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Devoght J, Comhair J, Morelli G, Rigo JM, D'Hooge R, Touma C, Palme R, Dewachter I, vandeVen M, Harvey RJ, Schiffmann SN, Piccart E, Brône B. Dopamine-mediated striatal activity and function is enhanced in GlyRα2 knockout animals. iScience 2023; 26:107400. [PMID: 37554441 PMCID: PMC10404725 DOI: 10.1016/j.isci.2023.107400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/27/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023] Open
Abstract
The glycine receptor alpha 2 (GlyRα2) is a ligand-gated ion channel which upon activation induces a chloride conductance. Here, we investigated the role of GlyRα2 in dopamine-stimulated striatal cell activity and behavior. We show that depletion of GlyRα2 enhances dopamine-induced increases in the activity of putative dopamine D1 receptor-expressing striatal projection neurons, but does not alter midbrain dopamine neuron activity. We next show that the locomotor response to d-amphetamine is enhanced in GlyRα2 knockout animals, and that this increase correlates with c-fos expression in the dorsal striatum. 3-D modeling revealed an increase in the neuronal ensemble size in the striatum in response to D-amphetamine in GlyRα2 KO mice. Finally, we show enhanced appetitive conditioning in GlyRα2 KO animals that is likely due to increased motivation, but not changes in associative learning or hedonic response. Taken together, we show that GlyRα2 is an important regulator of dopamine-stimulated striatal activity and function.
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Affiliation(s)
- Jens Devoght
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Joris Comhair
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Giovanni Morelli
- Brain Development and Disease Laboratory, Instituto Italiano di Tecnologia, 16163 Genova, Italy
| | | | - Rudi D'Hooge
- Laboratory for Biological Psychology, University of Leuven, 3000 Leuven, Belgium
| | - Chadi Touma
- Department of Behavioural Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Rupert Palme
- Institute of Biochemistry, University of Veterinary Medicine Vienna, Vienna A-1210, Austria
| | - Ilse Dewachter
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | | | - Robert J. Harvey
- School of Health, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Serge N. Schiffmann
- Laboratory of Neurophysiology, Université libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Bert Brône
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
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2
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Vena AA, Zandy SL, Cofresí RU, Gonzales RA. Behavioral, neurobiological, and neurochemical mechanisms of ethanol self-administration: A translational review. Pharmacol Ther 2020; 212:107573. [PMID: 32437827 PMCID: PMC7580704 DOI: 10.1016/j.pharmthera.2020.107573] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2020] [Indexed: 12/16/2022]
Abstract
Alcohol use disorder has multiple characteristics including excessive ethanol consumption, impaired control over drinking behaviors, craving and withdrawal symptoms, compulsive seeking behaviors, and is considered a chronic condition. Relapse is common. Determining the neurobiological targets of ethanol and the adaptations induced by chronic ethanol exposure is critical to understanding the clinical manifestation of alcohol use disorders, the mechanisms underlying the various features of the disorder, and for informing medication development. In the present review, we discuss ethanol's interactions with a variety of neurotransmitter systems, summarizing findings from preclinical and translational studies to highlight recent progress in the field. We then describe animal models of ethanol self-administration, emphasizing the value, limitations, and validity of commonly used models. Lastly, we summarize the behavioral changes induced by chronic ethanol self-administration, with an emphasis on cue-elicited behavior, the role of ethanol-related memories, and the emergence of habitual ethanol seeking behavior.
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Affiliation(s)
- Ashley A Vena
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, United States of America
| | | | - Roberto U Cofresí
- Psychological Sciences, University of Missouri, United States of America
| | - Rueben A Gonzales
- Division of Pharmacology and Toxicology, College of Pharmacy and Institute for Neuroscience, The University of Texas at Austin, United States of America.
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3
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Cover KK, Gyawali U, Kerkhoff WG, Patton MH, Mu C, White MG, Marquardt AE, Roberts BM, Cheer JF, Mathur BN. Activation of the Rostral Intralaminar Thalamus Drives Reinforcement through Striatal Dopamine Release. Cell Rep 2020; 26:1389-1398.e3. [PMID: 30726725 PMCID: PMC6402336 DOI: 10.1016/j.celrep.2019.01.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/29/2018] [Accepted: 01/09/2019] [Indexed: 11/29/2022] Open
Abstract
Glutamatergic projections of the thalamic rostral intralaminar nuclei of the thalamus (rILN) innervate the dorsal striatum (DS) and are implicated in dopamine (DA)-dependent incubation of drug seeking. However, the mechanism by which rILN signaling modulates reward seeking and striatal DA release is unknown. We find that activation of rILN inputs to the DS drives cholinergic interneuron burst-firing behavior and DA D2 receptor-dependent post-burst pauses in cholinergic interneuron firing. In vivo, optogenetic activation of this pathway drives reinforcement in a DA D1 receptor-dependent manner, and chemogenetic suppression of the rILN reduces dopaminergic nigrostriatal terminal activity as measured by fiber photometry. Altogether, these data provide evidence that the rILN activates striatal cholinergic interneurons to enhance the pursuit of reward through local striatal DA release and introduce an additional level of complexity in our understanding of striatal DA signaling. Cover et al. identify a glutamatergic thalamostriatal pathway that locally elicits striatal dopamine release to drive reward-related behavior in mice.
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Affiliation(s)
- Kara K Cover
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Utsav Gyawali
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Willa G Kerkhoff
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary H Patton
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Chaoqi Mu
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael G White
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ashley E Marquardt
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Bradley M Roberts
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian N Mathur
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Lavoie A, Liu BH. Canine Adenovirus 2: A Natural Choice for Brain Circuit Dissection. Front Mol Neurosci 2020; 13:9. [PMID: 32174812 PMCID: PMC7056889 DOI: 10.3389/fnmol.2020.00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/14/2020] [Indexed: 12/15/2022] Open
Abstract
Canine adenovirus-2 (CAV) is a canine pathogen that has been used in a variety of applications, from vaccines against more infectious strains of CAV to treatments for neurological disorders. With recent engineering, CAV has become a natural choice for neuroscientists dissecting the connectivity and function of brain circuits. Specifically, as a reliable genetic vector with minimal immunogenic and cytotoxic reactivity, CAV has been used for the retrograde transduction of various types of projection neurons. Consequently, CAV is particularly useful when studying the anatomy and functions of long-range projections. Moreover, combining CAV with conditional expression and transsynaptic tracing results in the ability to study circuits with cell- and/or projection-type specificity. Lastly, with the well-documented knowledge of viral transduction, new innovations have been developed to increase the transduction efficiency of CAV and circumvent its tropism, expanding the potential of CAV for circuit analysis.
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Affiliation(s)
- Andréanne Lavoie
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Bao-Hua Liu
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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5
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Godfrey N, Borgland SL. Diversity in the lateral hypothalamic input to the ventral tegmental area. Neuropharmacology 2019; 154:4-12. [DOI: 10.1016/j.neuropharm.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/15/2019] [Accepted: 05/13/2019] [Indexed: 12/29/2022]
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Mulvihill KG, Brudzynski SM. Individual behavioural predictors of amphetamine-induced emission of 50 kHz vocalization in rats. Behav Brain Res 2018; 350:80-86. [PMID: 29758247 DOI: 10.1016/j.bbr.2018.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 01/21/2023]
Abstract
Measurement of ultrasonic vocalizations (USVs) produced by adult rats represents a highly useful index of emotional arousal. The associations found between 50 kHz USV production and a variety of behavioural and pharmacological protocols increasingly suggests they serve as a marker of positive motivational states. This study used a powerful within-subjects design to investigate the relationships among individual differences in approach to a sweet-food reward, predisposition to emit 50 kHz USVs spontaneously, and 50 kHz USVs emission following acute systemic administration of amphetamine. Both approach motivation and predisposition to call were found to not correlate with each other but did predict 50 kHz USV response to acute amphetamine. These two behavioural phenotypes appear to represent dissociable predictors of acute amphetamine-induced emission of 50 kHz USVs in a non-sensitization paradigm. In contrast to that, a measure of sucrose preference was not found to predict 50 kHz USV emission following amphetamine. Acute amphetamine was also found to increase average sound frequency of emitted USVs and selectively increase the proportion of Trill subtype 50 kHz USVs. Together, these data demonstrate that acute amphetamine-induced 50 kHz USVs in the adult rat represent more than just a univariate motivational state and may represent the product of dissociable subsystems of emotional behavior.
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Affiliation(s)
- Kevin G Mulvihill
- Department of Psychology, Brock University, St. Catharines, ON, L2S 3A1, Canada.
| | - Stefan M Brudzynski
- Department of Psychology, Brock University, St. Catharines, ON, L2S 3A1, Canada
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7
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Overlapping Brain Circuits for Homeostatic and Hedonic Feeding. Cell Metab 2018; 27:42-56. [PMID: 29107504 PMCID: PMC5762260 DOI: 10.1016/j.cmet.2017.09.021] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/11/2017] [Accepted: 09/25/2017] [Indexed: 12/20/2022]
Abstract
Central regulation of food intake is a key mechanism contributing to energy homeostasis. Many neural circuits that are thought to orchestrate feeding behavior overlap with the brain's reward circuitry both anatomically and functionally. Manipulation of numerous neural pathways can simultaneously influence food intake and reward. Two key systems underlying these processes-those controlling homeostatic and hedonic feeding-are often treated as independent. Homeostatic feeding is necessary for basic metabolic processes and survival, while hedonic feeding is driven by sensory perception or pleasure. Despite this distinction, their functional and anatomical overlap implies considerable interaction that is often overlooked. Here, we argue that the neurocircuits controlling homeostatic feeding and hedonic feeding are not completely dissociable given the current data and urge researchers to assess behaviors extending beyond food intake in investigations of the neural control of feeding.
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Striatal GPR88 Modulates Foraging Efficiency. J Neurosci 2017; 37:7939-7947. [PMID: 28729439 DOI: 10.1523/jneurosci.2439-16.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 06/08/2017] [Accepted: 06/14/2017] [Indexed: 11/21/2022] Open
Abstract
The striatum is anatomically and behaviorally implicated in behaviors that promote efficient foraging. To investigate this function, we studied instrumental choice behavior in mice lacking GPR88, a striatum-enriched orphan G-protein-coupled receptor that modulates striatal medium spiny neuron excitability. Our results reveal that hungry mice lacking GPR88 (KO mice) were slow to acquire food-reinforced lever press but could lever press similar to controls on a progressive ratio schedule. Both WT and KO mice discriminated between reward and no-reward levers; however, KO mice failed to discriminate based on relative quantity-reward (1 vs 3 food pellets) or effort (3 vs 9 lever presses). We also demonstrate preference for the high-reward (3 pellet) lever was selectively reestablished when GPR88 expression was restored to the striatum. We propose that GPR88 expression within the striatum is integral to efficient action-selection during foraging.SIGNIFICANCE STATEMENT Evolutionary pressure driving energy homeostasis favored detection and comparison of caloric value. In wild and laboratory settings, neural systems involved in energy homeostasis bias foraging to maximize energy efficiency. This is observed when foraging behaviors are guided by superior nutritional density or minimized caloric expenditure. The striatum is anatomically and functionally well placed to perform the sensory and motor integration necessary for efficient action selection during foraging. However, few studies have examined this behavioral phenomenon or elucidated underlying molecular mechanisms. Both humans and mice with nonfunctional GPR88 have been shown to present striatal dysfunctions and impaired learning. We demonstrate that GPR88 expression is necessary to efficiently integrate effort and energy density information guiding instrumental choice.
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Straley ME, Van Oeffelen W, Theze S, Sullivan AM, O'Mahony SM, Cryan JF, O'Keeffe GW. Distinct alterations in motor & reward seeking behavior are dependent on the gestational age of exposure to LPS-induced maternal immune activation. Brain Behav Immun 2017; 63:21-34. [PMID: 27266391 DOI: 10.1016/j.bbi.2016.06.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 11/18/2022] Open
Abstract
The dopaminergic system is involved in motivation, reward and the associated motor activities. Mesodiencephalic dopaminergic neurons in the ventral tegmental area (VTA) regulate motivation and reward, whereas those in the substantia nigra (SN) are essential for motor control. Defective VTA dopaminergic transmission has been implicated in schizophrenia, drug addiction and depression whereas dopaminergic neurons in the SN are lost in Parkinson's disease. Maternal immune activation (MIA) leading to in utero inflammation has been proposed to be a risk factor for these disorders, yet it is unclear how this stimulus can lead to the diverse disturbances in dopaminergic-driven behaviors that emerge at different stages of life in affected offspring. Here we report that gestational age is a critical determinant of the subsequent alterations in dopaminergic-driven behavior in rat offspring exposed to lipopolysaccharide (LPS)-induced MIA. Behavioral analysis revealed that MIA on gestational day 16 but not gestational day 12 resulted in biphasic impairments in motor behavior. Specifically, motor impairments were evident in early life, which were resolved by adolescence, but subsequently re-emerged in adulthood. In contrast, reward seeking behaviors were altered in offspring exposed MIA on gestational day 12. These changes were not due to a loss of dopaminergic neurons per se in the postnatal period, suggesting that they reflect functional changes in dopaminergic systems. This highlights that gestational age may be a key determinant of how MIA leads to distinct alterations in dopaminergic-driven behavior across the lifespan of affected offspring.
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Affiliation(s)
- Megan E Straley
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland; The Irish Centre for Fetal and Neonatal Translational Research (INFANT), Cork University Maternity Hospital, Cork, Ireland
| | - Wesley Van Oeffelen
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Sarah Theze
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Aideen M Sullivan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Siobhain M O'Mahony
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Gerard W O'Keeffe
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland; The Irish Centre for Fetal and Neonatal Translational Research (INFANT), Cork University Maternity Hospital, Cork, Ireland.
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10
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Klanker M, Fellinger L, Feenstra M, Willuhn I, Denys D. Regionally distinct phasic dopamine release patterns in the striatum during reversal learning. Neuroscience 2016; 345:110-123. [PMID: 27185487 DOI: 10.1016/j.neuroscience.2016.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 12/28/2022]
Abstract
Striatal dopamine (DA) plays a central role in reward-related learning and behavioral adaptation to changing environments. Recent studies suggest that rather than being broadcast as a uniform signal throughout the entire region, DA release dynamics diverge between different striatal regions. In a previous study, we showed that phasic DA release patterns in the ventromedial striatum (VMS) rapidly adapt during reversal learning. However, it is unknown how DA dynamics in the dorsolateral striatum (DLS) are modulated during such adaptive behavior. Here, we used fast-scan cyclic voltammetry to measure phasic DA release in the DLS during spatial reversal learning. In the DLS, we observed minor DA release after the onset of a visual cue signaling reward availability, followed by more pronounced DA release during more proximal reward cues (e.g., lever extension) and execution of the operant response (i.e., lever press), both in rewarded and non-rewarded trials. These release dynamics (minor DA after onset of the predictive visual cue, prominent DA during the operant response) did not change significantly during or following a reversal of response-reward contingencies. Notably, the DA increase to the lever press did not reflect a general signal related to the initiation of any motivated motor response, as we did not observe DA release when rats initiated nose pokes into the food receptacle during inter-trial intervals. This suggests that DA release in the DLS occurs selectively during the initiation and execution of a learned operant response. Together with our previous results obtained in the VMS, these findings reveal distinct phasic DA release patterns during adaptation of established behavior in DLS and VMS. The VMS DA signal, which is highly sensitive to reversal of response-reward contingences, may provide a teaching signal to guide reward-related learning and facilitate behavioral adaptation, whereas DLS DA may reflect a 'response execution signal' largely independent of outcome, that may be involved in initiation and energizing of operant behavior.
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Affiliation(s)
- Marianne Klanker
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, Postbus 22660, 1100 DD Amsterdam, The Netherlands.
| | - Lisanne Fellinger
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Matthijs Feenstra
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Ingo Willuhn
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Damiaan Denys
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, Postbus 22660, 1100 DD Amsterdam, The Netherlands
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Neuronal calcium sensor-1 deletion in the mouse decreases motivation and dopamine release in the nucleus accumbens. Behav Brain Res 2016; 301:213-25. [DOI: 10.1016/j.bbr.2015.12.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 12/24/2022]
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12
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Transcription factors FOXA1 and FOXA2 maintain dopaminergic neuronal properties and control feeding behavior in adult mice. Proc Natl Acad Sci U S A 2015; 112:E4929-38. [PMID: 26283356 DOI: 10.1073/pnas.1503911112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Midbrain dopaminergic (mDA) neurons are implicated in cognitive functions, neuropsychiatric disorders, and pathological conditions; hence understanding genes regulating their homeostasis has medical relevance. Transcription factors FOXA1 and FOXA2 (FOXA1/2) are key determinants of mDA neuronal identity during development, but their roles in adult mDA neurons are unknown. We used a conditional knockout strategy to specifically ablate FOXA1/2 in mDA neurons of adult mice. We show that deletion of Foxa1/2 results in down-regulation of tyrosine hydroxylase, the rate-limiting enzyme of dopamine (DA) biosynthesis, specifically in dopaminergic neurons of the substantia nigra pars compacta (SNc). In addition, DA synthesis and striatal DA transmission were reduced after Foxa1/2 deletion. Furthermore, the burst-firing activity characteristic of SNc mDA neurons was drastically reduced in the absence of FOXA1/2. These molecular and functional alterations lead to a severe feeding deficit in adult Foxa1/2 mutant mice, independently of motor control, which could be rescued by L-DOPA treatment. FOXA1/2 therefore control the maintenance of molecular and physiological properties of SNc mDA neurons and impact on feeding behavior in adult mice.
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McHugh PC, Buckley DA. The Structure and Function of the Dopamine Transporter and its Role in CNS Diseases. HORMONES AND TRANSPORT SYSTEMS 2015; 98:339-69. [DOI: 10.1016/bs.vh.2014.12.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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14
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Moran PM, O'Tuathaigh CM, Papaleo F, Waddington JL. Dopaminergic function in relation to genes associated with risk for schizophrenia. PROGRESS IN BRAIN RESEARCH 2014; 211:79-112. [DOI: 10.1016/b978-0-444-63425-2.00004-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Abstract
In this paper, we contend that the psychology of addiction is similar to the psychology of ordinary, non-addictive temptation in important respects, and explore the ways in which these parallels can illuminate both addiction and ordinary action. The incentive salience account of addiction proposed by Robinson and Berridge (1-3) entails that addictive desires are not in their nature different from many of the desires had by non-addicts; what is different is rather the way that addictive desires are acquired, which in turn affects their strength. We examine these "incentive salience" desires, both in addicts and non-addicts, contrasting them with more cognitive desires. On this account, the self-control challenge faced by addicted agents is not different in kind from that faced by non-addicted agents - though the two may, of course, differ greatly in degree of difficulty. We explore a general model of self-control for both the addict and the non-addict, stressing that self-control may be employed at three different stages, and examining the ways in which it might be strengthened. This helps elucidate a general model of intentional action.
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Affiliation(s)
- Brendan Dill
- Department of Linguistics and Philosophy, Massachusetts Institute of Technology , Cambridge, MA , USA
| | - Richard Holton
- Department of Philosophy, University of Cambridge , Cambridge , UK
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16
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Selective inhibition of phosphodiesterase 10A impairs appetitive and aversive conditioning and incentive salience attribution. Neuropharmacology 2013; 75:437-44. [DOI: 10.1016/j.neuropharm.2013.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/27/2013] [Accepted: 08/12/2013] [Indexed: 11/18/2022]
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17
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Skibicka KP. The central GLP-1: implications for food and drug reward. Front Neurosci 2013; 7:181. [PMID: 24133407 PMCID: PMC3796262 DOI: 10.3389/fnins.2013.00181] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/20/2013] [Indexed: 12/17/2022] Open
Abstract
Glucagon-like-peptide-1 (GLP-1) and its long acting analogs comprise a novel class of type 2 diabetes (T2D) treatment. What makes them unique among other T2D drugs is their concurrent ability to reduce food intake, a great benefit considering the frequent comorbidity of T2D and obesity. The precise neural site of action underlying this beneficial effect is vigorously researched. In accordance with the classical model of food intake control GLP-1 action on feeding has been primarily ascribed to receptor populations in the hypothalamus and the hindbrain. In contrast to this common view, relevant GLP-1 receptor populations are distributed more widely, with a prominent mesolimbic complement emerging. The physiological relevance of the mesolimbic GLP-1 is suggested by the demonstration that similar anorexic effects can be obtained by independent stimulation of the mesolimbic and hypothalamic GLP-1 receptors (GLP-1R). Results reviewed here support the idea that mesolimbic GLP-1R are sufficient to reduce hunger-driven feeding, the hedonic value of food and food-motivation. In parallel, emerging evidence suggests that the range of action of GLP-1 on reward behavior is not limited to food-derived reward but extends to cocaine, amphetamine, and alcohol reward. The new discoveries concerning GLP-1 action on the mesolimbic reward system significantly extend the potential therapeutic range of this drug target.
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Affiliation(s)
- Karolina P Skibicka
- Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg Gothenburg, Sweden
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18
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Patterson ZR, Abizaid A. Stress induced obesity: lessons from rodent models of stress. Front Neurosci 2013; 7:130. [PMID: 23898237 PMCID: PMC3721047 DOI: 10.3389/fnins.2013.00130] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 07/08/2013] [Indexed: 11/15/2022] Open
Abstract
Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further extend our understanding of stress-induced obesity.
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Carr GV, Jenkins KA, Weinberger DR, Papaleo F. Loss of dysbindin-1 in mice impairs reward-based operant learning by increasing impulsive and compulsive behavior. Behav Brain Res 2013; 241:173-84. [PMID: 23261874 PMCID: PMC3556458 DOI: 10.1016/j.bbr.2012.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/08/2012] [Accepted: 12/12/2012] [Indexed: 12/30/2022]
Abstract
The dystrobrevin-binding protein 1 (DTNBP1) gene, which encodes the dysbindin-1 protein, is a potential schizophrenia susceptibility gene. Polymorphisms in the DTNBP1 gene have been associated with altered cognitive abilities. In the present study, dysbindin-1 null mutant (dys-/-), heterozygous (dys+/-), and wild-type (dys+/+) mice, on a C57BL/6J genetic background, were tested in either a match to sample or nonmatch to sample visual discrimination task. This visual discrimination task was designed to measure rule learning and detect any changes in response timing over the course of testing. Dys-/- mice displayed significant learning deficits and required more trials to acquire this task. However, once criterion was reached, there were no differences between the genotypes on any behavioral measures. Dys-/- mice exhibited increased compulsive and impulsive behaviors compared to control littermates suggesting the inability to suppress incorrectly-timed responses underlies their increased time to acquisition. Indeed, group comparisons of behavior differences between the first and last day of testing showed that only dys-/- mice consistently decreased measures of perseverative, premature, timeout, and total responses. These findings illustrate how some aspects of altered cognitive performance in dys-/- mice might be related to increased impulsive and compulsive behaviors, analogous to cognitive deficits in some individuals with psychiatric disorders.
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Affiliation(s)
- Gregory V. Carr
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Kimberly A. Jenkins
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Daniel R. Weinberger
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
- Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, MD, USA
- Department of Psychiatry, Neurology, and Neuroscience and the Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Francesco Papaleo
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
- Dipartimento di Scienze del Farmaco, Universita’ degli Studi di Padova, Largo Meneghetti, 2, 35131 Padova, Italy
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Stuber GD, Mason AO. Integrating optogenetic and pharmacological approaches to study neural circuit function: current applications and future directions. Pharmacol Rev 2013; 65:156-70. [PMID: 23319548 DOI: 10.1124/pr.111.005611] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Optogenetic strategies to control genetically distinct populations of neurons with light have been rapidly evolving and widely adopted by the neuroscience community as one of the most important tool sets to study neural circuit function. Although optogenetics have already reshaped neuroscience by allowing for more precise control of circuit function compared with traditional techniques, current limitations of these approaches should be considered. Here, we discuss several strategies that combine optogenetic and contemporary pharmacological techniques to further increase the specificity of neural circuit manipulation. We also discuss recent advances that allow for the selective modulation of cellular function and gene expression with light. In addition, we outline a novel application of optogenetic circuit analysis for causally addressing the role of pathway-specific neural activity in mediating alterations in postsynaptic transcriptional processing in genetically defined neurons. By determining how optogenetic activation of specific neural circuits causally contributes to alterations in gene expression in a high-throughput fashion, novel biologic targets for future pharmacological intervention may be uncovered. Lastly, extending this experimental pipeline to selectively target pharmacotherapies to genetically defined neuronal populations or circuits will not only provide more selective control of neural circuits, but also may lead to the development of neural circuit specific pharmacological therapeutics.
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Affiliation(s)
- Garret D Stuber
- Departments of Psychiatry & Cell Biology and Physiology, UNC Neuroscience Center University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Moustafa AA, Herzallah MM, Gluck MA. Dissociating the cognitive effects of levodopa versus dopamine agonists in a neurocomputational model of learning in Parkinson's disease. NEURODEGENER DIS 2012; 11:102-11. [PMID: 23128796 DOI: 10.1159/000341999] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Levodopa and dopamine agonists have different effects on the motor, cognitive, and psychiatric aspects of Parkinson's disease (PD). METHODS Using a computational model of basal ganglia (BG) and prefrontal cortex (PFC) dopamine, we provide a theoretical synthesis of the dissociable effects of these dopaminergic medications on brain and cognition. Our model incorporates the findings that levodopa is converted by dopamine cells into dopamine, and thus activates prefrontal and striatal D(1) and D(2) dopamine receptors, whereas antiparkinsonian dopamine agonists directly stimulate D(2) receptors in the BG and PFC (although some have weak affinity to D(1) receptors). RESULTS In agreement with prior neuropsychological studies, our model explains how levodopa enhances, but dopamine agonists impair or have no effect on, stimulus-response learning and working memory. CONCLUSION Our model explains how levodopa and dopamine agonists have differential effects on motor and cognitive processes in PD.
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Affiliation(s)
- Ahmed A Moustafa
- Marcs Institute for Brain and Behaviour and Foundational Processes of Behaviour, School of Social Sciences and Psychology, University of Western Sydney, Sydney, N.S.W., Australia.
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Abstract
Obesity is typically associated with abnormal eating behaviors. Brain imaging studies in humans implicate the involvement of dopamine (DA)-modulated circuits in pathologic eating behavior(s). Food cues increase striatal extracellular DA, providing evidence for the involvement of DA in the nonhedonic motivational properties of food. Food cues also increase metabolism in the orbitofrontal cortex indicating the association of this region with the motivation for food consumption. Similar to drug-addicted subjects, striatal DA D2 receptor availability is reduced in obese subjects, which may predispose obese subjects to seek food as a means to temporarily compensate for understimulated reward circuits. Decreased DA D2 receptors in the obese subjects are also associated with decreased metabolism in prefrontal regions involved in inhibitory control, which may underlie their inability to control food intake. Gastric stimulation in obese subjects activates cortical and limbic regions involved with self-control, motivation, and memory. These brain regions are also activated during drug craving in drug-addicted subjects. Obese subjects have increased metabolism in the somatosensory cortex, which suggests an enhanced sensitivity to the sensory properties of food. The reduction in DA D2 receptors in obese subjects coupled with the enhanced sensitivity to food palatability could make food their most salient reinforcer putting them at risk for compulsive eating and obesity. The results from these studies suggest that multiple but similar brain circuits are disrupted in obesity and drug addiction and suggest that strategies aimed at improving DA function might be beneficial in the treatment and prevention of obesity.
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Woodside B, Budin R, Wellman MK, Abizaid A. Many mouths to feed: the control of food intake during lactation. Front Neuroendocrinol 2012; 33:301-14. [PMID: 23000403 DOI: 10.1016/j.yfrne.2012.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 01/07/2023]
Abstract
Providing nutrients to their developing young is perhaps the most energetically demanding task facing female mammals. In this paper we focus primarily on studies carried out in rats to describe the changes in the maternal brain that enable the dam to meet the energetic demands of her offspring. In rats, providing milk for their litter is associated with a dramatic increase in caloric intake, a reduction in energy expenditure and changes in the pattern of energy utilization as well as storage. These behavioral and physiological adaptations result, in part, from alterations in the central pathways controlling energy balance. Differences in circulating levels of metabolic hormones such as leptin, ghrelin and insulin as well as in responsiveness to these signals between lactating and nonlactating animals, contribute to the modifications in energy balance pathways seen postpartum. Suckling stimulation from the pups both directly, and through the hormonal state that it induces in the mother, plays a key role in facilitating these adaptations.
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Affiliation(s)
- Barbara Woodside
- Center for Studies in Behavioral Neurobiology/Groupe de recherches en neurobiologie comportementale, Concordia University, Montreal, Canada.
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24
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Fowler CD, Kenny PJ. Utility of genetically modified mice for understanding the neurobiology of substance use disorders. Hum Genet 2012; 131:941-57. [PMID: 22190154 PMCID: PMC3977433 DOI: 10.1007/s00439-011-1129-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 12/11/2011] [Indexed: 01/09/2023]
Abstract
Advances in our ability to modify the mouse genome have enhanced our understanding of the genetic and neurobiological mechanisms contributing to addiction-related behaviors underlying substance use and abuse. These experimentally induced manipulations permit greater spatial and temporal specificity for modification of gene expression within specific cellular populations and during select developmental time periods. In this review, we consider the current mouse genetic model systems that have been employed to understand aspects of addiction and highlight significant conceptual advances achieved related to substance use and abuse. The mouse models reviewed herein include conventional knock-out and knock-in, conditional knockout, transgenic, inducible transgenic, mice suitable for optogenetic control of discrete neuronal populations, and phenotype-selected mice. By establishing a reciprocal investigatory relationship between genetic findings in humans and genomic manipulations in mice, a far better understanding of the discrete neuromechanisms underlying addiction can be achieved, which is likely to provide a strong foundation for developing and validating novel therapeutics for the treatment of substance abuse disorders.
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Affiliation(s)
- Christie D. Fowler
- Laboratory of Behavioral and Molecular Neuroscience, Department of Molecular Therapeutics, The Scripps Research Institute, Scripps, Florida, Jupiter, FL 33458, USA. Laboratory of Behavioral and Molecular Neuroscience, Department of Neuroscience, The Scripps Research Institute, Scripps, Florida, Jupiter, FL 33458, USA
| | - Paul J. Kenny
- Laboratory of Behavioral and Molecular Neuroscience, Department of Molecular Therapeutics, The Scripps Research Institute, Scripps, Florida, Jupiter, FL 33458, USA. Laboratory of Behavioral and Molecular Neuroscience, Department of Neuroscience, The Scripps Research Institute, Scripps, Florida, Jupiter, FL 33458, USA
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Jedynak JP, Cameron CM, Robinson TE. Repeated methamphetamine administration differentially alters fos expression in caudate-putamen patch and matrix compartments and nucleus accumbens. PLoS One 2012; 7:e34227. [PMID: 22514626 PMCID: PMC3326007 DOI: 10.1371/journal.pone.0034227] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/26/2012] [Indexed: 12/13/2022] Open
Abstract
Background The repeated administration of psychostimulant drugs produces a persistent and long-lasting increase (“sensitization”) in their psychomotor effects, which is thought to be due to changes in the neural circuitry that mediate these behaviors. One index of neuronal activation used to identify brain regions altered by repeated exposure to drugs involves their ability to induce immediate early genes, such as c-fos. Numerous reports have demonstrated that past drug experience alters the ability of drugs to induce c-fos in the striatum, but very few have examined Fos protein expression in the two major compartments in the striatum—the so-called patch/striosome and matrix. Methodology/Principal Findings In the present study, we used immunohistochemistry to investigate the effects of pretreatment with methamphetamine on the ability of a subsequent methamphetamine challenge to induce Fos protein expression in the patch and matrix compartments of the dorsolateral and dorsomedial caudate-putamen and in the ventral striatum (nucleus accumbens). Animals pretreated with methamphetamine developed robust psychomotor sensitization. A methamphetamine challenge increased the number of Fos-positive cells in all areas of the dorsal and ventral striatum. However, methamphetamine challenge induced Fos expression in more cells in the patch than in the matrix compartment in the dorsolateral and dorsomedial caudate-putamen. Furthermore, past experience with methamphetamine increased the number of methamphetamine-induced Fos positive cells in the patch compartment of the dorsal caudate putamen, but not in the matrix or in the core or shell of the nucleus accumbens. Conclusions/Significance These data suggest that drug-induced alterations in the patch compartment of the dorsal caudate-putamen may preferentially contribute to some of the enduring changes in brain activity and behavior produced by repeated treatment with methamphetamine.
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Affiliation(s)
- Jakub P Jedynak
- Neuroscience Program, University of Michigan, Ann Arbor, Michigan, United States of America.
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26
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Liang J, Ma SS, Li YJ, Ping XJ, Hu L, Cui CL. Dynamic changes of tyrosine hydroxylase and dopamine concentrations in the ventral tegmental area-nucleus accumbens projection during the expression of morphine-induced conditioned place preference in rats. Neurochem Res 2012; 37:1482-9. [PMID: 22396106 DOI: 10.1007/s11064-012-0739-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 02/07/2012] [Accepted: 02/20/2012] [Indexed: 11/28/2022]
Abstract
Our previous study demonstrated that morphine dose- and time-dependently elevated dopamine (DA) concentrations in the nucleus accumbens (NAc) during the expression of morphine-induced conditioned place preference (CPP) in rats. However, still unknown are how DA concentrations dynamically change during the morphine-induced CPP test and whether tyrosine hydroxylase (TH) activity in the ventral tegmental area (VTA) plays a vital role in this process. In the present study, we measured dynamic changes in TH and phosphorylated TH serine 40 (pTH Ser(40)) and pTH Ser(31) proteins in the VTA, and DA concentrations in the NAc at 5 min intervals during a 30 min morphine-induced CPP test. Rats that underwent morphine-induced CPP training significantly preferred the morphine-paired chamber during the CPP expression test, an effect that lasted at least 30 min in the drug-free state. DA concentrations in the NAc markedly increased at 15 min when the rats were returned to the CPP boxes to assess the expression of preference for the previously drug-paired chamber. DA concentrations then declined 2 h after the CPP test. TH and pTH Ser(40) levels, but not pTH Ser(31) levels, in the VTA were enhanced during the CPP test. These results indicated that TH and the phosphorylation of TH Ser(40) in the VTA may be responsible for DA synthesis and release in the NAc during the behavioral expression of conditioned reward elicited by a drug-associated context.
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Affiliation(s)
- Jing Liang
- Neuroscience Research Institute and Department of Neurobiology, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100083, People's Republic of China
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Pardo M, Lopez-Cruz L, Valverde O, Ledent C, Baqi Y, Müller CE, Salamone JD, Correa M. Adenosine A2A receptor antagonism and genetic deletion attenuate the effects of dopamine D2 antagonism on effort-based decision making in mice. Neuropharmacology 2012; 62:2068-77. [PMID: 22261384 DOI: 10.1016/j.neuropharm.2011.12.033] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/30/2011] [Accepted: 12/27/2011] [Indexed: 11/17/2022]
Abstract
Brain dopamine (DA) and adenosine interact in the regulation of behavioral activation and effort-related processes. In the present studies, a T-maze task was developed in mice for the assessment of effort-related decision making. With this task, the two arms of the maze have different reinforcement densities, and a vertical barrier is positioned in the arm with the higher density (HD), presenting the animal with an effort-related challenge. Under control conditions mice prefer the HD arm, and climb the barrier to obtain the larger amount of food. The DA D(2) receptor antagonist haloperidol decreased selection of the HD arm and increased selection of the arm with the low density of reinforcement. However, the HD arm was still the preferred choice in haloperidol-treated mice trained with barriers in both arms. Pre-feeding the mice to reduce food motivation dramatically increased omissions, an effect that was distinct from the actions of haloperidol. Co-administration of theophylline, a nonselective adenosine receptor antagonist, partially reversed the effects of haloperidol. This effect seems to be mediated by the A(2A) receptor but not the A(1) receptor, since the A(2A) antagonist MSX-3, but not the A(1) antagonist CPT, dose dependently reversed the effects of haloperidol on effort-related choice and on c-Fos expression in the dorsal striatum and nucleus accumbens. In addition, adenosine A(2A) receptor knockout mice were resistant to the effects of haloperidol on effort-related choice in the maze. These results indicate that DA D(2) and adenosine A(2A) receptors interact to regulate effort-related decision making and effort expenditure in mice.
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Affiliation(s)
- M Pardo
- Àrea de Psicobiologia, Campus de Riu Sec, Universitat Jaume I, 12071 Castelló, Spain.
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28
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Palmiter R. Dopamine signaling as a neural correlate of consciousness. Neuroscience 2011; 198:213-20. [DOI: 10.1016/j.neuroscience.2011.06.089] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/13/2011] [Accepted: 06/17/2011] [Indexed: 10/17/2022]
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Son JH, Latimer C, Keefe KA. Impaired formation of stimulus-response, but not action-outcome, associations in rats with methamphetamine-induced neurotoxicity. Neuropsychopharmacology 2011; 36:2441-51. [PMID: 21775980 PMCID: PMC3194071 DOI: 10.1038/npp.2011.131] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Methamphetamine (METH) induces neurotoxic changes, including partial striatal dopamine depletions, which are thought to contribute to cognitive dysfunction in rodents and humans. The dorsal striatum is implicated in action-outcome (A-O) and stimulus-response (S-R) associations underlying instrumental learning. Thus, the present study examined the long-term consequences of METH-induced neurotoxicity on A-O and S-R associations underlying appetitive instrumental behavior. Rats were pretreated with saline or a neurotoxic regimen of METH (4 × 7.5-10 mg/kg). Rats trained on random ratio (RR) or random interval (RI) schedules of reinforcement were then subjected to outcome devaluation or contingency degradation, followed by an extinction test. All rats then were killed, and brains removed for determination of striatal dopamine loss. The results show that: (1) METH pretreatment induced a partial 45-50% decrease in striatal dopamine tissue content in dorsomedial and dorsolateral striatum; (2) METH-induced neurotoxicity did not alter acquisition of instrumental behavior on either RR or RI schedules; (3) outcome devaluation and contingency degradation similarly decreased responding in saline- and METH-pretreated rats trained on the RR schedule, suggesting intact A-O associations guiding behavior; (4) outcome devaluation after training on the RI schedule decreased extinction responding only in METH-pretreated rats, suggesting impaired S-R associations. Overall, these data suggest that METH-induced neurotoxicity, possibly due to impairment of the function of dorsolateral striatal circuitry, may decrease cognitive flexibility by impairing the ability to automatize behavioral patterns.
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Affiliation(s)
- Jong-Hyun Son
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, USA
| | - Christine Latimer
- Department of Neuroscience, Westminster College, Salt Lake City, UT, USA
| | - Kristen A Keefe
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, USA,Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, 30 S 2000 E Rm 102, Salt Lake City, UT 84112, USA, Tel: +1 801 585 1253, Fax: +1 801 585 5111, E-mail:
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Skibicka KP, Dickson SL. Ghrelin and food reward: the story of potential underlying substrates. Peptides 2011; 32:2265-73. [PMID: 21621573 DOI: 10.1016/j.peptides.2011.05.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/11/2011] [Accepted: 05/12/2011] [Indexed: 10/18/2022]
Abstract
The incidence of obesity is increasing at an alarming rate and this worldwide epidemic represents a significant decrease in life span and quality of life of a large part of the affected population. Therefore an understanding of mechanisms underlying food overconsumption and obesity development is urgent and essential to find potential treatments. Research investigating mechanisms underlying obesity and the control of food intake has recently experienced a major shift in focus, from the brain's hypothalamus to additional important neural circuits controlling emotion, cognition and motivated behavior. Among them, the mesolimbic system, and the changes in reward and motivated behavior for food, emerge as new promising treatment targets. Furthermore, there is also growing appreciation of the impact of peripheral hormones that signal nutrition status to the mesolimbic areas, and especially the only known circulating orexigenic hormone, ghrelin. This review article provides a synthesis of recent evidence concerning the impact of manipulation of ghrelin and its receptor on models of food reward/food motivation behavior and the mesolimbic circuitry. Particular attention is given to the potential neurocircuitry and neurotransmitter systems downstream of ghrelin's effects on food reward.
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Affiliation(s)
- Karolina P Skibicka
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 11, SE-405 30 Gothenburg, Sweden.
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Penner MR, Mizumori SJY. Neural systems analysis of decision making during goal-directed navigation. Prog Neurobiol 2011; 96:96-135. [PMID: 21964237 DOI: 10.1016/j.pneurobio.2011.08.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/06/2011] [Accepted: 08/29/2011] [Indexed: 10/17/2022]
Abstract
The ability to make adaptive decisions during goal-directed navigation is a fundamental and highly evolved behavior that requires continual coordination of perceptions, learning and memory processes, and the planning of behaviors. Here, a neurobiological account for such coordination is provided by integrating current literatures on spatial context analysis and decision-making. This integration includes discussions of our current understanding of the role of the hippocampal system in experience-dependent navigation, how hippocampal information comes to impact midbrain and striatal decision making systems, and finally the role of the striatum in the implementation of behaviors based on recent decisions. These discussions extend across cellular to neural systems levels of analysis. Not only are key findings described, but also fundamental organizing principles within and across neural systems, as well as between neural systems functions and behavior, are emphasized. It is suggested that studying decision making during goal-directed navigation is a powerful model for studying interactive brain systems and their mediation of complex behaviors.
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Affiliation(s)
- Marsha R Penner
- Department of Psychology, University of Washington, Seattle, WA 98195-1525, United States
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32
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Shiflett MW, Balleine BW. Molecular substrates of action control in cortico-striatal circuits. Prog Neurobiol 2011; 95:1-13. [PMID: 21704115 PMCID: PMC3175490 DOI: 10.1016/j.pneurobio.2011.05.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 05/24/2011] [Accepted: 05/27/2011] [Indexed: 11/24/2022]
Abstract
The purpose of this review is to describe the molecular mechanisms in the striatum that mediate reward-based learning and action control during instrumental conditioning. Experiments assessing the neural bases of instrumental conditioning have uncovered functional circuits in the striatum, including dorsal and ventral striatal sub-regions, involved in action-outcome learning, stimulus-response learning, and the motivational control of action by reward-associated cues. Integration of dopamine (DA) and glutamate neurotransmission within these striatal sub-regions is hypothesized to enable learning and action control through its role in shaping synaptic plasticity and cellular excitability. The extracellular signal regulated kinase (ERK) appears to be particularly important for reward-based learning and action control due to its sensitivity to combined DA and glutamate receptor activation and its involvement in a range of cellular functions. ERK activation in striatal neurons is proposed to have a dual role in both the learning and performance factors that contribute to instrumental conditioning through its regulation of plasticity-related transcription factors and its modulation of intrinsic cellular excitability. Furthermore, perturbation of ERK activation by drugs of abuse may give rise to behavioral disorders such as addiction.
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Boureau YL, Dayan P. Opponency revisited: competition and cooperation between dopamine and serotonin. Neuropsychopharmacology 2011; 36:74-97. [PMID: 20881948 PMCID: PMC3055522 DOI: 10.1038/npp.2010.151] [Citation(s) in RCA: 297] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 08/03/2010] [Accepted: 08/03/2010] [Indexed: 11/08/2022]
Abstract
Affective valence lies on a spectrum ranging from punishment to reward. The coding of such spectra in the brain almost always involves opponency between pairs of systems or structures. There is ample evidence for the role of dopamine in the appetitive half of this spectrum, but little agreement about the existence, nature, or role of putative aversive opponents such as serotonin. In this review, we consider the structure of opponency in terms of previous biases about the nature of the decision problems that animals face, the conflicts that may thus arise between Pavlovian and instrumental responses, and an additional spectrum joining invigoration to inhibition. We use this analysis to shed light on aspects of the role of serotonin and its interactions with dopamine.
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Affiliation(s)
- Y-Lan Boureau
- The Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - Peter Dayan
- Gatsby Computational Neuroscience Unit, London, UK
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34
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Wall VZ, Parker JG, Fadok JP, Darvas M, Zweifel L, Palmiter RD. A behavioral genetics approach to understanding D1 receptor involvement in phasic dopamine signaling. Mol Cell Neurosci 2010; 46:21-31. [PMID: 20888914 DOI: 10.1016/j.mcn.2010.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 09/23/2010] [Indexed: 11/28/2022] Open
Abstract
Dopamine-producing neurons fire with both basal level tonic patterns and phasic bursts. Varying affinities of the five dopamine receptors have led to a hypothesis that higher affinity receptors are primarily activated by basal level tonic dopamine, while lower affinity receptors may be tuned to be sensitive to higher levels caused by phasic bursts. Genetically modified mice provide a method to begin to probe this hypothesis. Here we discuss three mouse models. Dopamine-deficient mice were used to determine which behaviors require dopamine. These behaviors were then analyzed in mice lacking D1 receptors and in mice with reduced phasic dopamine release. Comparison of the latter two mouse models revealed a similar failure to learn about and respond normally to cues that indicate either a positive or negative outcome, giving support to the hypothesis that phasic dopamine release and the D1 receptor act in the same pathway. However, the D1 receptor likely has additional roles beyond those of phasic dopamine detection, because D1 receptor knockout mice have deficits in addition to what has been observed in mice with reduced phasic dopamine release.
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Affiliation(s)
- Valerie Z Wall
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
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35
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Li YC, Gao WJ. GSK-3β activity and hyperdopamine-dependent behaviors. Neurosci Biobehav Rev 2010; 35:645-54. [PMID: 20727368 DOI: 10.1016/j.neubiorev.2010.08.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 07/28/2010] [Accepted: 08/11/2010] [Indexed: 01/28/2023]
Abstract
Dopamine plays important roles in normal brain function and many neuropsychiatric disorders. Classically, dopamine receptors are positively coupled to G protein-mediated signaling to regulate cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)-dopamine and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) and Ca(2+) pathways. However, emerging evidence indicates that under hyperdopaminergic conditions, the protein kinase B (Akt)-glycogen synthase kinase 3β (GSK-3β) signaling cascade may mediate dopamine actions via D(2)-like receptors. This cAMP-independent signaling pathway involves the regulation of downstream synaptic targets, e.g., AMPA receptor, NMDA receptors, and thus synaptic plasticity. Here we provide an overview of how this novel signaling pathway relays dopamine receptor-mediated responses, particularly hyperdopamine-dependent behaviors. We discuss the relevance of the Akt/GSK-3β signaling cascade for the expression of dopamine-dependent behaviors and the drug actions associated with dopaminergic systems.
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Affiliation(s)
- Yan-Chun Li
- Department of Neurobiology & Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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Restricting dopaminergic signaling to either dorsolateral or medial striatum facilitates cognition. J Neurosci 2010; 30:1158-65. [PMID: 20089924 DOI: 10.1523/jneurosci.4576-09.2010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dopaminergic projections to the ventral and dorsomedial striatum are important for reward, motivation, and goal-directed learning, whereas projections to the dorsolateral striatum are implicated in motor control, habitual enactment of motor skills, visuospatial learning, and memory. These conclusions are derived from studies of rodents with lesions or pharmacological blockade of dopamine signaling to specific brain regions. In contrast, we investigated the behavioral abilities of dopamine-deficient mice in which dopamine signaling was restored to only the medial striatum by viral rescue. These mice displayed intact spatial memory, visuospatial and discriminatory learning. However, acquisition of operant behavior was delayed, and their motivation to obtain food rewards was blunted. We compare these behavioral results with our published results obtained from mice with dopamine signaling restored only to the dorsolateral striatum. We observe that most behaviors are restored with dopamine signaling restored to either brain region and conclude that the action of dopamine in either one of these nonoverlapping striatal areas can support cognitive processes independently of dopamine signaling in the other area.
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37
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Fulton S. Appetite and reward. Front Neuroendocrinol 2010; 31:85-103. [PMID: 19822167 DOI: 10.1016/j.yfrne.2009.10.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 10/06/2009] [Accepted: 10/06/2009] [Indexed: 12/14/2022]
Abstract
The tendency to engage in or maintain feeding behaviour is potently influenced by the rewarding properties of food. Affective and goal-directed behavioural responses for food have been assessed in response to various physiological, pharmacological and genetic manipulations to provide much insight into the neural mechanisms regulating motivation for food. In addition, several lines of evidence tie the actions of metabolic signals, neuropeptides and neurotransmitters to the modulation of the reward-relevant circuitry including midbrain dopamine neurons and corticolimbic nuclei that encode emotional and cognitive aspects of feeding. Along these lines, this review pulls together research describing the peripheral and central signalling molecules that modulate the rewarding effects of food and the underlying neural pathways.
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Affiliation(s)
- Stephanie Fulton
- CRCHUM and Montreal Diabetes Research Center, Department of Nutrition, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.
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Rada P, Barson JR, Leibowitz SF, Hoebel BG. Opioids in the hypothalamus control dopamine and acetylcholine levels in the nucleus accumbens. Brain Res 2009; 1312:1-9. [PMID: 19948154 DOI: 10.1016/j.brainres.2009.11.055] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/17/2009] [Accepted: 11/20/2009] [Indexed: 10/20/2022]
Abstract
The experimental question is whether hypothalamic opioids, known to stimulate consummatory behavior, control a link to the nucleus accumbens (NAc). It was hypothesized that opioids injected in the hypothalamic paraventricular nucleus (PVN) alter the balance of dopamine (DA) and acetylcholine (ACh) in the NAc in a manner that fosters appetite for food or ethanol. Rats were implanted with two guide shafts, one in the NAc to measure extracellular DA and ACh by microdialysis and the other in the PVN for microinjection of opioid mu- and delta-agonists, an antagonist, or saline vehicle. The compounds tested were morphine, the mu-receptor agonist [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-Enkephalin (DAMGO), the delta-receptor agonist D-Ala-Gly-Phe-Met-NH2 (DALA), and the opioid antagonist naloxone methiodide (m-naloxone). Morphine in the PVN increased the release of accumbens DA (+41%) and decreased ACh (-35%). Consistent with this, the opioid antagonist m-naloxone decreased DA (-24%) and increased ACh (+19%). In terms of receptor involvement, DAMGO dose-dependently increased DA to up to 209% of baseline. Simultaneously, ACh levels were markedly decreased to 55% of baseline. The agonist DALA produced a smaller but significant, 34% increase in DA, without affecting ACh. In contrast, control injections of saline had no significant effect. These results demonstrate that mu- and delta-opioids in the PVN contribute to the control of accumbens DA and ACh release and suggest that this circuit from the PVN to the NAc may be one of the mechanisms underlying opiate-induced ingestive behavior as well as naltrexone therapy for overeating and alcoholism.
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Affiliation(s)
- Pedro Rada
- Laboratory of Behavioral Physiology, School of Medicine, University of Los Andes, Mérida, Venezuela
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Santesso DL, Evins AE, Frank MJ, Schetter EC, Bogdan R, Pizzagalli DA. Single dose of a dopamine agonist impairs reinforcement learning in humans: evidence from event-related potentials and computational modeling of striatal-cortical function. Hum Brain Mapp 2009; 30:1963-76. [PMID: 18726908 DOI: 10.1002/hbm.20642] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Animal findings have highlighted the modulatory role of phasic dopamine (DA) signaling in incentive learning, particularly in the acquisition of reward-related behavior. In humans, these processes remain largely unknown. In a recent study, we demonstrated that a single low dose of a D2/D3 agonist (pramipexole)-assumed to activate DA autoreceptors and thus reduce phasic DA bursts-impaired reward learning in healthy subjects performing a probabilistic reward task. The purpose of this study was to extend these behavioral findings using event-related potentials and computational modeling. Compared with the placebo group, participants receiving pramipexole showed increased feedback-related negativity to probabilistic rewards and decreased activation in dorsal anterior cingulate regions previously implicated in integrating reinforcement history over time. Additionally, findings of blunted reward learning in participants receiving pramipexole were simulated by reduced presynaptic DA signaling in response to reward in a neural network model of striatal-cortical function. These preliminary findings offer important insights on the role of phasic DA signals on reinforcement learning in humans and provide initial evidence regarding the spatiotemporal dynamics of brain mechanisms underlying these processes.
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Affiliation(s)
- Diane L Santesso
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
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40
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Restriction of dopamine signaling to the dorsolateral striatum is sufficient for many cognitive behaviors. Proc Natl Acad Sci U S A 2009; 106:14664-9. [PMID: 19667174 DOI: 10.1073/pnas.0907299106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The striatum is a vital substrate for performance, procedural memory, and learning. The ventral and medial striatum are thought to be critical for acquisition of tasks while the dorsolateral striatum is important for performance and habitual enactment of skills. Evidence based on cortical, thalamic, and amygdaloid inputs to the striatum suggests a medio-lateral zonation imposed on the classical dorso-ventral distinction. We therefore investigated the functional significance of dopaminergic signaling in cognitive tasks by studying dopamine-deficient (DD) mice and mice with dopamine signaling restored to only the dorsolateral (DL) striatum by viral rescue (vrDD-DL mice). Whereas DD mice failed in all of the tasks examined here, vrDD-DL mice displayed intact discriminatory learning, object recognition, visuospatial learning and spatial memory. Acquisition of operant behavior for food rewards was delayed in vrDD-DL mice and their motivation in a progressive ratio experiments was reduced. Therefore, dopaminergic signaling in the dorsolateral striatum is sufficient for mice to learn several different cognitive tasks although the rate of learning some of them was reduced. These results indicate that dopaminergic signaling in the ventromedial striatum is not absolutely necessary for mastery of these behaviors, but may facilitate them.
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Lex B, Hauber W. The role of dopamine in the prelimbic cortex and the dorsomedial striatum in instrumental conditioning. Cereb Cortex 2009; 20:873-83. [PMID: 19605519 DOI: 10.1093/cercor/bhp151] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The prelimbic (PL) region of the prefrontal cortex and the posterior subregion of the dorsomedial striatum (pDMS) are components of a corticostriatal circuit subserving instrumental learning. Here, we examined whether dopamine (DA) signals conveyed to the PL and pDMS are critical for instrumental learning. Rats with 6-hydroxydopamine or vehicle infusion into the PL and pDMS were trained to press 2 levers, either for food pellets or a sucrose solution. Thereafter, we tested whether the animals were sensitive 1) to a selective degradation of 1 of 2 outcomes using a specific satiety procedure and 2) to a selective degradation of 1 of 2 contingencies controlling instrumental behavior. Rats with PL DA depletion displayed a reduced rate of lever presses but appeared to be sensitive to outcome devaluation and contingency degradation. Thus, PL DA seems to modulate lever pressing but does not support instrumental conditioning. In contrast, rats with pDMS DA depletion had intact response rates and were sensitive to selective outcome devaluation; however, they showed a reduced sensitivity to contingency degradation. Therefore, pDMS DA signaling seems not to be involved in maintaining lever pressing but instead contributes to instrumental conditioning by supporting the detection of causal relationships between an action and its consequences.
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Affiliation(s)
- Bjoern Lex
- Abteilung Tierphysiologie, Biologisches Institut, Universität Stuttgart, D-70550 Stuttgart, Germany
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42
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Disruption of NMDAR-dependent burst firing by dopamine neurons provides selective assessment of phasic dopamine-dependent behavior. Proc Natl Acad Sci U S A 2009; 106:7281-8. [PMID: 19342487 DOI: 10.1073/pnas.0813415106] [Citation(s) in RCA: 309] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Midbrain dopamine (DA) neurons fire in 2 characteristic modes, tonic and phasic, which are thought to modulate distinct aspects of behavior. However, the inability to selectively disrupt these patterns of activity has hampered the precise definition of the function of these modes of signaling. Here, we addressed the role of phasic DA in learning and other DA-dependent behaviors by attenuating DA neuron burst firing and subsequent DA release, without altering tonic neural activity. Disruption of phasic DA was achieved by selective genetic inactivation of NMDA-type, ionotropic glutamate receptors in DA neurons. Disruption of phasic DA neuron activity impaired the acquisition of numerous conditioned behavioral responses, and dramatically attenuated learning about cues that predicted rewarding and aversive events while leaving many other DA-dependent behaviors unaffected.
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Avila I, Reilly MP, Sanabria F, Posadas-Sánchez D, Chavez CL, Banerjee N, Killeen P, Castañeda E. Modeling operant behavior in the Parkinsonian rat. Behav Brain Res 2008; 198:298-305. [PMID: 19073222 DOI: 10.1016/j.bbr.2008.11.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 11/18/2008] [Accepted: 11/21/2008] [Indexed: 10/21/2022]
Abstract
Mathematical principles of reinforcement (MPR; Killeen, 1994) is a quantitative model of operant behavior that contains three parameters representing motor capacity (delta), motivation (a), and short term memory (lambda). The present study applied MPR to characterize the effects of bilateral infusions of 6-OHDA into the substantia nigra pars compacta in the rat, a model of Parkinson's disease. Rats were trained to lever press under a 5-component fixed-ratio (5, 15, 30, 60, and 100) schedule of food reinforcement. Rats were tested for 15 days prior to dopamine lesions and again for 15 days post-lesion. To characterize functional loss relative to lesion size, rats were grouped according to the extent and the degree of lateralization of their dopamine loss. Response rates decreased as a function of dopamine depletion, primarily at intermediate ratios. MPR accounted for 98% of variance in pre- and post-lesion response rates. Consistent with reported disruptions in motor behavior induced by dopaminergic lesions, estimates of delta increased when dopamine was severely depleted. There was no support for different estimates of a based on pre- and post-lesion performance of any lesion group, suggesting that dopamine loss has negligible effects on incentive motivation. The present study demonstrates the usefulness of combining operant techniques with a theoretical model to better understand the effects of a neurochemical manipulation.
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Affiliation(s)
- Irene Avila
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
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Yin HH, Ostlund SB, Balleine BW. Reward-guided learning beyond dopamine in the nucleus accumbens: the integrative functions of cortico-basal ganglia networks. Eur J Neurosci 2008; 28:1437-48. [PMID: 18793321 PMCID: PMC2756656 DOI: 10.1111/j.1460-9568.2008.06422.x] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here we challenge the view that reward-guided learning is solely controlled by the mesoaccumbens pathway arising from dopaminergic neurons in the ventral tegmental area and projecting to the nucleus accumbens. This widely accepted view assumes that reward is a monolithic concept, but recent work has suggested otherwise. It now appears that, in reward-guided learning, the functions of ventral and dorsal striata, and the cortico-basal ganglia circuitry associated with them, can be dissociated. Whereas the nucleus accumbens is necessary for the acquisition and expression of certain appetitive Pavlovian responses and contributes to the motivational control of instrumental performance, the dorsal striatum is necessary for the acquisition and expression of instrumental actions. Such findings suggest the existence of multiple independent yet interacting functional systems that are implemented in iterating and hierarchically organized cortico-basal ganglia networks engaged in appetitive behaviors ranging from Pavlovian approach responses to goal-directed instrumental actions controlled by action-outcome contingencies.
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Affiliation(s)
- Henry H Yin
- Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA.
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Palmiter RD. Dopamine signaling in the dorsal striatum is essential for motivated behaviors: lessons from dopamine-deficient mice. Ann N Y Acad Sci 2008; 1129:35-46. [PMID: 18591467 PMCID: PMC2720267 DOI: 10.1196/annals.1417.003] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Genetically engineered mice that lack tyrosine hydroxylase in all dopaminergic neurons become hypoactive and aphagic, and they starve by 4 weeks of age. However, they can be rescued by daily treatment with l-dopa, which restores activity and feeding for about 10 hours. Thus, these mice can be examined in both dopamine-depleted and dopamine-replete states. A series of behavioral experiments lead to the primary conclusion that in the dopamine-depleted state these mice are not motivated to engage in goal-directed behaviors. Nevertheless, they still have a preference for sucrose, they can learn the location of food rewards, and they can form a conditioned-place preference for drugs. Dopamine signaling can be restored to the striatum by several different viral gene-therapy procedures. Restoring dopamine signaling selectively to the dorsal striatum is sufficient to allow feeding, locomotion, and reward-based learning. The rescued mice appear to have normal motivation to engage in all goal-directed behaviors that have been tested. The results suggest that dopamine facilitates the output from dorsal striatum, which provides a permissive signal allowing feeding and other goal-directed behaviors.
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Affiliation(s)
- Richard D Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, Box 357370, University of Washington, Seattle, WA 98195, USA.
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Pizzagalli DA, Evins AE, Schetter EC, Frank MJ, Pajtas PE, Santesso DL, Culhane M. Single dose of a dopamine agonist impairs reinforcement learning in humans: behavioral evidence from a laboratory-based measure of reward responsiveness. Psychopharmacology (Berl) 2008; 196:221-32. [PMID: 17909750 PMCID: PMC2268635 DOI: 10.1007/s00213-007-0957-y] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 09/17/2007] [Indexed: 12/01/2022]
Abstract
RATIONALE The dopaminergic system, particularly D2-like dopamine receptors, has been strongly implicated in reward processing. Animal studies have emphasized the role of phasic dopamine (DA) signaling in reward-related learning, but these processes remain largely unexplored in humans. OBJECTIVES To evaluate the effect of a single, low dose of a D2/D3 agonist--pramipexole--on reinforcement learning in healthy adults. Based on prior evidence indicating that low doses of DA agonists decrease phasic DA release through autoreceptor stimulation, we hypothesized that 0.5 mg of pramipexole would impair reward learning due to presynaptic mechanisms. MATERIALS AND METHODS Using a double-blind design, a single 0.5-mg dose of pramipexole or placebo was administered to 32 healthy volunteers, who performed a probabilistic reward task involving a differential reinforcement schedule as well as various control tasks. RESULTS As hypothesized, response bias toward the more frequently rewarded stimulus was impaired in the pramipexole group, even after adjusting for transient adverse effects. In addition, the pramipexole group showed reaction time and motor speed slowing and increased negative affect; however, when adverse physical side effects were considered, group differences in motor speed and negative affect disappeared. CONCLUSIONS These findings show that a single low dose of pramipexole impaired the acquisition of reward-related behavior in healthy participants, and they are consistent with prior evidence suggesting that phasic DA signaling is required to reinforce actions leading to reward. The potential implications of the present findings to psychiatric conditions, including depression and impulse control disorders related to addiction, are discussed.
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Affiliation(s)
- Diego A Pizzagalli
- Department of Psychology, Harvard University, 1220 William James Hall, 33 Kirkland Street, Cambridge, MA 02138, USA.
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Palmiter RD. Is dopamine a physiologically relevant mediator of feeding behavior? Trends Neurosci 2007; 30:375-81. [PMID: 17604133 DOI: 10.1016/j.tins.2007.06.004] [Citation(s) in RCA: 296] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 05/21/2007] [Accepted: 06/15/2007] [Indexed: 10/23/2022]
Abstract
The hypothalamus integrates various hormonal and neuronal signals to regulate appetite and metabolism and thereby serves a homeostatic purpose in the regulation of body weight. Additional neural circuits that are superimposed on this system have the potential to override the homeostatic signals, resulting in either gluttony or anorexia at the extremes. Midbrain dopamine neurons have long been implicated in mediating reward behavior and the motivational aspects of feeding behavior. Recent results reveal that hormones implicated in regulating the homeostatic system also impinge directly on dopamine neurons; for example, leptin and insulin directly inhibit dopamine neurons, whereas ghrelin activates them. Here, I discuss the predictions and implications of these new findings as they relate to dopamine signaling and the physiology of appetite control.
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Affiliation(s)
- Richard D Palmiter
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98195-7370, USA.
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