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Kesby JP, Turner KM. The Translational Utility of Circuit-Based Manipulations in Preclinical Models. Biol Psychiatry Glob Open Sci 2024; 4:103-104. [PMID: 38298780 PMCID: PMC10829644 DOI: 10.1016/j.bpsgos.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 11/11/2023] [Indexed: 02/02/2024] Open
Affiliation(s)
- James P. Kesby
- Queensland Centre for Mental Health Research, Brisbane, Queensland, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Karly M. Turner
- School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
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2
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Srivastav S, Cui X, Varela RB, Kesby JP, Eyles D. Increasing dopamine synthesis in nigrostriatal circuits increases phasic dopamine release and alters dorsal striatal connectivity: implications for schizophrenia. Schizophrenia (Heidelb) 2023; 9:69. [PMID: 37798312 PMCID: PMC10556015 DOI: 10.1038/s41537-023-00397-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 09/18/2023] [Indexed: 10/07/2023]
Abstract
One of the most robust neurochemical abnormalities reported in patients with schizophrenia is an increase in dopamine (DA) synthesis and release, restricted to the dorsal striatum (DS). This hyper functionality is strongly associated with psychotic symptoms and progresses in those who later transition to schizophrenia. To understand the implications of this progressive neurobiology on brain function, we have developed a model in rats which we refer to as EDiPs (Enhanced Dopamine in Prodromal schizophrenia). The EDiPs model features a virally mediated increase in dorsal striatal (DS) DA synthesis capacity across puberty and into adulthood. This protocol leads to progressive changes in behaviour and neurochemistry. Our aim in this study was to explore if increased DA synthesis capacity alters the physiology of DA release and DS connectivity. Using fast scan cyclic voltammetry to assess DA release we show that evoked/phasic DA release is increased in the DS of EDiPs rats, whereas tonic/background levels of DA remain unaffected. Using quantitative immunohistochemistry methods to quantify DS synaptic architecture we show a presynaptic marker for DA release sites (Bassoon) was elevated within TH axons specifically within the DS, consistent with the increased phasic DA release in this region. Alongside changes in DA systems, we also show increased density of vesicular glutamate transporter 1 (VGluT1) synapses in the EDiPs DS suggesting changes in cortical connectivity. Our data may prove relevant in understanding the long-term implications for DS function in response to the robust and prolonged increases in DA synthesis uptake and release reported in schizophrenia.
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Affiliation(s)
- Sunil Srivastav
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Xiaoying Cui
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia
| | | | - James P Kesby
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia
| | - Darryl Eyles
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia.
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Conn KA, Alexander S, Burne THJ, Kesby JP. Antagonism of D2 receptors via raclopride ameliorates amphetamine-induced associative learning deficits in male mice. Behav Brain Res 2023; 454:114649. [PMID: 37643667 DOI: 10.1016/j.bbr.2023.114649] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/09/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Dopamine levels in the dorsomedial striatum (DMS) are highly dynamic and are thought to underly the encoding of action-outcome associations. Although it is known that amphetamine disrupts the learning that is required for goal-directed action, the role of D1 and D2 receptors in this process has not been established. In this study, we examined the role of D1 and D2 receptor antagonists on learning in response to amphetamine. We used the outcome-specific devaluation task to examine goal-directed action in male C57BL6/J mice treated systemically with either a D1 antagonist (SCH-23990; 0.01 mg/kg) or a D2 antagonist (raclopride; 0.5 mg/kg) and then administered amphetamine (1 mg/kg). The mice were injected repeatedly throughout the instrumental training phase of the task to assess the impact on the learning of action-outcomes, and the subsequent choice test assessing performance of goal-directed action was conducted drug free. Effects of chronic drug administration on locomotor behaviour was assessed before and after the choice test. Treatment during learning with either amphetamine, or the D1 or D2 antagonists, impaired the subsequent performance of goal-directed action. The amphetamine-induced impairment in goal-directed action was reversed in mice treated with raclopride, but not when treated with SCH-23990. By contrast, amphetamine-induced hyperactivity was reversed in mice treated with SCH-23990, but not in mice treated with raclopride. Taken together, these data support the role of a balance of dopamine receptor signalling after amphetamine treatment. While overall D1 receptor availability is necessary to promote learning, in a state of elevated dopamine, modifying D2 receptor function can ameliorate learning deficits.
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Affiliation(s)
- Kyna-Anne Conn
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Suzy Alexander
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Thomas H J Burne
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia; Queensland Centre for Mental Health Research, Wacol, QLD 4076, Australia
| | - James P Kesby
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia; Queensland Centre for Mental Health Research, Wacol, QLD 4076, Australia.
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4
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Young MK, Conn KA, Das J, Zou S, Alexander S, Burne TH, Kesby JP. Activity in the Dorsomedial Striatum Underlies Serial Reversal Learning Performance Under Probabilistic Uncertainty. Biol Psychiatry Glob Open Sci 2023; 3:1030-1041. [PMID: 37881585 PMCID: PMC10593872 DOI: 10.1016/j.bpsgos.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Background Corticostriatal circuits, particularly the dorsomedial striatum (DMS) and lateral orbitofrontal cortex, are critical for navigating reversal learning under probabilistic uncertainty. These same areas are implicated in the reversal learning impairments observed in individuals with psychosis as well as their psychotic symptoms, suggesting that they may share a common neurobiological substrate. To address this question, we used psychostimulant exposure and specific activation of the DMS during reversal learning in mice to assess corticostriatal activity. Methods We used amphetamine treatment to induce psychosis-relevant neurobiology in male mice during reversal learning and to examine pathway-specific corticostriatal activation. To determine the causal role of DMS activity, we used chemogenetics to drive midbrain inputs during a range of probabilistic contingencies. Results Mice treated with amphetamine showed altered punishment learning, which was associated with decreased shifting after losses and increased perseverative errors after reversals. Reversal learning performance and strategies were dependent on increased activity in lateral orbitofrontal cortex to DMS circuits as well as in the DMS itself. Specific activation of midbrain to DMS circuits also decreased shifting after losses and reversal learning performance. However, these alterations were dependent on the probabilistic contingency. Conclusions Our work suggests that the DMS plays a multifaceted role in reversal learning. Increasing DMS activity impairs multiple reversal learning processes dependent on the level of uncertainty, confirming its role in the maintenance and selection of incoming cortical inputs. Together, these outcomes suggest that elevated dopamine levels in the DMS could contribute to decision-making impairments in individuals with psychosis.
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Affiliation(s)
- Madison K. Young
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Kyna-Anne Conn
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Joyosmita Das
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Simin Zou
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Suzy Alexander
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, Brisbane, Queensland, Australia
| | - Thomas H.J. Burne
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, Brisbane, Queensland, Australia
| | - James P. Kesby
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, Brisbane, Queensland, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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Baker A, Suetani S, Cosgrove P, Siskind D, Murray GK, Scott JG, Kesby JP. Reversal learning in those with early psychosis features contingency-dependent changes in loss response and learning. Cogn Neuropsychiatry 2023; 28:342-360. [PMID: 37737715 DOI: 10.1080/13546805.2023.2259019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023]
Abstract
INTRODUCTION People with psychotic disorders commonly feature broad decision-making impairments that impact their functional outcomes. Specific associative/reinforcement learning problems have been demonstrated in persistent psychosis. But these phenotypes may differ in early psychosis, suggesting that aspects of cognition decline over time. METHODS The present proof-of-concept study examined goal-directed action and reversal learning in controls and those with early psychosis. RESULTS Equivalent performance was observed between groups during outcome-specific devaluation, and reversal learning at an 80:20 contingency (reward probability for high:low targets). But when the low target reward probability was increased (80:40) those with early psychosis altered their response to loss, whereas controls did not. Computational modelling confirmed that in early psychosis there was a change in punishment learning that increased the chance of staying with the same stimulus after a loss, multiple trials into the future. In early psychosis, the magnitude of this response was greatest in those with higher IQ and lower clinical severity scores. CONCLUSIONS We show preliminary evidence that those with early psychosis present with a phenotype that includes altered responding to loss and hyper-adaptability in response to outcome changes. This may reflect a compensatory response to overcome the milieu of corticostriatal changes associated with psychotic disorders.
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Affiliation(s)
- Andrea Baker
- Queensland Centre for Mental Health Research, Brisbane, Australia
| | - Shuichi Suetani
- Queensland Centre for Mental Health Research, Brisbane, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
- School of Medicine and Dentistry, Griffith University, Brisbane, Australia
- Institute for Urban Indigenous Health, Brisbane, Australia
| | - Peter Cosgrove
- Queensland Centre for Mental Health Research, Brisbane, Australia
| | - Dan Siskind
- Queensland Centre for Mental Health Research, Brisbane, Australia
- Metro South Addiction and Mental Health Services, Brisbane, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Graham K Murray
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - James G Scott
- Queensland Centre for Mental Health Research, Brisbane, Australia
- Child Health Research Centre, University of Queensland, Brisbane, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James P Kesby
- Queensland Centre for Mental Health Research, Brisbane, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
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Arnautovska U, Vitangcol K, Kesby JP, Warren N, Rossell SL, Neill E, Harris A, Galletly C, Castle D, Siskind D. Verbal and visual learning ability in patients with treatment-resistant schizophrenia: A 1-year follow-up study. Schizophr Res Cogn 2023; 33:100283. [PMID: 37006704 PMCID: PMC10063404 DOI: 10.1016/j.scog.2023.100283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Objective In the general population, repeated cognitive testing produces learning effects with potential for improved test performance. It is currently unclear whether the same effect of repeated cognitive testing on cognition pertains to people living with schizophrenia, a condition often associated with significant cognitive impairments. This study aims to evaluate learning ability in people with schizophrenia and-considering the evidence that antipsychotic medication can additionally impair cognitive performance-explore the potential impact of anticholinergic burden on verbal and visual learning. Method The study included 86 patients with schizophrenia, treated with clozapine, who had persisting negative symptoms. They were assessed at baseline, weeks 8, 24 and 52 using Positive and Negative Syndrome Scale, Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-R (BVMT-R). Results There were no significant improvements in verbal or visual learning across all measurements. Neither the clozapine/norclozapine ratio nor anticholinergic cognitive burden significantly predicted participants' total learning. Premorbid IQ was significantly associated with verbal learning on the HVLT-R. Conclusions These findings advance our understanding of cognitive performance in people with schizophrenia and demonstrate limited learning performance in individuals with treatment-refractory schizophrenia.
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Affiliation(s)
- Urska Arnautovska
- Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia
- Metro South Addictions and Mental Health Service, Woolloongabba, QLD 4102, Australia
- Corresponding authors at: PAH Southside Clinical Unit, Faculty of Medicine, Princess Alexandra Hospital, 199 Ipswich Rd, Woolloongabba, QLD 4102, Australia.
| | - Kathryn Vitangcol
- Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia
| | - James P. Kesby
- Queensland Centre for Mental Health Research, Wacol, QLD 4076, Australia
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4067, Australia
| | - Nicola Warren
- Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia
- Metro South Addictions and Mental Health Service, Woolloongabba, QLD 4102, Australia
| | - Susan L. Rossell
- Centre for Mental Health, School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC 5062, Australia
- Department of Psychiatry, St Vincent's Hospital Melbourne, Fitzroy, VIC 3065, Australia
| | - Erica Neill
- Centre for Mental Health, School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC 5062, Australia
| | - Anthony Harris
- Specialty of Psychiatry, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
- Westmead Institute for Medical Research, Westmead, NSW 2145, Australia
| | - Cherrie Galletly
- Discipline of Psychiatry, Adelaide Medical School, University of Adelaide, SA 5005, Australia
- Northern Adelaide Local Health Network, Adelaide, SA 5005, Australia
| | - David Castle
- Department of Psychiatry, St Vincent's Hospital Melbourne, Fitzroy, VIC 3065, Australia
- Centre for Complex Intervention, Centre for Addiction and Mental Health, Toronto 2283, Canada
- Department of Psychiatry, The University of Toronto, Toronto 2283, Canada
| | - Dan Siskind
- Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia
- Metro South Addictions and Mental Health Service, Woolloongabba, QLD 4102, Australia
- Corresponding authors at: PAH Southside Clinical Unit, Faculty of Medicine, Princess Alexandra Hospital, 199 Ipswich Rd, Woolloongabba, QLD 4102, Australia.
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Conn KA, Zou S, Das J, Alexander S, Burne TH, Kesby JP. Activating the dorsomedial and ventral midbrain projections to the striatum differentially impairs goal-directed action in male mice. Neuropharmacology 2023; 234:109550. [PMID: 37085011 DOI: 10.1016/j.neuropharm.2023.109550] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 03/29/2023] [Accepted: 04/17/2023] [Indexed: 04/23/2023]
Abstract
The cognitive symptoms of schizophrenia are wide ranging and include impaired goal-directed action. This could be driven by an increase in dopamine transmission in the dorsomedial striatum, a pathophysiological hallmark of schizophrenia. Although commonly associated with psychotic symptoms, dopamine signalling in this region also modulates associative learning that aids in the execution of actions. To gain a better understanding of the role of subcortical dopamine in learning and decision-making, we assessed goal-directed action in male mice using the cross-species outcome-specific devaluation task (ODT). First, we administered systemic amphetamine during training to determine the impact of altered dopaminergic signaling on associative learning. Second, we used pathway-specific chemogenetic approaches to activate the dorsomedial and ventral striatal pathways (that originate in the midbrain) to separately assess learning and performance. Amphetamine treatment during learning led to a dose-dependent impairment in goal-directed action. Activation of both striatal pathways during learning also impaired performance. However, when these pathways were activated during choice, only activation of the ventral pathway impaired goal-directed action. This suggests that elevated transmission in the dorsomedial striatal pathway impairs associative learning processes that guide the goal-directed execution of actions. By contrast, elevated transmission of the ventral striatal pathway disrupts the encoding of outcome values that are important for both associative learning and choice performance. These findings highlight the differential roles of the dorsomedial and ventral inputs into the striatum in goal-directed action and provides insight into how striatal dopamine signaling may contribute to the cognitive problems in those with schizophrenia.
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Affiliation(s)
- Kyna-Anne Conn
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Simin Zou
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Joyosmita Das
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Suzy Alexander
- Queensland Centre for Mental Health Research, Wacol, QLD, 4076, Australia
| | - Thomas Hj Burne
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia; Queensland Centre for Mental Health Research, Wacol, QLD, 4076, Australia
| | - James P Kesby
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia; Queensland Centre for Mental Health Research, Wacol, QLD, 4076, Australia; QIMR Berghofer Medical Research Institute, Herston, QLD, 4029, Australia.
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8
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Arnautovska U, Kesby JP, Korman N, Rebar AL, Chapman J, Warren N, Rossell SL, Dark FL, Siskind D. Biopsychology of Physical Activity in People with Schizophrenia: An Integrative Perspective on Barriers and Intervention Strategies. Neuropsychiatr Dis Treat 2022; 18:2917-2926. [PMID: 36544549 PMCID: PMC9763049 DOI: 10.2147/ndt.s393775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
People with severe mental illness such as schizophrenia experience high physical comorbidity, leading to a 15-20-year mortality gap compared with the general population. Lifestyle behaviours such as physical activity (PA) play important roles in the quest to bridge this gap. Interventions to increase PA engagement in this population have potential to be efficacious; however, their effectiveness can be hindered by low participant engagement, including low adherence and high drop-out, and by implementation of interventions that are not designed to compensate for the cognitive and motivational impairments characteristic for this group. Moreover, and importantly, the negative symptoms of schizophrenia are associated with neurobiological changes in the brain, which-based on principles of biopsychology-can contribute to poor motivation and impaired decision-making processes and behavioural maintenance. To increase PA levels in people with schizophrenia, better understanding of these neurological changes that impact PA engagement is needed. This has the potential to inform the design of interventions that, through enhancement of motivation, could effectively increase PA levels in this specific population. Incorporating strategies that address the dopamine dysregulation associated with schizophrenia, such as boosting the role of reward and self-determined motivation, may improve long-term PA maintenance, leading to habitual PA. Consideration of motivation and behavioural maintenance is also needed to impart health benefits such as prevention of chronic disease, which is associated with currently low PA levels in this high metabolic risk population. Taking a biopsychological perspective, we outline the neural pathways involved in motivation that are impacted by schizophrenia and propose strategies for promoting motivation for and PA engagement from adoption to habit formation.
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Affiliation(s)
- Urska Arnautovska
- Faculty of Medicine, The University of Queensland, Woolloongabba, QLD, Australia.,Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia
| | - James P Kesby
- Centre for Mental Health, Griffith University, Nathan, QLD, Australia.,Queensland Centre for Mental Health Research, Wacol, QLD, 4076, Australia
| | - Nicole Korman
- Faculty of Medicine, The University of Queensland, Woolloongabba, QLD, Australia.,Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia
| | - Amanda L Rebar
- Motivation of Health Behaviours Lab, Appleton Institute, School of Health, Medical, and Applied Sciences; Central Queensland University, Rockhampton, QLD, Australia
| | - Justin Chapman
- Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia.,Centre for Mental Health, Griffith University, Nathan, QLD, Australia
| | - Nicola Warren
- Faculty of Medicine, The University of Queensland, Woolloongabba, QLD, Australia.,Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia
| | - Susan L Rossell
- Centre for Mental Health, School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia.,Psychiatry, St Vincent's Hospital Melbourne, Fitzroy, VIC, Australia
| | - Frances L Dark
- Faculty of Medicine, The University of Queensland, Woolloongabba, QLD, Australia.,Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia
| | - Dan Siskind
- Faculty of Medicine, The University of Queensland, Woolloongabba, QLD, Australia.,Metro South Addictions and Mental Health Service, Woolloongabba, QLD, Australia.,Queensland Centre for Mental Health Research, Wacol, QLD, 4076, Australia
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9
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Kesby JP, Murray GK, Knolle F. Neural Circuitry of Salience and Reward Processing in Psychosis. Biol Psychiatry Glob Open Sci 2021; 3:33-46. [PMID: 36712572 PMCID: PMC9874126 DOI: 10.1016/j.bpsgos.2021.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 11/25/2021] [Accepted: 12/01/2021] [Indexed: 02/01/2023] Open
Abstract
The processing of salient and rewarding stimuli is integral to engaging our attention, stimulating anticipation for future events, and driving goal-directed behaviors. Widespread impairments in these processes are observed in psychosis, which may be associated with worse functional outcomes or mechanistically linked to the development of symptoms. Here, we summarize the current knowledge of behavioral and functional neuroimaging in salience, prediction error, and reward. Although each is a specific process, they are situated in multiple feedback and feedforward systems integral to decision making and cognition more generally. We argue that the origin of salience and reward processing dysfunctions may be centered in the subcortex during the earliest stages of psychosis, with cortical abnormalities being initially more spared but becoming more prominent in established psychotic illness/schizophrenia. The neural circuits underpinning salience and reward processing may provide targets for delaying or preventing progressive behavioral and neurobiological decline.
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Affiliation(s)
- James P. Kesby
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia,QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia,Address correspondence to James Kesby, Ph.D.
| | - Graham K. Murray
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia,Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom,Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
| | - Franziska Knolle
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom,Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany,Franziska Knolle, Ph.D.
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Flintoff J, Kesby JP, Siskind D, Burne TH. Treating cognitive impairment in schizophrenia with GLP-1RAs: an overview of their therapeutic potential. Expert Opin Investig Drugs 2021; 30:877-891. [PMID: 34213981 DOI: 10.1080/13543784.2021.1951702] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Schizophrenia is a neuropsychiatric disorder that affects approximately 1% of individuals worldwide. There are no available medications to treat cognitive impairment in this patient population currently. Preclinical evidence suggests that glucagon-like peptide-1 receptor agonists (GLP-1 RAs) improve cognitive function. There is a need to evaluate how GLP-1 RAs alter specific domains of cognition and whether they will be of therapeutic benefit in individuals with schizophrenia. AREAS COVERED This paper summarizes the effects of GLP-1 RAs on metabolic processes in the brain and how these mechanisms relate to improved cognitive function. We provide an overview of preclinical studies that demonstrate GLP-1 RAs improve cognition and comment on their potential therapeutic benefit in individuals with schizophrenia. EXPERT OPINION To understand the benefits of GLP-1 RAs in individuals with schizophrenia, further preclinical research with rodent models relevant to schizophrenia symptomology are needed. Moreover, preclinical studies must focus on using a wider range of behavioral assays to understand whether important aspects of cognition such as executive function, attention, and goal-directed behavior are improved using GLP-1 RAs. Further research into the specific mechanisms of how GLP-1 RAs affect cognitive function and their interactions with antipsychotic medication commonly prescribed is necessary.
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Affiliation(s)
- Jonathan Flintoff
- Queensland Brain Institute, the University of Queensland, St Lucia, QLD, Australia
| | - James P Kesby
- Queensland Brain Institute, the University of Queensland, St Lucia, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Dan Siskind
- Queensland Centre for Mental Health Research, Wacol, QLD, Australia.,Metro South Addiction and Mental Health Service, Woolloongabba, QLD, Australia
| | - Thomas Hj Burne
- Queensland Brain Institute, the University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, Wacol, QLD, Australia
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11
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Cui X, Pertile RAN, Du Z, Wei W, Sun Z, Eyles DW, Kesby JP. Developmental Inhibition of Long Intergenic Non-Coding RNA, HOTAIRM1, Impairs Dopamine Neuron Differentiation and Maturation. Int J Mol Sci 2021; 22:ijms22147268. [PMID: 34298885 PMCID: PMC8306845 DOI: 10.3390/ijms22147268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/16/2022] Open
Abstract
The dopaminergic (DA) system is important for a range of brain functions and subcortical DA development precedes many cortical maturational processes. The dysfunction of DA systems has been associated with neuropsychiatric disorders such as schizophrenia, depression, and addiction. DA neuron cell fate is controlled by a complex web of transcriptional factors that dictate DA neuron specification, differentiation, and maturation. A growing body of evidence suggests that these transcriptional factors are under the regulation of newly discovered non-coding RNAs. However, with regard to DA neuron development, little is known of the roles of non-coding RNAs. The long non-coding RNA (lncRNA) HOX-antisense intergenic RNA myeloid 1 (HOTAIRM1) is present in adult DA neurons, suggesting it may have a modulatory role in DA systems. Moreover, HOTAIRM1 is involved in the neuronal differentiation in human stem cells suggesting it may also play a role in early DA neuron development. To determine its role in early DA neuron development, we knocked down HOTAIRM1 using RNAi in vitro in a human neuroblastoma cell line, and in vivo in mouse DA progenitors using a novel in utero electroporation technique. HOTAIRM1 inhibition decreased the expression of a range of key DA neuron specification factors and impaired DA neuron differentiation and maturation. These results provide evidence of a functional role for HOTAIRM1 in DA neuron development and differentiation. Understanding of the role of lncRNAs in the development of DA systems may have broader implications for brain development and neurodevelopmental disorders such as schizophrenia.
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Affiliation(s)
- Xiaoying Cui
- Queensland Centre for Mental Health Research, Wacol, QLD 4076, Australia; (X.C.); (D.W.E.)
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - Renata Ap. Nedel Pertile
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - Zilong Du
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - Wei Wei
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - Zichun Sun
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - Darryl W. Eyles
- Queensland Centre for Mental Health Research, Wacol, QLD 4076, Australia; (X.C.); (D.W.E.)
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
| | - James P. Kesby
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia; (R.A.N.P.); (Z.D.); (W.W.); (Z.S.)
- QIMR Berghofer Medical Research Institute, Herston, QLD 4029, Australia
- Correspondence: ; Tel.: +61-7-3346-6363; Fax: +61-7-3346-6301
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12
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Baek EJ, Kim H, Basova LA, Rosander A, Kesby JP, Semenova S, Marcondes MCG. Sex differences and Tat expression affect dopaminergic receptor expression and response to antioxidant treatment in methamphetamine-sensitized HIV Tat transgenic mice. Neuropharmacology 2020; 178:108245. [PMID: 32783894 DOI: 10.1016/j.neuropharm.2020.108245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 06/11/2020] [Accepted: 07/14/2020] [Indexed: 02/07/2023]
Abstract
Methamphetamine (Meth) abuse is a common HIV comorbidity. Males and females differ in their patterns of Meth use, associated behaviors, and responses, but the underlying mechanisms and impact of HIV infection are unclear. Transgenic mice with inducible HIV-1 Tat protein in the brain (iTat) replicate many neurological aspects of HIV infection in humans. We previously showed that Tat induction enhances the Meth sensitization response associated with perturbation of the dopaminergic system, in male iTat mice. Here, we used the iTat mouse model to investigate sex differences in individual and interactive effects of Tat and Meth challenge on locomotor sensitization, brain expression of dopamine receptors (DRDs) and regulatory adenosine receptors (ADORAs). Because Meth administration increases the production of reactive oxygen species (ROS), we also determined whether the effects of Meth could be rescued by concomitant treatment with the ROS scavenger N-acetyl cysteine (NAC). After Meth sensitization and a 7-day abstinence period, groups of Tat+ and Tat-male and female mice were challenged with Meth in combination with NAC. We confirmed that Tat expression and Meth challenge suppressed DRD mRNA and protein in males and females' brains, and showed that females were particularly susceptible to the effects of Meth on D1-like and D2-like DRD subtypes and ADORAs. The expression of these markers differed strikingly between males and females, and between females in different phases of the estrous cycle, in a Tat -dependent manner. NAC attenuated Meth-induced locomotor sensitization and preserved DRD expression in all groups except for Tat + females. These data identify complex interactions between sex, Meth use, and HIV infection on addiction responses, with potential implications for the treatment of male and female Meth users in the context of HIV, especially those with cognitive disorders.
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Affiliation(s)
- Eun Ji Baek
- The Scripps Research Institute, Neurosciences Department, La Jolla, CA, 92037, USA; Queensland Brain Institute, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Hahoon Kim
- The Scripps Research Institute, Neurosciences Department, La Jolla, CA, 92037, USA; Queensland Brain Institute, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Liana A Basova
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA; The Scripps Research Institute, Neurosciences Department, La Jolla, CA, 92037, USA
| | - Ashley Rosander
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - James P Kesby
- Queensland Brain Institute, University of Queensland, St. Lucia, QLD, 4072, Australia; Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, 4029, Australia; Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Maria Cecilia Garibaldi Marcondes
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA; The Scripps Research Institute, Neurosciences Department, La Jolla, CA, 92037, USA.
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13
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Conn KA, Burne THJ, Kesby JP. Subcortical Dopamine and Cognition in Schizophrenia: Looking Beyond Psychosis in Preclinical Models. Front Neurosci 2020; 14:542. [PMID: 32655348 PMCID: PMC7325949 DOI: 10.3389/fnins.2020.00542] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/01/2020] [Indexed: 12/18/2022] Open
Abstract
Schizophrenia is characterized by positive, negative and cognitive symptoms. All current antipsychotic treatments feature dopamine-receptor antagonism that is relatively effective at addressing the psychotic (positive) symptoms of schizophrenia. However, there is no clear evidence that these medications improve the negative or cognitive symptoms, which are the greatest predictors of functional outcomes. One of the most robust pathophysiological observations in patients with schizophrenia is increased subcortical dopamine neurotransmission, primarily in the associative striatum. This brain area has an important role in a range of cognitive processes. Dopamine is also known to play a major part in regulating a number of cognitive functions impaired in schizophrenia but much of this research has been focused on cortical dopamine. Emerging research highlights the strong influence subcortical dopamine has on a range of cognitive domains, including attention, reward learning, goal-directed action and decision-making. Nonetheless, the precise role of the associative striatum in the cognitive impairments observed in schizophrenia remains poorly understood, presenting an opportunity to revisit its contribution to schizophrenia. Without a better understanding of the mechanisms underlying cognitive dysfunction, treatment development remains at a standstill. For this reason, improved preclinical animal models are needed if we are to understand the complex relationship between subcortical dopamine and cognition. A range of new techniques are facillitating the discrete manipulation of dopaminergic neurotransmission and measurements of cognitive performance, which can be investigated using a variety of sensitive translatable tasks. This has the potential to aid the successful incorporation of recent clinical research to address the lack of treatment strategies for cognitive symptoms in schizophrenia. This review will give an overview on the current state of research focused on subcortical dopamine and cognition in the context of schizophrenia research. We also discuss future strategies and approaches aimed at improving the translational outcomes for the treatment of cognitive deficits in schizophrenia.
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Affiliation(s)
- Kyna-Anne Conn
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Thomas H J Burne
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, Wacol, QLD, Australia
| | - James P Kesby
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
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14
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Kesby JP, Chang A, Najera JA, Marcondes MCG, Semenova S. Brain Reward Function after Chronic and Binge Methamphetamine Regimens in Mice Expressing the HIV-1 TAT Protein. Curr HIV Res 2020; 17:126-133. [PMID: 31269883 DOI: 10.2174/1570162x17666190703165408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/11/2019] [Accepted: 06/21/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Methamphetamine abuse and human immunodeficiency virus (HIV) are common comorbidities. HIV-associated proteins, such as the regulatory protein TAT, may contribute to brain reward dysfunction, inducing an altered sensitivity to methamphetamine reward and/or withdrawal in this population. OBJECTIVE These studies examined the combined effects of TAT protein expression and, chronic and binge methamphetamine regimens on brain reward function. METHODS Transgenic mice with inducible brain expression of the TAT protein were exposed to either saline, a chronic, or a binge methamphetamine regimen. TAT expression was induced via doxycycline treatment during the last week of methamphetamine exposure. Brain reward function was assessed daily throughout the regimens, using the intracranial self-stimulation procedure, and after a subsequent acute methamphetamine challenge. RESULTS Both methamphetamine regimens induced withdrawal-related decreases in reward function. TAT expression substantially, but not significantly increased the withdrawal associated with exposure to the binge regimen compared to the chronic regimen, but did not alter the response to acute methamphetamine challenge. TAT expression also led to persistent changes in adenosine 2B receptor expression in the caudate putamen, regardless of methamphetamine exposure. These results suggest that TAT expression may differentially affect brain reward function, dependent on the pattern of methamphetamine exposure. CONCLUSION The subtle effects observed in these studies highlight that longer-term TAT expression, or its induction at earlier stages of methamphetamine exposure, may be more consequential at inducing behavioral and neurochemical effects.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, United States.,Queensland Brain Institute, The University of Queensland, St. Lucia, Qld, Australia.,UQ Centre for Clinical Research, The University of Queensland, Brisbane, Qld, Australia
| | - Ariel Chang
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, United States
| | - Julia A Najera
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA, United States
| | - Maria Cecilia G Marcondes
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA, United States.,San Diego Biomedical Research Institute, San Diego, CA 92121, United States
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, United States
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15
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Ryan AE, Mowry BJ, Kesby JP, Scott JG, Greer JM. Is there a role for antibodies targeting muscarinic acetylcholine receptors in the pathogenesis of schizophrenia? Aust N Z J Psychiatry 2019; 53:1059-1069. [PMID: 31347380 DOI: 10.1177/0004867419864438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Muscarinic receptor dysfunction has been suggested to play an important role in the pathophysiology of schizophrenia. Recently, it has also become clear that immune reactivity directed against neurotransmitter receptors may play a pathogenic role in some cases of schizophrenia. The aim of this review is to summarize the case for muscarinic receptor dysfunction in schizophrenia and the evidence supporting the hypothesis that this dysfunction is related to the development of muscarinic receptor-targeting antibodies. METHOD The article reviews studies of muscarinic receptors and the presence and potential role(s) of anti-muscarinic acetylcholine receptor antibodies in people with schizophrenia. RESULTS There is accumulating evidence that altered or deficient muscarinic signalling underlies some of the key clinical features of schizophrenia. Although the number of studies investigating anti-muscarinic acetylcholine receptor antibodies in schizophrenia is relatively small, they consistently demonstrate that such antibodies are present in a proportion of patients. This evidence suggests that these antibodies could have pathogenic effects or exist as a biomarker to an unknown pathophysiological process in schizophrenia. CONCLUSION The presence of elevated levels of anti-muscarinic acetylcholine receptor antibodies may identify a subgroup of people with schizophrenia, potentially informing aetiopathogenesis, clinical presentation and treatment. To date, all studies have examined antibodies in participants with chronic schizophrenia, who have likely received antipsychotic medication for many years. As these medications modulate immune functions and regulate receptor densities, it is recommended that future studies screen for the presence of anti-muscarinic antibodies in people experiencing their first episode of psychosis.
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Affiliation(s)
- Alexander E Ryan
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
| | - Bryan J Mowry
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - James P Kesby
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - James G Scott
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia.,School of Public Health, The University of Queensland, Brisbane, QLD, Australia.,Metro North Mental Health, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Judith M Greer
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
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Boutros N, Der-Avakian A, Kesby JP, Lee S, Markou A, Semenova S. Effects of adolescent alcohol exposure on stress-induced reward deficits, brain CRF, monoamines and glutamate in adult rats. Psychopharmacology (Berl) 2018; 235:737-747. [PMID: 29181815 DOI: 10.1007/s00213-017-4789-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/13/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Adolescent alcohol exposure may increase depression vulnerability in adulthood by increasing the anhedonic response to stress. METHODS Male Wistar rats (postnatal days 28-53) were exposed to binge-like adolescent intermittent ethanol (AIE) or water. In adulthood, rats were exposed to social defeat, consisting of daily confrontations with an aggressive conspecific, followed by testing of brain reward function in a discrete-trial current-intensity intracranial self-stimulation procedure for 10 consecutive days. Neurochemistry and corticotropin-releasing factor (CRF) and CRF receptor 1 (CRFR1) mRNA levels were assessed in corticolimbic brain areas on day 11 of social defeat stress. RESULTS Social defeat elevated reward thresholds in both AIE- and water-exposed rats indicating stress-induced anhedonia. However, AIE-exposed rats were more likely to show threshold elevations after repeated stress compared to water-exposed rats. AIE exposure decreased CRF mRNA levels in the nucleus accumbens and increased CRFR1 mRNA levels in the prefrontal cortex, while stress increased CRF mRNA levels in the central amygdala. In the caudate putamen, AIE exposure decreased dopamine turnover, while stress increased glutamate and serotonin metabolism and turnover. CONCLUSIONS These results demonstrate increased risk of repeated stress-induced anhedonia after AIE exposure, an effect that may be due to alterations in brain CRF and dopamine systems. These results suggest that the increased rates of depression reported in people with a history of adolescent alcohol exposure may be related to alterations in brain reward and stress systems that may contribute to increased stress-induced anhedonia.
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Affiliation(s)
| | | | - James P Kesby
- University of California San Diego, La Jolla, CA, USA.,Queensland Brain Institute, The University of Queensland, St. Lucia, Queensland, Australia
| | - Soon Lee
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Athina Markou
- University of California San Diego, La Jolla, CA, USA
| | - Svetlana Semenova
- University of California San Diego, La Jolla, CA, USA. .,PAREXEL International, 1560 E Chevy Chase Dr, Glendale, CA, 91206, USA.
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17
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Kesby JP, Eyles DW, McGrath JJ, Scott JG. Dopamine, psychosis and schizophrenia: the widening gap between basic and clinical neuroscience. Transl Psychiatry 2018; 8:30. [PMID: 29382821 PMCID: PMC5802623 DOI: 10.1038/s41398-017-0071-9] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/10/2017] [Accepted: 10/26/2017] [Indexed: 12/18/2022] Open
Abstract
The stagnation in drug development for schizophrenia highlights the need for better translation between basic and clinical research. Understanding the neurobiology of schizophrenia presents substantial challenges but a key feature continues to be the involvement of subcortical dopaminergic dysfunction in those with psychotic symptoms. Our contemporary knowledge regarding dopamine dysfunction has clarified where and when dopaminergic alterations may present in schizophrenia. For example, clinical studies have shown patients with schizophrenia show increased presynaptic dopamine function in the associative striatum, rather than the limbic striatum as previously presumed. Furthermore, subjects deemed at high risk of developing schizophrenia show similar presynaptic dopamine abnormalities in the associative striatum. Thus, our view of subcortical dopamine function in schizophrenia continues to evolve as we accommodate this newly acquired information. However, basic research in animal models has been slow to incorporate these clinical findings. For example, psychostimulant-induced locomotion, the commonly utilised phenotype for positive symptoms in rodents, is heavily associated with dopaminergic activation in the limbic striatum. This anatomical misalignment has brought into question how we assess positive symptoms in animal models and represents an opportunity for improved translation between basic and clinical research. The current review focuses on the role of subcortical dopamine dysfunction in psychosis and schizophrenia. We present and discuss alternative phenotypes that may provide a more translational approach to assess the neurobiology of positive symptoms in schizophrenia. Incorporation of recent clinical findings is essential if we are to develop meaningful translational animal models.
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Affiliation(s)
- JP Kesby
- 0000 0000 9320 7537grid.1003.2Queensland Brain Institute, The University of Queensland, St. Lucia, QLD Australia ,0000 0000 9320 7537grid.1003.2Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD Australia
| | - DW Eyles
- 0000 0000 9320 7537grid.1003.2Queensland Brain Institute, The University of Queensland, St. Lucia, QLD Australia ,0000 0004 0606 3563grid.417162.7Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD Australia
| | - JJ McGrath
- 0000 0000 9320 7537grid.1003.2Queensland Brain Institute, The University of Queensland, St. Lucia, QLD Australia ,0000 0004 0606 3563grid.417162.7Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD Australia ,0000 0001 1956 2722grid.7048.bNational Centre for Register-based Research, Aarhus University, Aarhus C, Denmark
| | - JG Scott
- 0000 0000 9320 7537grid.1003.2Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD Australia ,0000 0004 0606 3563grid.417162.7Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD Australia ,0000 0001 0688 4634grid.416100.2Metro North Mental Health, Royal Brisbane and Women’s Hospital, Herston, QLD Australia
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Kesby JP, Chang A, Markou A, Semenova S. Modeling human methamphetamine use patterns in mice: chronic and binge methamphetamine exposure, reward function and neurochemistry. Addict Biol 2018; 23:206-218. [PMID: 28224681 PMCID: PMC5565728 DOI: 10.1111/adb.12502] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/26/2017] [Accepted: 02/03/2017] [Indexed: 11/29/2022]
Abstract
Different methamphetamine use patterns in human subjects may contribute to inconsistent findings regarding the effects of methamphetamine abuse on brain and behavior. The present study investigated whether human-derived chronic and binge methamphetamine use patterns have differential effects on reward and neurochemistry in mice. Brain reward function in mice was evaluated during acute/prolonged withdrawal, and in response to methamphetamine challenge using the intracranial self-stimulation procedure. Brain dopaminergic, serotonergic and glutamatergic neurochemistry was determined with high-performance liquid chromatography. Chronic and binge regimens induced withdrawal-related decreases in reward function that were more severe during the binge regimen during cycles 1-2. Despite large differences in methamphetamine dose, both regimens induced similar reward deficits during cycles 3-4. Neither methamphetamine regimen led to persistent alterations in the sensitivity to the reward-enhancing effects of acute methamphetamine challenge. The binge regimen severely depleted striatal dopamine levels and increased brain glutamine levels. The chronic regimen had milder effects on striatal dopamine levels and altered cortical dopamine and serotonin levels. This work highlights that the magnitude of acute/prolonged withdrawal may not reflect amount or frequency of methamphetamine intake. In contrast, the array of underlying neurochemical alterations was methamphetamine regimen dependent. Thus, stratifying methamphetamine-dependent individuals based on use pattern may help to cater therapeutic interventions more appropriately by targeting use pattern-specific neurotransmitter systems.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
- Queensland Brain Institute, The University of Queensland, St. Lucia, Qld, Australia
| | - Ariel Chang
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Athina Markou
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Svetlana Semenova
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
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19
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Milienne-Petiot M, Kesby JP, Graves M, van Enkhuizen J, Semenova S, Minassian A, Markou A, Geyer MA, Young JW. The effects of reduced dopamine transporter function and chronic lithium on motivation, probabilistic learning, and neurochemistry in mice: Modeling bipolar mania. Neuropharmacology 2016; 113:260-270. [PMID: 27732870 DOI: 10.1016/j.neuropharm.2016.07.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/21/2016] [Accepted: 07/24/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND Bipolar disorder (BD) mania patients exhibit poor cognition and reward-seeking/hypermotivation, negatively impacting a patient's quality of life. Current treatments (e.g., lithium), do not treat such deficits. Treatment development has been limited due to a poor understanding of the neural mechanisms underlying these behaviors. Here, we investigated putative mechanisms underlying cognition and reward-seeking/motivational changes relevant to BD mania patients using two validated mouse models and neurochemical analyses. METHODS The effects of reducing dopamine transporter (DAT) functioning via genetic (knockdown vs. wild-type littermates), or pharmacological (GBR12909- vs. vehicle-treated C57BL/6J mice) means were assessed in the probabilistic reversal learning task (PRLT), and progressive ratio breakpoint (PRB) test, during either water or chronic lithium treatment. These tasks quantify reward learning and effortful motivation, respectively. Neurochemistry was performed on brain samples of DAT mutants ± chronic lithium using high performance liquid chromatography. RESULTS Reduced DAT functioning increased reversals in the PRLT, an effect partially attenuated by chronic lithium. Chronic lithium alone slowed PRLT acquisition. Reduced DAT functioning increased motivation (PRB), an effect attenuated by lithium in GBR12909-treated mice. Neurochemical analyses revealed that DAT knockdown mice exhibited elevated homovanillic acid levels, but that lithium had no effect on these elevated levels. CONCLUSIONS Reducing DAT functioning recreates many aspects of BD mania including hypermotivation and improved reversal learning (switching), as well as elevated homovanillic acid levels. Chronic lithium only exerted main effects, impairing learning and elevating norepinephrine and serotonin levels of mice, not specifically treating the underlying mechanisms identified in these models.
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Affiliation(s)
- Morgane Milienne-Petiot
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - James P Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Mary Graves
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Jordy van Enkhuizen
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Arpi Minassian
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Mark A Geyer
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Jared W Young
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA.
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20
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Soontornniyomkij V, Kesby JP, Morgan EE, Bischoff-Grethe A, Minassian A, Brown GG, Grant I. Effects of HIV and Methamphetamine on Brain and Behavior: Evidence from Human Studies and Animal Models. J Neuroimmune Pharmacol 2016; 11:495-510. [PMID: 27484318 PMCID: PMC4985024 DOI: 10.1007/s11481-016-9699-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/26/2016] [Indexed: 10/21/2022]
Abstract
Methamphetamine (Meth) use is frequent among HIV-infected persons. Combined HIV and Meth insults may exacerbate neural injury in vulnerable neuroanatomic structures or circuitries in the brain, leading to increased behavioral disturbance and cognitive impairment. While acute and chronic effects of Meth in humans and animal models have been studied for decades, the neurobehavioral effects of Meth in the context of HIV infection are much less explored. In-depth understanding of the scope of neurobehavioral phenotypes and mechanisms in HIV/Meth intersection is needed. The present report summarizes published research findings, as well as unpublished data, in humans and animal models with regard to neurobehavioral disturbance, neuroimaging, and neuropathology, and in vitro experimental systems, with an emphasis on findings emerging from the National Institute on Drug Abuse (NIDA) funded Translational Methamphetamine AIDS Research Center (TMARC). Results from human studies and animal (primarily HIV-1 gp120 transgenic mouse) models thus far suggest that combined HIV and Meth insults increase the likelihood of neural injury in the brain. The neurobehavioral effects include cognitive impairment and increased tendencies toward impaired behavioral inhibition and social cognition. These impairments are relevant to behaviors that affect personal and social risks, e.g. worse medication adherence, riskier behaviors, and greater likelihood of HIV transmission. The underlying mechanisms may include electrochemical changes in neuronal circuitries, injury to white matter microstructures, synaptodendritic damage, and selective neuronal loss. Utilization of research methodologies that are valid across species is instrumental in generating new knowledge with clinical translational value.
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Affiliation(s)
- Virawudh Soontornniyomkij
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA.
| | - James P Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
- Queensland Brain Institute, The University of Queensland, St. Lucia, Qld, Australia
| | - Erin E Morgan
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Amanda Bischoff-Grethe
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Arpi Minassian
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Gregory G Brown
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Igor Grant
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
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Kesby JP, Markou A, Semenova S. The effects of HIV-1 regulatory TAT protein expression on brain reward function, response to psychostimulants and delay-dependent memory in mice. Neuropharmacology 2016; 109:205-215. [PMID: 27316905 DOI: 10.1016/j.neuropharm.2016.06.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/08/2016] [Accepted: 06/13/2016] [Indexed: 10/21/2022]
Abstract
Depression and psychostimulant abuse are common comorbidities among humans with immunodeficiency virus (HIV) disease. The HIV regulatory protein TAT is one of multiple HIV-related proteins associated with HIV-induced neurotoxicity. TAT-induced dysfunction of dopamine and serotonin systems in corticolimbic brain areas may result in impaired reward function, thus, contributing to depressive symptoms and psychostimulant abuse. Transgenic mice with doxycycline-induced TAT protein expression in the brain (TAT+, TAT- control) show neuropathology resembling brain abnormalities in HIV+ humans. We evaluated brain reward function in response to TAT expression, nicotine and methamphetamine administration in TAT+ and TAT- mice using the intracranial self-stimulation procedure. We evaluated the brain dopamine and serotonin systems with high-performance liquid chromatography. The effects of TAT expression on delay-dependent working memory in TAT+ and TAT- mice using the operant delayed nonmatch-to-position task were also assessed. During doxycycline administration, reward thresholds were elevated by 20% in TAT+ mice compared with TAT- mice. After the termination of doxycycline treatment, thresholds of TAT+ mice remained significantly higher than those of TAT- mice and this was associated with changes in mesolimbic serotonin and dopamine levels. TAT+ mice showed a greater methamphetamine-induced threshold lowering compared with TAT- mice. TAT expression did not alter delay-dependent working memory. These results indicate that TAT expression in mice leads to reward deficits, a core symptom of depression, and a greater sensitivity to methamphetamine-induced reward enhancement. Our findings suggest that the TAT protein may contribute to increased depressive-like symptoms and continued methamphetamine use in HIV-positive individuals.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA; Queensland Brain Institute, The University of Queensland, St. Lucia, Qld, Australia
| | - Athina Markou
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Svetlana Semenova
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
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Kesby JP, Markou A, Semenova S. Effects of HIV/TAT protein expression and chronic selegiline treatment on spatial memory, reversal learning and neurotransmitter levels in mice. Behav Brain Res 2016; 311:131-140. [PMID: 27211061 DOI: 10.1016/j.bbr.2016.05.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/28/2016] [Accepted: 05/16/2016] [Indexed: 02/08/2023]
Abstract
Neurotoxic viral protein TAT may contribute to deficits in dopaminergic and cognitive function in individuals infected with human immunodeficiency virus. Transgenic mice with brain-specific doxycycline-induced TAT expression (TAT+, TAT- control) show impaired cognition. However, previously reported TAT-induced deficits in reversal learning may be compromised by initial learning deficits. We investigated the effects of TAT expression on memory retention/recall and reversal learning, and neurotransmitter function. We also investigated if TAT-induced effects can be reversed by improving dopamine function with selegiline, a monoamine oxidase inhibitor. Mice were tested in the Barnes maze and TAT expression was induced after the task acquisition. Selegiline treatment continued throughout behavioral testing. Dopamine, serotonin and glutamate tissue levels in the prefrontal/orbitofrontal cortex, hippocampus and caudate putamen were measured using high performance liquid chromatography. Neither TAT expression nor selegiline altered memory retention. On day 2 of reversal learning testing, TAT+ mice made fewer errors and used more efficient search strategies than TAT- mice. TAT expression decreased dopamine turnover in the caudate putamen, increased serotonin turnover in the hippocampus and tended to increase the conversion of glutamate to glutamine in all regions. Selegiline decreased dopamine and serotonin metabolism in all regions and increased glutamate levels in the caudate putamen. In the absence of impaired learning, TAT expression does not impair spatial memory retention/recall, and actually facilitates reversal learning. Selegiline-induced increases in dopamine metabolism did not affect cognitive function. These findings suggest that TAT-induced alterations in glutamate signaling, but not alterations in monoamine metabolism, may underlie the facilitation of reversal learning.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA; Queensland Brain Institute, The University of Queensland, St. Lucia, Qld, Australia
| | - Athina Markou
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Svetlana Semenova
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
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McKenna BS, Brown GG, Archibald S, Scadeng M, Bussell R, Kesby JP, Markou A, Soontornniyomkij V, Achim C, Semenova S. Microstructural changes to the brain of mice after methamphetamine exposure as identified with diffusion tensor imaging. Psychiatry Res 2016; 249:27-37. [PMID: 27000304 PMCID: PMC4831583 DOI: 10.1016/j.pscychresns.2016.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 02/01/2016] [Accepted: 02/23/2016] [Indexed: 01/09/2023]
Abstract
Methamphetamine (METH) is an addictive psychostimulant inducing neurotoxicity. Human magnetic resonance imaging and diffusion tensor imaging (DTI) of METH-dependent participants find various structural abnormities. Animal studies demonstrate immunohistochemical changes in multiple cellular pathways after METH exposure. Here, we characterized the long-term effects of METH on brain microstructure in mice exposed to an escalating METH binge regimen using in vivo DTI, a methodology directly translatable across species. Results revealed four patterns of differential fractional anisotropy (FA) and mean diffusivity (MD) response when comparing METH-exposed (n=14) to saline-treated mice (n=13). Compared to the saline group, METH-exposed mice demonstrated: 1) decreased FA with no change in MD [corpus callosum (posterior forceps), internal capsule (left), thalamus (medial aspects), midbrain], 2) increased MD with no change in FA [posterior isocortical regions, caudate-putamen, hypothalamus, cerebral peduncle, internal capsule (right)], 3) increased FA with decreased MD [frontal isocortex, corpus callosum (genu)], and 4) increased FA with no change or increased MD [hippocampi, amygdala, lateral thalamus]. MD was negatively associated with calbindin-1 in hippocampi and positively with dopamine transporter in caudate-putamen. These findings highlight distributed and differential METH effects within the brain suggesting several distinct mechanisms. Such mechanisms likely change brain tissue differentially dependent upon neural location.
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Affiliation(s)
- Benjamin S McKenna
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Gregory G Brown
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA.
| | - Sarah Archibald
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Miriam Scadeng
- Department of Radiology, School of Medicine, University of California, San Diego, 200 West Arbor Drive, M/C 0834, La Jolla, CA 92103, USA
| | - Robert Bussell
- Department of Radiology, School of Medicine, University of California, San Diego, 200 West Arbor Drive, M/C 0834, La Jolla, CA 92103, USA
| | - James P Kesby
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Virawudh Soontornniyomkij
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Cristian Achim
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
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Soontornniyomkij V, Kesby JP, Soontornniyomkij B, Kim JJ, Kisseleva T, Achim CL, Semenova S, Jeste DV. Age and High-Fat Diet Effects on Glutamine Synthetase Immunoreactivity in Liver and Hippocampus and Recognition Memory in Mice. Curr Aging Sci 2016; 9:301-309. [PMID: 27071478 PMCID: PMC5063669 DOI: 10.2174/1874609809666160413113311] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/22/2016] [Accepted: 04/11/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND High-Fat Diet (HFD)-induced obesity may promote agerelated memory impairment via disturbances of ammonia-glutamine metabolism. OBJECTIVE We studied the effects of age and long-term HFD exposure on Glutamine Synthetase (GS) expression in the liver and hippocampus and recognition memory in mice. METHODS Adult (5-month-old) and aged (15-month-old) male C57BL/6 mice were exposed to control diet (CD, 14% calories from fat) or HFD (60% fat). Novel place recognition testing was conducted and tissue was collected after 4 and 5 months on HFD, respectively. Tissue GS expression levels were assessed using immunohistochemistry and image analysis. RESULTS The obese mice developed moderate/severe hepatic steatosis. GS immunoreactivity was observed in perivenous hepatocytes and in hippocampal astrocytes and neuropil. Hepatic GS immunoreactivity density was higher in aged mice on HFD (n = 8) than CD (n = 13, P = 0.004). In aged mice, hippocampal GS immunoreactivity density was higher with HFD than CD (P = 0.037). In the novel place recognition test, aged mice were classified into impaired (n = 7) and unimpaired (n = 12), relative to adult mice (n = 22). Hippocampal GS immunoreactivity density was higher in impaired than unimpaired aged mice (P < 0.05). CONCLUSION Long-term exposure of aged mice to HFD was associated with increased GS expression in the liver and hippocampus. Novel place recognition impairment in aged mice was associated with increased hippocampal GS expression. These findings suggest that excess ammonia is involved in the age-related effects of HFD exposure and in neurotoxicity.
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Affiliation(s)
- Virawudh Soontornniyomkij
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - James P. Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, USA
| | | | - Jane J. Kim
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Tatiana Kisseleva
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Cristian L. Achim
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Dilip V. Jeste
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, USA
- Sam and Rose Stein Institute for Research on Aging, School of Medicine, University of California San Diego, La Jolla, California, USA
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Kesby JP, Kim JJ, Scadeng M, Woods G, Kado DM, Olefsky JM, Jeste DV, Achim CL, Semenova S. Spatial Cognition in Adult and Aged Mice Exposed to High-Fat Diet. PLoS One 2015; 10:e0140034. [PMID: 26448649 PMCID: PMC4598128 DOI: 10.1371/journal.pone.0140034] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/21/2015] [Indexed: 01/14/2023] Open
Abstract
Aging is associated with a decline in multiple aspects of cognitive function, with spatial cognition being particularly sensitive to age-related decline. Environmental stressors, such as high-fat diet (HFD) exposure, that produce a diabetic phenotype and metabolic dysfunction may indirectly lead to exacerbated brain aging and promote the development of cognitive deficits. The present work investigated whether exposure to HFD exacerbates age-related cognitive deficits in adult versus aged mice. Adult (5 months old) and aged (15 months old) mice were exposed to control diet or HFD for three months prior to, and throughout, behavioral testing. Anxiety-like behavior in the light-dark box test, discrimination learning and memory in the novel object/place recognition tests, and spatial learning and memory in the Barnes maze test were assessed. HFD resulted in significant gains in body weight and fat mass content with adult mice gaining significantly more weight and adipose tissue due to HFD than aged mice. Weight gain was attributed to food calories sourced from fat, but not total calorie intake. HFD increased fasting insulin levels in all mice, but adult mice showed a greater increase relative to aged mice. Behaviorally, HFD increased anxiety-like behavior in adult but not aged mice without significantly affecting spatial cognition. In contrast, aged mice fed either control or HFD diet displayed deficits in novel place discrimination and spatial learning. Our results suggest that adult mice are more susceptible to the physiological and anxiety-like effects of HFD consumption than aged mice, while aged mice displayed deficits in spatial cognition regardless of dietary influence. We conclude that although HFD induces systemic metabolic dysfunction in both adult and aged mice, overall cognitive function was not adversely affected under the current experimental conditions.
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Affiliation(s)
- James P. Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jane J. Kim
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Miriam Scadeng
- Department of Radiology, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Gina Woods
- Department of Family Medicine & Public Health and Internal Medicine, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Deborah M. Kado
- Department of Family Medicine & Public Health and Internal Medicine, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jerrold M. Olefsky
- Department of Family Medicine & Public Health and Internal Medicine, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Dilip V. Jeste
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, United States of America
- Sam and Rose Stein Institute for Research on Aging, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Cristian L. Achim
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, United States of America
- Sam and Rose Stein Institute for Research on Aging, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Kesby JP, Heaton RK, Young JW, Umlauf A, Woods SP, Letendre SL, Markou A, Grant I, Semenova S. Methamphetamine Exposure Combined with HIV-1 Disease or gp120 Expression: Comparison of Learning and Executive Functions in Humans and Mice. Neuropsychopharmacology 2015; 40:1899-909. [PMID: 25652249 PMCID: PMC4839513 DOI: 10.1038/npp.2015.39] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/15/2015] [Accepted: 01/27/2015] [Indexed: 11/09/2022]
Abstract
Methamphetamine dependence is a common comorbid condition among people living with HIV, and may exacerbate HIV-associated neurocognitive disorders. Animal models of neuroAIDS suggest that the gp120 protein may also cause cognitive impairment. The present work evaluated the separate and combined effects of HIV/gp120 and methamphetamine on learning and executive functions in both humans and transgenic mice. Human participants were grouped by HIV serostatus (HIV+ or HIV-) and lifetime methamphetamine dependence (METH+ or METH-). A neurocognitive test battery included domain-specific assessments of learning and executive functions. Mice (gp120+ and gp120-) were exposed to either a methamphetamine binge (METH+) or saline (METH-), then tested in the attentional-set-shifting task to assess learning and executive functions. In humans, HIV status was associated with significant impairments in learning, but less so for executive functions. The frequency of learning impairments varied between groups, with the greatest impairment observed in the HIV+/METH+ group. In mice, gp120 expression was associated with impairments in learning but not reversal learning (executive component). The greatest proportion of mice that failed to complete the task was observed in the gp120+/METH+ group, suggesting greater learning impairments. Our cross-species study demonstrated that HIV in humans and gp120 in mice impaired learning, and that a history of methamphetamine exposure increased the susceptibility to HIV-associated neurocognitive deficits in both species. Finally, the similar pattern of results in both species suggest that the gp120 protein may contribute to HIV-associated learning deficits in humans.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Robert K Heaton
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jared W Young
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA,Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Anya Umlauf
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Steven P Woods
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Scott L Letendre
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Igor Grant
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA,Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA, Tel: +858 534 1528, Fax: +858 534 9917, E mail:
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Kesby JP, Markou A, Semenova S. Cognitive deficits associated with combined HIV gp120 expression and chronic methamphetamine exposure in mice. Eur Neuropsychopharmacol 2015; 25:141-50. [PMID: 25476577 PMCID: PMC4289653 DOI: 10.1016/j.euroneuro.2014.07.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 07/25/2014] [Accepted: 07/26/2014] [Indexed: 01/01/2023]
Abstract
Methamphetamine abuse is common among individuals infected by human immunodeficiency virus (HIV). Neurocognitive outcomes tend to be worse in methamphetamine users with HIV. However, it is unclear whether discrete cognitive domains are susceptible to impairment after combined HIV infection and methamphetamine abuse. The expression of HIV/gp120 protein induces neuropathology in mice similar to HIV-induced pathology in humans. We investigated the separate and combined effects of methamphetamine exposure and gp120 expression on cognitive function in transgenic (gp120-tg) and control mice. The mice underwent an escalating methamphetamine binge regimen and were tested in novel object/location recognition, object-in-place recognition, and Barnes maze tests. gp120 expression disrupted performance in the object-in-place test (i.e. similar time spent with all objects, regardless of location), indicating deficits in associative recognition memory. gp120 expression also altered reversal learning in the Barnes maze, suggesting impairments in executive function. Methamphetamine exposure impaired spatial strategy in the Barnes maze, indicating deficits in spatial learning. Methamphetamine-exposed gp120-tg mice had the lowest spatial strategy scores in the final acquisition trials in the Barnes maze, suggesting greater deficits in spatial learning than all of the other groups. Although HIV infection involves interactions between multiple proteins and processes, in addition to gp120, our findings in gp120-tg mice suggest that humans with the dual insult of HIV infection and methamphetamine abuse may exhibit a broader spectrum of cognitive deficits than those with either factor alone. Depending on the cognitive domain, the combination of both insults may exacerbate deficits in cognitive performance compared with each individual insult.
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Affiliation(s)
- James P Kesby
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | - Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA.
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28
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Der-Avakian A, Mazei-Robison MS, Kesby JP, Nestler EJ, Markou A. Enduring deficits in brain reward function after chronic social defeat in rats: susceptibility, resilience, and antidepressant response. Biol Psychiatry 2014; 76:542-9. [PMID: 24576687 PMCID: PMC4117827 DOI: 10.1016/j.biopsych.2014.01.013] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/24/2013] [Accepted: 01/19/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Anhedonia, or diminished interest or pleasure in rewarding activities, characterizes depression and reflects deficits in brain reward circuitries. Social stress induces anhedonia and increases risk of depression, although the effect of social stress on brain reward function is incompletely understood. METHODS This study assessed the following: 1) brain reward function in rats (using the intracranial self-stimulation procedure) and protein levels of brain-derived neurotrophic factor and related signaling molecules in response to chronic social defeat, 2) brain reward function during social defeat and long-term treatment with the antidepressants fluoxetine (5 mg/kg/day) and desipramine (10 mg/kg/day), and 3) forced swim test behavior after social defeat and fluoxetine treatment. RESULTS Social defeat profoundly and persistently decreased brain reward function, reflecting an enduring anhedonic response, in susceptible rats, whereas resilient rats showed no long-term brain reward deficits. In the ventral tegmental area, social defeat, regardless of susceptibility or resilience, decreased brain-derived neurotrophic factor and increased phosphorylated AKT, whereas only susceptibility was associated with increased phosphorylated mammalian target of rapamycin. Fluoxetine and desipramine reversed lower, but not higher, stress-induced brain reward deficits in susceptible rats. Fluoxetine decreased immobility in the forced swim test, as did social defeat. CONCLUSIONS These results suggest that the differential persistent anhedonic response to psychosocial stress may be mediated by ventral tegmental area signaling molecules independent of brain-derived neurotrophic factor and indicate that greater stress-induced anhedonia is associated with resistance to antidepressant treatment. Consideration of these behavioral and neurobiological factors associated with resistance to stress and antidepressant action may promote the discovery of novel targets to treat stress-related mood disorders.
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Affiliation(s)
- Andre Der-Avakian
- Department of Psychiatry; University of California San Diego, La Jolla, CA 92093-0603; USA
| | | | - James P Kesby
- Department of Psychiatry; University of California San Diego, La Jolla, CA 92093-0603; USA
| | - Eric J Nestler
- Fishberg Department of Neuroscience and Friedman Brain Institute; Icahn School of Medicine at Mount Sinai, New York, NY 10029; USA
| | - Athina Markou
- Department of Psychiatry, University of California San Diego, La Jolla, California.
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Kesby JP, Hubbard DT, Markou A, Semenova S. Expression of HIV gp120 protein increases sensitivity to the rewarding properties of methamphetamine in mice. Addict Biol 2014; 19:593-605. [PMID: 23252824 DOI: 10.1111/adb.12023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Methamphetamine abuse and human immunodeficiency virus (HIV) infection induce neuropathological changes in corticolimbic brain areas involved in reward and cognitive function. Little is known about the combined effects of methamphetamine and HIV infection on cognitive and reward processes. The HIV/gp120 protein induces neurodegeneration in mice, similar to HIV-induced pathology in humans. We investigated the effects of gp120 expression on associative learning, preference for methamphetamine and non-drug reinforcers, and sensitivity to the conditioned rewarding properties of methamphetamine in transgenic (tg) mice expressing HIV/gp120 protein (gp120-tg). gp120-tg mice learned the operant response for food at the same rate as non-tg mice. In the two-bottle choice procedure with restricted access to drugs, gp120-tg mice exhibited greater preference for methamphetamine and saccharin than non-tg mice, whereas preference for quinine was similar between genotypes. Under conditions of unrestricted access to methamphetamine, the mice exhibited a decreased preference for increasing methamphetamine concentrations. However, male gp120-tg mice showed a decreased preference for methamphetamine at lower concentrations than non-tg male mice. gp120-tg mice developed methamphetamine-induced conditioned place preference at lower methamphetamine doses compared with non-tg mice. No differences in methamphetamine pharmacokinetics were found between genotypes. These results indicate that gp120-tg mice exhibit no deficits in associative learning or reward/motivational function for a natural reinforcer. Interestingly, gp120 expression resulted in increased preference for methamphetamine and a highly palatable non-drug reinforcer (saccharin) and increased sensitivity to methamphetamine-induced conditioned reward. These data suggest that HIV-positive individuals may have increased sensitivity to methamphetamine, leading to high methamphetamine abuse potential in this population.
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Affiliation(s)
- James P. Kesby
- Department of Psychiatry; School of Medicine; University of California San Diego; La Jolla CA USA
| | - David T. Hubbard
- Department of Psychiatry; School of Medicine; University of California San Diego; La Jolla CA USA
| | - Athina Markou
- Department of Psychiatry; School of Medicine; University of California San Diego; La Jolla CA USA
| | - Svetlana Semenova
- Department of Psychiatry; School of Medicine; University of California San Diego; La Jolla CA USA
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Kesby JP, Cui X, Burne THJ, Eyles DW. Altered dopamine ontogeny in the developmentally vitamin D deficient rat and its relevance to schizophrenia. Front Cell Neurosci 2013; 7:111. [PMID: 23882183 PMCID: PMC3713405 DOI: 10.3389/fncel.2013.00111] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/26/2013] [Indexed: 11/13/2022] Open
Abstract
Schizophrenia is a heterogeneous group of disorders with unknown etiology. Although abnormalities in multiple neurotransmitter systems have been linked to schizophrenia, alterations in dopamine (DA) neurotransmission remain central to the treatment of this disorder. Given that schizophrenia is considered a neurodevelopmental disorder we have hypothesized that abnormal DA signaling in the adult patient may result from altered DA signaling during fetal brain development. Environmental and genetic risk factors can be modeled in rodents to allow for the investigation of early neurodevelopmental pathogenesis that may lead to clues into the etiology of schizophrenia. To address this we created an animal model of one such risk factor, developmental vitamin D (DVD) deficiency. DVD-deficient adult rats display an altered behavioral profile in response to DA releasing and blocking agents that are reminiscent of that seen in schizophrenia patients. Furthermore, developmental studies revealed that DVD deficiency also altered cell proliferation, apoptosis, and neurotransmission across the embryonic brain. In particular, DVD deficiency reduces the expression of crucial dopaminergic specification factors and alters DA metabolism in the developing brain. We speculate such alterations in fetal brain development may change the trajectory of DA neuron ontogeny to induce the behavioral abnormalities observed in adult offspring. The widespread evidence that both dopaminergic and structural changes are present in people who develop schizophrenia prior to onset also suggest that early alterations in development are central to the disease. Taken together, early alterations in DA ontogeny may represent a core feature in the pathology of schizophrenia. Such a mechanism could bring together evidence from multiple risk factors and genetic vulnerabilities to form a convergent pathway in disease pathophysiology.
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Affiliation(s)
- James P. Kesby
- Department of Psychiatry, School of Medicine, University of California San DiegoLa Jolla, CA, USA
| | - Xiaoying Cui
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
| | - Thomas H. J. Burne
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
- Queensland Centre for Mental Health Research, The Park Centre for Mental HealthWacol, QLD, Australia
| | - Darryl W. Eyles
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
- Queensland Centre for Mental Health Research, The Park Centre for Mental HealthWacol, QLD, Australia
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Kesby JP, Eyles DW, Burne THJ, McGrath JJ. The effects of vitamin D on brain development and adult brain function. Mol Cell Endocrinol 2011; 347:121-7. [PMID: 21664231 DOI: 10.1016/j.mce.2011.05.014] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/21/2011] [Accepted: 05/02/2011] [Indexed: 10/25/2022]
Abstract
A role for vitamin D in brain development and function has been gaining support over the last decade. Multiple lines of evidence suggest that this vitamin is actually a neuroactive steroid that acts on brain development, leading to alterations in brain neurochemistry and adult brain function. Early deficiencies have been linked with neuropsychiatric disorders, such as schizophrenia, and adult deficiencies have been associated with a host of adverse brain outcomes, including Parkinson's disease, Alzheimer's disease, depression and cognitive decline. This review summarises the current state of research on the actions of vitamin D in the brain and the consequences of deficiencies in this vitamin. Furthermore, we discuss specific implications of vitamin D status on the neurotransmitter, dopamine.
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Affiliation(s)
- James P Kesby
- Queensland Brain Institute, University of Queensland, St. Lucia, Qld 4076, Australia
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Kesby JP, Cui X, Ko P, McGrath JJ, Burne THJ, Eyles DW. Developmental vitamin D deficiency alters dopamine turnover in neonatal rat forebrain. Neurosci Lett 2009; 461:155-8. [PMID: 19500655 DOI: 10.1016/j.neulet.2009.05.070] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 05/19/2009] [Accepted: 05/27/2009] [Indexed: 10/20/2022]
Abstract
There is growing evidence that low vitamin D impacts adversely on brain development. The current study investigated the impact of developmental vitamin D (DVD) deficiency on dopamine and serotonin metabolism in the neonatal rat brain. DVD-deficiency resulted in an altered dopaminergic metabolic profile in the forebrain, with a decrease in the conversion of dihydroxyphenylacetic acid (DOPAC) to homovanillic acid (HVA). Correspondingly, expression of the enzyme required for this conversion, catechol-O-methyl transferase (COMT), was decreased. These results suggest that DVD-deficiency influences dopamine turnover during development.
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Affiliation(s)
- James P Kesby
- School of Biomedical Science, University of Queensland, Qld 4072, Australia
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Kesby JP, Burne THJ, McGrath JJ, Eyles DW. Developmental vitamin D deficiency alters MK 801-induced hyperlocomotion in the adult rat: An animal model of schizophrenia. Biol Psychiatry 2006; 60:591-6. [PMID: 16697353 DOI: 10.1016/j.biopsych.2006.02.033] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 02/21/2006] [Accepted: 02/22/2006] [Indexed: 01/03/2023]
Abstract
BACKGROUND Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. The behavioral phenotype of adult rats subjected to transient low prenatal vitamin D is characterized by spontaneous hyperlocomotion but normal prepulse inhibition of acoustic startle (PPI). The aim of this study was to examine the impact of selected psychotropic agents and one well-known antipsychotic agent on the behavioral phenotype of DVD deplete rats. METHODS Control versus DVD deplete adult rats were assessed on holeboard, open field and PPI. In the open field, animals were given MK-801 and/or haloperidol. For PPI, the animals were given apomorphine or MK-801. RESULTS DVD deplete rats had increased baseline locomotion on the holeboard task and increased locomotion in response to MK-801 compared to control rats. At low doses, haloperidol antagonized the MK-801 hyperactivity of DVD deplete rats preferentially and, at a high dose, resulted in a more pronounced reduction in spontaneous locomotion in DVD deplete rats. DVD depletion did not affect either baseline or drug-mediated PPI response. CONCLUSIONS These results suggest that DVD deficiency is associated with a persistent alteration in neuronal systems associated with motor function but not those associated with sensory motor gating. In light of the putative association between low prenatal vitamin D and schizophrenia, the discrete behavioral differences associated with the DVD model may help elucidate the neurobiological correlates of schizophrenia.
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Affiliation(s)
- James P Kesby
- School of Biomedical Science, University of Queensland, Brisbane, Australia
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