demonstrate that activation of glutamatergic projections from ventral mPFC to accumbens shell, previously implicated in inhibition of cocaine relapse, promotes heroin relapse.
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159
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Dias C, Wang YT, Phillips AG. Facilitated extinction of morphine conditioned place preference with Tat-GluA2(3Y) interference peptide. Behav Brain Res 2012; 233:389-97. [PMID: 22633960 DOI: 10.1016/j.bbr.2012.05.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 05/12/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023]
Abstract
Neuroplasticity including long-term depression (LTD) has been implicated in both learning processes and addiction. LTD can be blocked by intravenous administration of the interference peptide Tat-GluA2(3Y) that prevents regulated endocytosis of the alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) receptor. In this study, Tat-GluA2(3Y) was used to assess the role of LTD in the induction, expression, extinction and reinstatement of morphine-induced conditioned place preference (CPP). CPP was established in rats by pairing morphine (5 mg/kg, i.p.) or saline with a specific environmental context using a balanced protocol. Tat-GluA2(3Y) (0; 1.5; 2.25 nmol/g; i.v.), scrambled peptide (Tat-GluA2(Sc)), or vehicle was administered during the acquisition phase or prior to the test for CPP. Tat-GluA2(3Y) had no effect on the induction or initial expression of morphine-induced CPP. Rats that received Tat-GluA2(3Y) or Tat-GluA2(Sc) during acquisition were subsequently tested for 11 consecutive days in order to extinguish morphine CPP. CPP was then reinstated by an injection of morphine (5 mg/kg, i.p.). Co-administration of morphine and Tat-GluA2(3Y) during acquisition greatly facilitated extinction of CPP without affecting morphine-induced reinstatement of CPP. Using an intermittent retest schedule with bi-weekly tests to measure the maintenance of CPP, Tat-GluA2(3Y) during the acquisition phase had no effect on the maintenance of CPP. We propose that co-administration of Tat-GluA2(3Y) with morphine during acquisition of CPP weakens the association between morphine and contextual cues leading to rapid extinction of morphine CPP with repeated daily testing.
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Affiliation(s)
- C Dias
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Room 5825, Vancouver, BC, V6T 2A1, Canada.
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160
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Czachowski CL, Delory MJ, Pope JD. Behavioral and neurotransmitter specific roles for the ventral tegmental area in reinforcer-seeking and intake. Alcohol Clin Exp Res 2012; 36:1659-68. [PMID: 22432593 DOI: 10.1111/j.1530-0277.2012.01774.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 01/17/2012] [Indexed: 01/21/2023]
Abstract
BACKGROUND The ventral tegmental area (VTA) is a pivotal relay site within the reinforcement circuit that has been shown to play a role in ethanol (EtOH)-motivated behaviors. The primary dopamine projections within this system originate in the VTA and innervate several areas including the nucleus accumbens (NAc) and prefrontal cortex (PFC), and the PFC has afferent glutamate projections to the VTA and the NAc. The following studies utilized 2 different operant paradigms, one focusing on reinforcer-seeking and the other on reinforcer drinking (both with an EtOH and a sucrose reinforcer solution), to elucidate regulation of these behaviors by the posterior VTA, and the specific roles of dopamine and glutamate in this region. METHODS The present experiments assessed the effects of microinjections of the glutamate (AMPA/kainate) antagonist CNQX and the dopamine D1-like antagonist SCH23390 in the posterior VTA, as well as transient chemical inactivation of this region using tetrodotoxin (TTX). In 4 separate experiments (2 dopamine, 2 glutamate, both with TTX), male Long Evans rats were trained to complete a single response requirement that resulted in access to 10% EtOH or 2% sucrose for a 20-minute drinking period. RESULTS Prior to microinjections, EtOH-reinforced subjects were consuming approximately 0.45 to 0.65 g/kg EtOH and making approximately 50 responses during intermittent nonreinforced artificial cerebrospinal fluid sessions (Sucrose groups had similar baseline response levels). Overall, TTX inactivation of the VTA consistently decreased reinforcer-seeking but not intake in all experiments. CNQX also dose-dependently decreased EtOH-seeking, with no significant effect on sucrose-seeking or reinforcer intake. SCH23390 had no significant effects on reinforcer-seeking, and very moderately decreased intake of both EtOH and sucrose. CONCLUSIONS Inactivation of the posterior VTA implicated this region in reinforcer-seeking as opposed to reinforcer intake. Overall, the present findings provide support for the importance of posterior VTA glutamate activity specifically in EtOH-seeking behavior in animals consuming pharmacologically relevant amounts of EtOH.
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Affiliation(s)
- Cristine L Czachowski
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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161
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Madsen HB, Brown RM, Short JL, Lawrence AJ. Investigation of the neuroanatomical substrates of reward seeking following protracted abstinence in mice. J Physiol 2012; 590:2427-42. [PMID: 22393250 DOI: 10.1113/jphysiol.2011.225219] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Persistent vulnerability to relapse represents a major challenge in the treatment of drug addiction. The brain circuitry that underlies relapse-like behaviour can be investigated using animal models of drug seeking. As yet there have been no comprehensive brain mapping studies that have specifically examined the neuroanatomical substrates of cue-induced opiate seeking following abstinence in a mouse operant paradigm. The aim of this study was to compare the brain regions involved in sucrose vs. morphine seeking following protracted abstinence in mice. Male CD1 mice were trained to respond for either sucrose (10% w/v) or intravenous morphine (0.1 mg kg(-1) per infusion) in an operant paradigm in the presence of a discrete cue. Once stable responding was established, mice were subjected to abstinence in their home cages for 3 weeks and then perfused for tissue collection, or returned to the operant chambers to assess cue-induced reward seeking before being perfused for tissue collection. Brain tissue was processed for Fos immunohistochemistry and Fos expression was quantified in a range of brain nuclei. We identified unique patterns of neuronal activation for sucrose and morphine seeking mice as well as some overlap. Structures activated in both ‘relapse' groups included the anterior cingulate and orbitofrontal cortex, nucleus accumbens shell, bed nucleus of the stria terminalis, substantia nigra pars compacta, ventral tegmental area, hippocampus, periaqueductal grey, locus coeruleus and lateral habenula. Structures that were more activated in morphine seeking mice included the nucleus accumbens core, basolateral amygdala, substantia nigra pars reticulata, and the central nucleus of the amygdala. The dorsal raphe was the only structure examined that was specifically activated in sucrose seeking mice. Overall our findings support a cortico-striatal limbic circuit driving opiate seeking, and we have identified some additional circuitry potentially relevant to reward seeking following abstinence.
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Affiliation(s)
- Heather B Madsen
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Vic, Australia, 3010
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162
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LaLumiere RT, Smith KC, Kalivas PW. Neural circuit competition in cocaine-seeking: roles of the infralimbic cortex and nucleus accumbens shell. Eur J Neurosci 2012; 35:614-22. [PMID: 22321070 DOI: 10.1111/j.1460-9568.2012.07991.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Following cocaine self-administration and extinction training, activity in the infralimbic cortex (IL) suppresses cocaine-seeking behavior. IL inactivation induces cocaine-seeking whereas activation suppresses cocaine-reinstated drug-seeking. We asked how the suppression of cocaine-seeking induced by IL activation integrates with the circuitry promoting reinstated cocaine-seeking. Following cocaine self-administration and extinction training, rats underwent cue-induced reinstatement. In order to activate IL projections, microinjections of PEPA, a positive allosteric modulator of AMPA receptors, were made into the IL in combination with microinjections into a variety of nuclei known to regulate cocaine-seeking. Intra-IL PEPA administration suppressed cue-induced reinstatement without affecting locomotor activity. The suppression of cocaine-seeking was reversed by activating dopamine neurons in the ventral tegmental area with microinjections of the μ-opioid receptor agonist DAMGO, and was partially reversed by dopamine microinjections into the prelimbic cortex or basolateral amygdala. Previous evidence suggests that the nucleus accumbens shell both promotes and suppresses cocaine-seeking. The suppression of cue-induced cocaine seeking by PEPA in the IL was reversed by intra-shell microinjections of either dopamine or the AMPA receptor antagonist CNQX, suggesting that the accumbens shell bidirectionally regulates cocaine-seeking depending on whether dopamine input is mimicked or glutamate input is inhibited. Together, these findings indicate that the IL acts 'upstream' from structures promoting cocaine-seeking, including from the mesolimbic dopamine projections to the prelimbic cortex and basolateral amygdala, and that the accumbens shell may be a crucial point of integration between the circuits that promote (ventral tegmental area) and inhibit (IL) reinstated cocaine-seeking.
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Affiliation(s)
- Ryan T LaLumiere
- Department of Psychology, University of Iowa, Iowa City, IA 52242, USA.
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163
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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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164
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Van den Oever MC, Spijker S, Smit AB. The synaptic pathology of drug addiction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:469-91. [PMID: 22351069 DOI: 10.1007/978-3-7091-0932-8_21] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A hallmark of drug addiction is the uncontrollable desire to consume drugs at the expense of severe negative consequences. Moreover, addicts that successfully refrain from drug use have a high vulnerability to relapse even after months or years of abstinence. In this chapter, we will discuss the current understanding of drug-induced neuroplasticity within the mesocorticolimbic brain system that contributes to the development of addiction and the persistence of relapse to drug seeking. I particular, we will focus at animal models that can be translated to human addiction. Although dopaminergic transmission is important for the acute effects of drug intake, the long-lived behavioral abnormalities associated with addiction are thought to arise from pathological plasticity in glutamatergic neurotransmission. The nature of changes in excitatory synaptic plasticity depends on several factors, including the type of drug, the brain area, and the time-point studied in the transition of drug exposure to withdrawal and relapse to drug seeking. Identification of drug-induced neuroplasticity is crucial to understand how molecular and cellular adaptations contribute to the end stage of addiction, which from a clinical perspective, is a time-point where pharmacotherapy may be most effectively employed.
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Affiliation(s)
- Michel C Van den Oever
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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165
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Pereira M, Morrell JI. Functional mapping of the neural circuitry of rat maternal motivation: effects of site-specific transient neural inactivation. J Neuroendocrinol 2011; 23:1020-35. [PMID: 21815954 PMCID: PMC3196804 DOI: 10.1111/j.1365-2826.2011.02200.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The present review focuses on recent studies from our laboratory examining the neural circuitry subserving rat maternal motivation across postpartum. We employed a site-specific neural inactivation method by infusion of bupivacaine to map the maternal motivation circuitry using two complementary behavioural approaches: unconditioned maternal responsiveness and choice of pup- over cocaine-conditioned incentives in a concurrent pup/cocaine choice conditioned place preference task. Our findings revealed that, during the early postpartum period, distinct brain structures, including the medial preoptic area, ventral tegmental area and medial prefrontal cortex infralimbic and anterior cingulate subregions, contribute a pup-specific bias to the motivational circuitry. As the postpartum period progresses and the pups grow older, it is further revealed that maternal responsiveness becomes progressively less dependent on the medial preoptic area and medial prefrontal cortex infralimbic activity, and more distributed in the maternal circuitry, such that additional network components, including the medial prefrontal cortex prelimbic subregion, are recruited with maternal experience, and contribute to the expression of late postpartum maternal behaviour. Collectively, our findings provide strong evidence that the remarkable ability of postpartum females to successfully care for their developing infants is subserved by a distributed neural network that carries out efficient and dynamic processing of complex, constantly changing incoming environmental and pup-related stimuli, ultimately allowing the progression of appropriate expression and waning of maternal responsiveness across the postpartum period.
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Affiliation(s)
- M Pereira
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark Campus, Newark, NJ 07102, USA.
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166
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Rose JE, McClernon FJ, Froeliger B, Behm FM, Preud'homme X, Krystal AD. Repetitive transcranial magnetic stimulation of the superior frontal gyrus modulates craving for cigarettes. Biol Psychiatry 2011; 70:794-799. [PMID: 21762878 DOI: 10.1016/j.biopsych.2011.05.031] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 05/22/2011] [Accepted: 05/25/2011] [Indexed: 11/24/2022]
Abstract
BACKGROUND Previous functional magnetic resonance imaging studies have shown strong correlations between cue-elicited craving for cigarettes and activation of the superior frontal gyrus (SFG). Repetitive transcranial magnetic stimulation (rTMS) offers a noninvasive means to reversibly affect brain cortical activity, which can be applied to testing hypotheses about the causal role of SFG in modulating craving. METHODS Fifteen volunteer smokers were recruited to investigate the effects of rTMS on subjective responses to smoking versus neutral cues and to controlled presentations of cigarette smoke. On different days, participants were exposed to three conditions: 1) high-frequency (10 Hz) rTMS directed at the SFG; 2) low-frequency (1 Hz) rTMS directed at the SFG; and 3) low-frequency (1 Hz) rTMS directed at the motor cortex (control condition). RESULTS Craving ratings in response to smoking versus neutral cues were differentially affected by the 10-Hz versus 1-Hz SFG condition. Craving after smoking cue presentations was elevated in the 10-Hz SFG condition, whereas craving after neutral cue presentations was reduced. Upon smoking in the 10-Hz SFG condition, ratings of immediate craving reduction as well as the intensity of interoceptive airway sensations were also attenuated. CONCLUSIONS These results support the view that the SFG plays a role in modulating craving reactivity; moreover, the results suggest that the SFG plays a role in both excitatory and inhibitory influences on craving, consistent with prior research demonstrating the role of the prefrontal cortex in the elicitation as well as inhibition of drug-seeking behaviors.
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Affiliation(s)
- Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina.
| | - F Joseph McClernon
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina; Durham Veterans Affairs Medical Center and Veterans Integrated Service Network Number 6 Mental Illness Research, Education, and Clinical Center, Durham, North Carolina
| | - Brett Froeliger
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Frédérique M Behm
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Xavier Preud'homme
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Andrew D Krystal
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
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167
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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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168
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Badiani A, Belin D, Epstein D, Calu D, Shaham Y. Opiate versus psychostimulant addiction: the differences do matter. Nat Rev Neurosci 2011; 12:685-700. [PMID: 21971065 DOI: 10.1038/nrn3104] [Citation(s) in RCA: 355] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The publication of the psychomotor stimulant theory of addiction in 1987 and the finding that addictive drugs increase dopamine concentrations in the rat mesolimbic system in 1988 have led to a predominance of psychobiological theories that consider addiction to opiates and addiction to psychostimulants as essentially identical phenomena. Indeed, current theories of addiction - hedonic allostasis, incentive sensitization, aberrant learning and frontostriatal dysfunction - all argue for a unitary account of drug addiction. This view is challenged by behavioural, cognitive and neurobiological findings in laboratory animals and humans. Here, we argue that opiate addiction and psychostimulant addiction are behaviourally and neurobiologically distinct and that the differences have important implications for addiction treatment, addiction theories and future research.
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Affiliation(s)
- Aldo Badiani
- Department of Physiology and Pharmacology Vittorio Erspamer, Sapienza University of Rome, Rome, Italy.
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169
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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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170
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Song H, li J, Lu CL, Kang L, Xie L, Zhang YY, Zhou XB, Zhong S. Tetrodotoxin alleviates acute heroin withdrawal syndrome: A multicentre, randomized, double-blind, placebo-controlled study. Clin Exp Pharmacol Physiol 2011; 38:510-4. [DOI: 10.1111/j.1440-1681.2011.05539.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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171
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Ghasemzadeh MB, Vasudevan P, Giles C, Purgianto A, Seubert C, Mantsch JR. Glutamatergic plasticity in medial prefrontal cortex and ventral tegmental area following extended-access cocaine self-administration. Brain Res 2011; 1413:60-71. [PMID: 21855055 DOI: 10.1016/j.brainres.2011.06.041] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 06/11/2011] [Accepted: 06/16/2011] [Indexed: 12/29/2022]
Abstract
Glutamate signaling in prefrontal cortex and ventral tegmental area plays an important role in the molecular and behavioral plasticity associated with addiction to drugs of abuse. The current study investigated the expression and postsynaptic density redistribution of glutamate receptors and synaptic scaffolding proteins in dorsomedial and ventromedial prefrontal cortex and ventral tegmental area after cocaine self-administration. After 14 days of extended-access (6h/day) cocaine self-administration, rats were exposed to one of three withdrawal regimen for 10 days. Animals either stayed in home cages (Home), returned to self-administration boxes with the levers withdrawn (Box), or underwent extinction training (Extinction). Extinction training was associated with significant glutamatergic plasticity. In dorsomedial prefrontal cortex of the Extinction group, there was an increase in postsynaptic density GluR1, PSD95, and actin proteins; while postsynaptic density mGluR5 protein decreased and there was no change in NMDAR1, Homer1b/c, or PICK1 proteins. These changes were not observed in ventromedial prefrontal cortex or ventral tegmental area. In ventral tegmental area, Extinction training reversed the decreased postsynaptic density NMDAR1 protein in the Home and Box withdrawal groups. These data suggest that extinction of drug seeking is associated with selective glutamatergic plasticity in prefrontal cortex and ventral tegmental area that include modulation of receptor trafficking to postsynaptic density.
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Affiliation(s)
- M Behnam Ghasemzadeh
- Department of Biomedical Sciences, Integrative Neuroscience Research Center, Marquette University, Milwaukee, WI 53201, USA.
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172
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Millan EZ, McNally GP. Accumbens shell AMPA receptors mediate expression of extinguished reward seeking through interactions with basolateral amygdala. Learn Mem 2011; 18:414-21. [PMID: 21677189 DOI: 10.1101/lm.2144411] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Extinction is the reduction in drug seeking when the contingency between drug seeking behavior and the delivery of drug reward is broken. Here, we investigated a role for the nucleus accumbens shell (AcbSh). Rats were trained to respond for 4% (v/v) alcoholic beer in one context (Context A) followed by extinction in a second context (Context B). Rats were subsequently tested in the training context, A (ABA), or the extinction context, B (ABB). Pre-test injections of the glutamate AMPA receptor antagonist, NBQX (1 µg) into AcbSh had no effect on renewal of alcoholic beer seeking when rats were returned to the training context (ABA). However, NBQX increased responding when rats were tested in the extinction context (ABB). In a second experiment, rats received training, extinction, and test in the same context. Pre-test injections of NBQX (0, 0.3, and 1 µg) into the AcbSh dose-dependently attenuated expression of extinction. We also found that NBQX in the AcbSh had no effect on initial acquisition of extinction or the motivation to respond for reward as measured by break point on a progressive ratio schedule. Finally, we show that pharmacological disconnection of a basolateral amygdala (BLA) → AcbSh pathway via NBQX in AcbSh combined with reversible inactivation of the contralateral BLA attenuates expression of extinction. Together, these results suggest that AcbSh AMPA receptors mediate expression of extinguished reward seeking through glutamatergic inputs from the BLA.
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Affiliation(s)
- E Zayra Millan
- University of New South Wales, Sydney, NSW, 2052, Australia
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173
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Waters RP, See RE. Chronic cocaine self-administration attenuates the anxiogenic-like and stress potentiating effects of the benzodiazepine inverse agonist, FG 7142. Pharmacol Biochem Behav 2011; 99:408-13. [PMID: 21635914 DOI: 10.1016/j.pbb.2011.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 05/09/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
Stress is a well-known risk factor in relapse to drug abuse. Several forms of stress in animals have been used with varied degrees of success to elicit reinstatement of drug-seeking after chronic drug self-administration. Here, we tested the ability of the benzodiazepine (BZ) inverse agonist, FG 7142, to elicit anxiety-like behavior and potentiate stress responses in rats as measured by standard behavioral and hormonal indices and for its ability to affect reinstatement of cocaine-seeking in rats with a prior history of cocaine self-administration. FG 7142 elicited anxiety-like behavior on the elevated plus maze (EPM) in cocaine-naïve rats, and cocaine-naïve rats injected with FG 7142 exhibited increased plasma corticosterone levels following EPM exposure. However, in animals with a history of cocaine self-administration, FG 7142 failed to affect elevated plus maze performance and did not affect plasma corticosterone response to the EPM. Furthermore, FG 7142 failed to reinstate cocaine-seeking, nor did it alter conditioned cue-induced reinstatement. These data indicate that the anxiety-related and stress potentiating qualities of BZ inverse agonism are attenuated in cocaine-experienced animals and do not lead to reinstatement of cocaine-seeking.
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Affiliation(s)
- R Parrish Waters
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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174
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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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175
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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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176
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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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177
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The suppressive effect of an intra-prefrontal cortical infusion of BDNF on cocaine-seeking is Trk receptor and extracellular signal-regulated protein kinase mitogen-activated protein kinase dependent. J Neurosci 2011; 31:834-42. [PMID: 21248106 DOI: 10.1523/jneurosci.4986-10.2011] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cocaine-mediated neuroadaptations in the prefrontal cortical-nucleus accumbens pathway underlie drug-seeking in animals with a cocaine self-administration (SA) history. Neuroplasticity in the cortico-accumbens pathway is regulated, in part, by the expression and availability of neurotrophic factors, such as BDNF. We have previously demonstrated that infusion of BDNF into the dorsomedial prefrontal cortex (dmPFC) immediately after the last of 10 cocaine SA sessions attenuates contextual, cue- and cocaine prime-induced reinstatement of cocaine-seeking (Berglind et al., 2007) and normalizes cocaine-induced disruption of glutamatergic transmission in the nucleus accumbens (Berglind et al., 2009). In the present study, the suppressive effect of intra-dmPFC BDNF on cocaine-seeking is shown to depend on Trk receptor-mediated activation of extracellular signal-regulated kinase (ERK) signaling in the dmPFC. The tyrosine kinase inhibitor, K252a, and the mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitor, U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), prevented BDNF's suppressive effects on cocaine-seeking. Vehicle-infused rats with a cocaine SA history showed significant decreases in ERK and cyclic AMP response element binding protein (CREB), but not Akt, phosphorylation after the final cocaine SA session that were reversed by intra-dmPFC BDNF. Additionally, BDNF's ability to normalize cocaine-mediated decreases in ERK and CREB phosphorylation was blocked by U0126, demonstrating that ERK/MAPK activation mediated the behavioral effects. This study elucidates a mechanism whereby BDNF/TrkB (tropomyosin receptor kinase B) activates ERK-regulated CREB phosphorylation in the dmPFC to counteract the neuroadaptations induced by cocaine SA and subsequent relapse to cocaine-seeking.
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178
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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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179
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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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180
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Economidou D, Dalley JW, Everitt BJ. Selective norepinephrine reuptake inhibition by atomoxetine prevents cue-induced heroin and cocaine seeking. Biol Psychiatry 2011; 69:266-74. [PMID: 21109233 DOI: 10.1016/j.biopsych.2010.09.040] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 09/26/2010] [Accepted: 09/28/2010] [Indexed: 01/09/2023]
Abstract
BACKGROUND Preventing relapse to drug use is a major challenge for drug addiction treatment. We have recently shown that impulsivity predating drug-taking increases the susceptibility to relapse to cocaine seeking and that treatment with the anti-impulsivity drug atomoxetine (ATO), a selective norepinephrine re-uptake inhibitor (norepinephrine transporter), prevents relapse. Here, we investigated further the effects of ATO on cue-maintained heroin and cocaine seeking and relapse and compared these effects with those of the anti-impulsivity stimulant drug methylphenidate (MPH). METHODS Rats were trained to seek and self-administer cocaine or heroin under a second-order schedule of reinforcement. After acquisition of stable responding, groups of rats (n = 10-12) were treated, in a within-subject design, with either ATO or MPH (.3-3.0 mg/kg IP), and the effects on cocaine and heroin seeking were measured. The effects of ATO (.3-1.0 mg/kg) on cue-induced relapse to cocaine seeking after a 1-week period of abstinence were also studied. RESULTS Atomoxetine significantly decreased both cue-controlled cocaine and heroin seeking, whereas MPH had no significant effect. Atomoxetine also significantly attenuated cue-induced relapse to cocaine seeking after abstinence. The effects of ATO were selective for cue-controlled drug-seeking, because it did not affect responding in the absence of the drug-paired cue; nor did it alter responding for oral sucrose, except minimally at the highest dose, or locomotor activity. CONCLUSIONS Selective norepinephrine transporter inhibition by ATO might be an effective treatment for the prevention of relapse to both stimulant and opiate addiction.
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Affiliation(s)
- Daina Economidou
- Behavioral and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Addenbrooke’s Hospital, United Kingdom.
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181
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Parsegian A, Glen WB, Lavin A, See RE. Methamphetamine self-administration produces attentional set-shifting deficits and alters prefrontal cortical neurophysiology in rats. Biol Psychiatry 2011; 69:253-9. [PMID: 21051037 PMCID: PMC3052930 DOI: 10.1016/j.biopsych.2010.09.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/26/2010] [Accepted: 09/01/2010] [Indexed: 01/25/2023]
Abstract
BACKGROUND Chronic methamphetamine abusers exhibit deficits in tasks requiring intact prefrontal cortex function, and prefrontal cortex dysfunction has been implicated in the loss of control over drug use. This study used a combination of behavioral and electrophysiologic assessments in rats with a history of long access methamphetamine self-administration to determine methamphetamine-induced changes in prefrontal cortex-dependent attentional set-shifting performance, drug-seeking, and prefrontal cortex neuronal activity. METHODS Male Long-Evans rats self-administered methamphetamine (.02 mg/infusion, intravenous) or received yoked saline infusions for 6 hours a day for 14 days. Cognitive flexibility was assessed using an attentional set-shifting task before 2 weeks of self-administration and 1 day after self-administration. Animals then underwent 11 days of abstinence, followed by three subsequent tests for context-induced drug seeking. Finally, animals were anesthetized, and single-unit in vivo extracellular recordings were performed in the dorsomedial prefrontal cortex. RESULTS Methamphetamine-experienced rats showed escalated drug intake and context-induced drug-seeking following abstinence. During the extradimensional set-shift component, meth-experienced rats showed selective impairments that were identical to deficits produced by excitotoxic lesions of the prefrontal cortex. Rats with a history of chronic methamphetamine intake also exhibited higher basal firing frequency and a significantly greater proportion of burst-firing cells in the prefrontal cortex compared with yoked-saline controls. CONCLUSIONS Prefrontal cortex-specific alterations in neuronal function may play a key role in methamphetamine-induced attentional deficits and drug-seeking. These data support the possibility that targeting prefrontal cortex pathology may improve treatment outcome in methamphetamine addiction.
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Affiliation(s)
- Aram Parsegian
- Department of Neurosciences, Medical University of South Carolina, Charleston, 29425, USA
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182
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Pockros LA, Pentkowski NS, Swinford SE, Neisewander JL. Blockade of 5-HT2A receptors in the medial prefrontal cortex attenuates reinstatement of cue-elicited cocaine-seeking behavior in rats. Psychopharmacology (Berl) 2011; 213:307-20. [PMID: 21079923 PMCID: PMC3072217 DOI: 10.1007/s00213-010-2071-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/25/2010] [Indexed: 01/07/2023]
Abstract
RATIONALE The action of serotonin (5-HT) at the 5-HT(2A) receptor subtype is thought to be involved in cocaine-seeking behavior that is motivated by exposure to drug-associated cues and drug priming. 5-HT(2A) receptors are densely clustered in the ventromedial prefrontal cortex (vmPFC), an area that plays a role in mediating cocaine-seeking behavior. OBJECTIVES This study examined the hypothesis that M100907, a 5-HT(2A) receptor antagonist, infused directly in the vmPFC attenuates cue- and cocaine-primed reinstatement of cocaine-seeking behavior. METHODS Rats trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues underwent extinction training during which operant responses produced no consequences. Once behavior extinguished, rats were tested for reinstatement of responding elicited by either response-contingent presentations of the cocaine-paired light/tone cues or by cocaine-priming injections (10 mg/kg, i.p.) within 1 min after pretreatment with microinfusions of M100907 (0.1, 0.3, 1.0, or 1.5 μg/0.2 μl/side) into the vmPFC. RESULTS Intra-vmPFC M100907 decreased cue-elicited reinstatement at the two highest doses (1.0 and 1.5 μg) but produced only a slight decrease in cocaine-primed reinstatement that was not dose dependent. The decrease in cue reinstatement was not likely due to impaired ability to respond since intra-vmPFC M100907 infusions had minimal effect on cocaine self-administration and no effect on cue-elicited sucrose-seeking behavior, or spontaneous or cocaine-induced locomotion. M100907 infusions into the adjacent anterior cingulate cortex had no effect on cue reinstatement. CONCLUSIONS The results suggest that the blockade of 5-HT(2A) receptors in the vmPFC selectively attenuates the incentive motivational effects of cocaine-paired cues.
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Affiliation(s)
- Lara A. Pockros
- Department of Psychology, Arizona State University, 950 S. McAllister, Tempe, AZ 85287, USA
| | - Nathan S. Pentkowski
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA
| | - Sarah E. Swinford
- Department of Psychology, Arizona State University, 950 S. McAllister, Tempe, AZ 85287, USA
| | - Janet L. Neisewander
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA
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183
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Interaction of the basolateral amygdala and orbitofrontal cortex is critical for drug context-induced reinstatement of cocaine-seeking behavior in rats. Neuropsychopharmacology 2011; 36:711-20. [PMID: 21124303 PMCID: PMC3020992 DOI: 10.1038/npp.2010.209] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The basolateral amygdala (BLA) and lateral orbitofrontal cortex (OFC) are critical elements of the neural circuitry that regulates drug context-induced reinstatement of cocaine-seeking behavior. Given the existence of dense reciprocal anatomical connections between these brain regions, this study tested the hypothesis that serial information processing by the BLA and OFC is necessary for drug context-induced cocaine-seeking behavior. Male Sprague-Dawley rats were trained to lever press for un-signaled cocaine infusions (0.15 mg/infusion, i.v.) in a distinct environment (cocaine-paired context) then underwent extinction training in a different environment (extinction context). During four subsequent test sessions, rats were re-exposed to the cocaine-paired and extinction contexts in order to assess cocaine-seeking behavior (non-reinforced active lever responding). Immediately before each test session, rats received microinfusions of the GABA(A)/GABA(B) agonist cocktail, baclofen+muscimol (BM: 1.0/.01 mM), or vehicle unilaterally into the BLA plus the contralateral or ipsilateral OFC, or unilaterally into the OFC alone. Exposure to the previously cocaine-paired context, but not the extinction context, reinstated extinguished cocaine-seeking behavior. BM-induced unilateral OFC inactivation failed to alter this behavior, similar to the effect of unilateral BLA inactivation in our previous study (Fuchs et al, 2007). Conversely, neural inactivation of the BLA plus the contralateral or ipsilateral OFC equally attenuated drug context-induced cocaine seeking without altering food-reinforced instrumental responding, relative to vehicle pretreatment. These findings suggest that the BLA and OFC co-regulate drug context-induced motivation for cocaine either through sequential information processing via intra- and interhemispheric connections or by providing converging input to a downstream brain region.
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184
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Gremel CM, Young EA, Cunningham CL. Blockade of opioid receptors in anterior cingulate cortex disrupts ethanol-seeking behavior in mice. Behav Brain Res 2011; 219:358-62. [PMID: 21219940 DOI: 10.1016/j.bbr.2010.12.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/17/2010] [Accepted: 12/22/2010] [Indexed: 11/16/2022]
Abstract
The anterior cingulate cortex (ACC) and opioid receptors have been suggested to play a role in attributing incentive motivational properties to drug-related cues. We examined whether blockade of ACC opioid receptors would reduce cue-induced ethanol-seeking behavior in mice. We show that intra-ACC opioid receptor blockade disrupted expression of an ethanol-induced conditioned place preference, suggesting that endogenous opioid modulation in the ACC may be critical for maintaining the cue's conditioned rewarding effects.
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Affiliation(s)
- Christina M Gremel
- Department of Behavioral Neuroscience, Portland Alcohol Research Center, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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185
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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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186
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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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187
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Baron SG, Gobbini MI, Engell AD, Todorov A. Amygdala and dorsomedial prefrontal cortex responses to appearance-based and behavior-based person impressions. Soc Cogn Affect Neurosci 2010; 6:572-81. [PMID: 21030482 DOI: 10.1093/scan/nsq086] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We explored the neural correlates of learning about people when the affective value of both facial appearance and behavioral information is manipulated. Participants were presented with faces that were either rated as high or low on trustworthiness. Subsequently, we paired these faces with positive, negative, or no behavioral information. Prior to forming face-behavior associations, a cluster in the right amygdala responded more strongly to untrustworthy than to trustworthy faces. During learning, a cluster in the dorsomedial prefrontal cortex (dmPFC) responded more strongly to faces paired with behaviors than faces not paired with behaviors. We also observed that the activity in the dmPFC was correlated with behavioral learning performance assessed after scanning. Interestingly, individual differences in the initial amygdala response to face trustworthiness prior to learning modulated the relationship between dmPFC activity and learning. This finding suggests that the activity of the amygdala can affect the interaction between dmPFC activity and learning.
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Affiliation(s)
- Sean G Baron
- Department of Psychology, Princeton University, Princeton, NJ 08540, USA.
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188
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Lu H, Cheng PL, Lim BK, Khoshnevisrad N, Poo MM. Elevated BDNF after cocaine withdrawal facilitates LTP in medial prefrontal cortex by suppressing GABA inhibition. Neuron 2010; 67:821-33. [PMID: 20826313 DOI: 10.1016/j.neuron.2010.08.012] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2010] [Indexed: 11/26/2022]
Abstract
Medial prefrontal cortex (mPFC) is known to be involved in relapse after cocaine withdrawal, but the underlying cellular mechanism remains largely unknown. Here, we report that after terminating repeated cocaine exposure in rats, a gradual increase in the expression of brain-derived neurotrophic factor (BDNF) in the mPFC facilitates activity-induced long-term potentiation (LTP) of excitatory synapses on layer V pyramidal neurons. This enhanced synaptic plasticity could be attributed to BDNF-induced suppression of GABAergic inhibition in the mPFC by reducing the surface expression of GABA(A) receptors. The BDNF effect was mediated by BDNF-TrkB-phosphatase 2A signaling pathway. Downregulating TrkB expression bilaterally in the mPFC reduced the locomotor hypersensitivity to cocaine 8 days after cocaine withdrawal. Thus, elevated BDNF expression after cocaine withdrawal sensitizes the excitatory synapses in the mPFC to undergo activity-induced persistent potentiation that may contribute to cue-induced drug craving and drug-seeking behavior.
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Affiliation(s)
- Hui Lu
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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189
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Altered dopamine modulation of inhibition in the prefrontal cortex of cocaine-sensitized rats. Neuropsychopharmacology 2010; 35:2292-304. [PMID: 20664581 PMCID: PMC2939941 DOI: 10.1038/npp.2010.107] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A functionally hypoactive prefrontal cortex (PFC) is thought to contribute to decreased cognitive inhibitory control over drug-seeking behavior in cocaine addicts. Alterations in PFC dopamine (DA) and γ-aminobutyric acid (GABA) transmission are involved in the development of behavioral sensitization to cocaine, and repeated exposure to cocaine decreases DA D2 receptor (D2R) function in the PFC. We used recordings in PFC slices from adult rats to investigate how repeated cocaine treatment followed by 2 weeks of withdrawal affects DA modulation of GABA transmission and interneuron firing. In agreement with previous results in drug-naïve animals we found that in saline-treated control animals DA (20 μM) modulated evoked inhibitory post-synaptic currents (eIPSCs) in a biphasic, time- and receptor-dependent manner. Activation of D2Rs transiently reduced, whereas D1 receptor activation persistently increased the amplitude of eIPSCs. In cocaine-sensitized animals the D2R-dependent modulation of eIPSCs was abolished and the time course of DA effects was altered. In both saline- and cocaine-treated animals the effects of DA on eIPSCs were paralleled by distinct changes in spontaneous IPSCs (sIPSCs). In cocaine-treated animals the alterations in DA modulation of eIPSCs and sIPSCs correlated with a lack of D2R-specific reduction in action potential-independent GABA release, which might normally oppose D1-dependent increases in GABA transmission. Recordings from interneurons furthermore show that D2R activation can increase current-evoked spike firing in saline, but not in cocaine-treated animals. Altered DA regulation of inhibition during cocaine withdrawal could disturb normal cortical processing and contribute to a hypoactive PFC.
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190
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Thiel KJ, Engelhardt B, Hood LE, Peartree NA, Neisewander JL. The interactive effects of environmental enrichment and extinction interventions in attenuating cue-elicited cocaine-seeking behavior in rats. Pharmacol Biochem Behav 2010; 97:595-602. [PMID: 20869391 DOI: 10.1016/j.pbb.2010.09.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/07/2010] [Accepted: 09/16/2010] [Indexed: 10/19/2022]
Abstract
Cues associated with cocaine can elicit craving and relapse. Attempts have been made to employ extinction therapy, which is aimed at attenuating the incentive motivational effects of cocaine cues, as a treatment for cocaine addiction; however, this approach has been largely unsuccessful perhaps due to the inability to extinguish all cues associated with cocaine use while in a clinic. Recently, environmental enrichment (EE) during abstinence has been proposed as a strategy to attenuate cue-elicited cocaine craving. The present study used an animal model to examine whether the utility of extinction toward attenuating cue-elicited cocaine-seeking behavior could be enhanced by also providing EE. All rats were trained to self-administer cocaine while housed in isolated conditions and then subsequently underwent 17 days of forced abstinence, during which they were either housed in pairs or under EE and they either received daily 1-h extinction sessions or similar handling without exposure to the self-administration environment. Following this intervention period, all rats were tested for cue-elicited cocaine-seeking behavior. To examine whether effects of these interventions persist, all rats were subsequently single-housed for an additional 7-day forced abstinence period, followed by a second test for cue-elicited cocaine-seeking behavior. We found that although daily extinction training and EE each attenuated subsequent cue-elicited cocaine-seeking behavior, the combined treatment of extinction training+EE completely prevented it. However, once these interventions were discontinued, their protective effects diminished. These findings suggest that combining behavioral therapy approaches may improve outcomes; however, future work is needed to improve the longevity of these strategies beyond their implementation.
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Affiliation(s)
- Kenneth J Thiel
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104, USA
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191
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Target-specific encoding of response inhibition: increased contribution of AMPA to NMDA receptors at excitatory synapses in the prefrontal cortex. J Neurosci 2010; 30:11493-500. [PMID: 20739571 DOI: 10.1523/jneurosci.1550-10.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Impulse control suppresses actions that are inappropriate in one context, but may be beneficial in others. The medial prefrontal cortex (mPFC) mediates this process by providing a top-down signal to inhibit competing responses, although the mechanism by which the mPFC acquires this ability is unknown. To that end, we examined synaptic changes in the mPFC associated with learning to inhibit an incorrect response. Rats were trained in a simple response inhibition task to withhold responding until a signal was presented. We then measured synaptic plasticity of excitatory synapses in the mPFC, using whole-cell patch-clamp recordings, in brain slices prepared from trained rats. Response inhibition training significantly increased the relative contribution of AMPA receptors to the overall EPSC in prelimbic, but not infralimbic, neurons of the mPFC. This potentiation of synaptic transmission closely paralleled the acquisition and extinction of response inhibition. Using a retrograde fluorescent tracer, we observed that these plastic changes were selective for efferents projecting to the ventral striatum, but not the dorsal striatum or amygdala. Therefore, we suggest that response inhibition is encoded by a selective strengthening of a subset of corticostriatal projections, uncovering a synaptic mechanism of impulse control. This information could be exploited in therapeutic interventions for disorders of impulse control, such as addiction, attention deficit-hyperactivity disorder, and schizophrenia.
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192
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Perry JL, Joseph JE, Jiang Y, Zimmerman RS, Kelly TH, Darna M, Huettl P, Dwoskin LP, Bardo MT. Prefrontal cortex and drug abuse vulnerability: translation to prevention and treatment interventions. ACTA ACUST UNITED AC 2010; 65:124-49. [PMID: 20837060 DOI: 10.1016/j.brainresrev.2010.09.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 08/19/2010] [Accepted: 09/02/2010] [Indexed: 01/25/2023]
Abstract
Vulnerability to drug abuse is related to both reward seeking and impulsivity, two constructs thought to have a biological basis in the prefrontal cortex (PFC). This review addresses similarities and differences in neuroanatomy, neurochemistry and behavior associated with PFC function in rodents and humans. Emphasis is placed on monoamine and amino acid neurotransmitter systems located in anatomically distinct subregions: medial prefrontal cortex (mPFC); lateral prefrontal cortex (lPFC); anterior cingulate cortex (ACC); and orbitofrontal cortex (OFC). While there are complex interconnections and overlapping functions among these regions, each is thought to be involved in various functions related to health-related risk behaviors and drug abuse vulnerability. Among the various functions implicated, evidence suggests that mPFC is involved in reward processing, attention and drug reinstatement; lPFC is involved in decision-making, behavioral inhibition and attentional gating; ACC is involved in attention, emotional processing and self-monitoring; and OFC is involved in behavioral inhibition, signaling of expected outcomes and reward/punishment sensitivity. Individual differences (e.g., age and sex) influence functioning of these regions, which, in turn, impacts drug abuse vulnerability. Implications for the development of drug abuse prevention and treatment strategies aimed at engaging PFC inhibitory processes that may reduce risk-related behaviors are discussed, including the design of effective public service announcements, cognitive exercises, physical activity, direct current stimulation, feedback control training and pharmacotherapies. A major challenge in drug abuse prevention and treatment rests with improving intervention strategies aimed at strengthening PFC inhibitory systems among at-risk individuals.
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Affiliation(s)
- Jennifer L Perry
- Center for Drug Abuse Research Translation, University of Kentucky, Lexington, KY 40536-0509, USA
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193
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Stimulation of medial prefrontal cortex serotonin 2C (5-HT(2C)) receptors attenuates cocaine-seeking behavior. Neuropsychopharmacology 2010; 35:2037-48. [PMID: 20520599 PMCID: PMC3055305 DOI: 10.1038/npp.2010.72] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Serotonin 2C receptor (5-HT(2C)R) agonists administered systemically attenuate both cocaine-primed and cue-elicited reinstatement of extinguished cocaine-seeking behavior. To further elucidate the function of these receptors in addiction-like processes, this study examined the effects of microinfusing the 5-HT(2C)R agonist MK212 (0, 10, 30, 100 ng/side/0.2 microl) into the medial prefrontal cortex (mPFC) on cocaine self-administration and reinstatement of extinguished cocaine-seeking behavior. Male Sprague-Dawley rats were trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues. Once responding stabilized, rats received MK212 microinfusions before tests for maintenance of cocaine self-administration. Next, extinction training to reduce cocaine-seeking behavior, defined as responses performed without cocaine reinforcement available, occurred until low extinction baselines were achieved. Rats then received MK212 microinfusions before tests for reinstatement of extinguished cocaine-seeking behavior elicited by cocaine-priming injections (10 mg/kg, i.p.) or response-contingent presentations of the cocaine-associated cues; operant responses during cocaine-primed reinstatement tests produced no consequences. MK212 microinfusions into the prelimbic and infralimbic, but not anterior cingulate, regions of the mPFC dose-dependently attenuated both cocaine-primed and cue-elicited reinstatement of extinguished cocaine-seeking behavior, but did not reliably affect cocaine self-administration. A subsequent experiment showed that the effects of MK212 (100 ng/side/0.2 microl) on reinstatement of extinguished cocaine-seeking behavior were blocked by co-administration of the 5-HT(2C)R antagonist SB242084 (200 ng/side/0.2 microl). MK212 administered alone into the mPFC as a drug prime produced no discernable effects on cocaine-seeking behavior. These findings suggest that stimulation of 5-HT(2C)Rs in the mPFC attenuates the incentive motivational effects produced by sampling cocaine or exposure to drug-paired cues.
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194
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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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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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196
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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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197
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Moussawi K, Kalivas PW. Group II metabotropic glutamate receptors (mGlu2/3) in drug addiction. Eur J Pharmacol 2010; 639:115-22. [PMID: 20371233 DOI: 10.1016/j.ejphar.2010.01.030] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/18/2009] [Accepted: 01/20/2010] [Indexed: 12/21/2022]
Abstract
Drug addiction is characterized by maladaptive decision-making and dysfunctional brain circuitry regulating motivated behaviors, resulting in loss of the behavioral flexibility needed to abstain from drug seeking. Hence, addicts face high risk of relapse even after prolonged periods of abstinence from drug use. This is thought to result from long-lasting drug-induced neuroadaptations of glutamate and dopaminergic transmission in the mesocorticolimbic and cortico-striatal circuits where group II metabotropic glutamate receptors (mGlu(2/3) receptors) are densely expressed. mGlu(2/3) receptors presynaptically control glutamate as well as dopamine release throughout the mesocorticolimbic structures involved in reward processing and drug seeking, and their function is reduced after prolonged exposure to drugs of abuse. In pre-clinical models, mGlu(2/3) receptors have been shown to regulate both reward processing and drug seeking, in part through the capacity to control release of dopamine and glutamate respectively. Specifically, mGlu(2/3) receptor agonists administered systemically or locally into certain brain structures reduce the rewarding value of commonly abused drugs and inhibit the reinstatement of drug seeking. Given the ability of mGlu(2/3) receptor agonists to compensate for and possibly reverse drug-induced neuroadaptations in mesocorticolimbic circuitry, this class of receptors emerges as a new therapeutic target for reducing relapse in drug addiction.
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Affiliation(s)
- Khaled Moussawi
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
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198
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Frohmader KS, Wiskerke J, Wise RA, Lehman MN, Coolen LM. Methamphetamine acts on subpopulations of neurons regulating sexual behavior in male rats. Neuroscience 2010; 166:771-84. [PMID: 20045448 PMCID: PMC2837118 DOI: 10.1016/j.neuroscience.2009.12.070] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 12/22/2009] [Accepted: 12/28/2009] [Indexed: 01/27/2023]
Abstract
Methamphetamine (Meth) is a highly addictive stimulant. Meth abuse is commonly associated with the practice of sexual risk behavior and increased prevalence of Human Immunodeficiency Virus and Meth users report heightened sexual desire, arousal, and sexual pleasure. The biological basis for this drug-sex nexus is unknown. The current study demonstrates that Meth administration in male rats activates neurons in brain regions of the mesolimbic system that are involved in the regulation of sexual behavior. Specifically, Meth and mating co-activate cells in the nucleus accumbens core and shell, basolateral amygdala, and anterior cingulate cortex. These findings illustrate that in contrast to current belief drugs of abuse can activate the same cells as a natural reinforcer, that is sexual behavior, and in turn may influence compulsive seeking of this natural reward.
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Affiliation(s)
- K S Frohmader
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada, N6A 5C1
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LaLumiere RT, Niehoff KE, Kalivas PW. The infralimbic cortex regulates the consolidation of extinction after cocaine self-administration. Learn Mem 2010; 17:168-75. [PMID: 20332188 DOI: 10.1101/lm.1576810] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The infralimbic cortex (IL) regulates the consolidation of extinction learning for fear conditioning. Whether the IL influences the consolidation of extinction learning for cocaine self-administration is unknown. To address this issue, male Sprague-Dawley rats underwent 2 wk of cocaine self-administration followed by extinction training. On the first 5 d of extinction, rats underwent brief (15- or 30-min) extinction sessions and received intra-IL microinjections immediately after each extinction session. On days 6-12 of extinction, rats underwent full-length (2-h) extinction sessions that were used to assess the retention of the extinction learning from the short sessions. IL inactivation via microinjections of the GABA agonists baclofen and muscimol (BM) immediately after the extinction sessions (days 1-5) impaired the retention of extinction learning. Control experiments demonstrated that this effect was not due to inactivation of the prelimbic cortex or due to effects of the drugs on the subsequent day's behavior. In contrast, post-training intra-IL microinjections of the allosteric AMPA receptor potentiator 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluorophenoxyacetamide (PEPA) enhanced retention of the extinction learning. As evidence suggests a role for the beta-adrenergic receptors in memory consolidation, other rats received microinjections of the beta(2)-adrenergic receptor agonist clenbuterol or antagonist ICI-118,551 (ICI). Post-training intra-IL administration of clenbuterol or pre-training administration of ICI enhanced or impaired, respectively, the retention of extinction learning. These data indicate that the IL, and specifically the glutamatergic and beta-adrenergic systems in the IL, regulates the consolidation of extinction of cocaine self-administration and that the IL can be manipulated to influence the retention of extinction.
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Affiliation(s)
- Ryan T LaLumiere
- Neurobiology of Addiction Research Center, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Bradberry CW. Cortical and sub-cortical effects in primate models of cocaine use: implications for addiction and the increased risk of psychiatric illness. Neurotox Res 2010; 19:235-42. [PMID: 20151242 DOI: 10.1007/s12640-010-9156-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 01/21/2010] [Accepted: 01/21/2010] [Indexed: 11/28/2022]
Abstract
Drug abuse is a serious risk factor for the incidence and severity of multiple psychiatric illnesses. Understanding the neurobiological consequences of repeated exposure to abused drugs can help to inform how those risks are manifested in terms of specific neurochemical mechanisms and brain networks. This review examines selective studies in non-human primates that employed a cocaine self-administration model. Neurochemical consequences of chronic exposure appear to differ from observations in rodent studies. Whereas chronic intermittent exposure in the rodent is usually associated with a dose-dependent increase in dopaminergic response to a cocaine challenge, in the rhesus monkey, high cumulative exposure was not observed to cause a sensitized dopamine response. These non-human primate observations are concordant with clinical findings in human users. The results of cue exposure studies on dopaminergic transmission are also reviewed. Direct microdialysis measurements indicate that there is not a sustained increase in dopamine associated with cocaine-linked cues. As an alternative to striatal dopaminergic mechanisms mediating cue effects, single unit studies in prefrontal cortex during self-administration in monkeys suggests the orbitofrontal and anterior cingulate cortex are strongly engaged by cocaine cues. Based on the strong clinical imaging literature on cortical and cognitive dysfunction associated with addiction, it is proposed that the strong engagement of cortical systems during repeated cocaine reinforcement results in maladaptive changes that contribute to the risks of drug use for exacerbation of other psychiatric disorders.
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Affiliation(s)
- Charles W Bradberry
- Department of Psychiatry, University of Pittsburgh, VA Pittsburgh Health Services, 3501 Fifth Ave, Rm 4078, Pittsburgh, PA 15261, USA.
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