201
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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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202
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Febo M, Felix-Ortiz AC, Johnson TR. Inactivation or inhibition of neuronal activity in the medial prefrontal cortex largely reduces pup retrieval and grouping in maternal rats. Brain Res 2010; 1325:77-88. [PMID: 20156425 DOI: 10.1016/j.brainres.2010.02.027] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/02/2010] [Accepted: 02/06/2010] [Indexed: 12/19/2022]
Abstract
Previous research suggests that the maternal medial prefrontal cortex (mPFC) may play a role in maternal care and that cocaine sensitization before pregnancy can affect neuronal activity within this region. The present work was carried out to test whether the mPFC does actually play a role in the expression of maternal behaviors in the rats and to understand what specific behaviors this cortical area may modulate. In the first experiment, tetrodotoxin (TTX) was used to chemically inactivate the mPFC during tests for maternal behavior latencies. Lactating rats were tested on postpartum days 7-9. The results of this first experiment indicate that there is a large effect of TTX-induced inactivation on retrieval behavior latencies. TTX nearly abolished the expression of maternal retrieval of pups without significantly impairing locomotor activity. In the second experiment, GABA-mediated inhibition was used to test maternal behavior latencies and durations of maternal and other behaviors in postpartum dams. In agreement with experiment 1, it was observed that dams capable of retrieving are rendered incapable by inhibition in the mPFC. GABA-mediated inhibition in the mPFC largely reduced retrieval without altering other indices of maternal care and non-specific behavior such as ambulation time, self-grooming, and inactivity. Moreover, in both experiments, dams were able to establish contact with pups within seconds. The overall results indicate that the mPFC may play an active role in modulating maternal care, particularly retrieval behavior. External factors that affect the function of the frontal cortical site may result in significant impairments in maternal goal-directed behavior as reported in our earlier work.
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Affiliation(s)
- Marcelo Febo
- Department of Psychology, Northeastern University, Boston, Massachusetts 02115, USA.
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203
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O'Connor EC, Parker D, Rollema H, Mead AN. The alpha4beta2 nicotinic acetylcholine-receptor partial agonist varenicline inhibits both nicotine self-administration following repeated dosing and reinstatement of nicotine seeking in rats. Psychopharmacology (Berl) 2010; 208:365-76. [PMID: 19967529 DOI: 10.1007/s00213-009-1739-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 11/16/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The alpha4beta2 nicotinic acetylcholine receptor partial agonist varenicline has greater efficacy than other pharmacotherapeutic aids for smoking cessation. This presents an opportunity to evaluate the predictive validity of rat models of nicotine taking and relapse. The aim of this study was to evaluate the ability of varenicline to attenuate nicotine self-administration and relapse, as modelled by the reinstatement model of nicotine relapse in rats. MATERIALS AND METHODS Rats were trained to respond for intravenous nicotine under a fixed ratio schedule of reinforcement. The effects of varenicline (0.3-3.0 mg/kg s.c.) on both nicotine and food self-administration and reinstatement of nicotine seeking were evaluated. RESULTS AND DISCUSSION Varenicline dose-dependently reduced nicotine self-administration and attenuated both nicotine prime and combined nicotine prime plus nicotine-paired cue-induced reinstatement. Varenicline had no effect on cue-induced reinstatement in the absence of a nicotine prime nor did it induce reinstatement when given alone. CONCLUSION The effects of varenicline on nicotine-induced reinstatement of drug-seeking are consistent with the demonstrated clinical efficacy of varenicline for smoking cessation.
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Affiliation(s)
- Eoin C O'Connor
- School of Psychology, University of Sussex, Falmer, Brighton BN19QG, UK
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204
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Myers KM, Carlezon WA. Extinction of drug- and withdrawal-paired cues in animal models: relevance to the treatment of addiction. Neurosci Biobehav Rev 2010; 35:285-302. [PMID: 20109490 DOI: 10.1016/j.neubiorev.2010.01.011] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 01/14/2010] [Accepted: 01/20/2010] [Indexed: 12/22/2022]
Abstract
Conditioned drug craving and withdrawal elicited by cues paired with drug use or acute withdrawal are among the many factors contributing to compulsive drug taking. Understanding how to stop these cues from having these effects is a major goal of addiction research. Extinction is a form of learning in which associations between cues and the events they predict are weakened by exposure to the cues in the absence of those events. Evidence from animal models suggests that conditioned responses to drug cues can be extinguished, although the degree to which this occurs in humans is controversial. Investigations into the neurobiological substrates of extinction of conditioned drug craving and withdrawal may facilitate the successful use of drug cue extinction within clinical contexts. While this work is still in the early stages, there are indications that extinction of drug- and withdrawal-paired cues shares neural mechanisms with extinction of conditioned fear. Using the fear extinction literature as a template, it is possible to organize the observations on drug cue extinction into a cohesive framework.
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Affiliation(s)
- Karyn M Myers
- Behavioral Genetics Laboratory, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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205
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Tye KM, Cone JJ, Schairer WW, Janak PH. Amygdala neural encoding of the absence of reward during extinction. J Neurosci 2010; 30:116-25. [PMID: 20053894 PMCID: PMC6632518 DOI: 10.1523/jneurosci.4240-09.2010] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/28/2009] [Accepted: 11/10/2009] [Indexed: 11/21/2022] Open
Abstract
The basolateral amygdala complex (BLA) has been identified as a critical structure mediating fear extinction. However, little is known about the functional role of neurons in the BLA during the extinction of a reward-seeking behavior. Here, we used in vivo electrophysiology procedures in freely moving rats to investigate whether and how the BLA encodes the extinction of responding for sucrose. We recorded 330 neurons from 15 rats during a within-session extinction procedure following training under a partial reinforcement schedule. Several distinct populations of neurons change their response profiles as the rat ceases to respond for the omitted reinforcer. One population of neurons (32 of 330; 10%), which responded selectively to port entries in the presence, but not the absence, of sucrose during maintenance, subsequently developed a phasic response to port entries in the absence of sucrose during the extinction epoch only. The relative proportion of these "reinforcement-omission" neurons per rat was correlated with response intensity during extinction, as well as with the rate at which reward-seeking behavior was extinguished. A subpopulation of neurons responded with opposite phasic changes in activity to port entries in the presence of sucrose and to port entries during extinction, demonstrating that BLA neurons may contribute to the detection of value differences between expected and actual outcomes. Another population of neurons (47 of 330; 14%) responded to the empty port only during extinction. Because BLA neural correlates reflect the omission of an expected reward, these neuronal populations may contribute to the expression of behavior during extinction.
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Affiliation(s)
- Kay M Tye
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, California 94608, USA.
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206
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Buffalari DM, See RE. Amygdala mechanisms of Pavlovian psychostimulant conditioning and relapse. Curr Top Behav Neurosci 2010; 3:73-99. [PMID: 21161750 DOI: 10.1007/7854_2009_18] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Psychostimulant addiction often consists of periods of sustained drug abstinence disrupted by periods of relapse and renewed heavy drug use. Prevention of relapse remains the greatest challenge to the successful treatment of drug addiction. Drug-associated cues are a primary trigger for relapse, as they can elicit intense craving for the drug. These cues become associated with the drug reward through Pavlovian learning processes that develop over multiple drug-cue pairings. The amygdala (AMY) is critical for such drug-related learning. Intrinsic and extrinsic circuitry position the AMY to integrate cue and drug-related information and influence drug-seeking and drug-taking behaviors. Animal models of conditioned drug reward, drug use, and relapse have confirmed the necessary role of the AMY for drug conditioned cues to control motivated behavior. Neurons within the AMY are responsive to the primary effects of psychostimulants, and more critically, they also respond to the presentation of drug-associated cues. The mechanisms by which conditioned cues come to influence drug-seeking behavior likely involve long-term plasticity and neuroadaptations within the AMY. A greater understanding of the associative learning mechanisms that depend upon the AMY and related limbic and cortical structures, and the process by which drug cues come to gain control over behavior that maintains the addictive state, will facilitate the development of more effective addiction treatments.
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Affiliation(s)
- Deanne M Buffalari
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA.
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207
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Lasseter HC, Xie X, Ramirez DR, Fuchs RA. Prefrontal cortical regulation of drug seeking in animal models of drug relapse. Curr Top Behav Neurosci 2010; 3:101-17. [PMID: 21161751 PMCID: PMC4381832 DOI: 10.1007/7854_2009_19] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Prefrontal cortical dysfunction is thought to underlie maladaptive behaviors displayed by chronic drug users, most notably the high propensity for relapse that severely impedes successful treatment of drug addiction. In animal models of drug relapse, exposure to drug-associated stimuli, small amounts of drug, and acute stressors powerfully reinstate drug seeking by critically engaging the prefrontal cortex, with the anterior cingulate, prelimbic, infralimbic, and orbitofrontal subregions making distinct contributions to drug seeking. Hence, from an addiction treatment perspective, it is necessary to fully explicate the involvement of the prefrontal cortex in drug relapse.
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Affiliation(s)
- Heather C Lasseter
- Department of Psychology, University of North Carolina, Chapel Hill, NC 27599-3270, USA
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208
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Lovaglio J, Lin JY, Roman C, Reilly S. Basolateral amygdala and morphine-induced taste avoidance in the rat. Physiol Behav 2009; 99:419-23. [PMID: 20015452 DOI: 10.1016/j.physbeh.2009.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 11/02/2009] [Accepted: 12/07/2009] [Indexed: 11/26/2022]
Abstract
The present experiment examined the influence of excitotoxic lesions of the basolateral amygdala (BLA) on morphine-induced saccharin avoidance. Neurologically intact subjects rapidly learned to avoid drinking the taste conditioned stimulus (CS), an effect that was sustained throughout the experiment. Although the BLA-lesioned (BLAX) rats showed CS avoidance over the first few trials, the effect was not sustained. That is, by the end of the experiment, the BLAX rats were drinking the same amount of saccharin after seven saccharin-morphine trials as they did on the first trial (i.e., prior to the morphine injections). Potential interpretations of the results are discussed including a disruption of the mechanism that governs drug-induced taste avoidance in normal subjects and the more rapid development of tolerance in BLAX rats.
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Affiliation(s)
- Jamie Lovaglio
- University of Illinois at Chicago, Biologic Resources Laboratory, 1840 West Taylor St, Chicago, IL 60612, USA
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209
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Kufahl PR, Zavala AR, Singh A, Thiel KJ, Dickey ED, Joyce JN, Neisewander JL. c-Fos expression associated with reinstatement of cocaine-seeking behavior by response-contingent conditioned cues. Synapse 2009; 63:823-35. [PMID: 19533625 DOI: 10.1002/syn.20666] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The capability of cocaine cues to generate craving in cocaine-dependent humans, even after extended abstinence, is modeled in rats using cue reinstatement of extinguished cocaine-seeking behavior. We investigated neural activity associated with incentive motivational effects of cocaine cues using c-fos mRNA and Fos protein expression as markers. Unlike preceding studies, we used response-contingent presentation of discrete cues to elicit cocaine seeking. Rats were first trained to press a lever, resulting in cocaine reinforcement and light and tone cues. Rats then underwent extinction training, during which lever presses decreased. On the test day, rats either received response-contingent cocaine cues or received no cues. The cues reinstated extinguished cocaine-seeking behavior on the test day. In general, cue-elicited c-fos mRNA and protein expression were similar and both were enhanced in the prefrontal cortex, ventral tegmental area (VTA), dorsal striatum, and nucleus accumbens. Cues elicited more widespread Fos protein expression relative to our previous research in which cues were presented noncontingently without prior extinction training, including increases in the VTA, substantia nigra, ventral subiculum, and lateral entorhinal cortex. We also observed a correlation between cocaine-seeking behavior and Fos in the agranular insula (AgI) and basolateral amygdala (BLA). The findings suggest that connections between BLA and AgI play a role in cue-elicited incentive motivation for cocaine and that reinstatement of cocaine seeking by response-contingent cues activates a similar corticolimbic circuit as that observed with other modes of cue presentation; however, activation of midbrain and ventral hippocampal regions may be unique to reinstatement by response-contingent cues.
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Affiliation(s)
- Peter R Kufahl
- Department of Psychology, Arizona State University, PO Box 871104, Tempe, Arizona 85287-1104, USA
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210
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Orbitofrontal and anterior cingulate cortex neurons selectively process cocaine-associated environmental cues in the rhesus monkey. J Neurosci 2009; 29:11619-27. [PMID: 19759309 DOI: 10.1523/jneurosci.3206-09.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Encounters with stimuli associated with drug use are believed to contribute to relapse. To probe the neurobiology of environmentally triggered drug use, we have conducted single-unit recordings in rhesus monkeys during presentation of two distinct types of drug paired cues that differentially support drug-seeking. The animals were highly conditioned to these cues via exposure during self-administration procedures conducted over a 4 year period. The cues studied were a discriminative cue that signaled response-contingent availability of cocaine, and a discrete cue that was temporally paired with the cocaine infusion (0.1 or 0.5 mg/kg). Two cortical regions consistently activated by cocaine-associated cues in human imaging studies are the orbitofrontal (OFC) and anterior cingulate cortex (ACC), though little is known about cortical neuronal activity responses to drug cues. We simultaneously recorded single-unit activity in OFC and ACC as well as in dorsal striatum in rhesus monkeys during cocaine self-administration. Dorsal striatal neurons were less engaged by drug cues than cortical regions. Between OFC and ACC, distinct functionality was apparent in neuronal responses. OFC neurons preferentially responded to the discriminative cue, consistent with a role in cue-induced drug-seeking. In contrast, the ACC did not respond more to the discriminative cue than to the discrete cue. Also distinct from the OFC, ACC showed sustained firing throughout the 18 s duration of the discrete cue. This pattern of sustained activation in ACC is consistent with a role in reward expectation and/or in mediating behavioral effects of discrete cues paired with drug infusions.
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211
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Lasseter HC, Ramirez DR, Xie X, Fuchs RA. Involvement of the lateral orbitofrontal cortex in drug context-induced reinstatement of cocaine-seeking behavior in rats. Eur J Neurosci 2009; 30:1370-81. [PMID: 19769591 PMCID: PMC2758926 DOI: 10.1111/j.1460-9568.2009.06906.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Orbitofrontal cortex (OFC) damage produces impaired decision-making, impulsivity and perseveration and potentially contributes to compulsive drug seeking in cocaine users. To further explore this phenomenon, we assessed the role of the lateral OFC (lOFC) in drug context-induced cocaine-seeking behavior in the reinstatement model of drug relapse. Rats were trained to lever press for intravenous cocaine infusions in a distinct environmental context (cocaine-paired context) followed by extinction training in a different context (extinction-paired context). Reinstatement of cocaine seeking (non-reinforced lever presses) was assessed in the cocaine context in the absence of response-contingent stimuli. In Experiment 1, we evaluated whether acute inhibition of lOFC output alters context-induced cocaine-seeking behavior by infusing the GABA(B + A) agonists (baclofen + muscimol) or vehicle into the lOFC immediately before exposure to the cocaine-paired context. In Experiments 2 and 3, we assessed how prolonged loss of lOFC output affects drug context-induced cocaine seeking by administering bilateral N-methyl-d-aspartic acid or sham lesions of the lOFC either before or after self-administration and extinction training. Remarkably, IOFC functional inactivation attenuated, post-training lesions failed to alter and pre-training lesions potentiated drug context-induced cocaine seeking without altering responding in the extinction context. These results suggest that neural activity in the lOFC promotes context-induced cocaine-seeking behavior. However, prolonged loss of lOFC output enhances the motivational salience of cocaine-paired contextual stimuli probably by eliciting compensatory neuroadaptations, with the effects of post-training lOFC lesions reflecting an intermediate state of compensatory neuroplasticity. Overall, these findings support the idea that OFC dysfunction may promote cue reactivity and enhance relapse propensity in cocaine users.
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Affiliation(s)
| | - Donna R. Ramirez
- Department of Psychology, University of North Carolina, Chapel Hill, NC, US
| | - Xiaohu Xie
- Department of Psychology, University of North Carolina, Chapel Hill, NC, US
| | - Rita A. Fuchs
- Department of Psychology, University of North Carolina, Chapel Hill, NC, US
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212
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Nair SG, Adams-Deutsch T, Epstein DH, Shaham Y. The neuropharmacology of relapse to food seeking: methodology, main findings, and comparison with relapse to drug seeking. Prog Neurobiol 2009; 89:18-45. [PMID: 19497349 PMCID: PMC2745723 DOI: 10.1016/j.pneurobio.2009.05.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 04/09/2009] [Accepted: 05/26/2009] [Indexed: 12/15/2022]
Abstract
Relapse to old, unhealthy eating habits is a major problem in human dietary treatments. The mechanisms underlying this relapse are unknown. Surprisingly, until recently this clinical problem has not been systematically studied in animal models. Here, we review results from recent studies in which a reinstatement model (commonly used to study relapse to abused drugs) was employed to characterize the effect of pharmacological agents on relapse to food seeking induced by either food priming (non-contingent exposure to small amounts of food), cues previously associated with food, or injections of the pharmacological stressor yohimbine. We also address methodological issues related to the use of the reinstatement model to study relapse to food seeking, similarities and differences in mechanisms underlying reinstatement of food seeking versus drug seeking, and the degree to which the reinstatement procedure provides a suitable model for studying relapse in humans. We conclude by discussing implications for medication development and future research. We offer three tentative conclusions: (1)The neuronal mechanisms of food-priming- and cue-induced reinstatement are likely different from those of reinstatement induced by the pharmacological stressor yohimbine. (2)The neuronal mechanisms of reinstatement of food seeking are possibly different from those of ongoing food-reinforced operant responding. (3)The neuronal mechanisms underlying reinstatement of food seeking overlap to some degree with those of reinstatement of drug seeking.
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Affiliation(s)
- Sunila G. Nair
- Behavioral Neuroscience Branch, NIDA/IRP, 251 Bayview Boulevard, Baltimore, MD, 21224
| | - Tristan Adams-Deutsch
- Behavioral Neuroscience Branch, NIDA/IRP, 251 Bayview Boulevard, Baltimore, MD, 21224
| | - David H. Epstein
- Clinical Pharmacology and Therapeutics Research Branch, NIDA/IRP, 251 Bayview Boulevard, Baltimore, MD, 21224
| | - Yavin Shaham
- Behavioral Neuroscience Branch, NIDA/IRP, 251 Bayview Boulevard, Baltimore, MD, 21224
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213
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Mashhoon Y, Tsikitas LA, Kantak KM. Dissociable effects of cocaine-seeking behavior following D1 receptor activation and blockade within the caudal and rostral basolateral amygdala in rats. Eur J Neurosci 2009; 29:1641-53. [PMID: 19419427 DOI: 10.1111/j.1460-9568.2009.06705.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Research with dopamine D(1) receptor antagonists or neuronal inactivating agents suggests that there is dissociable regulation of cocaine-seeking behavior by the rostral and caudal basolateral amygdala. In the present study, discrete infusions of the D(1) receptor agonist SKF 81297 (0.0-0.8 microg per side) were compared with those of the D(1) receptor antagonist SCH 23390 (0.0-2.0 microg per side) to demonstrate directly the importance of D(1) receptor mechanisms within the rostral and caudal basolateral amygdala for their functional heterogeneity in regulating cocaine-seeking behavior. Under a second-order schedule, cocaine-seeking behavior was studied during maintenance (cocaine and cocaine cues present) and reinstatement (only cocaine cues present). Food-maintained responding was used to examine the specificity of maximal behaviorally effective doses of SKF 81297 and SCH 23390. The results demonstrated that the D(1) agonist (0.4 or 0.8 microg) increased and the D(1) antagonist (1.0 microg) decreased cocaine-seeking behavior during maintenance when infused into the caudal but not the rostral basolateral amygdala. Cocaine intake was not affected by the agonist, and was decreased by the antagonist. During reinstatement, the D(1) agonist (0.4 microg) increased and the D(1) antagonist (1.0 microg) decreased cocaine-seeking behavior when infused into the rostral but not the caudal basolateral amygdala. In tests for behavioral specificity, the above effective doses of SKF 81297 and SCH 23390 used in self-administration experiments did not alter food-maintained responding. However, the 2.0-microg dose of SCH 23390 suppressed drug-maintained and food-maintained responding after infusion into both subregions. Collectively, these findings indicate dissociable sensitivity to D(1) receptor ligands within the caudal and rostral basolateral amygdala for altering cocaine-seeking behavior under different conditions that model phases of addiction.
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Affiliation(s)
- Yasmin Mashhoon
- Laboratory of Behavioral Neuroscience, Department of Psychology, Boston University, Boston, MA, USA
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214
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Smith RJ, Tahsili-Fahadan P, Aston-Jones G. Orexin/hypocretin is necessary for context-driven cocaine-seeking. Neuropharmacology 2009; 58:179-84. [PMID: 19591850 DOI: 10.1016/j.neuropharm.2009.06.042] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 06/29/2009] [Indexed: 01/22/2023]
Abstract
Orexin/hypocretin signaling at the orexin 1 receptor (OX(1)R) has recently been implicated in addiction and relapse. We examined the role of the orexin system in cocaine-seeking elicited by a drug-associated context following abstinence or extinction from chronic cocaine self-administration. Male Sprague-Dawley rats self-administered cocaine in 2-h sessions for 10 days, followed by extinction training or extended abstinence in the home cage. The OX(1)R antagonist SB-334867 (SB; 10, 20, or 30 mg/kg, i.p.) was administered prior to re-exposure to the cocaine self-administration environment. We found that pretreatment with SB significantly attenuated cocaine-seeking when rats were placed back into the self-administration environment following either 1 day or 2 weeks of abstinence (no extinction), or following extinction of cocaine-seeking in an alternative environment (distinct from the training environment). These results indicate that orexin signaling at OX(1)R is critical for conditioned cocaine-seeking elicited by a drug-associated context, following either extinction or abstinence.
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Affiliation(s)
- Rachel J Smith
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Ave., 403 Basic Science Bldg., Charleston, SC 29425-5100, USA
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215
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Abstract
Addiction is associated with neuroplasticity in the corticostriatal brain circuitry that is important for guiding adaptive behaviour. The hierarchy of corticostriatal information processing that normally permits the prefrontal cortex to regulate reinforcement-seeking behaviours is impaired by chronic drug use. A failure of the prefrontal cortex to control drug-seeking behaviours can be linked to an enduring imbalance between synaptic and non-synaptic glutamate, termed glutamate homeostasis. The imbalance in glutamate homeostasis engenders changes in neuroplasticity that impair communication between the prefrontal cortex and the nucleus accumbens. Some of these pathological changes are amenable to new glutamate- and neuroplasticity-based pharmacotherapies for treating addiction.
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216
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Guo Y, Wang HL, Xiang XH, Zhao Y. The role of glutamate and its receptors in mesocorticolimbic dopaminergic regions in opioid addiction. Neurosci Biobehav Rev 2009; 33:864-73. [DOI: 10.1016/j.neubiorev.2009.02.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 02/10/2009] [Accepted: 02/19/2009] [Indexed: 11/28/2022]
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217
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Brown RM, Lawrence AJ. Neurochemistry underlying relapse to opiate seeking behaviour. Neurochem Res 2009; 34:1876-87. [PMID: 19418222 DOI: 10.1007/s11064-009-9967-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 03/27/2009] [Indexed: 11/24/2022]
Abstract
Relapse is a major clinical problem and remains a major challenge in the treatment of addictions. A goal of current research is to gain a greater understanding of the neurochemistry underlying relapse to opiate use. Factors which trigger relapse in humans such as stress, exposure to opiates and/or drug-associated cues, can also trigger opiate-seeking in animals. This review will overview preclinical studies relating to the neurochemistry of opiate-seeking with a focus on studies published from 2005 to present.
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Affiliation(s)
- Robyn M Brown
- Howard Florey Institute, University of Melbourne, Parkville, VIC 3010, Australia
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218
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Peters J, Kalivas PW, Quirk GJ. Extinction circuits for fear and addiction overlap in prefrontal cortex. Learn Mem 2009; 16:279-88. [PMID: 19380710 DOI: 10.1101/lm.1041309] [Citation(s) in RCA: 567] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Extinction is a form of inhibitory learning that suppresses a previously conditioned response. Both fear and drug seeking are conditioned responses that can lead to maladaptive behavior when expressed inappropriately, manifesting as anxiety disorders and addiction, respectively. Recent evidence indicates that the medial prefrontal cortex (mPFC) is critical for the extinction of both fear and drug-seeking behaviors. Moreover, a dorsal-ventral distinction is apparent within the mPFC, such that the prelimbic (PL-mPFC) cortex drives the expression of fear and drug seeking, whereas the infralimbic (IL-mPFC) cortex suppresses these behaviors after extinction. For conditioned fear, the dorsal-ventral dichotomy is accomplished via divergent projections to different subregions of the amygdala, whereas for drug seeking, it is accomplished via divergent projections to the subregions of the nucleus accumbens. Given that the mPFC represents a common node in the extinction circuit for these behaviors, treatments that target this region may help alleviate symptoms of both anxiety and addictive disorders by enhancing extinction memory.
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Affiliation(s)
- Jamie Peters
- Department of Psychiatry, University of Puerto Rico School of Medicine, San Juan, Puerto Rico 00936.
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219
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Prefrontal cortex AMPA receptor plasticity is crucial for cue-induced relapse to heroin-seeking. Nat Neurosci 2009; 11:1053-8. [PMID: 19160503 DOI: 10.1038/nn.2165] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Associative learning processes have an important role in the initiation and persistence of heroin-seeking. Here we show in a rat self-administration model that reexposure to cues previously associated with heroin results in downregulation of AMPA receptor subunit GluR2 and concomitant upregulation of clathrin-coat assembly protein AP2ml in synaptic membranes of the medial prefrontal cortex (mPFC). Reduced AMPA receptor expression in synaptic membranes was associated with a decreased AMPA/NMDA current ratio and increased rectification index in mPFC pyramidal neurons. Systemic or ventral (but not dorsal) mPFC injections of a peptide inhibiting GluR2 endocytosis attenuated both the rectification index and cue-induced relapse to heroin-seeking, without affecting sucrose-seeking. We conclude that GluR2 receptor endocytosis and the resulting synaptic depression in ventral mPFC are crucial for cue-induced relapse to heroin-seeking. As reexposure to conditioned stimuli is a major cause for heroin relapse, inhibition of GluR2 endocytosis may provide a new target for the treatment of heroin addiction.
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220
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Dopamine D1 receptor antagonism in the prelimbic cortex blocks the reinstatement of heroin-seeking in an animal model of relapse. Int J Neuropsychopharmacol 2009; 12:431-6. [PMID: 19236732 PMCID: PMC2747000 DOI: 10.1017/s1461145709000054] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
In brain regions that have been implicated in the reinstatement of drug-seeking, the prelimbic cortex has emerged as a critical regulator of relapse behaviours. Here, the effects of prelimbic cortex dopamine (DA) D(1) receptor antagonism on drug-seeking produced by heroin-paired cues, or by a single priming dose of heroin are examined. Rats lever-pressed daily for i.v. heroin discretely paired with a conditioned stimulus during 3-h sessions for a period of 2 wk, followed by extinction and reinstatement of drug-seeking by previously heroin-paired cues (tone+light) or heroin-priming injections (0.25 mg/kg) in the absence of heroin reinforcement. Intracranial infusion of the DA D(1) receptor antagonist, SCH 23390 (0.02-2.0 microg/side), into the prelimbic cortex potently and dose dependently attenuated heroin-seeking in response to either cue presentations or a priming dose of heroin. These results suggest that DA D1 receptors regulate prefrontal cortex pathways necessary for the reinstatement of heroin-seeking.
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221
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Nic Dhonnchadha B, Fox R, Stutz S, Rice KC, Cunningham K. Blockade of the serotonin 5-HT2A receptor suppresses cue-evoked reinstatement of cocaine-seeking behavior in a rat self-administration model. Behav Neurosci 2009; 123:382-96. [PMID: 19331461 PMCID: PMC3830454 DOI: 10.1037/a0014592] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The serotonin 5-HT2A receptor (5-HT-sub(2A)R) may play a role in reinstatement of drug-seeking. This study investigated the ability of a selective 5-HT-sub(2A)R antagonist to suppress reinstatement evoked by exposure to cues conditioned to cocaine self-administration. Cocaine self-administration (0.75 mg/kg/0.1 mL/6 s infusion; FR 4) was trained in naïve, free-fed rats to allow interpretation of results independent from changes related to food deprivation stress. Pretreatment with the selective 5-HT-sub(2A)R antagonist M100907 (volinanserin) failed to reduce rates of operant responding for cocaine infusions. On the other hand, M100907 (0.001-0.8 mg/kg ip) significantly suppressed the cue-induced reinstatement of cocaine-seeking behavior following extinction; effective M100907 doses did not alter operant responding for cues previously associated with sucrose self-administration. Importantly, a greater magnitude of active lever presses on the initial extinction session (high extinction responders) predicted the maximal susceptibility to M100907-induced suppression of cue-evoked reinstatement. The findings indicate that blockade of the 5-HT-sub(2A)R attenuates the incentive-motivational effects of cocaine-paired cues, particularly in high extinction responders, and suggests that M100907 may afford a therapeutic advance in suppression of cue-evoked craving and/or relapse.
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Affiliation(s)
- B.Á. Nic Dhonnchadha
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - R.G. Fox
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - S.J. Stutz
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - K. C. Rice
- Chemical Biology Research Branch, Drug Design and Synthesis Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - K.A. Cunningham
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
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222
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Berglind WJ, Whitfield TW, LaLumiere RT, Kalivas PW, McGinty JF. A single intra-PFC infusion of BDNF prevents cocaine-induced alterations in extracellular glutamate within the nucleus accumbens. J Neurosci 2009; 29:3715-9. [PMID: 19321768 PMCID: PMC2683065 DOI: 10.1523/jneurosci.5457-08.2009] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/23/2009] [Accepted: 02/10/2009] [Indexed: 11/21/2022] Open
Abstract
The glutamatergic pathway arising in the dorsomedial prefrontal cortex (dmPFC) and projecting to the nucleus accumbens (NAc) core is a critical component of the reward circuitry that underlies reinstatement to cocaine-seeking behavior. Brain-derived neurotrophic factor (BDNF) is expressed by and modulates PFC-NAc neurons. BDNF infusion into the dmPFC attenuates reinstatement to cocaine-seeking behavior, as well as some cocaine-induced molecular adaptations within the NAc. In the present study, it is demonstrated that a single intra-dmPFC infusion of BDNF prevents cocaine self-administration-induced reduction in basal extracellular glutamate, as well as cocaine prime-induced increases in extracellular glutamate levels within the NAc. These data suggest that intra-PFC BDNF attenuates reinstatement to cocaine-seeking behavior by normalizing cocaine-induced neuroadaptations that alter glutamate neurotransmission within the NAc.
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Affiliation(s)
- William J. Berglind
- Department of Neurosciences and Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Timothy W. Whitfield
- Department of Neurosciences and Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ryan T. LaLumiere
- Department of Neurosciences and Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Peter W. Kalivas
- Department of Neurosciences and Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jacqueline F. McGinty
- Department of Neurosciences and Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
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223
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Shi J, Liu TT, Wang X, Epstein DH, Zhao LY, Zhang XL, Lu L. Tetrodotoxin reduces cue-induced drug craving and anxiety in abstinent heroin addicts. Pharmacol Biochem Behav 2009; 92:603-7. [PMID: 19268686 DOI: 10.1016/j.pbb.2009.02.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 02/14/2009] [Accepted: 02/24/2009] [Indexed: 11/17/2022]
Abstract
BACKGROUND Tetrodotoxin (TTX) is a neurotoxin found in puffer fish and other marine animals. New clinical studies suggest that low-dose TTX can safely relieve severe, treatment-resistant cancer pain. The therapeutic potential of TTX in addiction is supported by studies in laboratory animals. The purpose of this double-blind, placebo-controlled study was to assess the effect of a single intramuscular dose of TTX on cue-induced craving and anxiety in abstinent heroin addicts. METHODS Forty-five abstinent heroin addicts were randomly assigned to three treatment groups: placebo, 5 microg TTX, or 10 microg TTX. Participants were exposed to a neutral video or a heroin-related video. Craving, anxiety, blood pressure, and heart rate were measured pre- and post-exposure. RESULTS Heroin-related cues increased both craving and anxiety and had no effect on blood pressure and heart rate. A single dose of TTX dose-dependently attenuated the increases in craving and anxiety while having no effect on blood pressure or heart rate. CONCLUSION The results suggest that low-dose TTX is acutely effective in reducing cue-induced increases in heroin craving and associated anxiety.
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Affiliation(s)
- Jie Shi
- National Institute on Drug Dependence, Peking University, Beijing 100083, China
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224
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Martin-Fardon R, Baptista MAS, Dayas CV, Weiss F. Dissociation of the effects of MTEP [3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]piperidine] on conditioned reinstatement and reinforcement: comparison between cocaine and a conventional reinforcer. J Pharmacol Exp Ther 2009; 329:1084-90. [PMID: 19258516 DOI: 10.1124/jpet.109.151357] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To advance understanding of the potential of metabotropic glutamate receptor (mGluR) 5 as treatment targets for cocaine addiction, the effects of MTEP [3-[(2-methyl-1,3-thiazol-4-yl) ethynyl]piperidine] (a selective mGluR5 antagonist) on conditioned reinstatement of cocaine seeking were examined. To test whether modification of conditioned reinstatement by MTEP is selective for drug-directed behavior or reflects general actions on motivated behavior, effects of MTEP on reinstatement induced by a stimulus conditioned to palatable conventional reward, sweetened condensed milk (SCM), were also evaluated. Previous data suggest that mGluR manipulations preferentially interfere with conditioned reinstatement compared with cocaine self-administration. Therefore, the effects of MTEP on cocaine self-administration were compared with MTEP's effects on SCM-reinforced behavior using the same cocaine doses and SCM concentrations employed for establishing conditioned reinstatement. Male Wistar rats were trained to associate a discriminative stimulus (S(D)) with response-contingent availability of cocaine or SCM and subjected to reinstatement tests after extinction of cocaine or SCM-reinforced behavior. MTEP (0.3-10 mg/kg i.p.) dose-dependently attenuated the response-reinstating effects of both the cocaine S(D) and SCM S(D). MTEP also decreased cocaine self-administration without a clear graded dose-response profile and did not modify SCM-reinforced responding. The findings implicate mGluR5-regulated glutamate transmission in appetitive behavior controlled by reward-related stimuli but without selectivity for cocaine seeking. However, the data suggest a differential role for mGluR5 in the acute reinforcing effects of cocaine versus conventional reward. These observations identify mGluR5 as potential treatment targets for cocaine relapse prevention, although the profile of action of mGluR5 antagonists remains to be more closely examined for potential anhedonic effects.
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Affiliation(s)
- R Martin-Fardon
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, SP30-2120, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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225
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The medial prefrontal cortex regulates the differential expression of morphine-conditioned place preference following a single exposure to controllable or uncontrollable stress. Neuropsychopharmacology 2009; 34:834-43. [PMID: 18368036 PMCID: PMC2653625 DOI: 10.1038/npp.2008.34] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Experiential factors, such as stress, are major determinants of vulnerability to drug addiction and relapse. The behavioral controllability of the stressor is a major determinant of how exposure to a stressor impacts addictive processes. Recent evidence suggests that controllable stressors, such as escapable shock (ES), activate ventral regions of the medial prefrontal cortex (mPFCv), whereas physically identical, but uncontrollable stress (inescapable shock, IS) does not. This activation is critical to the blunting effect that control has on neurochemical and behavioral sequelae of stress. Our laboratory has previously shown that IS, but not ES, potentiates morphine-conditioned place preference (CPP). However, the role of the mPFCv in this phenomenon is unknown. The present experiments investigated the role of the mPFCv during ES and IS in determining the effects of the stressor on subsequent morphine-CPP. Intra-mPFCv microinjection of the GABA(A) agonist muscimol 1 h before ES led ES to potentiate morphine-CPP, as does IS. Conversely, the potentiation of morphine-CPP normally observed in IS rats was blocked by intra-mPFCv microinjection of the GABA(A) antagonist picrotoxin 1 h before IS. These results suggest that during stress, activation of the mPFCv prevents subsequent potentiation of morphine-CPP, whereas inactivation of the mPFCv during stress does not. Thus, activation of the mPFCv during a stress experience is both necessary and sufficient to block the impact of stress on morphine-CPP, and control over stress blunts stress-induced potentiation of morphine effects by activating the mPFCv.
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226
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Szczytkowski JL, Lysle DT. Conditioned effects of heroin on proinflammatory mediators require the basolateral amygdala. Eur J Neurosci 2009; 28:1867-76. [PMID: 18973600 DOI: 10.1111/j.1460-9568.2008.06472.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heroin administration alters the induction of nitric oxide, a molecule known to play a critical role in immune function. Previous research has shown that these alterations can be conditioned to environmental stimuli that have been associated with drug administration. Little is known about the brain areas that mediate these effects; however, the basolateral amygdala (BLA) has been implicated in the formation of stimulus-reward associations within models of drug abuse. The present study sought to determine whether inactivation of the BLA would alter heroin's conditioned effects on the expression of inducible nitric oxide synthase (iNOS) and the proinflammatory cytokines TNF-alpha and IL-1beta in the rat. The conditioning procedure involved repeated pairing of heroin with placement into a standard conditioning chamber. To test the conditioned response, animals were returned to the previously drug-paired environment 6 days after the final conditioning session. Prior to testing, animals received intra-BLA microinfusions of a mixture of the GABA agonists muscimol and baclofen. Following removal from the chambers on test day, all animals received subcutaneous lipopolysaccharide to induce systemic expression of iNOS, TNF-alpha and IL-1beta. Analyses using real-time RT-PCR indicated that inactivation of the BLA blocked the suppressive effect of heroin-associated environmental stimuli on iNOS induction and on the expression of the proinflammatory cytokines TNF-alpha and IL-1beta in spleen and liver tissue. This study is important because it is the first to demonstrate that heroin's conditioned effects on proinflammatory mediators require the BLA. These findings may have significant implications for the treatment of heroin users.
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Affiliation(s)
- Jennifer L Szczytkowski
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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227
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Fuchs RA, Lasseter HC, Ramirez DR, Xie X. Relapse to drug seeking following prolonged abstinence: the role of environmental stimuli. ACTA ACUST UNITED AC 2008; 5:251-258. [PMID: 20016771 DOI: 10.1016/j.ddmod.2009.03.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Successful treatment of drug addiction must involve relapse prevention informed by our understanding of the neurobiological bases of drug relapse. In humans, exposure to drug-associated environmental stimuli can elicit drug craving and relapse. Because exposure to drug-paired stimuli similarly induces drug-seeking behavior in laboratory animals, several animal models of drug relapse have been developed. Here, we review animal models of cue-induced drug relapse and critically evaluate their validity and utility in addressing human relapse behaviors.
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Affiliation(s)
- R A Fuchs
- Department of Psychology, University of North Carolina, NC 27599-3270
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228
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Nucleus accumbens shell and core involvement in drug context-induced reinstatement of cocaine seeking in rats. Psychopharmacology (Berl) 2008; 200:545-56. [PMID: 18597075 PMCID: PMC2613506 DOI: 10.1007/s00213-008-1234-4] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 06/09/2008] [Indexed: 12/28/2022]
Abstract
RATIONALE The nucleus accumbens (NAC) is a functionally heterogeneous brain region with respect to its involvement in cocaine-seeking behavior triggered by drug-associated explicit conditioned stimuli, foot shock stress, or cocaine itself in the reinstatement animal model of drug relapse. However, it is not known whether the NAC or its subregions are critical for reinstatement of cocaine-seeking behavior produced by re-exposure to a previously cocaine-paired environmental context. OBJECTIVES The present study was designed to evaluate potentially unique contributions of the NAC core and shell to this behavior. MATERIALS AND METHODS Rats were trained to lever press for unsignaled cocaine infusions (0.15 mg/infusion, intravenous) in a distinct environmental context. Lever responding was then extinguished in a distinctly different environmental context (extinction context) during a minimum of seven daily training sessions. Subsequently, using a counterbalanced testing design, rats were re-exposed to the cocaine-paired context or the extinction context while cocaine seeking (i.e., responding on the previously cocaine-reinforced lever) was assessed. Before each test session, neural activity was inhibited selectively in the NAC core or shell using bilateral microinfusions of the gamma-aminobutyric acid agonists, baclofen and muscimol (0/0 or 1.0/0.1 mM; 0.3 microl per hemisphere). RESULTS Neural inactivation of the NAC shell or core attenuated responding in the cocaine context and, interestingly, increased responding in the extinction context. Control experiments indicated no effects on general activity or food-reinforced instrumental behavior. CONCLUSIONS These findings suggest that both subregions of the NAC may promote context-induced reinstatement by facilitating drug context-induced motivation for cocaine and context discrimination.
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229
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Differential cocaine-induced modulation of glutamate and dopamine transporters after contingent and non-contingent administration. Neuropharmacology 2008; 55:771-9. [DOI: 10.1016/j.neuropharm.2008.06.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 11/16/2022]
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230
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Alvarez-Jaimes L, Polis I, Parsons LH. Attenuation of cue-induced heroin-seeking behavior by cannabinoid CB1 antagonist infusions into the nucleus accumbens core and prefrontal cortex, but not basolateral amygdala. Neuropsychopharmacology 2008; 33:2483-93. [PMID: 18059440 DOI: 10.1038/sj.npp.1301630] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As with other drugs of abuse, heroin use is characterized by a high incidence of relapse following detoxification that can be triggered by exposure to conditioned stimuli previously associated with drug availability. Recent findings suggest that cannabinoid CB(1) receptors modulate the motivational properties of heroin-conditioned stimuli that induce relapse behavior. However, the neural substrates through which CB(1) receptors modulate cue-induced heroin seeking have not been elucidated. In this study, we evaluated alterations in cue-induced reinstatement of heroin-seeking behavior produced by infusions of the CB(1) receptor antagonist SR 141716A (0, 0.3 and 3 microg per side) delivered into the prefrontal cortex (PFC), nucleus accumbens (NAC), and basolateral amygdala (BLA) of rats. Results show that following extinction of operant behavior the presentation of a discriminative stimulus conditioned to heroin availability reinstated nonreinforced lever pressing to levels comparable to preextinction levels. Intra-PFC SR 141716A dose-dependently reduced cue-induced reinstatement of heroin seeking, with a significant reduction following the 3 microg per side dose. In the NAC, both SR 141716A doses induced a significant reduction in cue-induced reinstatement, with the highest dose completely blocking the effect of the cue. In contrast, intra-BLA SR 141716A did not alter cue-induced reinstatement of responding while systemic administration of this antagonist (3 mg/kg, i.p.) significantly blocked cue-induced reinstatement in all three-placement groups (BLA, PFC, and NAC). These findings provide new insights into the neural mechanisms through which CB(1) receptors modulate the motivational properties of heroin-associated cues inducing relapse.
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Affiliation(s)
- Lily Alvarez-Jaimes
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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231
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Di Pietro NC, Mashhoon Y, Heaney C, Yager LM, Kantak KM. Role of dopamine D1 receptors in the prefrontal dorsal agranular insular cortex in mediating cocaine self-administration in rats. Psychopharmacology (Berl) 2008; 200:81-91. [PMID: 18584153 PMCID: PMC2587221 DOI: 10.1007/s00213-008-1149-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 03/22/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE Orbital/insular areas of the prefrontal cortex (PFC) are implicated in cocaine addiction. However, the role of dopamine D1 receptors in mediating cocaine self-administration in these sub-regions remains unknown. OBJECTIVES To define the role of the dorsal agranular insular (AId) sub-region of the PFC, we investigated the effects of D1 receptor manipulation on self-administration behavior maintained by cocaine and cocaine-related stimuli. MATERIALS AND METHODS Rats were trained to lever press for cocaine (1 mg/kg) under a fixed-interval 5-min (fixed-ratio 5:S) second-order schedule of reinforcement in the presence of conditioned light cues and contextual sound cues. Intra-AId infusions of vehicle, the D1-like receptor agonist SKF 81297 (0.1, 0.2, 0.4 microg/side) or the D1-like receptor antagonist SCH 23390 (1.0, 2.0, 4.0 microg/side), were administered prior to 1-h self-administration test sessions. Food-maintained responding under a second-order schedule was examined in separate rats to determine if pretreatment with D1 ligands produced general impairments in responding. RESULTS Infusion of SKF 81297 (0.2 and 0.4 microg/side) reduced active lever responses during the first 30 min of 1-h test sessions, but did not influence cocaine intake. Infusion of 4.0 microg/side SCH 23390 reduced active lever responses and cocaine intake throughout the 1-h test sessions. Additionally, this dose of SCH 23390 disrupted food-maintained responding and intake. CONCLUSIONS D1 receptor agonists and antagonists in the AId have diverse consequences and time courses of action. D1 receptor stimulation in the AId may reduce the motivating influence of cocaine-related stimuli on responding whereas D1 receptor blockade in this PFC sub-region produces global disruptions in behavior.
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232
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Zavala AR, Browning JR, Dickey ED, Biswas S, Neisewander JL. Region-specific involvement of AMPA/Kainate receptors in Fos protein expression induced by cocaine-conditioned cues. Eur Neuropsychopharmacol 2008; 18:600-11. [PMID: 18539009 PMCID: PMC4798851 DOI: 10.1016/j.euroneuro.2008.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/04/2008] [Accepted: 04/15/2008] [Indexed: 11/18/2022]
Abstract
This study investigated the effects of the AMPA/Kainate receptor antagonist, NBQX, on cue-elicited cocaine-seeking behavior and concomitant changes in Fos protein expression. After cocaine self-administration training, rats underwent 24 days of abstinence during which they were exposed daily either to the self-administration environment with response-contingent cues previously paired with cocaine infusions available (Extinction group) or to an alternate environment (No Extinction group). Subsequently, rats were tested for cocaine-seeking behavior (i.e., operant responses without cocaine reinforcement) elicited by the cocaine-associated cues after pretreatment with either vehicle or NBQX (10 mg/kg, IP). NBQX markedly attenuated cue-elicited cocaine-seeking behavior relative to vehicle pretreatment in the No Extinction group and also decreased cue-elicited Fos protein expression in a region-specific manner in the anterior cingulate and orbitofrontal cortices, basolateral amygdala, nucleus accumbens core, and dorsal caudate-putamen, suggesting involvement of AMPA glutamate systems in specific subregions of the neuronal circuitry activated by cocaine cues.
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Affiliation(s)
- Arturo R Zavala
- Department of Psychology, Arizona State University, Box 871104, Tempe, AZ 85287-1104, United States
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233
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Taylor JR, Olausson P, Quinn JJ, Torregrossa MM. Targeting extinction and reconsolidation mechanisms to combat the impact of drug cues on addiction. Neuropharmacology 2008; 56 Suppl 1:186-95. [PMID: 18708077 DOI: 10.1016/j.neuropharm.2008.07.027] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/11/2008] [Accepted: 07/20/2008] [Indexed: 02/01/2023]
Abstract
Drug addiction is a progressive and compulsive disorder, where recurrent craving and relapse to drug-seeking occur even after long periods of abstinence. A major contributing factor to relapse is drug-associated cues. Here we review behavioral and pharmacological studies outlining novel methods of effective and persistent reductions in cue-induced relapse behavior in animal models. We focus on extinction and reconsolidation of cue-drug associations as the memory processes that are the most likely targets for interventions. Extinction involves the formation of new inhibitory memories rather than memory erasure; thus, it should be possible to facilitate the extinction of cue-drug memories to reduce relapse. We propose that context-dependency of extinction might be altered by mnemonic agents, thereby enhancing the efficacy of cue-exposure therapy as treatment strategy. In contrast, interfering with memory reconsolidation processes can disrupt the integrity or strength of specific cue-drug memories. Reconsolidation is argued to be a distinct process that occurs over a brief time period after memory is reactivated/retrieved - when the memory becomes labile and vulnerable to disruption. Reconsolidation is thought to be an independent, perhaps opposing, process to extinction and disruption of reconsolidation has recently been shown to directly affect subsequent cue-drug memory retrieval in an animal model of relapse. We hypothesize that a combined approach aimed at both enhancing the consolidation of cue-drug extinction and interfering with the reconsolidation of cue-drug memories will have a greater potential for persistently inhibiting cue-induced relapse than either treatment alone.
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Affiliation(s)
- Jane R Taylor
- Department of Psychiatry, Division of Molecular Psychiatry, Yale University School of Medicine, S307 Connecticut Mental Health Center, Ribicoff Research Laboratories, 34 Park Street, New Haven, CT 06508, USA.
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234
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Goeders NE, Guerin GF. Effects of the combination of metyrapone and oxazepam on cocaine and food self-administration in rats. Pharmacol Biochem Behav 2008; 91:181-9. [PMID: 18692521 DOI: 10.1016/j.pbb.2008.07.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/11/2008] [Accepted: 07/14/2008] [Indexed: 11/28/2022]
Abstract
For several years, our laboratory has investigated the role for the HPA axis in cocaine reinforcement. Two classes of drugs that we have studied include corticosterone synthesis inhibitors (e.g., metyrapone) and benzodiazepine receptor agonists (e.g., oxazepam). In the experiments described in this manuscript, we tested the effects of various doses of metyrapone and oxazepam against several doses of self-administered cocaine. Behavioral, endocrine and pharmacokinetic measures of the effects of the combination of metyrapone and oxazepam on cocaine reward are presented. Combinations of metyrapone and oxazepam at doses that produced no observable effects when administered separately significantly reduced cocaine self-administration without affecting food-maintained responding during the same sessions. Changes in pharmacokinetics or endocrine function do not appear to mediate these effects, suggesting a central mechanism of action. Therefore, although these drugs produce their effects through distinct mechanisms, an additive effect on cocaine self-administration is obtained when these drugs are administered together, suggesting that combinations of low doses of metyrapone and oxazepam may be useful in reducing cocaine seeking with a reduced incidence of unwanted side effects and a decreased potential for abuse.
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Affiliation(s)
- Nicholas E Goeders
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, USA.
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235
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Kalivas PW, Lalumiere RT, Knackstedt L, Shen H. Glutamate transmission in addiction. Neuropharmacology 2008; 56 Suppl 1:169-73. [PMID: 18675832 DOI: 10.1016/j.neuropharm.2008.07.011] [Citation(s) in RCA: 258] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2008] [Revised: 07/05/2008] [Accepted: 07/08/2008] [Indexed: 01/06/2023]
Abstract
Cortico-striatal glutamate transmission has been implicated in both the initiation and expression of addiction related behaviors, such as locomotor sensitization and drug-seeking. While glutamate transmission onto dopamine cells in the ventral tegmental area undergoes transient plasticity important for establishing addiction-related behaviors, glutamatergic plasticity in the nucleus accumbens is critical for the expression of these behaviors. This information points to the value of exploring pharmacotherapeutic manipulation of glutamate plasticity in treating drug addiction.
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Affiliation(s)
- Peter W Kalivas
- Department of Neurosciences, 173 Ashley Ave, BSB410, Medical University of South Carolina, Charleston, SC 29464, USA.
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236
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Peters J, LaLumiere RT, Kalivas PW. Infralimbic prefrontal cortex is responsible for inhibiting cocaine seeking in extinguished rats. J Neurosci 2008; 28:6046-53. [PMID: 18524910 PMCID: PMC2585361 DOI: 10.1523/jneurosci.1045-08.2008] [Citation(s) in RCA: 427] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/03/2008] [Accepted: 05/04/2008] [Indexed: 11/21/2022] Open
Abstract
The rat prelimbic prefrontal cortex and nucleus accumbens core are critical for initiating cocaine seeking. In contrast, the neural circuitry responsible for inhibiting cocaine seeking during extinction is unknown. The present findings using inhibition of selected brain nuclei with GABA agonists show that the suppression of cocaine seeking produced by previous extinction training required activity in the rat infralimbic cortex. Conversely, the reinstatement of drug seeking by a cocaine injection in extinguished animals was suppressed by increasing neuronal activity in infralimbic cortex with the glutamate agonist AMPA. The cocaine seeking induced by inactivating infralimbic cortex resembled other forms of reinstated drug seeking by depending on activity in prelimbic cortex and the basolateral amygdala. A primary efferent projection from the infralimbic cortex is to the nucleus accumbens shell. Akin to infralimbic cortex, inhibition of the accumbens shell induced cocaine seeking in extinguished rats. However, bilateral inhibition of the shell also elicited increased locomotor activity. Nonetheless, unilateral inhibition of the accumbens shell did not increase motor activity, and simultaneous unilateral inactivation of the infralimbic cortex and shell induced cocaine seeking, suggesting that an interaction between these two structures is necessary for extinction training to inhibit cocaine seeking. The infralimbic cortex and accumbens shell appear to be recruited by extinction learning because inactivation of these structures before extinction training did not alter cocaine seeking. Together, these findings suggest that a neuronal network involving the infralimbic cortex and accumbens shell is recruited by extinction training to suppress cocaine seeking.
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Affiliation(s)
- Jamie Peters
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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237
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Zavala AR, Osredkar T, Joyce JN, Neisewander JL. Upregulation of Arc mRNA expression in the prefrontal cortex following cue-induced reinstatement of extinguished cocaine-seeking behavior. Synapse 2008; 62:421-31. [PMID: 18361437 PMCID: PMC2832122 DOI: 10.1002/syn.20502] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cocaine-associated cues acquire incentive motivational effects that manifest as cue-elicited craving in humans and cocaine-seeking behavior in rats. Here we examine the hypothesis that neuronal processes associated with incentive motivational effects of cocaine cues involve increased expression of the plasticity-associated gene, Arc. Rats trained to self-administer cocaine subsequently underwent extinction training, during which cocaine-seeking behavior (i.e., responses without cocaine reinforcement) progressively decreased. Rats were then tested for cocaine-seeking behavior either with or without response-contingent presentations of light/tone cues that had been previously paired with cocaine infusions during self-administration training. Cues elicited reinstatement of cocaine-seeking behavior and were accompanied by increased Arc mRNA levels in the orbitofrontal, prelimbic, and anterior cingulate cortices, suggesting Arc involvement in conditioned plasticity associated with incentive motivational effects of cocaine cues. Additionally, rats with a history of cocaine self-administration and extinction exhibited upregulation of Arc expression in several limbic and cortical regions relative to saline-yoked controls regardless of cue exposure condition, suggesting persistent neuroadaptations involving Arc within these regions.
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Affiliation(s)
- Arturo R Zavala
- Department of Psychology, Arizona State University, Tempe, Arizona 85287-1104, USA
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238
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Le Foll B, Forget B, Aubin HJ, Goldberg SR. Blocking cannabinoid CB1 receptors for the treatment of nicotine dependence: insights from pre-clinical and clinical studies. Addict Biol 2008; 13:239-52. [PMID: 18482433 DOI: 10.1111/j.1369-1600.2008.00113.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Tobacco use is one of the leading preventable causes of death in developed countries. Since existing medications are only partially effective in treating tobacco smokers, there is a great need for improved medications for smoking cessation. It has been recently proposed that cannabinoid CB(1) receptor antagonists represent a new class of therapeutic agents for drug dependence, and notably, nicotine dependence. Here, we will review current evidence supporting the use of this class of drugs for smoking cessation treatment. Pre-clinical studies indicate that nicotine exposure produces changes in endocannabinoid content in the brain. In experimental animals, N-piperidinyl-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide (rimonabant, SR141716) and N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), two cannabinoid CB(1) receptor antagonists, block nicotine self-administration behavior, an effect that may be related to the blockade of the dopamine-releasing effects of nicotine in the brain. Rimonabant also seems efficacious in decreasing the influence of nicotine-associated stimuli over behavior, suggesting that it may act on two distinct neuronal pathways, those implicated in drug-taking behavior and those involved in relapse phenomena. The utility of rimonabant has been evaluated in several clinical trials. It seems that rimonabant is an efficacious treatment for smoking cessation, although its efficacy does not exceed that of nicotine-replacement therapy and its use may be limited by emotional side effects (nausea, anxiety and depression, mostly). Rimonabant also appears to decrease relapse rates in smokers. These findings indicate significant, but limited, utility of rimonabant for smoking cessation.
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Affiliation(s)
- Bernard Le Foll
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada.
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239
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Opposing roles for the nucleus accumbens core and shell in cue-induced reinstatement of food-seeking behavior. Neuroscience 2008; 154:877-84. [DOI: 10.1016/j.neuroscience.2008.04.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 04/02/2008] [Accepted: 04/03/2008] [Indexed: 11/24/2022]
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240
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Role of ventral medial prefrontal cortex in incubation of cocaine craving. Neuropharmacology 2008; 56 Suppl 1:177-85. [PMID: 18565549 DOI: 10.1016/j.neuropharm.2008.04.022] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 04/14/2008] [Accepted: 04/18/2008] [Indexed: 11/21/2022]
Abstract
Cue-induced drug-seeking in rodents progressively increases after withdrawal from cocaine, suggesting that cue-induced cocaine craving incubates over time. Here, we explored the role of the medial prefrontal cortex (mPFC, a brain area previously implicated in cue-induced cocaine seeking) in this incubation. We trained rats to self-administer cocaine for 10days (6h/day, infusions were paired with a tone-light cue), and then assessed after 1 or 30 withdrawal days the effect of exposure to cocaine cues on lever presses in extinction tests. We found that cue-induced cocaine-seeking in the extinction tests was higher after 30 withdrawal days than after 1day. The time-dependent increases in extinction responding were associated with large (ventral mPFC) or modest (dorsal mPFC) increases in ERK phosphorylation (a measure of ERK activity and an index of neuronal activation). After 30 withdrawal days, ventral but not dorsal injections of muscimol+baclofen (GABAa+GABAb receptor agonists that inhibit neuronal activity) decreased extinction responding. After 1 withdrawal day, ventral but not dorsal mPFC injections of bicuculline+saclofen (GABAa+GABAb receptor antagonists that increase neuronal activity) strongly increased extinction responding. Finally, muscimol+baclofen had minimal effect on extinction responding after 1day, and in cocaine-experienced rats, ventral mPFC injections of muscimol+baclofen or bicuculline+saclofen had no effect on lever presses for an oral sucrose solution. The present results indicate that ventral mPFC neuronal activity plays an important role in the incubation of cocaine craving.
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241
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Hearing MC, Miller SW, See RE, McGinty JF. Relapse to cocaine seeking increases activity-regulated gene expression differentially in the prefrontal cortex of abstinent rats. Psychopharmacology (Berl) 2008; 198:77-91. [PMID: 18311559 PMCID: PMC5440231 DOI: 10.1007/s00213-008-1090-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 01/22/2008] [Indexed: 02/05/2023]
Abstract
RATIONALE Alterations in the activity of the prefrontal and orbitofrontal cortices of cocaine addicts have been linked with re-exposure to cocaine-associated stimuli. OBJECTIVES Using an animal model of relapse to cocaine seeking, the present study investigated the expression patterns of four different activity-regulated genes within prefrontal cortical brain regions after 22 h or 15 days of abstinence during context-induced relapse. MATERIALS AND METHODS Rats self-administered cocaine or received yoked-saline for 2 h/day for 10 days followed by 22 h or 2 weeks of abstinence when they were re-exposed to the self-administration chamber with or without levers available to press for 1 h. Brains were harvested and sections through the prefrontal cortex were processed for in situ hybridization using radioactive oligonucleotide probes encoding c-fos, zif/268, arc, and bdnf. RESULTS Re-exposure to the chamber in which rats previously self-administered cocaine but not saline, regardless of lever availability, increased the expression of all genes in the medial prefrontal and orbitofrontal cortices at both time points with one exception: bdnf mRNA was significantly increased in the medial prefrontal cortex at 22 h only if levers previously associated with cocaine delivery were available to press. Furthermore, re-exposure of rats to the chambers in which they received yoked saline enhanced both zif/268 and arc expression selectively in the orbitofrontal cortex after 15 days of abstinence. CONCLUSIONS These results support convergent evidence that cocaine-induced changes in the prefrontal cortex are important in regulating drug seeking following abstinence and may provide additional insight into the molecular mechanisms involved in these processes.
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Affiliation(s)
- M. C. Hearing
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue BSB 403, Charleston, SC 29245, USA
| | - S. W. Miller
- Department of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29245, USA
| | - R. E. See
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue BSB 403, Charleston, SC 29245, USA
| | - J. F. McGinty
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue BSB 403, Charleston, SC 29245, USA
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242
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Lai YT, Fan HY, Cherng CG, Chiang CY, Kao GS, Yu L. Activation of amygdaloid PKC pathway is necessary for conditioned cues-provoked cocaine memory performance. Neurobiol Learn Mem 2008; 90:164-70. [PMID: 18442936 DOI: 10.1016/j.nlm.2008.03.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 03/07/2008] [Accepted: 03/16/2008] [Indexed: 01/23/2023]
Abstract
Drug-associated cues are critical in reinstating the drug taking behavior even during prolonged abstinence and thus are thought to be a key factor to induce drug craving and to cause relapse. Amygdaloid complex has been known for its physiological function in mediating emotional experience storage and emotional cues-regulated memory retrieval. This study was undertaken to examine the role of basolateral nuclei of amygdala and the intracellular signaling molecule in drug cues-elicited cocaine memory retrieval. Systemic anisomycin treatment prior to the retrieval test abolished the cues-provoked cocaine conditioned place preference (CPP) memory. Likewise, a similar blockade of cues-provoked cocaine CPP performance was achieved by infusion of anisomycin and cycloheximide into the basolateral nuclei of amygdala before the test. Intra-amygdaloid infusion of H89, a protein kinase A inhibitor, or U0126, a MEK inhibitor, did not affect retrieval of the cues-elicited cocaine CPP memory. In contrast, intra-amygdaloid infusion of NPC 15437, a PKC inhibitor, abolished the cues-elicited cocaine CPP expression, while left the memory per se intact. Intra-amygdaloid infusion of NPC 15437 did not seem to affect locomotor activity or exert observable aversive effect. Taken together, our results suggest that activation of PKC signaling pathway and probably downstream de novo protein synthesis in the basolateral nuclei of amygdala is required for the cues-elicited cocaine memory performance. However, temporary inhibition of this signaling pathway does not seem to affect cocaine CPP memory per se.
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Affiliation(s)
- Yu-Ting Lai
- Behavioral Neuropharmacology Laboratory, Institute of Behavioral Medicine, National Cheng Kung University College of Medicine, 1 University Road, Tainan 701, Taiwan, ROC
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243
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Glutamate release in the nucleus accumbens core is necessary for heroin seeking. J Neurosci 2008; 28:3170-7. [PMID: 18354020 DOI: 10.1523/jneurosci.5129-07.2008] [Citation(s) in RCA: 280] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Long-term changes in glutamate transmission in the nucleus accumbens core (NAcore) contribute to the reinstatement of drug seeking after extinction of cocaine self-administration. Whether similar adaptations in glutamate transmission occur during heroin and cue-induced reinstatement of heroin seeking is unknown. After 2 weeks of heroin self-administration and 2 weeks of subsequent extinction training, heroin seeking was induced by a noncontingent injection of heroin or by presentation of light/tone cues previously paired with heroin infusions. Microdialysis was conducted in the NAcore during reinstatement of heroin seeking in animals extinguished from heroin self-administration or in subjects receiving parallel (yoked) noncontingent saline or heroin. Reinstatement by either heroin or cue increased extracellular glutamate in the NAcore in the self-administration group, but no increase was elicited during heroin-induced reinstatement in the yoked control groups. The increase in glutamate during heroin-induced drug seeking was abolished by inhibiting synaptic transmission in the NAcore with tetrodotoxin or by inhibiting glutamatergic afferents to the NAcore from the prelimbic cortex. Supporting critical involvement of glutamate release, heroin seeking induced by cue or heroin was blocked by inhibiting AMPA/kainate glutamate receptors in the NAcore. Interestingly, although a heroin-priming injection increased dopamine equally in animals trained to self-administer heroin and in yoked-saline subjects, inhibition of dopamine receptors in the NAcore also blocked heroin- and cue-induced drug seeking. Together, these findings show that recruitment of the glutamatergic projection from the prelimbic cortex to NAcore is necessary to initiate the reinstatement of heroin seeking.
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244
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Kalivas PW. Cocaine and amphetamine-like psychostimulants: neurocircuitry and glutamate neuroplasticity. DIALOGUES IN CLINICAL NEUROSCIENCE 2008. [PMID: 18286799 PMCID: PMC3202508 DOI: 10.31887/dcns.2007.9.4/pkalivas] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Although the pharmacology of amphetamine-like psychostimulants at dopamine transporters is well understood, addiction to this class of drugs has proven difficult to deal with. The reason for this disconnection is that while the molecular mechanism of amphetamine action is critical to reinforce drug use, it is only the first step in a sequence of widespread neuroplastic events in brain circuitry. This review outlines the affect of psychostimulants on mesocorticolimbic dopamine projections that mediate their reinforcing effect, and how this action ultimately leads to enduring pathological neuroplasticity in glutamatergic projections from the prefrontal cortex to the nucleus accumbens. Molecular neuroadaptations induced by psychostimulant abuse are described in glutamate neurotransmission, and from this information potential pharmacotherapeutic targets are identified, based upon reversing or countermanding psychostimulant-induced neuroplasticity.
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Affiliation(s)
- Peter W Kalivas
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
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245
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Peters J, Vallone J, Laurendi K, Kalivas PW. Opposing roles for the ventral prefrontal cortex and the basolateral amygdala on the spontaneous recovery of cocaine-seeking in rats. Psychopharmacology (Berl) 2008; 197:319-26. [PMID: 18066533 DOI: 10.1007/s00213-007-1034-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 11/25/2007] [Indexed: 11/28/2022]
Abstract
RATIONALE The neural circuitry subserving cocaine-seeking after extinction vs abstinence alone requires different constituent brain structures. Spontaneous recovery of cocaine-seeking, a model, which incorporates both extinction and abstinence, depends on an unknown neural circuit. OBJECTIVES The present study examined the hypothesis that the spontaneous recovery of cocaine-seeking would require overlapping but distinct neural circuits compared to models that incorporate either extinction or abstinence alone. MATERIAL AND METHODS Rats were trained to self-administer cocaine (0.2 mg/inf), then responding on the cocaine-paired lever was extinguished, followed by an additional period of abstinence in the home cage. Finally, rats were returned to the self-administration context for a test of spontaneous recovery (SR TEST). Just before the SR TEST, discrete brain regions were inactivated with a GABA agonist cocktail (1 mM baclofen + 0.1mM muscimol) to determine the relative importance of these brain regions in the spontaneous recovery of cocaine-seeking. RESULTS The inactivation of the ventromedial prefrontal cortex (vPFC) enhanced cocaine-seeking, whereas the inactivation of the basolateral amygdala (BLA) attenuated spontaneous recovery. Inactivation of the nucleus accumbens core (Core) resembled the effects of BLA inactivation, but these results were confounded by an inhibitory effect of the vehicle treatment. Finally, the spontaneous recovery of cocaine-seeking was unaltered by manipulations of the dorsomedial prefrontal cortex (dPFC) and the nucleus accumbens shell (Shell). CONCLUSIONS The neural circuitry subserving cocaine-seeking behavior in a spontaneous recovery model requires the BLA and possibly the Core, like extinction models. In addition, this behavior is subject to regulation by vPFC, in a manner functionally opposite to that of the BLA.
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Affiliation(s)
- Jamie Peters
- Department of Neurosciences, Basic Science Building, Suite 403, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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246
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Repeated amphetamine administration induces Fos in prefrontal cortical neurons that project to the lateral hypothalamus but not the nucleus accumbens or basolateral amygdala. Psychopharmacology (Berl) 2008; 197:179-89. [PMID: 18080115 PMCID: PMC2553393 DOI: 10.1007/s00213-007-1021-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 11/09/2007] [Indexed: 02/04/2023]
Abstract
RATIONALE The development of sensitization to amphetamine (AMPH) is dependent on increases in excitatory outflow from the medial prefrontal cortex (mPFC) to subcortical centers. These projections are clearly important for the progressive enhancement of the behavioral response during drug administration that persists through withdrawal. OBJECTIVES The objective of this study was to identify the mPFC subcortical pathway(s) activated by a sensitizing regimen of AMPH. MATERIALS AND METHODS Using retrograde labeling techniques, Fos activation was evaluated in the predominant projection pathways of the mPFC of sensitized rats after a challenge injection of AMPH. RESULTS There was a significant increase in Fos-immunoreactive cells in the mPFC, nucleus accumbens (NAc), basolateral amygdala (BLA), and lateral hypothalamus (LH) of rats treated repeatedly with AMPH when compared to vehicle-treated controls. The mPFC pyramidal neurons that project to the LH but not the NAc or BLA show a significant induction of Fos after repeated AMPH treatment. In addition, we found a dramatic increase in Fos-activated orexin neurons. CONCLUSIONS The LH, a region implicated in natural and drug reward processes, may play a role in the development and persistence of sensitization to repeated AMPH through its connections with the mPFC and possibly through its orexin neurons.
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Abstract
Drug addiction presents as a chronic relapsing disorder characterized by persistent drug-seeking and drug-taking behaviours. Given the significant detrimental effects of this disease both socially and economically, a considerable amount of research has been dedicated to understanding a number of issues in addiction, including behavioural and neuropharmacological factors that contribute to the development, loss of control and persistence of compulsive addictive behaviours. In this review, we will give a broad overview of various theories of addiction, animal models of addiction and relapse, drugs of abuse, and the neurobiology of drug dependence and relapse. Although drugs of abuse possess diverse neuropharmacological profiles, activation of the mesocorticolimbic system, particularly the ventral tegmental area, nucleus accumbens, amygdala and prefrontal cortex via dopaminergic and glutamatergic pathways, constitutes a common pathway by which various drugs of abuse mediate their acute reinforcing effects. However, long-term neuroadaptations in this circuitry likely underlie the transition to drug dependence and cycles of relapse. As further elucidated in more comprehensive reviews of various subtopics on addiction in later sections of this special issue, it is anticipated that continued basic neuroscience research will aid in the development of effective therapeutic interventions for the long-term treatment of drug-dependent individuals.
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Affiliation(s)
- M W Feltenstein
- Department of Neurosciences, Medical Universiy of South Carolina, Charleston, SC 29425, USA.
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248
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Diergaarde L, Pattij T, Poortvliet I, Hogenboom F, de Vries W, Schoffelmeer ANM, De Vries TJ. Impulsive choice and impulsive action predict vulnerability to distinct stages of nicotine seeking in rats. Biol Psychiatry 2008; 63:301-8. [PMID: 17884016 DOI: 10.1016/j.biopsych.2007.07.011] [Citation(s) in RCA: 294] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 07/13/2007] [Accepted: 07/13/2007] [Indexed: 11/18/2022]
Abstract
BACKGROUND Although heavy smoking has been associated with impulsivity in humans, it is not clear whether poor impulse control represents a risk factor in the etiology of nicotine dependence. METHODS To address this issue, rats were selected on the basis of individual differences in impulsivity in the delayed reward task (impulsive choice) and the 5-choice serial reaction time task (impulsive action). Subsequently, rats were subjected to a nicotine self-administration (SA) paradigm tailored to measure the motivational properties of nicotine and nicotine-associated stimuli. In separate groups, differences in electrically evoked dopamine release in slice preparations obtained from several mesolimbic brain regions were determined. RESULTS Impulsive action was associated with an enhanced motivation to initiate and maintain nicotine SA. In contrast, impulsive choice predicted a diminished ability to inhibit nicotine seeking during abstinence and an enhanced vulnerability to relapse upon re-exposure to nicotine cues. Impulsive action was associated with reduced dopamine release in the accumbens core and impulsive choice with reduced dopamine release in accumbens core, shell, and medial prefrontal cortex. CONCLUSIONS The strong association between sub-dimensions of impulsivity and nicotine SA implies that interventions aimed to improve impulse control might help to reduce susceptibility to nicotine dependence and/or lead to successful smoking cessation.
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Affiliation(s)
- Leontien Diergaarde
- Center for Neurogenomics and Cognitive Research, Department of Anatomy and Neurosciences, VU Medical Center, Amsterdam, The Netherlands.
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249
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Rogers JL, Ghee S, See RE. The neural circuitry underlying reinstatement of heroin-seeking behavior in an animal model of relapse. Neuroscience 2008; 151:579-88. [PMID: 18061358 PMCID: PMC2238688 DOI: 10.1016/j.neuroscience.2007.10.012] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 09/24/2007] [Accepted: 10/18/2007] [Indexed: 11/26/2022]
Abstract
Reinstatement of extinguished drug-seeking has been utilized in the study of the neural substrates of relapse to drugs of abuse, particularly cocaine. However, limited studies have examined the circuitry that drives the reinstatement of heroin-seeking behavior in the presence of conditioned cues, or by heroin itself. In order to test the hypothesis that the circuitry underlying reinstatement in heroin-experienced animals would show overlapping, yet distinct differences from cocaine-experienced animals, we used transient inhibition of several cortical, striatal, and limbic brain regions during reinstatement of heroin-seeking produced by heroin-paired cues, or by a single priming dose of heroin. Rats lever pressed for i.v. heroin discretely paired with a conditioned stimulus (CS) during daily 3-h sessions for a period of 2 weeks, followed by daily extinction of lever responding. Subsequent reinstatement of heroin-seeking was measured as lever responding in the absence of heroin reinforcement. The first set of reinstatement tests involved response-contingent CS presentations following bilateral intracranial infusion of either a combination of GABA receptor agonists (baclofen-muscimol, B/M) or vehicle (saline) into one of 13 different brain regions. The second set of reinstatement tests involved a single heroin injection (0.25 mg/kg, s.c.) following either B/M or vehicle infusions. Our results showed that vehicle-infused animals reinstated to both CS presentations and a priming injection of heroin, while B/M inactivation of several areas known to be important for the reinstatement of cocaine-seeking also attenuated heroin-seeking in response to CS presentations and/or a priming dose of heroin. However, as predicted, inactivation of areas previously shown to not affect cocaine-seeking significantly attenuated heroin-seeking, supporting the hypothesis that the circuitry underlying the reinstatement of heroin-seeking is more diffusely distributed than that for cocaine.
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Affiliation(s)
- J L Rogers
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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250
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Läck AK, Diaz MR, Chappell A, DuBois DW, McCool BA. Chronic ethanol and withdrawal differentially modulate pre- and postsynaptic function at glutamatergic synapses in rat basolateral amygdala. J Neurophysiol 2007; 98:3185-96. [PMID: 17898152 PMCID: PMC2269699 DOI: 10.1152/jn.00189.2007] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Withdrawal anxiety is a significant factor contributing to continued alcohol abuse in alcoholics. This anxiety is long-lasting, can manifest well after the overt physical symptoms of withdrawal, and is frequently associated with relapse in recovering alcoholics. The neurobiological mechanisms governing these withdrawal-associated increases in anxiety are currently unknown. The basolateral amygdala (BLA) is a major emotional center in the brain and regulates the expression of both learned fear and anxiety. Neurotransmitter system alterations within this brain region may therefore contribute to withdrawal-associated anxiety. Because evidence suggests that glutamate-gated neurotransmitter receptors are sensitive to acute ethanol exposure, we examined the effect of chronic intermittent ethanol (CIE) and withdrawal (WD) on glutamatergic synaptic transmission in the BLA. We found that slices prepared from CIE and WD animals had significantly increased contributions by synaptic NMDA receptors. In addition, CIE increased the amplitude of AMPA-receptor-mediated spontaneous excitatory postsynaptic currents (sEPSCs), whereas only WD altered the amplitude and kinetics of tetrodotoxin-resistant spontaneous events (mEPSCs). Similarly, the frequency of sEPSCs was increased in both CIE and WD neurons, although only WD increased the frequency of mEPSCs. These data suggest that CIE and WD differentially alter both pre- and postsynaptic properties of BLA glutamatergic synapses. Finally, we show that microinjection of the AMPA-receptor antagonist, DNQX, can attenuate withdrawal-related anxiety-like behavior. Together, our results suggest that increased glutamatergic function may contribute to anxiety expressed during withdrawal from chronic ethanol.
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Affiliation(s)
- Anna K Läck
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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