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Mews P, Sosnick L, Gurung A, Sidoli S, Nestler EJ. Decoding cocaine-induced proteomic adaptations in the mouse nucleus accumbens. Sci Signal 2024; 17:eadl4738. [PMID: 38626009 PMCID: PMC11170322 DOI: 10.1126/scisignal.adl4738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 03/28/2024] [Indexed: 04/18/2024]
Abstract
Cocaine use disorder (CUD) is a chronic neuropsychiatric condition that results from enduring cellular and molecular adaptations. Among substance use disorders, CUD is notable for its rising prevalence and the lack of approved pharmacotherapies. The nucleus accumbens (NAc), a region that is integral to the brain's reward circuitry, plays a crucial role in the initiation and continuation of maladaptive behaviors that are intrinsic to CUD. Leveraging advancements in neuroproteomics, we undertook a proteomic analysis that spanned membrane, cytosolic, nuclear, and chromatin compartments of the NAc in a mouse model. The results unveiled immediate and sustained proteomic modifications after cocaine exposure and during prolonged withdrawal. We identified congruent protein regulatory patterns during initial cocaine exposure and reexposure after withdrawal, which contrasted with distinct patterns during withdrawal. Pronounced proteomic shifts within the membrane compartment indicated adaptive and long-lasting molecular responses prompted by cocaine withdrawal. In addition, we identified potential protein translocation events between soluble-nuclear and chromatin-bound compartments, thus providing insight into intracellular protein dynamics after cocaine exposure. Together, our findings illuminate the intricate proteomic landscape that is altered in the NAc by cocaine use and provide a dataset for future research toward potential therapeutics.
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Affiliation(s)
- Philipp Mews
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Lucas Sosnick
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ashik Gurung
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Eric J. Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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2
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Kallupi M, Ciccocioppo R. Cue-induced reinstatement of seeking behavior in male rats is independent from the rewarding value of the primary reinforcer: Effect of mGluR5 blockade. Neuropharmacology 2023; 240:109694. [PMID: 37659439 PMCID: PMC11094430 DOI: 10.1016/j.neuropharm.2023.109694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023]
Abstract
Environmental conditioning factors have a profound impact on alcohol-seeking behavior and the maintenance of alcohol use in individuals with alcohol dependence. Cues associated with alcohol, depending on the perceived value of the primary reinforcer, gain salience and can trigger relapse. This study investigates the correlation between the reward magnitude of the primary reinforcer and the reinstatement evoked by cues predictive of their availability in male rats. Rat self-administration procedures were used to test reinstatement, with reinforcers consisting of 10% alcohol, 10% sucrose, or 2% sodium chloride (NaCl) experienced under need-state conditions. The effect of MTEP ([(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine), a selective metabotropic glutamate receptor 5 (mGluR5) antagonist, on motivation and reinstatement behaviors was also evaluated. RESULTS: demonstrate that under Fixed Ratio 1 (FR1) schedule, the three reinforcers maintain operant responding with the following order of magnitude 10% sucrose >2% NaCl >10% alcohol > water. Under a progressive ratio (PR) schedule of reinforcement, rats exhibit a significantly higher breakpoint for 2% NaCl (under Na-depletion), followed by 10% sucrose and 10% alcohol. After extinction, a significant reinstatement is observed with the magnitude order of 10% sucrose >10% alcohol >2% NaCl. However, only re-exposure to alcohol-paired cues induced significant reinstatement of alcohol-seeking after 4 and 8 months. Treatment with MTEP significantly reduces reinstatement of responding across all reinforcers, with the strongest effect observed on alcohol-seeking. These findings suggest that mGluR5 plays a general role in controlling cue-reactivity, but the effect is prominent in the case of alcohol compared to natural rewards. In conclusion, the results demonstrate a remarkable dissociation between the rewarding magnitude of the primary reinforcer and its ability to trigger relapse upon presentation of a cue previously associated with it. Importantly, alcohol, despite having lower intrinsic motivational value compared to a natural reward (sucrose) or a consummatory stimulus experienced under need state conditions (NaCl), can elicit more robust and longer-term reinstatement of seeking responses. Finally, our data demonstrate a significant involvement of the mGluR5 system in the regulation of seeking behavior.
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Affiliation(s)
- Marsida Kallupi
- Department of Psychiatry, University of California, San Diego, USA.
| | - Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
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3
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Berro LF, España RA, Mong JA, Gould RW. Editorial: Sleep and circadian rhythm disruptions associated with substance use disorders. Front Neurosci 2023; 17:1165084. [PMID: 37144091 PMCID: PMC10151812 DOI: 10.3389/fnins.2023.1165084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/30/2023] [Indexed: 05/06/2023] Open
Affiliation(s)
- Lais F. Berro
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United States
| | - Rodrigo A. España
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, United States
| | - Jessica A. Mong
- Department of Pharmacology, University of Maryland, Baltimore, MD, United States
| | - Robert W. Gould
- Department of Physiology and Pharmacology, School of Medicine, Wake Forest University, Winston-Salem, NC, United States
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4
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Domi A, Lucente E, Cadeddu D, Adermark L. Nicotine but not saline self-administering or yoked control conditions produces sustained neuroadaptations in the accumbens shell. Front Mol Neurosci 2023; 16:1105388. [PMID: 36760603 PMCID: PMC9907443 DOI: 10.3389/fnmol.2023.1105388] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
Introduction Using yoked animals as the control when monitoring operant drug-self-administration is considered the golden standard. However, instrumental learning per se recruits several neurocircuits that may produce distinct or overlapping neuroadaptations with drugs of abuse. The aim of this project was to assess if contingent responding for nicotine or saline in the presence of a light stimulus as a conditioned reinforcer is associated with sustained neurophysiological adaptations in the nucleus accumbens shell (nAcS), a brain region repeatedly associated with reward related behaviors. Methods To this end, nicotine-or saline-administrating rats and yoked-saline stimulus-unpaired training conditions were assessed in operant boxes over four consecutive weeks. After four additional weeks of home cage forced abstinence and subsequent cue reinforced responding under extinction conditions, ex vivo electrophysiology was performed in the nAcS medium spiny neurons (MSNs). Results Whole cell recordings conducted in voltage and current-clamp mode showed that excitatory synapses in the nAcS were altered after prolonged forced abstinence from nicotine self-administration. We observed an increase in sEPSC amplitude in animals with a history of contingent nicotine SA potentially indicating higher excitability of accumbal MSNs, which was further supported by current clamp recordings. Interestingly no sustained neuroadaptations were elicited in saline exposed rats from nicotine associated visual cues compared to the yoked controls. Conclusion The data presented here indicate that nicotine self-administration produces sustained neuroadaptations in the nAcS while operant responding driven by nicotine visual stimuli has no long-term effects on MSNs in nAcS.
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Affiliation(s)
- Ana Domi
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,*Correspondence: Ana Domi, ✉
| | - Erika Lucente
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Davide Cadeddu
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Louise Adermark
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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5
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Effects of isoflurane anesthesia on addictive behaviors in rats. Psychopharmacology (Berl) 2022; 239:3621-3632. [PMID: 36109391 DOI: 10.1007/s00213-022-06236-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 09/05/2022] [Indexed: 10/14/2022]
Abstract
RATIONALE Recently, it has been suggested that isoflurane might reduce dopamine release from rat midbrain dopaminergic neurons, the neurobiological substrate implicated in the reinforcing effects of abused drugs and nondrug rewards. However, little is known about effects of isoflurane on neurobehavioral activity associated with chronic exposure to psychoactive substances. OBJECTIVE The present study was designed to investigate the effects of isoflurane on cocaine-reinforced behavior. Using behavioral paradigm in rats, we evaluated the effects of isoflurane on cocaine self-administration under fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement. We also tested the effects of isoflurane on lever responding by nondrug reinforcers (sucrose and food) in drug-naive rats to control for the nonselective effects of isoflurane on cocaine- and nicotine-taking behavior. To further assess the ability of isoflurane to modulate the motivation for taking a drug, we evaluated the effects of isoflurane on nicotine self-administration. Using different groups of rats, the effects of isoflurane on the locomotor activity induced by a single intraperitoneal injection of cocaine (15 mg/kg) were also examined. RESULTS Isoflurane significantly suppressed the self-administration of cocaine and nicotine without affecting food consumption. Unlike food-reinforced responding, responding for sucrose reinforcement was decreased by isoflurane. Isoflurane reduced breaking points under a PR schedule of reinforcement in a dose-dependent manner, indicating its efficacy in decreasing the incentive value of cocaine. Isoflurane also attenuated acute cocaine-induced hyperlocomotion. CONCLUSIONS The results provided evidence that isoflurane decreases cocaine- and nicotine-reinforced responses, while isoflurane effect is not selective for cocaine- and nicotine-maintained responding. These results suggest that isoflurane inhibitions of cocaine- and nicotine-maintenance responses may be related to decreased effects of dopamine, and further investigation will need to elucidate this relationship.
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Chronic Red Bull Consumption during Adolescence: Effect on Mesocortical and Mesolimbic Dopamine Transmission and Cardiovascular System in Adult Rats. Pharmaceuticals (Basel) 2021; 14:ph14070609. [PMID: 34202876 PMCID: PMC8308486 DOI: 10.3390/ph14070609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 11/17/2022] Open
Abstract
Energy drinks are very popular nonalcoholic beverages among adolescents and young adults for their stimulant effects. Our study aimed to investigate the effect of repeated intraoral Red Bull (RB) infusion on dopamine transmission in the nucleus accumbens shell and core and in the medial prefrontal cortex and on cardiac contractility in adult rats exposed to chronic RB consumption. Rats were subjected to 4 weeks of RB voluntary consumption from adolescence to adulthood. Monitoring of in vivo dopamine was carried out by brain microdialysis. In vitro cardiac contractility was studied on biomechanical properties of isolated left-ventricular papillary muscle. The main finding of the study was that, in treated animals, RB increased shell dopamine via a nonadaptive mechanism, a pattern similar to that of drugs of abuse. No changes in isometric and isotonic mechanical parameters were associated with chronic RB consumption. However, a prolonged time to peak tension and half-time of relaxation and a slower peak rate of tension fall were observed in RB-treated rats. It is likely that RB treatment affects left-ventricular papillary muscle contraction. The neurochemical results here obtained can explain the addictive properties of RB, while the cardiovascular investigation findings suggest a hidden papillary contractility impairment.
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Blazquez-Llorca L, Miguéns M, Montero-Crespo M, Selvas A, Gonzalez-Soriano J, Ambrosio E, DeFelipe J. 3D Synaptic Organization of the Rat CA1 and Alterations Induced by Cocaine Self-Administration. Cereb Cortex 2021; 31:1927-1952. [PMID: 33253368 PMCID: PMC7945021 DOI: 10.1093/cercor/bhaa331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/10/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022] Open
Abstract
The hippocampus plays a key role in contextual conditioning and has been proposed as an important component of the cocaine addiction brain circuit. To gain knowledge about cocaine-induced alterations in this circuit, we used focused ion beam milling/scanning electron microscopy to reveal and quantify the three-dimensional synaptic organization of the neuropil of the stratum radiatum of the rat CA1, under normal circumstances and after cocaine-self administration (SA). Most synapses are asymmetric (excitatory), macular-shaped, and in contact with dendritic spine heads. After cocaine-SA, the size and the complexity of the shape of both asymmetric and symmetric (inhibitory) synapses increased but no changes were observed in the synaptic density. This work constitutes the first detailed report on the 3D synaptic organization in the stratum radiatum of the CA1 field of cocaine-SA rats. Our data contribute to the elucidation of the normal and altered synaptic organization of the hippocampus, which is crucial for better understanding the neurobiological mechanisms underlying cocaine addiction.
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Affiliation(s)
- L Blazquez-Llorca
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - M Miguéns
- Departamento de Psicología Básica I, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - M Montero-Crespo
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - A Selvas
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - J Gonzalez-Soriano
- Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - E Ambrosio
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - J DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
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8
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Marusich JA, Gay EA, Watson SL, Blough BE. Synthetic cathinone self-administration in female rats modulates neurotransmitter levels in addiction-related brain regions. Behav Brain Res 2019; 376:112211. [PMID: 31493431 PMCID: PMC6783379 DOI: 10.1016/j.bbr.2019.112211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/13/2019] [Accepted: 09/03/2019] [Indexed: 12/25/2022]
Abstract
Synthetic cathinones are used for their stimulant-like properties. Stimulant-induced neurochemical changes are thought to occur at different times in different brain regions and neurotransmitter systems. This study sought to examine the behavioral and neurochemical effects of α-pyrrolidinopentiophenone (α-PVP) and mephedrone (4MMC) in female rats. Methods probed the chronology of effects of synthetic cathinone exposure. Female rats were trained to self-administer α-PVP, 4MMC, or saline. Drug exposure ceased after 7 days of autoshaping for half of each drug group; the other half self-administered for another 21 days. Amygdala, hippocampus, hypothalamus, PFC, striatum, and thalamus were extracted, and tissue was analyzed with electrochemical detection and liquid chromatography mass spectrometry. Responding was minimal during autoshaping; thus, most infusions were delivered noncontingently in the autoshaping phase. Rats acquired self-administration of α-PVP and 4MMC. Synthetic cathinone administration, and duration of exposure produced several effects on neurotransmitters. α-PVP primarily increased serotonin, 5-hydroxy-3-acetic acid (5-HIAA), norepinephrine, and glutamate in hypothalamus. In contrast, 4MMC decreased serotonin and 5-HIAA in several brain regions. Longer durations of exposure to both synthetic cathinones increased 5-HIAA, norepinephrine, and glutamate in multiple brain regions compared to the short exposure during autoshaping. Notably, both α-PVP and 4MMC produced minimal changes in dopamine levels, suggesting that the dopaminergic effects of these synthetic cathinones are transient. These alterations in neurotransmitter levels indicate that synthetic cathinone use may produce differential neurochemical changes during the transition from use to abuse.
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Affiliation(s)
- Julie A Marusich
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA.
| | - Elaine A Gay
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA
| | - Scott L Watson
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA
| | - Bruce E Blough
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA
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Bassareo V, Talani G, Frau R, Porru S, Rosas M, Kasture SB, Peana AT, Loi E, Sanna E, Acquas E. Inhibition of Morphine- and Ethanol-Mediated Stimulation of Mesolimbic Dopamine Neurons by Withania somnifera. Front Neurosci 2019; 13:545. [PMID: 31275092 PMCID: PMC6593272 DOI: 10.3389/fnins.2019.00545] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/13/2019] [Indexed: 12/21/2022] Open
Abstract
Morphine- and ethanol-induced stimulation of neuronal firing of ventral tegmental area (VTA) dopaminergic neurons and of dopamine (DA) transmission in the shell of the nucleus accumbens (AcbSh) represents a crucial electrophysiological and neurochemical response underlying the ability of these compounds to elicit motivated behaviors and trigger a cascade of plasticity-related biochemical events. Previous studies indicate that the standardized methanolic extract of Withania somnifera roots (WSE) prevents morphine- and ethanol-elicited conditioned place preference and oral ethanol self-administration. Aim of the present research was to investigate whether WSE may also interfere with the ability of morphine and ethanol to stimulate VTA dopaminergic neurons and thus AcbSh DA transmission as assessed in male Sprague-Dawley rats by means of patch-clamp recordings in mesencephalic slices and in vivo brain microdialysis, respectively. Morphine and ethanol significantly stimulated spontaneous firing rate of VTA neurons and DA transmission in the AcbSh. WSE, at concentrations (200-400 μg/ml) that significantly reduce spontaneous neuronal firing of VTA DA neurons via a GABAA- but not GABAB-mediated mechanism, suppressed the stimulatory actions of both morphine and ethanol. Moreover, in vivo administration of WSE at a dose (75 mg/kg) that fails to affect basal DA transmission, significantly prevented both morphine- and ethanol-elicited increases of DA in the AcbSh. Overall, these results highlight the ability of WSE to interfere with morphine- and ethanol-mediated central effects and suggest a mechanistic interpretation of the efficacy of this extract to prevent the motivational properties of these compounds.
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Affiliation(s)
- Valentina Bassareo
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.,Centre of Excellence on Neurobiology of Addiction, University of Cagliari, Cagliari, Italy
| | - Giuseppe Talani
- Institute of Neuroscience, National Research Council, Cagliari, Italy
| | - Roberto Frau
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Simona Porru
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Michela Rosas
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | | | - Alessandra T Peana
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - Eleonora Loi
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Enrico Sanna
- Centre of Excellence on Neurobiology of Addiction, University of Cagliari, Cagliari, Italy.,Institute of Neuroscience, National Research Council, Cagliari, Italy.,Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Elio Acquas
- Centre of Excellence on Neurobiology of Addiction, University of Cagliari, Cagliari, Italy.,Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
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10
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Marusich JA, Gay EA, Blough BE. Analysis of neurotransmitter levels in addiction-related brain regions during synthetic cathinone self-administration in male Sprague-Dawley rats. Psychopharmacology (Berl) 2019; 236:903-914. [PMID: 30191259 PMCID: PMC6401347 DOI: 10.1007/s00213-018-5011-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/19/2018] [Indexed: 01/26/2023]
Abstract
RATIONALE Synthetic cathinones are used as stimulants of abuse. Different stimulants may induce distinct rates of disease progression, yielding neurochemical changes that may vary across brain regions or neurotransmitter systems. OBJECTIVES This research sought to behaviorally and chemically differentiate stages of synthetic cathinone abuse through rodent self-administration and measurement of the neurotransmitter profile in multiple brain regions. METHODS Male rats were trained to self-administer α-PVP, mephedrone (4MMC), or saline. Half of each drug group stopped self-administering after autoshaping; the other half self-administered for another 21 days. Brain tissue from amygdala, hippocampus, hypothalamus, PFC, striatum, and thalamus was profiled with electrochemical detection to assess neurotransmitter levels. RESULTS During autoshaping, the majority of infusions were delivered noncontingently. In the self-administration phase, rats responded more for α-PVP and 4MMC than for saline, demonstrating that both synthetic cathinones were reinforcing. Longer durations of exposure elevated 5-HIAA in hypothalamus, PFC, and hippocampus, indicating that learning may produce changes in addiction-related brain regions. Both synthetic cathinones decreased norepinephrine in hippocampus, while α-PVP decreased glutamate in hippocampus and PFC, and 4MMC decreased glutamate in thalamus. Furthermore, α-PVP increased dopaminergic metabolites in striatum, whereas 4MMC decreased serotonin in the amygdala, hippocampus, and PFC. Interestingly, neither synthetic cathinone affected dopamine levels despite their functional effects on the dopaminergic system. CONCLUSIONS In summary, the neurotransmitter changes observed here suggest that synthetic cathinone use likely produces sequential neurochemical changes during the transition from use to abuse. Consequently, treatment need may differ depending on the progression of synthetic cathinone abuse.
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Affiliation(s)
- Julie A Marusich
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, 136 Hermann, Research Triangle Park, NC, 27709, USA.
| | - Elaine A Gay
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, 136 Hermann, Research Triangle Park, NC, 27709, USA
| | - Bruce E Blough
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, 136 Hermann, Research Triangle Park, NC, 27709, USA
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Nguyen D, Nesarajah Y, Erb S, Ito R. Repeated Cocaine Exposure Attenuates the Desire to Actively Avoid: A Novel Active Avoidance Runway Task. Front Behav Neurosci 2018; 12:108. [PMID: 29910714 PMCID: PMC5992269 DOI: 10.3389/fnbeh.2018.00108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 05/08/2018] [Indexed: 11/22/2022] Open
Abstract
Drug addiction is a disorder in which drug seeking persists despite aversive consequences. While it is well documented in animal models of drug sensitization that repeated drug exposure enhances positive incentive motivation for drug and natural reinforcers, its effect on negative incentive motivation, defined here as the motivation to avoid a cued aversive outcome, remains an open question. In the present study, we designed a novel active avoidance (AA) runway paradigm to assess the effects of repeated cocaine exposure on the motivation to avoid an aversive outcome. Cocaine and saline pre-exposed rats were first trained to perform a conditioned AA lever press response to prevent the occurrence of foot shock administrations. The rats were subsequently tested in a runway apparatus, wherein they were required to traverse the length of a straight alley maze to reach the lever and emit a conditioned AA response. Run times were measured as an indication of negative incentive motivation. Cocaine pre-exposed rats demonstrated longer latencies to emit the conditioned AA response but showed no differences in latency to initiate runway behavior, nor in their acquisition of the AA response compared to the saline pre-exposed controls. Subsequent testing in an elevated plus maze revealed no differences in the expression of anxiety in cocaine pre-exposed rats compared to saline pre-exposed controls. Our results indicate that prior repeated cocaine exposure attenuated cued negative incentive motivation, which suggests that drug addiction may be attributable to a decrease in motivation to avoid aversive consequences associated with drug use.
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Affiliation(s)
- David Nguyen
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Yasika Nesarajah
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Suzanne Erb
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Rutsuko Ito
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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12
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Animal models of binge drinking, current challenges to improve face validity. Neurosci Biobehav Rev 2018; 106:112-121. [PMID: 29738795 DOI: 10.1016/j.neubiorev.2018.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/29/2018] [Accepted: 05/01/2018] [Indexed: 01/08/2023]
Abstract
Binge drinking (BD), i.e., consuming a large amount of alcohol in a short period of time, is an increasing public health issue. Though no clear definition has been adopted worldwide the speed of drinking seems to be a keystone of this behavior. Developing relevant animal models of BD is a priority for gaining a better characterization of the neurobiological and psychobiological mechanisms underlying this dangerous and harmful behavior. Until recently, preclinical research on BD has been conducted mostly using forced administration of alcohol, but more recent studies used scheduled access to alcohol, to model more voluntary excessive intakes, and to achieve signs of intoxications that mimic the human behavior. The main challenges for future research are discussed regarding the need of good face validity, construct validity and predictive validity of animal models of BD.
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13
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Tolerance to rewarding brain electrical stimulation: Differential effects of contingent and non-contingent activation of parabrachial complex and lateral hypothalamus. Behav Brain Res 2018; 336:15-21. [DOI: 10.1016/j.bbr.2017.08.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 01/03/2023]
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14
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Lai F, Cucca F, Frau R, Corrias F, Schlich M, Caboni P, Fadda AM, Bassareo V. Systemic Administration of Orexin a Loaded Liposomes Potentiates Nucleus Accumbens Shell Dopamine Release by Sucrose Feeding. Front Psychiatry 2018; 9:640. [PMID: 30559683 PMCID: PMC6287025 DOI: 10.3389/fpsyt.2018.00640] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 11/12/2018] [Indexed: 12/16/2022] Open
Abstract
Orexin neurons originate in the lateral and dorsomedial hypothalamus and perifornical area and produce two different neuropeptides: orexin A (OxA) and orexin B (OxB), which activate OxR1 and OxR2 receptors. In the lateral hypothalamus (LH) orexin neurons are involved in behavior motivated by natural rewards such as palatable food (sugar, high-fat food) and it has been demonstrated similarly that the orexin signaling in the ventral tegmental area (VTA) is implicated in the intake of high-fat food. The VTA is an important area involved in reward processing. Given the involvement of nucleus accumbens (NAc) shell dopamine (DA) in motivation for food, we intended to investigate the effect of OxA on the basal and feeding-activated DA transmission in the NAc shell. OxA is a large peptide and does not cross the blood-brain barrier and for this reason was loaded on two kinds of liposomes: anti-transferrin-monoclonal antibodies (OX26-mAb) and lactoferrin-modified stealth liposomes. The effect of IV administration of both OxA liposomes on NAc shell DA was studied by microdialysis in freely moving rats. OxA, administered using both kinds of liposomes, produced a delayed and transitory increase in dialysate DA in the NAc shell, strongly and lastingly potentiated the increase in dialysate DA elicited by sucrose pellet consumption and increased the number of eaten pellets. These effects of OxA on DA transmission and feeding were prevented by the OxR1 antagonist SB 334867. Hence, OxA acting on VTA OxR1 can facilitate sucrose-stimulated NAc shell DA transmission directly by increasing the basal activity of VTA DA neurons that send their projections to the NAc shell.
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Affiliation(s)
- Francesco Lai
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.,CNBS, University of Cagliari, Cagliari, Italy
| | - Flavia Cucca
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Roberto Frau
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Francesco Corrias
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Michele Schlich
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Anna Maria Fadda
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.,CNBS, University of Cagliari, Cagliari, Italy
| | - Valentina Bassareo
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy.,Cagliari Section, National Institute of Neuroscience, Monserrato, Italy
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15
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Serotonin 2B Receptors in Mesoaccumbens Dopamine Pathway Regulate Cocaine Responses. J Neurosci 2017; 37:10372-10388. [PMID: 28935766 DOI: 10.1523/jneurosci.1354-17.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/12/2017] [Accepted: 09/13/2017] [Indexed: 12/21/2022] Open
Abstract
Addiction is a maladaptive pattern of behavior following repeated use of reinforcing drugs in predisposed individuals, leading to lifelong changes. Common among these changes are alterations of neurons releasing dopamine in the ventral and dorsal territories of the striatum. The serotonin 5-HT2B receptor has been involved in various behaviors, including impulsivity, response to antidepressants, and response to psychostimulants, pointing toward putative interactions with the dopamine system. Despite these findings, it remains unknown whether 5-HT2B receptors directly modulate dopaminergic activity and the possible mechanisms involved. To answer these questions, we investigated the contribution of 5-HT2B receptors to cocaine-dependent behavioral responses. Male mice permanently lacking 5-HT2B receptors, even restricted to dopamine neurons, developed heightened cocaine-induced locomotor responses. Retrograde tracing combined with single-cell mRNA amplification indicated that 5-HT2B receptors are expressed by mesolimbic dopamine neurons. In vivo and ex vivo electrophysiological recordings showed that 5-HT2B-receptor inactivation in dopamine neurons affects their neuronal activity and increases AMPA-mediated over NMDA-mediated excitatory synaptic currents. These changes are associated with lower ventral striatum dopamine activity and blunted cocaine self-administration. These data identify the 5-HT2B receptor as a pharmacological intermediate and provide mechanistic insight into attenuated dopamine tone following exposure to drugs of abuse.SIGNIFICANCE STATEMENT Here we report that mice lacking 5-HT2B receptors totally or exclusively in dopamine neurons exhibit heightened cocaine-induced locomotor responses. Despite the sensitized state of these mice, we found that associated changes include lower ventral striatum dopamine activity and lower cocaine operant self-administration. We described the selective expression of 5-HT2B receptors in a subpopulation of dopamine neurons sending axons to the ventral striatum. Increased bursting in vivo properties of these dopamine neurons and a concomitant increase in AMPA synaptic transmission to ex vivo dopamine neurons were found in mice lacking 5-HT2B receptors. These data support the idea that the chronic 5-HT2B-receptor inhibition makes mice behave like animals already exposed to cocaine with higher cocaine-induced locomotion associated with changes in dopamine neuron reactivity.
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16
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Fortin SM, Roitman MF. Central GLP-1 receptor activation modulates cocaine-evoked phasic dopamine signaling in the nucleus accumbens core. Physiol Behav 2017; 176:17-25. [PMID: 28315693 PMCID: PMC5763906 DOI: 10.1016/j.physbeh.2017.03.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/23/2017] [Accepted: 03/14/2017] [Indexed: 11/24/2022]
Abstract
Drugs of abuse increase the frequency and magnitude of brief (1-3s), high concentration (phasic) dopamine release events in terminal regions. These are thought to be a critical part of drug reinforcement and ultimately the development of addiction. Recently, metabolic regulatory peptides, including the satiety signal glucagon-like peptide-1 (GLP-1), have been shown to modulate cocaine reward-driven behavior and sustained dopamine levels after cocaine administration. Here, we use fast-scan cyclic voltammetry (FSCV) to explore GLP-1 receptor (GLP-1R) modulation of dynamic dopamine release in the nucleus accumbens (NAc) during cocaine administration. We analyzed dopamine release events in both the NAc shell and core, as these two subregions are differentially affected by cocaine and uniquely contribute to motivated behavior. We found that central delivery of the GLP-1R agonist Exendin-4 suppressed the induction of phasic dopamine release events by intravenous cocaine. This effect was selective for dopamine signaling in the NAc core. Suppression of phasic signaling in the core by Exendin-4 could not be attributed to interference with cocaine binding to one of its major substrates, the dopamine transporter, as cocaine-induced increases in reuptake were unaffected. The results suggest that GLP-1R activation, instead, exerts its suppressive effects by altering dopamine release - possibly by suppressing the excitability of dopamine neurons. Given the role of NAc core dopamine in the generation of conditioned responses based on associative learning, suppression of cocaine-induced dopamine signaling in this subregion by GLP-1R agonism may decrease the reinforcing properties of cocaine. Thus, GLP-1Rs remain viable targets for the treatment and prevention of cocaine seeking, taking and relapse.
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Affiliation(s)
- Samantha M Fortin
- Graduate Program in Neuroscience, University of Illinois at Chicago, 840 South Wood Street, Chicago, IL 60612, USA.
| | - Mitchell F Roitman
- Graduate Program in Neuroscience, University of Illinois at Chicago, 840 South Wood Street, Chicago, IL 60612, USA; Department of Psychology, University of Illinois at Chicago, 1007 W Harrison St, Chicago, IL 60607, USA.
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17
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Bassareo V, Cucca F, Frau R, Di Chiara G. Changes in Dopamine Transmission in the Nucleus Accumbens Shell and Core during Ethanol and Sucrose Self-Administration. Front Behav Neurosci 2017; 11:71. [PMID: 28507512 PMCID: PMC5410575 DOI: 10.3389/fnbeh.2017.00071] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/07/2017] [Indexed: 12/15/2022] Open
Abstract
Ethanol, like other substances of abuse, preferentially increases dopamine (DA) transmission in the rat nucleus accumbens (NAc) following passive administration. It remains unclear, however, whether ethanol also increases NAc DA transmission following operant oral self-administration (SA). The NAc is made-up of a ventro-medial compartment, the shell and a dorso-lateral one, the core, where DA transmission responds differentially following exposure to drugs of abuse. Previous studies from our laboratory investigated changes in dialysate DA in the NAc shell and core of rats responding for sucrose pellets and for drugs of abuse. As a follow up to these studies, we recently investigated the changes in NAc shell and core DA transmission associated to oral SA of a 10% ethanol solution. For the purpose of comparison with literature studies utilizing sucrose + ethanol solutions, we also investigated the changes in dialysate DA associated to SA of 20% sucrose and 10% ethanol + 20% sucrose solutions. Rats were trained to acquire oral SA of the solutions under a Fixed Ratio 1 (FR1) schedule of nose-poking. After training, rats were monitored by microdialysis on three consecutive days under response contingent (active), reward omission (extinction trial) and response non-contingent (passive) presentation of ethanol, sucrose or ethanol + sucrose solutions. Active and passive ethanol administration produced a similar increase in dialysate DA in the two NAc subdivisions, while under extinction trial DA increased preferentially in the shell compared to the core. Conversely, under sucrose SA and extinction DA increased exclusively in the shell. These observations provide unequivocal evidence that oral SA of 10% ethanol increases dialysate DA in the NAc, and also suggest that stimuli conditioned to ethanol exposure contribute to the increase of dialysate DA observed in the NAc following ethanol SA. Comparison between the pattern of DA changes detected in the NAc subdivisions under sucrose and ethanol SA likewise suggests that the NAc shell and core DA play different roles in sucrose as compared to ethanol reinforcement.
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Affiliation(s)
- Valentina Bassareo
- Department of Biomedical Sciences, University of CagliariCagliari, Italy.,Institute of Neuroscience, Cagliari Section, University of CagliariCagliari, Italy
| | - Flavia Cucca
- Department of Biomedical Sciences, University of CagliariCagliari, Italy
| | - Roberto Frau
- Department of Biomedical Sciences, University of CagliariCagliari, Italy
| | - Gaetano Di Chiara
- Department of Biomedical Sciences, University of CagliariCagliari, Italy.,Institute of Neuroscience, Cagliari Section, University of CagliariCagliari, Italy.,National Institute of Neuroscience CNR, University of CagliariCagliari, Italy
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18
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Hammad AM, Althobaiti YS, Das SC, Sari Y. Effects of repeated cocaine exposure and withdrawal on voluntary ethanol drinking, and the expression of glial glutamate transporters in mesocorticolimbic system of P rats. Mol Cell Neurosci 2017; 82:58-65. [PMID: 28442364 DOI: 10.1016/j.mcn.2017.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/18/2017] [Accepted: 04/20/2017] [Indexed: 11/26/2022] Open
Abstract
Glutamatergic neurotransmission within the brain's reward circuits plays a major role in the reinforcing properties of both ethanol and cocaine. Glutamate homeostasis is regulated by several glutamate transporters, including glutamate transporter type 1 (GLT-1), cystine/glutamate transporter (xCT), and glutamate aspartate transporter (GLAST). Cocaine exposure has been shown to induce a dysregulation in glutamate homeostasis and a decrease in the expression of GLT-1 and xCT in the nucleus accumbens (NAc). In this study, alcohol preferring (P) rats were exposed to free-choice of ethanol (15% and 30%) and/or water for five weeks. On Week 6, rats were administered (i.p.) cocaine (10 and 20mg/kg) or saline for 12 consecutive days. This study tested two groups of rats: the first group was euthanized after seven days of repeated cocaine i.p. injection, and the second group was deprived from cocaine for five days and euthanized at Day 5 after cocaine withdrawal. Only repeated cocaine (20mg/kg, i.p.) exposure decreased ethanol intake from Day 3 through Day 8. Co-exposure of cocaine and ethanol decreased the relative mRNA expression and the expression of GLT-1 in the NAc but not in the medial prefrontal cortex (mPFC). Importantly, co-exposure of cocaine and ethanol decreased relative expression of xCT in the NAc but not in the mPFC. Our findings demonstrated that chronic cocaine exposure affects ethanol intake; and ethanol and cocaine co-abuse alters the expression of glial glutamate transporters.
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Affiliation(s)
- Alaa M Hammad
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Yusuf S Althobaiti
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Sujan C Das
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Youssef Sari
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA.
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19
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Singer BF, Bryan MA, Popov P, Robinson TE, Aragona BJ. Rapid induction of dopamine sensitization in the nucleus accumbens shell induced by a single injection of cocaine. Behav Brain Res 2017; 324:66-70. [PMID: 28223145 DOI: 10.1016/j.bbr.2017.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 01/24/2023]
Abstract
Repeated intermittent exposure to cocaine results in the neurochemical sensitization of dopamine (DA) transmission within the nucleus accumbens (NAc). Indeed, the excitability of DA neurons in the ventral tegmental area (VTA) is enhanced within hours of initial psychostimulant exposure. However, it is not known if this is accompanied by a comparably rapid change in the ability of cocaine to increase extracellular DA concentrations in the ventral striatum. To address this question we used fast-scan cyclic voltammetry (FSCV) in awake-behaving rats to measure DA responses in the NAc shell following an initial intravenous cocaine injection, and then again 2-h later. Both injections quickly elevated DA levels in the NAc shell, but the second cocaine infusion produced a greater effect than the first, indicating sensitization. This suggests that a single injection of cocaine induces sensitization-related plasticity very rapidly within the mesolimbic DA system.
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Affiliation(s)
- Bryan F Singer
- Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA.
| | - Myranda A Bryan
- Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA
| | - Pavlo Popov
- Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA
| | - Terry E Robinson
- Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA
| | - Brandon J Aragona
- Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA
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20
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Abstract
Classic hallucinogens share pharmacology as serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonists. Unique among most other Schedule 1 drugs, they are generally non-addictive and can be effective tools in the treatment of addiction. Mechanisms underlying these attributes are largely unknown. However, many preclinical studies show that 5-HT2C agonists counteract the addictive effects of drugs from several classes, suggesting this pharmacological property of classic hallucinogens may be significant. Drawing from a comprehensive analysis of preclinical behavior, neuroanatomy, and neurochemistry studies, this review builds rationale for this hypothesis, and also proposes a testable, neurobiological framework. 5-HT2C agonists work, in part, by modulating dopamine neuron activity in the ventral tegmental area-nucleus accumbens (NAc) reward pathway. We argue that activation of 5-HT2C receptors on NAc shell, GABAergic, medium spiny neurons inhibits potassium Kv1.x channels, thereby enhancing inhibitory activity via intrinsic mechanisms. Together with experiments that show that addictive drugs, such as cocaine, potentiate Kv1.x channels, thereby suppressing NAc shell GABAergic activity, this hypothesis provides a mechanism by which classic hallucinogen-mediated stimulation of 5-HT2C receptors could thwart addiction. It also provides a potential reason for the non-addictive nature of classic hallucinogens.
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Affiliation(s)
- Clinton E Canal
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, USA
| | - Kevin S Murnane
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, USA
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21
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Response contingency directs long-term cocaine-induced neuroplasticity in prefrontal and striatal dopamine terminals. Eur Neuropsychopharmacol 2016; 26:1667-72. [PMID: 27593624 DOI: 10.1016/j.euroneuro.2016.08.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 07/18/2016] [Accepted: 08/22/2016] [Indexed: 11/22/2022]
Abstract
Exposure to addictive substances such as cocaine is well-known to alter brain organisation. Cocaine-induced neuroadaptations depend on several factors, including drug administration paradigm. To date, studies addressing the consequences of cocaine exposure on dopamine transmission have either not been designed to investigate the role of response contingency or focused only on short-term neuroplasticity. We demonstrate a key role of response contingency in directing long-term cocaine-induced neuroplasticity throughout projection areas of the mesocorticolimbic dopamine system. We found enhanced electrically-evoked [(3)H]dopamine release from superfused brain slices of nucleus accumbens shell and core, dorsal striatum and medial prefrontal cortex three weeks after cessation of cocaine self-administration. In yoked cocaine rats receiving the same amount of cocaine passively, sensitised dopamine terminal reactivity was only observed in the nucleus accumbens core. Control sucrose self-administration experiments demonstrated that the observed neuroadaptations were not the result of instrumental learning per se. Thus, long-term withdrawal from cocaine self-administration is associated with widespread sensitisation of dopamine terminals throughout frontostriatal circuitries.
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22
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Leong KC, Berini CR, Ghee SM, Reichel CM. Extended cocaine-seeking produces a shift from goal-directed to habitual responding in rats. Physiol Behav 2016; 164:330-5. [PMID: 27321756 DOI: 10.1016/j.physbeh.2016.06.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/02/2016] [Accepted: 06/15/2016] [Indexed: 11/17/2022]
Abstract
Cocaine addiction is often characterized by a rigid pattern of behavior in which cocaine users continue seeking and taking drug despite negative consequences associated with its use. As such, full acquisition and relapse of drug-seeking behavior may be attributed to a shift away from goal-directed responding and a shift towards the maladaptive formation of rigid and habit-like responses. This rigid nature of habitual responding can be developed with extended training and is typically characterized by insensitivity to changes in outcome value. The present study determined whether cocaine (primary reinforcer) and cocaine associated cues (secondary reinforcer) could be devalued in rats with different histories of cocaine self-administration. Specifically, rats were trained on two schedules of cocaine self-administration (long-access vs. short-access). Following training the cocaine reinforcer was devalued through three separate pairings of lithium chloride with cocaine infusions. Cocaine history did not have an impact on devaluation of cocaine-associated cues. However, the reinforcing properties of cocaine were devalued only in rats on a short-access cocaine schedule but not those trained on a long-access schedule. Taken together this pattern of findings suggests that, in short access rats, devaluation is specific to the primary reinforcer and not associative stimuli such as cues. Importantly, rats that received extended training during self-administration displayed insensitivity to outcome devaluation of the primary reinforcer as well as all associative stimuli, thus displaying rigid behavioral responding similar to behavioral patterns found in addiction. Alternatively, long access cocaine exposure may have altered the devaluation threshold.
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Affiliation(s)
- Kah-Chung Leong
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Carole R Berini
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Shannon M Ghee
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Carmela M Reichel
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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23
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Varner EL, Jaquins-Gerstl A, Michael AC. Enhanced Intracranial Microdialysis by Reduction of Traumatic Penetration Injury at the Probe Track. ACS Chem Neurosci 2016; 7:728-36. [PMID: 27003503 PMCID: PMC7372793 DOI: 10.1021/acschemneuro.5b00331] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microdialysis provides deep insight into chemical neuroscience by enabling in vivo intracranial chemical monitoring. Nevertheless, implanting a microdialysis probe causes a traumatic penetration injury (TPI) of brain tissue at the probe track. The TPI, which is clearly documented by voltammetry and histochemical imaging, is a drawback because it perturbs the exact tissue from which the brain dialysate samples are derived. Our goal is to reduce, if not eventually eliminate, the TPI and its detrimental effects on neurochemical monitoring. Here, we demonstrate that combining a 5-day wait period after probe implantation with the continuous retrodialysis of a low-micromolar concentration of dexamethasone vastly reduces the TPI. Our approach to reducing the TPI reinstates normal evoked dopamine release activity in the tissue adjacent to the microdialysis probe, brings evoked dopamine release at the probe outlet into quantitative agreement with evoked dopamine release next to the probe, reinstates normal immunoreactivity for tyrosine hydroxylase and the dopamine transporter near the probe track, and greatly suppresses glial activation and scaring near the probe track. This reduction of the TPI and reinstatement of normal evoked dopamine release activity adjacent to the probe track appears to be due to dexamethasone's anti-inflammatory actions.
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Affiliation(s)
- Erika L Varner
- Department of Chemistry, University of Pittsburgh , 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Andrea Jaquins-Gerstl
- Department of Chemistry, University of Pittsburgh , 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Adrian C Michael
- Department of Chemistry, University of Pittsburgh , 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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24
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Pintsuk J, Borroto-Escuela DO, Pomierny B, Wydra K, Zaniewska M, Filip M, Fuxe K. Cocaine self-administration differentially affects allosteric A2A-D2 receptor-receptor interactions in the striatum. Relevance for cocaine use disorder. Pharmacol Biochem Behav 2016; 144:85-91. [PMID: 26987369 DOI: 10.1016/j.pbb.2016.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/04/2016] [Accepted: 03/11/2016] [Indexed: 11/25/2022]
Abstract
In the current study behavioral and biochemical experiments were performed to study changes in the allosteric A2AR-D2R interactions in the ventral and dorsal striatum after cocaine self-administration versus corresponding yoked saline control. By using ex vivo [(3)H]-raclopride/quinpirole competition experiments, the effects of the A2AR agonist CGS 21680 (100 nM) on the KiH and KiL values of the D2-like receptor (D2-likeR) were determined. One major result was a significant reduction in the D2-likeR agonist high affinity state observed with CGS 21680 after cocaine self-administration in the ventral striatum compared with the yoked saline group. The results therefore support the hypothesis that A2AR agonists can at least in part counteract the motivational actions of cocaine. This action is mediated via the D2-likeR by targeting the A2AR protomer of A2AR-D2-like R heteroreceptor complexes in the ventral striatum, which leads to the reduction of D2-likeR protomer recognition through the allosteric receptor-receptor interaction. In contrast, in the dorsal striatum the CGS 21680-induced antagonistic modulation in the D2-likeR agonist high affinity state was abolished after cocaine self-administration versus the yoked saline group probably due to a local dysfunction/disruption of the A2AR-D2-like R heteroreceptor complexes. Such a change in the dorsal striatum in cocaine self-administration can contribute to the development of either locomotor sensitization, habit-forming learning and/or the compulsive drug seeking by enhanced D2-likeR protomer signaling. Potential differences in the composition and stoichiometry of the A2AR-D2R heteroreceptor complexes, including differential recruitment of sigma 1 receptor, in the ventral and dorsal striatum may explain the differential regional changes observed in the A2A-D2-likeR interactions after cocaine self-administration.
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Affiliation(s)
- Julia Pintsuk
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Institute of Biomedicine and Translational Medicine, Department of Physiology, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia.
| | - Dasiel O Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Earth, Life and Environmental Sciences, Section of Physiology, Campus Scientifico Enrico Mattei, via Ca' le Suore 2, I-61029 Urbino, Italy.
| | - Bartosz Pomierny
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Karolina Wydra
- Laboratory of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, PL-31-343, Kraków, Poland.
| | - Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, PL-31-343, Kraków, Poland.
| | - Malgorzata Filip
- Laboratory of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, PL-31-343, Kraków, Poland.
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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25
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Increased mesocorticolimbic dopamine during acute and repeated social defeat stress: modulation by corticotropin releasing factor receptors in the ventral tegmental area. Psychopharmacology (Berl) 2015; 232:4469-79. [PMID: 26403083 PMCID: PMC4651830 DOI: 10.1007/s00213-015-4082-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/03/2015] [Indexed: 12/19/2022]
Abstract
RATIONALE Stress activates a subset of dopamine neurons in the ventral tegmental area (VTA), increasing extracellular dopamine in the medial prefrontal cortex (mPFC) and nucleus accumbens shell (NAcSh). The stress neuropeptide corticotropin releasing factor (CRF) and its receptors (CRF-R1 and CRF-R2) are located within the VTA and directly and indirectly influence dopaminergic activity. However, it has yet to be shown in vivo whether VTA CRF receptor activation is necessary for acute and repeated stress-induced dopamine efflux. OBJECTIVE With intra-VTA CRF-R1 and CRF-R2 antagonism during social defeat, we assessed whether blockade of these receptors could prevent stress-induced dopamine increases in the mPFC and NAcSh using in vivo microdialysis. METHODS Rats were microinjected with a CRF-R1 or CRF-R2 antagonist into the VTA prior to social defeat stress on days 1, 4, 7, and 10. In vivo microdialysis for dopamine in the mPFC and NAcSh was performed during stress on days 1 and 10. RESULTS During the first social defeat, extracellular dopamine was significantly elevated in both the mPFC and NAcSh, and this increase in the NAcSh was blocked by intra-VTA CRF-R2, but not CRF-R1, antagonism. During the final social defeat, the dopaminergic increase was neither sensitized nor habituated in the mPFC and NAcSh, and intra-VTA CRF-R2, but not CRF-R1, antagonism prevented the dopamine increase in both brain regions. CONCLUSION These findings show that CRF-R2 in the VTA is necessary for acute and repeated stress-induced dopamine efflux in the NAcSh, but is only recruited into mPFC-projecting dopamine neurons with repeated stress exposure.
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26
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Barr JL, Rasmussen BA, Tallarida CS, Scholl JL, Forster GL, Unterwald EM, Rawls SM. Ceftriaxone attenuates acute cocaine-evoked dopaminergic neurotransmission in the nucleus accumbens of the rat. Br J Pharmacol 2015; 172:5414-24. [PMID: 26375494 PMCID: PMC4950793 DOI: 10.1111/bph.13330] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Ceftriaxone is a β-lactam antibiotic and glutamate transporter activator that reduces the reinforcing effects of psychostimulants. Ceftriaxone also reduces locomotor activation following acute psychostimulant exposure, suggesting that alterations in dopamine transmission in the nucleus accumbens contribute to its mechanism of action. In the present studies we tested the hypothesis that pretreatment with ceftriaxone disrupts acute cocaine-evoked dopaminergic neurotransmission in the nucleus accumbens. EXPERIMENTAL APPROACH Adult male Sprague-Dawley rats were pretreated with saline or ceftriaxone (200 mg kg(-1) , i.p. × 10 days) and then challenged with cocaine (15 mg kg(-1) , i.p.). Motor activity, dopamine efflux (via in vivo microdialysis) and protein levels of tyrosine hydroxylase (TH), the dopamine transporter and organic cation transporter as well as α-synuclein, Akt and GSK3β were analysed in the nucleus accumbens. KEY RESULTS Ceftriaxone-pretreated rats challenged with cocaine displayed reduced locomotor activity and accumbal dopamine efflux compared with saline-pretreated controls challenged with cocaine. The reduction in cocaine-evoked dopamine levels was not counteracted by excitatory amino acid transporter 2 blockade in the nucleus accumbens. Pretreatment with ceftriaxone increased Akt/GSK3β signalling in the nucleus accumbens and reduced levels of dopamine transporter, TH and phosphorylated α-synuclein, indicating that ceftriaxone affects numerous proteins involved in dopaminergic transmission. CONCLUSIONS AND IMPLICATIONS These results are the first evidence that ceftriaxone affects cocaine-evoked dopaminergic transmission, in addition to its well-described effects on glutamate, and suggest that its ability to attenuate cocaine-induced behaviours, such as psychomotor activity, is due in part to reduced dopaminergic neurotransmission in the nucleus accumbens.
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Affiliation(s)
- J L Barr
- Department of Pharmacology and Centre for Substance Abuse ResearchTemple University School of MedicinePhiladelphiaPAUSA
| | - B A Rasmussen
- Department of Pharmacology and Centre for Substance Abuse ResearchTemple University School of MedicinePhiladelphiaPAUSA
| | - C S Tallarida
- Department of Pharmacology and Centre for Substance Abuse ResearchTemple University School of MedicinePhiladelphiaPAUSA
| | - J L Scholl
- Centre for Brain and Behaviour Research, Division of Basic Biomedical SciencesSanford School of Medicine at the University of South DakotaVermillionSDUSA
| | - G L Forster
- Centre for Brain and Behaviour Research, Division of Basic Biomedical SciencesSanford School of Medicine at the University of South DakotaVermillionSDUSA
| | - E M Unterwald
- Department of Pharmacology and Centre for Substance Abuse ResearchTemple University School of MedicinePhiladelphiaPAUSA
| | - S M Rawls
- Department of Pharmacology and Centre for Substance Abuse ResearchTemple University School of MedicinePhiladelphiaPAUSA
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Bassareo V, Cucca F, Frau R, Di Chiara G. Differential activation of accumbens shell and core dopamine by sucrose reinforcement with nose poking and with lever pressing. Behav Brain Res 2015; 294:215-23. [PMID: 26275926 DOI: 10.1016/j.bbr.2015.08.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 11/30/2022]
Abstract
In order to investigate the role of modus operandi in the changes of nucleus accumbens (NAc) dopamine (DA) transmission in sucrose reinforcement, extracellular DA was monitored by microdialysis in the NAc shell and core of rats trained on a fixed-ratio 1 schedule to respond for sucrose pellets by nose poking and lever pressing respectively. After training, rats were tested on three different sessions: sucrose reinforcement, extinction and passive sucrose presentation. In rats responding by nose poking dialysate DA increased in the shell but not in the core under reinforced as well as under extinction sessions. In contrast, in rats responding by lever pressing dialysate DA increased both in the accumbens shell and core under reinforced and extinction sessions. Response non-contingent sucrose presentation increased dialysate DA in the shell and core of rats trained to respond for sucrose by nose poking as well as in those trained by lever pressing. In rats trained to respond for sucrose by nose poking on a FR5 schedule dialysate DA also increased selectively in the NAc shell during reinforced responding and in both the shell and core under passive sucrose presentation. These findings, while provide an explanation for the discrepancies existing in the literature over the responsiveness of shell and core DA in rats responding for food, are consistent with the notion that NAc shell and core DA encode different aspects of reinforcement.
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Affiliation(s)
- V Bassareo
- Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy.
| | - F Cucca
- Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - R Frau
- Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy
| | - G Di Chiara
- Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy; CNR Institute of Neuroscience, Cagliari Section, Via Ospedale 72, 09124 Cagliari, Italy.
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Pisanu A, Lecca D, Valentini V, Bahi A, Dreyer JL, Cacciapaglia F, Scifo A, Piras G, Cadoni C, Di Chiara G. Impairment of acquisition of intravenous cocaine self-administration by RNA-interference of dopamine D1-receptors in the nucleus accumbens shell. Neuropharmacology 2015; 89:398-411. [PMID: 25446574 DOI: 10.1016/j.neuropharm.2014.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 01/17/2023]
Abstract
Microdialysis during i.v. drug self-administration (SA) have implicated nucleus accumbens (NAc) shell DA in cocaine and heroin reinforcement. However, this correlative evidence has not been yet substantiated by experimental evidence obtained by studying the effect of selective manipulation of NAc shell DA transmission on cocaine and heroin SA. In order to investigate this issue, DA D1a receptor (D1aR) expression was impaired in the NAc shell and core by locally infusing lentiviral vectors (LV) expressing specific D1aR-siRNAs (LV-siRNAs). Control rats were infused in the same areas with LV expressing GFP. Fifteen days later, rats were trained to acquire i.v. cocaine or heroin self-administration (SA). At the end of behavioral experiments, in order to evaluate the effect of LV-siRNA on D1aR expression, rats were challenged with amphetamine and the brains were processed for immunohistochemical detection of c-Fos and D1aR. Control rats acquired i.v. cocaine and heroin SA. Infusion of LV-siRNAs in the medial NAc shell reduced D1aR density and the number of c-Fos positive nuclei in the NAc shell, while sparing the core, and prevented the acquisition of cocaine, but not heroin SA. In turn, LV-siRNAs infusion in the core reduced D1aR density and the number of c-Fos positive nuclei in the same area, while sparing the shell, and failed to affect acquisition of cocaine. The differential effect of LV impairment of NAc shell D1aR on cocaine and heroin SA indicates that NAc shell DA acting on D1aR specifically mediates cocaine reinforcement.
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Affiliation(s)
- Augusta Pisanu
- Institute of Neuroscience, National Research Council of Italy, 09124 Cagliari, Italy
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Meyer AC, Bardo MT. Amphetamine self-administration and dopamine function: assessment of gene × environment interactions in Lewis and Fischer 344 rats. Psychopharmacology (Berl) 2015; 232:2275-85. [PMID: 25566972 PMCID: PMC4465863 DOI: 10.1007/s00213-014-3854-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 12/22/2014] [Indexed: 12/01/2022]
Abstract
RATIONALE Previous research suggests both genetic and environmental influences on substance abuse vulnerability. OBJECTIVES The current work sought to investigate the interaction of genes and environment on the acquisition of amphetamine self-administration as well as amphetamine-stimulated dopamine (DA) release in nucleus accumbens shell using in vivo microdialysis. METHODS Inbred Lewis (LEW) and Fischer (F344) rat strains were raised in either an enriched condition (EC), social condition (SC), or isolated condition (IC). Acquisition of amphetamine self-administration (0.1 mg/kg/infusion) was determined across an incrementing daily fixed ratio (FR) schedule. In a separate cohort of rats, extracellular DA and the metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) were measured in the nucleus accumbens shell following an acute amphetamine injection (1 mg/kg). RESULTS "Addiction-prone" LEW rats had greater acquisition of amphetamine self-administration on a FR1 schedule compared to "addiction-resistant" F344 rats when raised in the SC environment. These genetic differences were negated in both the EC and IC environments, with enrichment buffering against self-administration and isolation enhancing self-administration in both strains. On a FR5 schedule, the isolation-induced increase in amphetamine self-administration was greater in F344 than LEW rats. While no group differences were obtained in extracellular DA, gene × environment differences were obtained in extracellular levels of the metabolite DOPAC. In IC rats only, LEW rats showed attenuation in the amphetamine-induced decrease in DOPAC compared to F344 rats. IC LEW rats also had an attenuated DOPAC response to amphetamine compared to EC LEW rats. CONCLUSIONS The current results demonstrate gene × environment interactions in amphetamine self-administration and amphetamine-induced changes in extracellular DOPAC in nucleus accumbens (NAc) shell. However, the behavioral and neurochemical differences were not related directly, indicating that mechanisms independent of DA metabolism in NAc shell likely mediate the gene × environment effects in amphetamine self-administration.
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Affiliation(s)
- Andrew C. Meyer
- Department of Psychiatry, University of Vermont, Burlington, VT, USA
| | - Michael T. Bardo
- Department of Psychology, University of Kentucky, Lexington, KY, USA,Center for Drug Abuse Research Translation, Lexington, KY, USA
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Bassareo V, Cucca F, Musio P, Lecca D, Frau R, Di Chiara G. Nucleus accumbens shell and core dopamine responsiveness to sucrose in rats: role of response contingency and discriminative/conditioned cues. Eur J Neurosci 2015; 41:802-9. [PMID: 25645148 DOI: 10.1111/ejn.12839] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 12/19/2014] [Accepted: 12/20/2014] [Indexed: 11/27/2022]
Abstract
This study investigated by microdialysis the role of response contingency and food-associated cues in the responsiveness of dopamine transmission in the nucleus accumbens shell and core to sucrose feeding. In naive rats, single-trial non-contingent presentation and feeding of sucrose pellets increased dialysate shell dopamine and induced full habituation of dopamine responsiveness to sucrose feeding 24 and 48 h later. In rats trained to respond for sucrose pellets on a fixed ratio 1 (FR1) schedule, dialysate dopamine increased in the shell but not in the core during active responding as well as under extinction in the presence of sucrose cues. In rats yoked to the operant rats, the presentation of sucrose cues also increased dialysate dopamine selectively in the shell. In contrast, non-contingent sucrose presentation and feeding in FR1-trained and in yoked rats increased dialysate dopamine to a similar extent in the shell and core. It is concluded that, whereas non-contingent sucrose feeding activated dopamine transmission in the shell and core, response-contingent feeding activated, without habituation, dopamine transmission selectively in the shell as a result of the action of sucrose conditioned cues. These observations are consistent with a critical role of conditioned cues acquired during training and differential activation of shell vs. core dopamine for response-contingent sucrose feeding.
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Affiliation(s)
- V Bassareo
- Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124, Cagliari, Italy; National Institute of Neuroscience, University of Cagliari, Cagliari, Italy
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Huang X, Huang K, Zheng W, Beveridge TJR, Yang S, Li X, Li P, Zhou W, Liu Y. The effects of GSK-3β blockade on ketamine self-administration and relapse to drug-seeking behavior in rats. Drug Alcohol Depend 2015; 147:257-65. [PMID: 25497591 DOI: 10.1016/j.drugalcdep.2014.10.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 10/23/2014] [Accepted: 10/25/2014] [Indexed: 11/26/2022]
Abstract
RATIONALE The role of glycogen synthase kinase-3 (GSK-3) has recently been implicated in the neurochemical mechanism underlying ketamine-induced neuronal toxicity and behavioral disturbance. OBJECTIVES The primary goal of the present study was to determine the role of GSK-3β in ketamine self-administration (SA) and relapse to drug-seeking behavior after abstinence. METHODS In Experiment 1, the level of phosphorylated GSK-3β (p-GSK-3β) and total GSK-3β (t-GSK-3β) was determined in various brain areas following 14 days of ketamine SA. In Experiments 2 and 3, the effects of a GSK-3β inhibitor, SB216763 (2 and 4 mg/kg) and a GSK-3 inhibitor, lithium (LiCl, 100mg/kg) on the responding maintained by 0.5mg/kg/infusion ketamine SA were evaluated. In Experiments 4 and 5, rats underwent ketamine SA for 14 days followed by a 10-day abstinence period. The animals were treated with 2 or 4 mg/kg GSK-3β inhibitor, or 100mg/kg LiCl during the cue-induced relapse test. Seven days later, animals received the same drug treatment and underwent the drug-induced relapse test. Finally, the effect of saline and DMSO on locomotor activity was evaluated in Experiment 6. RESULTS Ketamine SA significantly decreased the ratio p-GSK-3β and t-GSK-3β (p-GSK-3β:t-GSK-3β) in the caudate putamen, nucleus accumbens, and ventral tegmental area. Both SB216763 and LiCl decreased responding on a progressive ratio schedule, but not on a fixed ratio schedule. Cue-induced relapse was suppressed only by 4mg/kg SB216763, whereas drug-induced relapse was inhibited by 2, 4 mg/kg SB216763 and LiCl. However, inactive responses were also suppressed by LiCl during progressive ratio and drug-induced relapse testing. CONCLUSIONS SB216763 was effective at decreasing ketamine SA under the PR schedule and reducing drug-seeking behavior after abstinence.
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Affiliation(s)
- Xianni Huang
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Kunyu Huang
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Wenhui Zheng
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Thomas J R Beveridge
- Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA; Ferring Pharmaceuticals Inc., 100 Interpace Pkwy, Parsippany, NJ 07054 USA
| | - Shujun Yang
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Xingxing Li
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Pengping Li
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China
| | - Wenhua Zhou
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China; Drug Addiction Research and Treatment Center of Ningbo, 42 Xibei St., Ningbo 315010, Zhejiang, PR China.
| | - Yu Liu
- Ningbo University School of Medicine, 818 Fenghua Road, Ningbo 315211, Zhejiang, PR China.
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Shimamoto A, Holly EN, Boyson CO, DeBold JF, Miczek KA. Individual differences in anhedonic and accumbal dopamine responses to chronic social stress and their link to cocaine self-administration in female rats. Psychopharmacology (Berl) 2015; 232:825-34. [PMID: 25178816 PMCID: PMC4310791 DOI: 10.1007/s00213-014-3725-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
RATIONALE Women are twice as likely as men to develop major depressive disorder. Exposure to chronic stress can induce depression in some vulnerable individuals, while others are resistant to depressive-like symptoms after equivalent levels of chronic stress. OBJECTIVES In female rats, individual differences in saccharin intake during chronic social defeat stress may predict subsequent cocaine self-administration, and may be attributed to alterations in mesolimbic dopamine activity. METHODS Female rats were exposed to 21 days of chronic social defeat stress, during which they were evaluated for their anhedonia-like responses in the form of saccharin intake. After chronic social defeat stress, the rats were tested for behavioral cross-sensitization to cocaine and escalated cocaine self-administration in a 24-h "binge." A separate group of animals underwent in vivo microdialysis of the nucleus accumbens (NAc) shell to assess dopamine (DA) in response to acute cocaine challenge. RESULTS Cluster analysis revealed two phenotypes among the stressed female rats based on their saccharin intake while being exposed to stress, termed stress-resistant (SR, 28 %) and stress-sensitive (SS, 72 %). The amount of cocaine self-administered during the 24-h "binge" was positively correlated with preceding saccharin intake. The NAc DA response to a cocaine challenge was significantly lower in SR rats than in the SS and non-stressed control rats. No other significant differences were observed in behavioral cross-sensitization or cocaine self-administration prior to the "binge." CONCLUSION Female rats showed individual differences in their anhedonic-like response to chronic social defeat stress, and these differences were reliably associated with subsequent cocaine-taking behavior.
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Affiliation(s)
- Akiko Shimamoto
- Department of Psychology, Tufts University, Medford, MA, USA,
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Wenzel JM, Rauscher NA, Cheer JF, Oleson EB. A role for phasic dopamine release within the nucleus accumbens in encoding aversion: a review of the neurochemical literature. ACS Chem Neurosci 2015; 6:16-26. [PMID: 25491156 DOI: 10.1021/cn500255p] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Survival is dictated by an organism's fitness in approaching positive stimuli and avoiding harm. While a rich literature outlines a role for mesolimbic dopamine in reward and appetitive behaviors, dopamine's involvement in aversion and avoidance behaviors remains controversial. Debate surrounding dopamine's function in the processing of negative stimuli likely stems from conflicting results reported by single-unit electrophysiological studies. Indeed, a number of studies suggest that midbrain dopaminergic cells are inhibited by the presentation of negative or fearful stimuli, while others report no change, or even an increase, in their activity. These disparate results may be due to population heterogeneity. Recent evidence demonstrates that midbrain dopamine neurons are heterogeneous in their projection targets, responses to environmental stimuli, pharmacology, and influences on motivated behavior. Thus, in order to assemble an accurate account of dopamine function during aversive stimulus experience and related behavior, it is necessary to examine the functional output of dopamine neural activity at mesolimbic terminal regions. This Review presents a growing body of evidence that dopamine release in the nucleus accumbens encodes not only reward, but also aversion. For example, our laboratory recently utilized fast-scan cyclic voltammetry to show that real-time changes in accumbal dopamine release are detected when animals are presented with predictors of aversion and its avoidance. These data, along with other reports, support a considerably more nuanced view of dopamine neuron function, wherein accumbal dopamine release is differentially modulated by positive and negative affective stimuli to promote adaptive behaviors.
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Affiliation(s)
| | - Noah A. Rauscher
- Department
of Psychology, University of Colorado, Denver, Colorado 80015, United States
| | | | - Erik B. Oleson
- Department
of Psychology, University of Colorado, Denver, Colorado 80015, United States
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Kufahl PR, Peartree NA, Heintzelman KL, Chung M, Neisewander JL. Region-specific effects of isoflurane anesthesia on Fos immunoreactivity in response to intravenous cocaine challenge in rats with a history of repeated cocaine administration. Brain Res 2015; 1594:256-66. [PMID: 25451087 PMCID: PMC4805112 DOI: 10.1016/j.brainres.2014.10.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 12/29/2022]
Abstract
We have previously shown that acute intravenous (i.v.) administration of cocaine increases Fos immunoreactivity in rats under isoflurane anesthesia. Given that Fos expression is a marker of neural activation, the results suggested that isoflurane is appropriate for imaging cocaine effects under anesthesia. However, most imaging research in this area utilizes subjects with a history of repeated cocaine exposure and this drug history may interact with anesthetic use differently from acute cocaine exposure. Thus, this study further examined Fos expression under isoflurane in rats with a history of repeated i.v. cocaine administration. Rats received daily injections of either saline or cocaine (2mg/kg, i.v.) across 7 consecutive days, followed by 5 days of no drug exposure. On the test day, rats were either nonanesthetized or anesthetized under isoflurane and were given an acute challenge of cocaine (2mg/kg, i.v.). Additional saline-exposed controls received a saline challenge. Ninety min after the drug challenge, the rats were perfused under isoflurane anesthesia and their brains were processed for Fos protein immunohistochemistry. We found that challenge injections of cocaine following a regimen of repeated cocaine exposure resulted in Fos expression in the prefrontal cortex and striatum roughly equivalent to that found in rats who had received the cocaine challenge after a history of vehicle injections. Additionally, isoflurane anesthesia resulted in a heterogeneous attenuation of cocaine-induced Fos expression, with the most robust effect in the orbital cortex but no effect in the nucleus accumbens core (NAcC). These results indicate that cocaine-induced Fos is preserved in the NAcC under isoflurane, suggesting that isoflurane can be used in imaging studies involving cocaine effects in this region.
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Affiliation(s)
- Peter R Kufahl
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States.
| | - Natalie A Peartree
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Krista L Heintzelman
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Maggie Chung
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Janet L Neisewander
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85287-4501, United States
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Abstract
There is abundant evidence that the dopamine (DA) neurons that project to the nucleus accumbens play a central role in neurobiological mechanisms underpinning drug dependence. This chapter considers the ways in which these projections facilitate the addiction to nicotine and tobacco. It focuses on the complimentary roles of the two principal subdivisions of the nucleus accumbens, the accumbal core and shell, in the acquisition and maintenance of nicotine-seeking behavior. The ways in which tonic and phasic firing of the neurons contributes to the ways in which the accumbens mediate the behavioral responses to nicotine are also considered. Experimental studies suggest that nicotine has relatively weak addictive properties which are insufficient to explain the powerful addictive properties of tobacco smoke. This chapter discusses hypotheses that seek to explain this conundrum. They implicate both discrete sensory stimuli closely paired with the delivery of tobacco smoke and contextual stimuli habitually associated with the delivery of the drug. The mechanisms by which each type of stimulus influence tobacco dependence are hypothesized to depend upon the increased DA release and overflow, respectively, in the two subdivisions of the accumbens. It is suggested that a majority of pharmacotherapies for tobacco dependence are not more successful because they fail to address this important aspect of the dependence.
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Affiliation(s)
- David J K Balfour
- Medical Research Institute, Division of Neuroscience, Ninewells Hospital and Medical School, Dundee, DD1 9SY, Scotland,
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Pomierny-Chamiolo L, Miszkiel J, Frankowska M, Pomierny B, Niedzielska E, Smaga I, Fumagalli F, Filip M. Withdrawal from cocaine self-administration and yoked cocaine delivery dysregulates glutamatergic mGlu5 and NMDA receptors in the rat brain. Neurotox Res 2014; 27:246-58. [PMID: 25408547 PMCID: PMC4353866 DOI: 10.1007/s12640-014-9502-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/06/2014] [Accepted: 11/06/2014] [Indexed: 12/16/2022]
Abstract
In human addicts and in animal models, chronic cocaine use leads to numerous alterations in glutamatergic transmission, including its receptors. The present study focused on metabotropic glutamatergic receptors type 5 (mGluR5) and N-methyl-D-aspartate receptor subunits (NMDAR: GluN1, GluN2A, GluN2B) proteins during cocaine self-administration and after 10-day of extinction training in rats. To discriminate the contingent from the non-contingent cocaine delivery, we employed the “yoked”-triad control procedure. Protein expression in rat prefrontal cortex, nucleus accumbens, hippocampus, and dorsal striatum was determined. We also examined the Homer1b/c protein, a member of the postsynaptic density protein family that links NMDAR to mGluR5. Our results revealed that cocaine self-administration selectively increased GluN1 and GluN2A subunit in the rat hippocampus and dorsal striatum, respectively, while mGluR5 protein expression was similarly increased in the dorsal striatum of both experimental groups. Withdrawal from both contingent and non-contingent cocaine delivery induced parallel increases in prefrontal cortical GluN2A protein expression, hippocampal mGluR5, and GluN1 protein expression as well as in accumbal GluN1 subunit expression, while the mGluR5 expression was reduced in the prefrontal cortex. Extinction training in animals with a history of cocaine self-administration resulted in an elevation of the hippocampal GluN2A/GluN2B subunits and accumbal mGluR5, and in a 50 % decrease of mGluR5 protein expression in the dorsal striatum. The latter reduction was associated with Homer1b/1c protein level decrease. Our results showed that both contingent and non-contingent cocaine administration produces numerous, brain region specific, alterations in the mGluR5, NMDA, and Homer1b/1c protein expression which are dependent on the modality of cocaine administration.
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Affiliation(s)
- Lucyna Pomierny-Chamiolo
- Department of Toxicology, Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University, Medical College, Medyczna 9, 30-688, Kraków, Poland,
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LeBlanc KH, Maidment NT, Ostlund SB. Impact of repeated intravenous cocaine administration on incentive motivation depends on mode of drug delivery. Addict Biol 2014; 19:965-71. [PMID: 23639056 DOI: 10.1111/adb.12063] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The incentive sensitization theory of addiction posits that repeated exposure to drugs of abuse, like cocaine, can lead to long-term adaptations in the neural circuits that support motivated behavior, providing an account of pathological drug-seeking behavior. Although pre-clinical findings provide strong support for this theory, much remains unknown about the conditions that support incentive sensitization. The current study examined whether the mode of cocaine administration is an important factor governing that drug's long-term impact on behavior. Separate groups of rats were allowed either to self-administer intravenous cocaine or were given an equivalent number and distribution of unsignaled cocaine or saline infusions. During the subsequent test of incentive motivation (Pavlovian-to-instrumental transfer), we found that rats with a history of cocaine self-administration showed strong cue-evoked food seeking, in contrast to rats given unsignaled cocaine or saline. This finding indicates that the manner in which cocaine is administered can determine its lasting behavioral effects, suggesting that subjective experiences during drug use play a critical role in the addiction process. Our findings may therefore have important implications for the study and treatment of compulsive drug seeking.
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Affiliation(s)
- Kimberly H. LeBlanc
- Department of Psychiatry and Biobehavioral Sciences; Semel Institute for Neuroscience and Human Behavior; UCLA; Los Angeles CA USA
- Brain Research Institute; UCLA; Los Angeles CA USA
| | - Nigel T. Maidment
- Department of Psychiatry and Biobehavioral Sciences; Semel Institute for Neuroscience and Human Behavior; UCLA; Los Angeles CA USA
- Brain Research Institute; UCLA; Los Angeles CA USA
| | - Sean B. Ostlund
- Department of Psychiatry and Biobehavioral Sciences; Semel Institute for Neuroscience and Human Behavior; UCLA; Los Angeles CA USA
- Brain Research Institute; UCLA; Los Angeles CA USA
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Gould RW, Duke AN, Nader MA. PET studies in nonhuman primate models of cocaine abuse: translational research related to vulnerability and neuroadaptations. Neuropharmacology 2014; 84:138-51. [PMID: 23458573 PMCID: PMC3692588 DOI: 10.1016/j.neuropharm.2013.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/07/2013] [Accepted: 02/07/2013] [Indexed: 01/11/2023]
Abstract
The current review highlights the utility of positron emission tomography (PET) imaging to study the neurobiological substrates underlying vulnerability to cocaine addiction and subsequent adaptations following chronic cocaine self-administration in nonhuman primate models of cocaine abuse. Environmental (e.g., social rank) and sex-specific influences on dopaminergic function and sensitivity to the reinforcing effects of cocaine are discussed. Cocaine-related cognitive deficits have been hypothesized to contribute to high rates of relapse and are described in nonhuman primate models. Lastly, the long-term consequences of cocaine on neurobiology are discussed. PET imaging and longitudinal, within-subject behavioral studies in nonhuman primates have provided a strong framework for designing pharmacological and behavioral treatment strategies to aid drug-dependent treatment seekers. Non-invasive PET imaging will allow for individualized treatment strategies. Recent advances in radiochemistry of novel PET ligands and other imaging modalities can further advance our understanding of stimulant use on the brain. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.
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Affiliation(s)
- Robert W Gould
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Angela N Duke
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA.
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA.
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Saddoris MP, Carelli RM. Cocaine self-administration abolishes associative neural encoding in the nucleus accumbens necessary for higher-order learning. Biol Psychiatry 2014; 75:156-64. [PMID: 24035479 PMCID: PMC3865233 DOI: 10.1016/j.biopsych.2013.07.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND Cocaine use is often associated with diminished cognitive function, persisting even after abstinence from the drug. Likely targets for these changes are the core and shell of the nucleus accumbens (NAc), which are critical for mediating the rewarding aspects of drugs of abuse as well as supporting associative learning. To understand this deficit, we recorded neural activity in the NAc of rats with a history of cocaine self-administration or control subjects while they learned Pavlovian first- and second-order associations. METHODS Rats were trained for 2 weeks to self-administer intravenous cocaine or water. Later, rats learned a first-order Pavlovian discrimination where a conditioned stimulus (CS)+ predicted food, and a control (CS-) did not. Rats then learned a second-order association where, absent any food reinforcement, a novel cued (SOC+) predicted the CS+ and another (SOC-) predicted the CS-. Electrophysiological recordings were taken during performance of these tasks in the NAc core and shell. RESULTS Both control subjects and cocaine-experienced rats learned the first-order association, but only control subjects learned the second-order association. Neural recordings indicated that core and shell neurons encoded task-relevant information that correlated with behavioral performance, whereas this type of encoding was abolished in cocaine-experienced rats. CONCLUSIONS The NAc core and shell perform complementary roles in supporting normal associative learning, functions that are impaired after cocaine experience. This impoverished encoding of motivational behavior, even after abstinence from the drug, might provide a key mechanism to understand why addiction remains a chronically relapsing disorder despite repeated attempts at sobriety.
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Affiliation(s)
- Michael P Saddoris
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina
| | - Regina M Carelli
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina; Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina.
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De Luca MA, Valentini V, Bimpisidis Z, Cacciapaglia F, Caboni P, Di Chiara G. Endocannabinoid 2-Arachidonoylglycerol Self-Administration by Sprague-Dawley Rats and Stimulation of in vivo Dopamine Transmission in the Nucleus Accumbens Shell. Front Psychiatry 2014; 5:140. [PMID: 25368584 PMCID: PMC4201088 DOI: 10.3389/fpsyt.2014.00140] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 09/23/2014] [Indexed: 01/09/2023] Open
Abstract
2-Arachidonoylglycerol (2-AG) is the most potent endogenous ligand of brain cannabinoid CB1 receptors and is synthesized on demand from 2-arachidonate-containing phosphoinositides by the action of diacylglycerol lipase in response to increased intracellular calcium. Several studies indicate that the endocannabinoid (eCB) system is involved in the mechanism of reward and that diverse drugs of abuse increase brain eCB levels. In addition, eCB are self-administered (SA) by squirrel monkeys, and anandamide increases nucleus accumbens (NAc) shell dopamine (DA) in rats. To date, there is no evidence on the reinforcing effects of 2-AG and its effects on DA transmission in rodents. In order to fill this gap, we studied intravenous 2-AG SA and monitored the effect of 2-AG on extracellular DA in the NAc shell and core via microdialysis in male Sprague-Dawley rats. Rats were implanted with jugular catheters and trained to self-administer 2-AG [25 mg/kg/inf intravenously (iv)] in single daily 1 h sessions for 5 weeks under initial fixed ratio (FR) 1 schedule. The ratio was subsequently increased to FR2. Active nose poking increased from the 6th SA session (acquisition phase) but no significant increase of nose pokes was observed after FR2. When 2-AG was substituted for vehicle (25th SA session, extinction phase), rate responding as well as number of injections slowly decreased. When vehicle was replaced with 2-AG, SA behavior immediately recovered (reacquisition phase). The reinforcing effects of 2-AG in SA behavior were fully blocked by the CB1 receptor inverse agonist/antagonist rimonabant (1 mg/kg intraperitoneally, 30 min before SA session). In the microdialysis studies, we observed that 2-AG (0.1-1.0 mg/kg iv) preferentially stimulates NAc shell as compared to the NAc core. NAc shell DA increased by about 25% over basal value at the highest doses tested (0.5 and 1.0 mg/kg iv). The results obtained suggest that the eCB system, via 2-AG, plays an important role in reward.
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Affiliation(s)
- Maria Antonietta De Luca
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy
| | - Valentina Valentini
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy ; Centre of Excellence for Studies on the Neurobiology of Addiction , Cagliari , Italy
| | - Zisis Bimpisidis
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy
| | - Fabio Cacciapaglia
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Gaetano Di Chiara
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy ; Centre of Excellence for Studies on the Neurobiology of Addiction , Cagliari , Italy ; Cagliari Section, Neuroscience Institute, National Research Council of Italy , Cagliari , Italy
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Kippin TE. Adaptations underlying the development of excessive alcohol intake in selectively bred mice. Alcohol Clin Exp Res 2013; 38:36-9. [PMID: 24354427 DOI: 10.1111/acer.12327] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 10/04/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND This commentary discusses the important contributions of the article in this issue by Matson and colleagues entitled "Selectively bred crossed high-alcohol-preferring mice drink to intoxication and develop functional tolerance, but not locomotor sensitization during free-choice ethanol access" as well as providing comparison to studies on other drugs of abuse. METHODS The findings of the target article are evaluated and compared to the larger literature of intake escalation and vulnerability to addiction observed with other drugs of abuse. RESULTS In their study, Matson and colleagues report that mice derived by crossing different lines selectively bred for high alcohol intake exhibit initial alcohol intakes associated with motor impairment followed by marked escalation of consumption and tolerance to the effects of alcohol on motor coordination. In contrast, no evidence of pharmacokinetic tolerance or sensitization of alcohol-induced locomotion was observed. These results demonstrate that the cHAP mice constitute an appropriate model for the study of excessive drinking, which is produced by escalated alcohol intake and functional changes, leading to excessive intoxication. CONCLUSIONS Future work should assess adaptations in motivational processes and subjective effects of alcohol as well as the potential genetic and epigenetic bases of escalated alcohol intake.
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Affiliation(s)
- Tod E Kippin
- Department of Psychological & Brain Sciences, Neuroscience Research Institute, and Institute for Collaborative Biotechnology, University of California, Santa Barbara, California
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Calipari ES, Beveridge TJR, Jones SR, Porrino LJ. Withdrawal from extended-access cocaine self-administration results in dysregulated functional activity and altered locomotor activity in rats. Eur J Neurosci 2013; 38:3749-57. [PMID: 24118121 DOI: 10.1111/ejn.12381] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 08/23/2013] [Accepted: 09/04/2013] [Indexed: 02/02/2023]
Abstract
Much work has focused on determining the consequences of cocaine self-administration on specific neurotransmitter systems, thus neglecting the global changes that occur. Previous imaging studies have focused on the effects of cocaine self-administration in the presence of high blood levels of cocaine, but have not determined the functional effects of cocaine self-administration after cocaine has cleared. Extended-access cocaine self-administration, where animals administer cocaine for 6 h each day, results in escalation in the rate of cocaine intake and is believed to model the transition from recreational use to addiction in humans. We aimed to determine the functional changes following acute (48 h) withdrawal from an extended-access, defined-intake self-administration paradigm (5 days, 40 injections/day, 6 h/day), a time point when behavioral changes are present. Using the 2-[(14) C]deoxyglucose method to measure rates of local cerebral glucose metabolism, an indicator of functional activity, we found reductions in circuits related to learning and memory, attention, sleep, and reward processing, which have important clinical implications for cocaine addiction. Additionally, lower levels of functional activity were found in the dorsal raphe and locus coeruleus, suggesting that cocaine self-administration may have broader effects on brain function than previously noted. These widespread neurochemical reductions were concomitant with substantial behavioral differences in these animals, highlighted by increased vertical activity and decreased stereotypy. These data demonstrate that behavioral and neurochemical impairments following cocaine self-administration are present in the absence of drug and persist after cocaine has been cleared.
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Affiliation(s)
- Erin S Calipari
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston Salem, NC, 27157, USA
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Region-specific effects on BDNF expression after contingent or non-contingent cocaine i.v. self-administration in rats. Int J Neuropsychopharmacol 2013; 16:913-8. [PMID: 23164369 DOI: 10.1017/s146114571200096x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) dynamic changes were investigated in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc) during use and the early phases of cocaine abstinence after 14 sessions (2 h self-administration/d; 0.25 mg/0.1 ml.6 s infusion) by employing a 'yoked control-operant paradigm'. The effect on BDNF was region-specific and dependent on the withdrawal time. In the NAc, BDNF protein levels increased immediately after the last self-administration session, with a larger increase in passively cocaine-exposed rats. In the mPFC, BDNF expression was elevated 24 h after the last self-administration session, independently of how the drug was encountered. No changes were found in NAc and mPFC 7 d after the last self-administration session. Analysis of transcript levels in the mPFC indicated that action on exon I might contribute to BDNF's cortical induction. These findings indicate a finely tuned modulation of BDNF expression during use and early phases of cocaine abstinence.
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Interactions between Δ(9)-tetrahydrocannabinol and heroin: self-administration in rhesus monkeys. Behav Pharmacol 2013; 23:754-61. [PMID: 23044830 DOI: 10.1097/fbp.0b013e32835a3907] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The cannabinoid receptor agonist Δ(9)-tetrahydrocannabinol (THC) enhances the antinociceptive effects of µ-opioid receptor agonists, raising the possibility of using a combination of THC and opioids for treating pain. This study examined the effects of noncontingent and contingent administration of THC on intravenous heroin self-administration in rhesus monkeys. Self-administration of different unit doses of heroin (0.0001-0.1 mg/kg/infusion) generated a typical inverted U-shaped dose-response curve. In one experiment (n=4), noncontingent THC (0.1-1.0 mg/kg) dose dependently shifted the heroin dose-response curve downward in three monkeys and slightly leftward in one monkey. In a second experiment (n=4), monkeys could self-administer THC alone (0.0032-0.032 mg/kg/infusion), heroin alone, or a mixture of THC and heroin. THC alone did not maintain responding above that obtained with saline; however, increasing the THC dose with heroin dose dependently decreased the number of infusions received and the rate of responding, as compared with data that were obtained with heroin alone. These results indicate that THC does not significantly enhance the positive reinforcing effects of heroin, further supporting the view that combining cannabinoid and opioid receptor agonists (e.g. for treating pain) does not increase, and might decrease, the abuse liability of individual drugs.
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Maguire DR, Yang W, France CP. Interactions between μ-opioid receptor agonists and cannabinoid receptor agonists in rhesus monkeys: antinociception, drug discrimination, and drug self-administration. J Pharmacol Exp Ther 2013; 345:354-62. [PMID: 23536317 DOI: 10.1124/jpet.113.204099] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cannabinoid receptor agonists enhance the antinociceptive effects of μ-opioid receptor agonists, which suggests that combinations of these drugs might enhance therapeutic effectiveness (e.g., analgesia). However, it is not clear whether combinations of these drugs also enhance abuse or dependence liability. This experiment examined whether combinations of cannabinoids and opioids that enhance antinociception also increase abuse-related effects by studying the effects of the cannabinoid receptor agonists 2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-5-(2-methyloctan-2-yl)phenol (CP 55,940) and (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate (WIN 55,212) on the antinociceptive, discriminative stimulus, and positive reinforcing effects of μ-opioid receptor agonists in rhesus monkeys. In one group of monkeys (n = 3), morphine (0.1-5.6 mg/kg s.c.), CP 55,940 (0.0032-0.032 mg/kg s.c.), and WIN 55,212 (0.1-1.0 mg/kg s.c.) dose-dependently increased tail withdrawal latency from 50°C water, and pretreatment with small, otherwise ineffective, doses of CP 55,940 and WIN 55,212 shifted the morphine dose-effect curve to the left. In monkeys (n = 3) discriminating 3.2 mg/kg morphine, CP 55,940 (0.01-0.032 mg/kg s.c.) and WIN 55,212 (0.1-1.78 mg/kg s.c.) attenuated the discriminative stimulus effects of morphine, shifting the dose-effect curve to the right. In monkeys (n = 4) self-administering heroin (0.32-32.0 µg/kg/infusion i.v.), CP 55,940 (0.001-0.032 mg/kg s.c.), and WIN 55,212 (0.1-1.0 mg/kg s.c.) shifted the heroin dose-effect curve rightward and downward. Cannabinoid receptor agonists CP 55,940 and WIN 55,212 enhanced the antinociceptive effects but not the discriminative stimulus or positive reinforcing effects of μ-opioid receptor agonists in rhesus monkeys, supporting the view that combining cannabinoid and opioid receptor agonists might result in enhanced treatment effectiveness for pain without similarly enhancing abuse and dependence liability.
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Affiliation(s)
- David R Maguire
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA
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Wydra K, Golembiowska K, Zaniewska M, Kamińska K, Ferraro L, Fuxe K, Filip M. Accumbal and pallidal dopamine, glutamate and GABA overflow during cocaine self-administration and its extinction in rats. Addict Biol 2013; 18:307-24. [PMID: 23311632 DOI: 10.1111/adb.12031] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We investigated the changes in dopamine (DA), glutamate and γ-aminobutyric acid (GABA) during cocaine self-administration in rats implanted with guide cannulae into the nucleus accumbens and ventral pallidum. After stabilized cocaine self-administration, separate groups of rats underwent extinction (10 days) procedure in which cocaine infusion was replaced by saline injections. With using a 'yoked' procedure, the effects of cocaine or its withdrawal on the level of neurotransmitters were evaluated by dual-probe microdialysis. Repeated cocaine administration reduced basal glutamate levels in the nucleus accumbens and ventral pallidum, whereas it did not affect basal accumbal DA levels. Only rats that self-administered cocaine had increased basal GABA overflow in both examined brain structures. Active or passive cocaine administration elevated extracellular accumbal DA, however, the extent of cocaine-evoked DA level was significantly higher in rats that self-administered cocaine while both groups of animals showed also an attenuation of GABA level in the nucleus accumbens. On day 10 of extinction training, rats previously given cocaine revealed decreases in the basal accumbal concentration of glutamate while the basal GABA levels were significantly enhanced as compared with baseline of saline-yoked controls. Potassium depolarization delayed the reduction of the accumbal and pallidal extracellular glutamate levels in the active and passive cocaine groups. The present data indicate that changes in DA and GABA neurotransmission during maintenance phase mirror the motivational aspects of cocaine intake. Depending on acute (24 hours) or late (10 days) cocaine withdrawal, different neurotransmitter systems (i.e. glutamate or GABA) seem to be involved.
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Affiliation(s)
- Karolina Wydra
- Laboratory of Drug Addiction Pharmacology; Department of Pharmacology; Institute of Pharmacology Polish Academy of Sciences; Poland
| | - Krystyna Golembiowska
- Department of Pharmacology; Institute of Pharmacology Polish Academy of Sciences; Poland
| | - Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology; Department of Pharmacology; Institute of Pharmacology Polish Academy of Sciences; Poland
| | - Katarzyna Kamińska
- Department of Pharmacology; Institute of Pharmacology Polish Academy of Sciences; Poland
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology; LTTA Centre; University of Ferrara; Italy
| | - Kjell Fuxe
- Department of Neuroscience; Karolinska Institutet; Sweden
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Bassareo V, Cucca F, Cadoni C, Musio P, Di Chiara G. Differential influence of morphine sensitization on accumbens shell and core dopamine responses to morphine- and food-conditioned stimuli. Psychopharmacology (Berl) 2013; 225:697-706. [PMID: 22960773 DOI: 10.1007/s00213-012-2856-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 08/20/2012] [Indexed: 11/26/2022]
Abstract
RATIONALE Sensitization of the incentive and dopamine (DA) stimulant properties of drug-conditioned stimuli (CSs) by repeated exposure to drugs of abuse has been assigned an important role in the genesis of drug addiction. OBJECTIVE To test in rats if morphine-induced sensitization potentiates incentive and DA-releasing properties in the nucleus accumbens (NAc) shell and core elicited by presentation of a morphine-conditioned stimulus(CS) and if this property generalizes to a non-drug-(palatable food, Fonzies)-CS. METHODS Controls and rats previously sensitized by morphine were trained via three daily sessions consisting of a 10-min presentation of CS (Fonzies filled box, FB) followed by s.c. saline and morphine (1 mg/kg) or by standard food and Fonzies. Rats were implanted with microdialysis probes and the next-day incentive reactions and NAc shell and core DA were monitored during CS presentation and subsequent morphine (1 mg/kg) administration or Fonzies feeding. RESULTS Morphine sensitization increased incentive and NAc shell and core DA responses to morphine-CS. Morphine conditioning per se increased incentive reactions and NAc shell but not core DA responses to FB presentation. Morphine sensitization potentiated incentive responses but did not affect NAc shell and core DA responses to Fonzies-CS. Fonzies conditioning increased incentive reactions and NAc core but not shell DA responses to FB presentation. CONCLUSIONS These observations confirm the prediction of the incentive sensitization theory in the case of drug-CS but not of non-drug-CS. NAc DA might be differentially involved in the expression of incentive sensitization of drug- and non-drug-CSs, thus providing a clue for the abnormal incentive properties of drug CSs.
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Affiliation(s)
- Valentina Bassareo
- Department of Biomedical Sciences, National Institute of Neuroscience, University of Cagliari, Via Ospedale 72, Cagliari, Italy
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Garcia-Keller C, Martinez SA, Esparza MA, Bollati F, Kalivas PW, Cancela LM. Cross-sensitization between cocaine and acute restraint stress is associated with sensitized dopamine but not glutamate release in the nucleus accumbens. Eur J Neurosci 2013; 37:982-95. [PMID: 23360446 DOI: 10.1111/ejn.12121] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 12/20/2022]
Abstract
Repeated administration of psychostimulant drugs or stress can elicit a sensitized response to the stimulating and reinforcing properties of the drug. Here we explore the mechanisms in the nucleus accumbens (NAc) whereby an acute restraint stress augments the acute locomotor response to cocaine. This was accomplished by a combination of behavioral pharmacology, microdialysis measures of extracellular dopamine and glutamate, and Western blotting for GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor (AMPAR). A single exposure to restraint stress 3 weeks before testing revealed that enduring locomotor sensitization to cocaine was paralleled by an increase in extracellular dopamine in the core, but not the shell subcompartment, of the NAc. Wistar rats pre-exposed to acute stress showed increased basal levels of glutamate in the core, but the increase in glutamate by acute cocaine was blunted. The alterations in extracellular glutamate seem to be relevant, as blocking AMPAR by 6-cyano-7-nitroquinoxaline-2,3-dione microinjection into the core prevented both the behavioral cross-sensitization and the augmented increase in cocaine-induced extracellular dopamine. Further implicating glutamate, the locomotor response to AMPAR stimulation in the core was potentiated, but not in the shell of pre-stressed animals, and this was accompanied by an increase in NAc GluR1 surface expression. This study provides evidence that the long-term expression of restraint stress-induced behavioral cross-sensitization to cocaine recapitulates some mechanisms thought to underpin the sensitization induced by daily cocaine administration, and shows that long-term neurobiological changes induced in the NAc by acute stress are consequential in the expression of cross-sensitization to cocaine.
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Affiliation(s)
- C Garcia-Keller
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Maguire DR, Li JX, Koek W, France CP. Effects of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) and quipazine on heroin self-administration in rhesus monkeys. Psychopharmacology (Berl) 2013; 225:173-85. [PMID: 22836370 PMCID: PMC3725280 DOI: 10.1007/s00213-012-2803-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 07/05/2012] [Indexed: 10/28/2022]
Abstract
RATIONALE The serotonin (5-HT) system is involved in pain modulation, and 5-HT receptor agonists can enhance antinociceptive effects of mu opioid receptor agonists. Less is known about the actions of 5-HT receptor agonists on other effects of opioids. OBJECTIVE This study examined the effects of non-contingent and contingent administration of the 5-HT(2A) receptor agonists DOM and quipazine on i.v. heroin self-administration in rhesus monkeys. RESULTS Heroin (0.0001-0.1 mg/kg/infusion) generated an inverted U-shaped dose-response function. Non-contingent administration of DOM (0.1-0.32 mg/kg) flattened the dose-response function in three monkeys and eliminated heroin self-administration in a fourth monkey. Contingent DOM (0.0032-0.032 mg/kg/infusion) alone did not maintain responding above that maintained by saline, and, when added to self-administered heroin, monkeys responded less than for the same unit doses of heroin alone. Non-contingent (0.32-3.2 mg/kg) and contingent (0.0032-0.56 mg/kg/infusion) administration of quipazine flattened the dose-response function in two monkeys, increasing responding maintained by small unit doses of heroin and saline, but failed to enhance responding for heroin in two other monkeys. CONCLUSION This study shows that DOM does not enhance, and might attenuate, the positive reinforcing effects of the mu opioid receptor agonist heroin. Quipazine increased responding for saline and small doses of heroin; those effects were modest and observed in only two subjects. Taken together, these data suggest that 5-HT(2A) receptor agonists do not significantly enhance the reinforcing effectiveness of mu opioid receptor agonists and support the view that administering 5-HT drugs in combination with opioids to treat pain might not enhance abuse liability.
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Affiliation(s)
- David R Maguire
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA
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50
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Valentini V, Piras G, De Luca MA, Perra V, Bordi F, Borsini F, Frau R, Di Chiara G. Evidence for a role of a dopamine/5-HT6 receptor interaction in cocaine reinforcement. Neuropharmacology 2012; 65:58-64. [PMID: 22982249 DOI: 10.1016/j.neuropharm.2012.08.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/27/2012] [Accepted: 08/28/2012] [Indexed: 11/29/2022]
Abstract
The putative 5-HT6 receptor agonist ST1936 has been shown to increase extracellular dopamine (DA) in the n.accumbens (NAc) shell and in the medial prefrontal cortex (PFCX). These observations suggest that 5-HT6 receptors modulate DA transmission in mesolimbic and mesocortical terminal DA areas. To investigate the behavioral counterpart of this interaction we studied in rats 1) the ability of ST1936 to maintain i.v. self-administration in fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement; 2) the effect of 5-HT6 receptor blockade on cocaine stimulated overflow of DA in dialysates from the PFCX and from the NAc shell and on cocaine i.v. self-administration. ST1936 was i.v. self-administered at unitary doses of 0.5-1 mg/kg on an FR1 and PR schedule of reinforcement, with breaking point of about 4. Pretreatment with the 5-HT6 antagonist SB271046 reduced by about 80% responding for ST1936. SB271046 also reduced cocaine-induced increase of dialysate DA in the NAc shell but not in the PFCX and impaired i.v. cocaine self-administration. These observations indicate that ST1936 behaves as a weak reinforcer and suggest that 5-HT6 receptors play a role in cocaine reinforcement via their facilitatory interaction with DA projections to the NAc shell. This novel 5-HT/DA interaction might provide the basis for a new pharmacotherapeutic strategy of cocaine addiction.
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Affiliation(s)
- V Valentini
- Department of Biological Sciences, University of Cagliari, Italy
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