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Jaehne EJ, Semaan H, Grosman A, Xu X, Schwarz Q, van den Buuse M. Enhanced methamphetamine sensitisation in a rat model of the brain-derived neurotrophic factor Val66Met variant: Sex differences and dopamine receptor gene expression. Neuropharmacology 2023; 240:109719. [PMID: 37742717 DOI: 10.1016/j.neuropharm.2023.109719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/29/2023] [Accepted: 09/17/2023] [Indexed: 09/26/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) and the Val66Met polymorphism may play a role in the development of psychosis and schizophrenia. The aim of this study was to investigate long-term effects of methamphetamine (Meth) on psychosis-like behaviour and dopamine receptor and dopamine transporter gene expression in a novel rat model of the BDNF Val66Met polymorphism. At the end of a 7-day subchronic Meth treatment, female rats with the Met/Met genotype selectively showed locomotor hyperactivity sensitisation to the acute effect of Meth. Male rats showed tolerance to Meth irrespective of Val66Met genotype. Two weeks later, female Met/Met rats showed increased locomotor activity following both saline treatment or a low dose of Meth, a hyperactivity which was not observed in other genotypes or in males. Baseline PPI did not differ between the groups but the disruption of PPI by acute treatment with apomorphine was absent in Meth-pretreated Met/Met rats. Female Met/Met rats selectively showed down-regulation of dopamine D2 receptor gene expression in striatum. Behavioural effects of MK-801 or its locomotor sensitisation by prior Meth pretreatment were not influenced by genotype. These data suggest a selective vulnerability of female Met/Met rats to short-term and long-term effects of Meth, which could model increased vulnerability to psychosis development associated with the BDNF Val66Met polymorphism.
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Affiliation(s)
- Emily J Jaehne
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Hayette Semaan
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Adam Grosman
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Xiangjun Xu
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, Australia
| | - Quenten Schwarz
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, Australia
| | - Maarten van den Buuse
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, Australia; Department of Pharmacology, University of Melbourne, Melbourne, Australia.
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Kim HY, Lee J, Kim HJ, Lee BE, Jeong J, Cho EJ, Jang HJ, Shin KJ, Kim MJ, Chae YC, Lee SE, Myung K, Baik JH, Suh PG, Kim JI. PLCγ1 in dopamine neurons critically regulates striatal dopamine release via VMAT2 and synapsin III. Exp Mol Med 2023; 55:2357-2375. [PMID: 37907739 PMCID: PMC10689754 DOI: 10.1038/s12276-023-01104-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 08/05/2023] [Accepted: 08/06/2023] [Indexed: 11/02/2023] Open
Abstract
Dopamine neurons are essential for voluntary movement, reward learning, and motivation, and their dysfunction is closely linked to various psychological and neurodegenerative diseases. Hence, understanding the detailed signaling mechanisms that functionally modulate dopamine neurons is crucial for the development of better therapeutic strategies against dopamine-related disorders. Phospholipase Cγ1 (PLCγ1) is a key enzyme in intracellular signaling that regulates diverse neuronal functions in the brain. It was proposed that PLCγ1 is implicated in the development of dopaminergic neurons, while the physiological function of PLCγ1 remains to be determined. In this study, we investigated the physiological role of PLCγ1, one of the key effector enzymes in intracellular signaling, in regulating dopaminergic function in vivo. We found that cell type-specific deletion of PLCγ1 does not adversely affect the development and cellular morphology of midbrain dopamine neurons but does facilitate dopamine release from dopaminergic axon terminals in the striatum. The enhancement of dopamine release was accompanied by increased colocalization of vesicular monoamine transporter 2 (VMAT2) at dopaminergic axon terminals. Notably, dopamine neuron-specific knockout of PLCγ1 also led to heightened expression and colocalization of synapsin III, which controls the trafficking of synaptic vesicles. Furthermore, the knockdown of VMAT2 and synapsin III in dopamine neurons resulted in a significant attenuation of dopamine release, while this attenuation was less severe in PLCγ1 cKO mice. Our findings suggest that PLCγ1 in dopamine neurons could critically modulate dopamine release at axon terminals by directly or indirectly interacting with synaptic machinery, including VMAT2 and synapsin III.
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Affiliation(s)
- Hye Yun Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jieun Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyun-Jin Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Byeong Eun Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jaewook Jeong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Eun Jeong Cho
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyun-Jun Jang
- Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju, 58245, Republic of Korea
| | - Kyeong Jin Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Min Ji Kim
- Department of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Young Chan Chae
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Seung Eun Lee
- Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Ja-Hyun Baik
- Department of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Pann-Ghill Suh
- Korea Brain Research Institute (KBRI), Daegu, 41062, Republic of Korea
| | - Jae-Ick Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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Hogarth S, Jaehne EJ, Xu X, Schwarz Q, van den Buuse M. Interaction of Brain-Derived Neurotrophic Factor with the Effects of Chronic Methamphetamine on Prepulse Inhibition in Mice Is Independent of Dopamine D3 Receptors. Biomedicines 2023; 11:2290. [PMID: 37626786 PMCID: PMC10452514 DOI: 10.3390/biomedicines11082290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
The aim of the present study was to gain a better understanding of the role of brain-derived neurotrophic factor (BDNF) and dopamine D3 receptors in the effects of chronic methamphetamine (METH) on prepulse inhibition (PPI), an endophenotype of psychosis. We compared the effect of a three-week adolescent METH treatment protocol on the regulation of PPI in wildtype mice, BDNF heterozygous mice (HET), D3 receptor knockout mice (D3KO), and double-mutant mice (DM) with both BDNF heterozygosity and D3 receptor knockout. Chronic METH induced disruption of PPI regulation in male mice with BDNF haploinsufficiency (HET and DM), independent of D3 receptor knockout. Specifically, these mice showed reduced baseline PPI, as well as attenuated disruption of PPI induced by acute treatment with the dopamine receptor agonist, apomorphine (APO), or the glutamate NMDA receptor antagonist, MK-801. In contrast, there were no effects of BDNF heterozygosity or D3 knockout on PPI regulation in female mice. Chronic METH pretreatment induced the expected locomotor hyperactivity sensitisation, where female HET and DM mice also showed endogenous sensitisation. Differential sex-specific effects of genotype and METH pretreatment were observed on dopamine receptor and dopamine transporter gene expression in the striatum and frontal cortex. Taken together, these results show a significant involvement of BDNF in the long-term effects of METH on PPI, particularly in male mice, but these effects appear independent of D3 receptors. The role of this receptor in psychosis endophenotypes therefore remains unclear.
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Affiliation(s)
- Samuel Hogarth
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia (E.J.J.)
| | - Emily J. Jaehne
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia (E.J.J.)
| | - Xiangjun Xu
- Centre for Cancer Biology, University of South Australia, Adelaide, SA 5000, Australia (Q.S.)
| | - Quenten Schwarz
- Centre for Cancer Biology, University of South Australia, Adelaide, SA 5000, Australia (Q.S.)
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia (E.J.J.)
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Bastioli G, Arnold JC, Mancini M, Mar AC, Gamallo-Lana B, Saadipour K, Chao MV, Rice ME. Voluntary Exercise Boosts Striatal Dopamine Release: Evidence for the Necessary and Sufficient Role of BDNF. J Neurosci 2022; 42:4725-4736. [PMID: 35577554 PMCID: PMC9186798 DOI: 10.1523/jneurosci.2273-21.2022] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 03/09/2022] [Accepted: 04/10/2022] [Indexed: 11/21/2022] Open
Abstract
Physical exercise improves motor performance in individuals with Parkinson's disease and elevates mood in those with depression. Although underlying factors have not been identified, clues arise from previous studies showing a link between cognitive benefits of exercise and increases in brain-derived neurotrophic factor (BDNF). Here, we investigated the influence of voluntary wheel-running exercise on BDNF levels in the striatum of young male wild-type (WT) mice, and on the striatal release of a key motor-system transmitter, dopamine (DA). Mice were allowed unlimited access to a freely rotating wheel (runners) or a locked wheel (controls) for 30 d. Electrically evoked DA release was quantified in ex vivo corticostriatal slices from these animals using fast-scan cyclic voltammetry. We found that exercise increased BDNF levels in dorsal striatum (dStr) and increased DA release in dStr and in nucleus accumbens core and shell. Increased DA release was independent of striatal acetylcholine (ACh), and persisted after a week of rest. We tested a role for BDNF in the influence of exercise on DA release using mice that were heterozygous for BDNF deletion (BDNF+/-). In contrast to WT mice, evoked DA release did not differ between BDNF+/- runners and controls. Complementary pharmacological studies using a tropomyosin receptor kinase B (TrkB) agonist in WT mouse slices showed that TrkB receptor activation also increased evoked DA release throughout striatum in an ACh-independent manner. Together, these data support a causal role for BDNF in exercise-enhanced striatal DA release and provide mechanistic insight into the beneficial effects of exercise in neuropsychiatric disorders, including Parkinson's, depression, and anxiety.SIGNIFICANCE STATEMENT Exercise has been shown to improve movement and cognition in humans and rodents. Here, we report that voluntary exercise for 30 d leads to an increase in evoked DA release throughout the striatum and an increase in BDNF in the dorsal (motor) striatum. The increase in DA release appears to require BDNF, indicated by the absence of DA release enhancement with running in BDNF+/- mice. Activation of BDNF receptors using a pharmacological agonist was also shown to boost DA release. Together, these data support a necessary and sufficient role for BDNF in exercise-enhanced DA release and provide mechanistic insight into the reported benefits of exercise in individuals with dopamine-linked neuropsychiatric disorders, including Parkinson's disease and depression.
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Affiliation(s)
| | - Jennifer C Arnold
- Neurosurgery, New York University Grossman School of Medicine, New York, New York 10016
| | | | - Adam C Mar
- Departments of Neuroscience and Physiology and
| | | | - Khalil Saadipour
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, New York, New York 10016
| | - Moses V Chao
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, New York, New York 10016
| | - Margaret E Rice
- Departments of Neuroscience and Physiology and
- Neurosurgery, New York University Grossman School of Medicine, New York, New York 10016
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Schmidt M, Rossetti AC, Brandwein C, Riva MA, Gass P, Elsner P, Hesse-Macabata J, Hipler UC, Smesny S, Milleit B. Brain Derived Neurotrophic Factor Deficiency is Associated with Cognitive Impairment and Elevated Phospholipase A2 Activity in Plasma of Mice. Neuroscience 2022; 480:167-177. [PMID: 34801657 DOI: 10.1016/j.neuroscience.2021.11.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 11/25/2022]
Abstract
Decreased levels of Brain-Derived Neurotrophic Factor (BDNF) are a common finding in schizophrenia. Another well-documented protein linked to schizophrenia is intracellular Ca2+-independent Phospholipase (PLA2). However, the potential association between PLA2 and BDNF with regard to schizophrenia has yet to be examined. In the present study, male and female BDNF knockout mice, a possible genetic model of schizophrenia, were exposed to prenatal stress and tested in the nest test, open field test and T-maze. Following behavioral tests, whole brain and plasma samples were harvested to measure the activity of PLA2. BDNF knockout mice showed cognitive deficits in the T-maze. Furthermore, there was a quadratic association of PLA2 with performance in the open field test. Moreover, BDNF deficiency and female sex were associated with elevated plasma PLA2 levels. The cognitive impairment of BDNF heterozygous mice as well as their increased PLA2 activity in plasma is consistent with findings in schizophrenia patients. The particular elevation of PLA2 activity in females may partly explain sex differences of clinical symptoms in schizophrenia (e.g. age of onset, severity of symptoms). Additionally, PLA2 was significantly correlated with body and adrenal weight after weaning, whereby the latter emphasizes the possible connection of PLA2 with steroidogenesis.
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Affiliation(s)
- Michaela Schmidt
- RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim (ZI), Medical Faculty of Mannheim, University of Heidelberg, J5, D-68159 Mannheim, Germany.
| | - Andrea Carlo Rossetti
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti, 9, I-20133 Milan, Italy
| | - Christiane Brandwein
- RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim (ZI), Medical Faculty of Mannheim, University of Heidelberg, J5, D-68159 Mannheim, Germany
| | - Marco Andrea Riva
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti, 9, I-20133 Milan, Italy
| | - Peter Gass
- RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim (ZI), Medical Faculty of Mannheim, University of Heidelberg, J5, D-68159 Mannheim, Germany
| | - Peter Elsner
- Department of Psychiatry, University Hospital Jena, D-07743 Jena, Germany
| | - Jana Hesse-Macabata
- Department of Dermatology, University Hospital Jena, Erfurter Straße 35, D-07743 Jena, Germany
| | - Uta-Christina Hipler
- Department of Dermatology, University Hospital Jena, Erfurter Straße 35, D-07743 Jena, Germany
| | - Stefan Smesny
- Department of Psychiatry, University Hospital Jena, D-07743 Jena, Germany
| | - Berko Milleit
- Department of Psychiatry, University Hospital Jena, D-07743 Jena, Germany; Department of Dermatology, University Hospital Jena, Erfurter Straße 35, D-07743 Jena, Germany
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Apawu AK, Callan SP, Mathews TA, Bowen SE. Repeated toluene exposure leads to neuroadaptation in dopamine release mechanisms within the nucleus accumbens core. Toxicol Appl Pharmacol 2020; 408:115260. [DOI: 10.1016/j.taap.2020.115260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/17/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
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Candidate metabolic biomarkers for schizophrenia in CNS and periphery: Do any possible associations exist? Schizophr Res 2020; 226:95-110. [PMID: 30935700 DOI: 10.1016/j.schres.2019.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
Due to the limitations of analytical techniques and the complicity of schizophrenia, nowadays it is still a challenge to diagnose and stratify schizophrenia patients accurately. Many attempts have been made to identify and validate available biomarkers for schizophrenia from CSF and/or peripheral blood in clinical studies with consideration to disease stages, antipsychotic effects and even gender differences. However, conflicting results handicap the validation and application of biomarkers for schizophrenia. In view of availability and feasibility, peripheral biomarkers have superior advantages over biomarkers in CNS. Meanwhile, schizophrenia is considered to be a devastating neuropsychiatric disease mainly taking place in CNS featured by widespread defects in multiple metabolic pathways whose dynamic interactions, until recently, have been difficult to difficult to investigate. Evidence for these alterations has been collected piecemeal, limiting the potential to inform our understanding of the interactions among relevant biochemical pathways. Taken these points together, it will be interesting to investigate possible associations of biomarkers between CNS and periphery. Numerous studies have suggested putative correlations within peripheral and CNS systems especially for dopaminergic and glutamatergic metabolic biomarkers. In addition, it has been demonstrated that blood concentrations of BDNF protein can also reflect its changes in the nervous system. In turn, BDNF also interacts with glutamatergic, dopaminergic and serotonergic systems. Therefore, this review will summarize metabolic biomarkers identified both in the CNS (brain tissues and CSF) and peripheral blood. Further, more attentions will be paid to discussing possible physical and functional associations between CNS and periphery, especially with respect to BDNF.
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Koo JW, Chaudhury D, Han MH, Nestler EJ. Role of Mesolimbic Brain-Derived Neurotrophic Factor in Depression. Biol Psychiatry 2019; 86:738-748. [PMID: 31327473 PMCID: PMC6814503 DOI: 10.1016/j.biopsych.2019.05.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 11/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is widely accepted as being critical for neural and synaptic plasticity throughout the nervous system. Recent work has shown that BDNF in the mesolimbic dopamine (DA) circuit, originating in ventral tegmental area DA neurons that project to the nucleus accumbens, is crucial in the development of depressive-like behaviors following exposure to chronic social defeat stress in mice. Whereas BDNF modulates DA signaling in encoding responses to acute defeat stress, BDNF signaling alone appears to be responsible for the behavioral effects after chronic social defeat stress. Very different patterns are seen with another widely used chronic stress paradigm in mice, chronic mild stress (also known as chronic variable or unpredictable stress), where DA signaling, but not BDNF signaling, is primarily responsible for the behavioral effects observed. This review discusses the molecular, cellular, and circuit basis of this dramatic discrepancy, which appears to involve the nature of the stress, its severity and duration, and its effects on distinct cell types within the ventral tegmental area-to-nucleus accumbens mesolimbic circuit.
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Affiliation(s)
- Ja Wook Koo
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41068, Republic of Korea
| | - Dipesh Chaudhury
- Division of Science, New York University Abu Dhabi (NYUAD), Saadiyat Island Campus, Abu Dhabi, PO Box 129188, United Arab Emirates
| | - Ming-Hu Han
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
| | - Eric J. Nestler
- Departments of Pharmacological Sciences and of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA,Address correspondence to: Ming-Hu Han, Ph.D. and Eric J. Nestler, MD., Ph.D., Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; and
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Toluene's effects on activity and extracellular dopamine in the mouse are altered by GABA A antagonism. Neurosci Lett 2017; 647:67-71. [PMID: 28288863 DOI: 10.1016/j.neulet.2017.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/16/2017] [Accepted: 03/02/2017] [Indexed: 02/02/2023]
Abstract
The abuse of inhalants like toluene continues to be widespread around the world, especially among children and teenagers. Despite its frequency of misuse, the dynamics between dopamine (DA) and gamma-aminobutyric acid (GABA) in response to toluene exposure remains unclear. To further decipher toluene's actions, we used a dynamic exposure system in combination with microdialysis to examine in vivo the effects of acutely inhaled toluene on DA release within the mouse caudate putamen (CPu). Results show that toluene inhalation produced increases in DA levels and locomotor activity. In mice that were pretreated with the GABAA antagonist, bicuculline, there was no change in the locomotor response during toluene but activity was potentiated following toluene exposure. Bicuculline pretreatment increased extracellular DA levels during toluene exposure, suggesting that DA and GABA-releasing neuron interaction may play a role in the rewarding properties of toluene.
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Parikh V, Naughton SX, Yegla B, Guzman DM. Impact of partial dopamine depletion on cognitive flexibility in BDNF heterozygous mice. Psychopharmacology (Berl) 2016; 233:1361-75. [PMID: 26861892 PMCID: PMC4814303 DOI: 10.1007/s00213-016-4229-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/30/2016] [Indexed: 12/17/2022]
Abstract
RATIONALE Cognitive flexibility is a key component of executive function and is disrupted in major psychiatric disorders. Brain-derived neurotrophic factor (BDNF) exerts neuromodulatory effects on synaptic transmission and cognitive/affective behaviors. However, the causal mechanisms linking BDNF hypofunction with executive deficits are not well understood. OBJECTIVES Here, we assessed the consequences of BDNF hemizygosity on cognitive flexibility in mice performing an operant conditioning task. As dopaminergic-glutamatergic interaction in the striatum is important for cognitive processing, and BDNF heterozygous (BDNF(+/-)) mice display a higher dopamine tone in the dorsal striatum, we also assessed the effects of partial striatal dopamine depletion on task performance and glutamate release. RESULTS BDNF(+/-) mice acquired discrimination learning as well as new rule learning during set-shifting as efficiently as wild-type mice. However, partial removal of striatal dopaminergic inputs with 6-hydroxydopamine (6-OHDA) impaired these cognitive processes by impeding the maintenance of a new learning strategy in both genotypes. BDNF mutants exhibited performance impairments during reversal learning, and these deficits were associated with increased perseveration to the previously acquired strategy. Partial dopamine depletion of the striatum reversed these cognitive impairments. Additionally, reduction in depolarization-evoked glutamate release noted in the dorsal striatum of BDNF(+/-) mice was not observed in 6-OHDA-infused BDNF mutants indicating normalization of glutamatergic transmission in these animals. CONCLUSIONS Our data illustrate that BDNF signaling regulates cognitive control processes presumably by maintaining striatal dopamine-glutamate balance. Moreover, aberrations in BDNF signaling may act as a common neurobiological substrate that accounts for executive dysfunction observed in multiple psychiatric conditions.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, USA.
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Manning EE, Halberstadt AL, van den Buuse M. BDNF-Deficient Mice Show Reduced Psychosis-Related Behaviors Following Chronic Methamphetamine. Int J Neuropsychopharmacol 2015; 19:pyv116. [PMID: 26453694 PMCID: PMC4851263 DOI: 10.1093/ijnp/pyv116] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/05/2015] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND One of the most devastating consequences of methamphetamine abuse is increased risk of psychosis. Brain-derived neurotrophic factor has been implicated in both psychosis and neuronal responses to methamphetamine. We therefore examined persistent psychosis-like behavioral effects of methamphetamine in brain-derived neurotrophic factor heterozygous mice. METHODS Mice were chronically treated with methamphetamine from 6 to 9 weeks of age, and locomotor hyperactivity to an acute D-amphetamine challenge was tested in photocell cages after a 2-week withdrawal period. RESULTS Methamphetamine-treated wild-type mice, but not brain-derived neurotrophic factor heterozygous mice, showed locomotor sensitization to acute 3mg/kg D-amphetamine. Qualitative analysis of exploration revealed tolerance to D-amphetamine effects on entropy in methamphetamine-treated brain-derived neurotrophic factor heterozygous mice, but not wild-type mice. CONCLUSIONS Chronic methamphetamine exposure induces contrasting profiles of behavioral changes in wild-type and brain-derived neurotrophic factor heterozygous mice, with attenuation of behaviors relevant to psychosis in methamphetamine-treated brain-derived neurotrophic factor heterozygous mice. This suggests that brain-derived neurotrophic factor signalling changes may contribute to development of psychosis in methamphetamine users.
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Affiliation(s)
| | | | - Maarten van den Buuse
- Florey Institute of Neuroscience and Mental Health Research, University of Melbourne, Victoria, Australia (Drs Manning and van den Buuse); Translational OCD Laboratory, Department of Psychiatry, University of Pittsburgh, PA (Dr Manning); Department of Psychiatry, University of California San Diego, La Jolla, CA (Dr Halberstadt); School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia (Dr van den Buuse).
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12
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Rooney KE, Wallace LJ. Computational modeling of extracellular dopamine kinetics suggests low probability of neurotransmitter release. Synapse 2015; 69:515-25. [PMID: 26248886 DOI: 10.1002/syn.21845] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/25/2015] [Accepted: 07/11/2015] [Indexed: 02/03/2023]
Abstract
Dopamine in the striatum signals the saliency of current environmental input and is involved in learned formation of appropriate responses. The regular baseline-firing rate of dopaminergic neurons suggests that baseline dopamine is essential for proper brain function. The first goal of the study was to estimate the likelihood of full exocytotic dopamine release associated with each firing event under baseline conditions. A computer model of extracellular space associated with a single varicosity was developed using the program MCell to estimate kinetics of extracellular dopamine. Because the literature provides multiple kinetic values for dopamine uptake depending on the system tested, simulations were run using different kinetic parameters. With all sets of kinetic parameters evaluated, at most, 25% of a single vesicle per varicosity would need to be released per firing event to maintain a 5-10 nM extracellular dopamine concentration, the level reported by multiple microdialysis experiments. The second goal was to estimate the fraction of total amount of stored dopamine released during a highly stimulated condition. This was done using the same model system to simulate published measurements of extracellular dopamine following electrical stimulation of striatal slices in vitro. The results suggest the amount of dopamine release induced by a single electrical stimulation may be as large as the contents of two vesicles per varicosity. We conclude that dopamine release probability at any particular varicosity is low. This suggests that factors capable of increasing release probability could have a powerful effect on sculpting dopamine signals.
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Affiliation(s)
- Katherine E Rooney
- Division of Pharmacology, College of Pharmacy, the Ohio State University, 500 W. 12th Avenue Columbus, Ohio, 43210
| | - Lane J Wallace
- Division of Pharmacology, College of Pharmacy, the Ohio State University, 500 W. 12th Avenue Columbus, Ohio, 43210.,500 West 12th Avenue Columbus, Ohio, 43210
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