| 1. |
- Alsiö, Johan, et al.
(författare)
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Enhanced Sucrose and Cocaine Self-Administration and Cue-Induced Drug Seeking after Loss of VGLUT2 in Midbrain Dopamine Neurons in Mice
- 2011
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 31:35, s. 12593-12603
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Tidskriftsartikel (refereegranskat)abstract
- The mesostriatal dopamine (DA) system contributes to several aspects of responses to rewarding substances and is implicated in conditions such as drug addiction and eating disorders. A subset of DA neurons has been shown to express the type 2 Vesicular glutamate transporter (Vglut2) and may therefore corelease glutamate. In the present study, we analyzed mice with a conditional deletion of Vglut2 in DA neurons (Vglut2(f/f;DAT-Cre)) to address the functional significance of the glutamate-DA cophenotype for responses to cocaine and food reinforcement. Biochemical parameters of striatal DA function were also examined by using DA receptor autoradiography, immediate-early gene quantitative in situ hybridization after cocaine challenge, and DA-selective in vivo chronoamperometry. Mice in which Vglut2 expression had been abrogated in DA neurons displayed enhanced operant self-administration of both high-sucrose food and intravenous cocaine. Furthermore, cocaine seeking maintained by drug-paired cues was increased by 76%, showing that reward-dependent plasticity is perturbed in these mice. In addition, several lines of evidence suggest that adaptive changes occurred in both the ventral and dorsal striatum in the absence of VGLUT2: DA receptor binding was increased, and basal mRNA levels of the DA-induced early genes Nur77 and c-fos were elevated as after cocaine induction. Furthermore, in vivo challenge of the DA system by potassium-evoked depolarization revealed less DA release in both striatal areas. This study demonstrates that absence of VGLUT2 in DA neurons leads to perturbations of reward consumption as well as reward-associated memory, features of particular relevance for addictive-like behavior.
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| 2. |
- Birgner, Carolina, et al.
(författare)
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VGLUT2 in dopamine neurons is required for psychostimulant-induced behavioural activation
- 2010
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 107:1, s. 389-394
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Tidskriftsartikel (refereegranskat)abstract
- The “One neuron-one neurotransmitter” concept has been challenged frequently during the last three decades, and the coexistence of neurotransmitters in individual neurons is now regarded as a common phenomenon. The functional significance of neurotransmitter coexistence is, however, less well understood. Several studies have shown that a subpopulation of dopamine (DA) neurons in the ventral tegmental area (VTA) expresses the vesicular glutamate transporter 2 (VGLUT2) and has been suggested to use glutamate as a cotransmitter. The VTA dopamine neurons project to limbic structures including the nucleus accumbens, and are involved in mediating the motivational and locomotor activating effects of psychostimulants. To determine the functional role of glutamate cotransmission by these neurons, we deleted VGLUT2 in DA neurons by using a conditional gene-targeting approach in mice. A DAT-Cre/Vglut2Lox mouse line (Vglut2f/f;DAT-Cre mice) was produced and analyzed by in vivo amperometry as well as by several behavioral paradigms. Although basal motor function was normal in the Vglut2f/f;DAT-Cre mice, their risk-taking behavior was altered. Interestingly, in both home-cage and novel environments, the gene targeted mice showed a greatly blunted locomotor response to the psychostimulant amphetamine, which acts via the midbrain DA system. Our results show that VGLUT2 expression in DA neurons is required for normal emotional reactivity as well as for psychostimulant-mediated behavioral activation.
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| 3. |
- Fortin, G. M., et al.
(författare)
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Glutamate corelease promotes growth and survival of midbrain dopamine neurons
- 2012
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 32:48, s. 17477-17491
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have proposed that glutamate corelease by mesostriatal dopamine (DA) neurons regulates behavioral activation by psychostimulants.How and when glutamate release by DA neurons might play this role remains unclear. Considering evidence for early expression of the type 2 vesicular glutamate transporter in mesencephalic DA neurons, we hypothesized that this cophenotype is particularly important during development. Using a conditional gene knock-out approach to selectively disrupt the Vglut2 gene in mouse DA neurons, we obtained in vitro and in vivo evidence for reduced growth and survival of mesencephalic DA neurons, associated with a decrease in the density of DA innervation in the nucleus accumbens, reduced activity-dependent DA release, and impaired motor behavior. These findings provide strong evidence for a functional role of the glutamatergic cophenotype in the development of mesencephalic DA neurons, opening new perspectives into the pathophysiology of neurodegenerative disorders involving the mesostriatal DA system.
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| 4. |
- Fredriksson, Robert, et al.
(författare)
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The polyamine transporter Slc18b1(VPAT) is important for both short and long time memory and for regulation of polyamine content in the brain.
- 2019
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 15:12
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Tidskriftsartikel (refereegranskat)abstract
- SLC18B1 is a sister gene to the vesicular monoamine and acetylcholine transporters, and the only known polyamine transporter, with unknown physiological role. We reveal that Slc18b1 knock out mice has significantly reduced polyamine content in the brain providing the first evidence that Slc18b1 is functionally required for regulating polyamine levels. We found that this mouse has impaired short and long term memory in novel object recognition, radial arm maze and self-administration paradigms. We also show that Slc18b1 KO mice have altered expression of genes involved in Long Term Potentiation, plasticity, calcium signalling and synaptic functions and that expression of components of GABA and glutamate signalling are changed. We further observe a partial resistance to diazepam, manifested as significantly lowered reduction in locomotion after diazepam treatment. We suggest that removal of Slc18b1 leads to reduction of polyamine contents in neurons, resulting in reduced GABA signalling due to long-term reduction in glutamatergic signalling.
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| 5. |
- Lagerström, Malin C., et al.
(författare)
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VGLUT2-Dependent Sensory Neurons in the TRPV1 Population Regulate Pain and Itch
- 2010
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Ingår i: Neuron. - : Elsevier BV. - 0896-6273 .- 1097-4199. ; 68:3, s. 529-542
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Tidskriftsartikel (refereegranskat)abstract
- The natural response to itch sensation is to scratch, which relieves the itch through an unknown mechanism. Interaction between pain and itch has been frequently demonstrated, and the selectivity hypothesis of itch, based on data from electrophysiological and behavioral experiments, postulates the existence of primary pain afferents capable of repressing itch. Here, we demonstrate that deletion of vesicular glutamate transporter (VGLUT) 2 in a subpopulation of neurons partly overlapping with the vanilloid receptor (TRPV1) primary afferents resulted in a dramatic increase in itch behavior accompanied by a reduced responsiveness to thermal pain. The increased itch behavior was reduced by administration of antihistaminergic drugs and by genetic deletion of the gastrin-releasing peptide receptor, demonstrating a dependence on VGLUT2 to maintain normal levels of both histaminergic and nonhistaminergic itch. This study establishes that VGLUT2 is a major player in TRPV1 thermal nociception and also serves to regulate a normal itch response.
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| 6. |
- Lindberg, Frida A, et al.
(författare)
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SLC38A10 deficiency in male mice affect plasma levels of threonine and histidine
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Solute carriers belong to the biggest group of transporters in the human genome, but more knowledge is needed in order to fully understand their function and possible role as therapeutic targets. SLC38 is a family of amino acid transporters, commonly referred to as SNATs, consisting of 11 members. The tenth member, SLC38A10, is one of the least characterized members and is the focus of this study. By using a knockout mouse model, we studied the biological effects of SLC38A10 deficiency in vivo. We performed a transcriptomic analysis of whole brain and found seven differentially expressed genes in SLC38A10 deficient mice (Gm48159, Nr4a1, Tuba1c, Lrrc56, mt-Tp, Hbb-bt and Snord116/9). By measuring amino acids in plasma, we found lower levels of threonine and histidine in males, while no amino acids were altered in females, suggesting that SLC38A10-/- might affect sexes differently. Using RT-qPCR, we investigated the effect of SLC38A10 deficiency on mRNA expression of other SLC38 members, Mtor and Rps6kb1 in brain, liver, lung, muscle and kidney, but no differences were found. A relative telomere length measurement was also made, as a marker for cellular age, but no differences were found between the genotypes. We conclude that SLC38A10 might be important for keeping amino acid homeostasis in plasma, at least in males, but no major effects were seen on transcriptomic expression or telomere length in whole brain.
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| 7. |
- Lindberg, Frida A., et al.
(författare)
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SLC38A10 Deficiency in Mice Affects Plasma Levels of Threonine and Histidine in Males but Not in Females : A Preliminary Characterization Study of SLC38A10(-/-) Mice
- 2023
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Solute carriers belong to the biggest group of transporters in the human genome, but more knowledge is needed to fully understand their function and possible role as therapeutic targets. SLC38A10, a poorly characterized solute carrier, is preliminary characterized here. By using a knockout mouse model, we studied the biological effects of SLC38A10 deficiency in vivo. We performed a transcriptomic analysis of the whole brain and found seven differentially expressed genes in SLC38A10-deficient mice (Gm48159, Nr4a1, Tuba1c, Lrrc56, mt-Tp, Hbb-bt and Snord116/9). By measuring amino acids in plasma, we found lower levels of threonine and histidine in knockout males, whereas no amino acid levels were affected in females, suggesting that SLC38A10(-/-) might affect sexes differently. Using RT-qPCR, we investigated the effect of SLC38A10 deficiency on mRNA expression of other SLC38 members, Mtor and Rps6kb1 in the brain, liver, lung, muscle, and kidney, but no differences were found. Relative telomere length measurement was also taken, as a marker for cellular age, but no differences were found between the genotypes. We conclude that SLC38A10 might be important for keeping amino acid homeostasis in plasma, at least in males, but no major effects were seen on transcriptomic expression or telomere length in the whole brain.
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| 8. |
- Lindberg, Frida A.
(författare)
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The Biological Importance of the Amino Acid Transporter SLC38A10 : Characterization of a Knockout Mouse
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The biggest group of transporters, the solute carriers (SLCs), has more than 400 members, and about 30% of these are still orphan. In order to decipher their biological function and possible role in disease, there is a need for characterization of these. Around 25% of SLCs are estimated to have amino acids as substrates, including transporters belonging to the SLC38 family. The SLC38 members are sometimes referred to their alternative name: sodium-coupled neutral amino acid transporters (SNATs). One of these transporters, SNAT10 (or SLC38A10), has been characterized as a bidirectional transporter of glutamate, glutamine, alanine and aspartate, as well as having an efflux of serine, and is ubiquitously expressed in the body. However, its biological importance is not yet understood. The aim with this thesis was to characterize a mouse model deficient in SNAT10 protein in order to find the biological importance of this transporter. In paper I, this is done by using a series of behavioral tests, including the open field test, elevated plus maze, rotarod and Y-maze, among others. The SNAT10 knockout mouse was found to have an increased risk-taking behavior, but no motor or spatial working memory impairments. Furthermore, the knockout mouse was found to have a decreased body weight. In paper II, an additional behavioral characterization was performed by using the multivariate concentric square field™ (MCSF) test. The MCSF test is an arena with different zones associated to different behavioral traits, which generates a behavioral profile depending on where the mouse spends its time. The result from this test implies that the SNAT10 deficient mouse has a lower explorative behavior than its wild type littermates. In paper III, gene expression was studied in whole brain and some genes related to cell cycle regulation and p53 expression were found to be differentially expressed in the knockout brain. Additional gene expression was studied in kidney, liver, lung and muscle, but no changes were found. Plasma levels of histidine and threonine were altered in males, but no altered amino acid levels were found in knockout females, suggesting a possible sex-specific effect. These studies together imply that SNAT10 might be involved in processes related to risk-taking and explorative behavior in the open field and MCSF tests. SNAT10 deficiency also affected amino acid levels in plasma, indicating a disrupted amino acid homeostasis.
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| 9. |
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| 10. |
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| 11. |
- Nordenankar, Karin, 1981-
(författare)
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Functional Analysis of the Vesicular Glutamate Transporter 2 in Specific Neuronal Circuits of the Brain
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A key issue in neuroscience is to determine the connection between neuronal circuits and behaviour. In the adult brain, all neuronal circuits include a glutamatergic component. Three proteins designated Vesicular glutamate transporter 1-3 (VGLUT1-3) possess the capability of packaging glutamate into presynaptic vesicles for release of glutamate at the nerve terminal. The present study aimed at determining the role of VGLUT2 in neuronal circuits of higher brain function, emotion, and reward-pocessing. A conditional knockout (cKO) strategy was utilised, and three different mouse lines were produced to delete VGLUT2 in specific neuronal circuits in a temporally and spatially controlled manner. First, we produced a cKO mouse in which Vglut2 was deleted in specific subpopulations of the cortex, amygdala and hippocampus from preadolescence. This resulted in blunted aspects in cognitive, emotional and social behaviour in a schizophrenia-related phenotype. Furthermore, we showed a downstream effect of the targeted deletion on the dopaminergic system. In a subsequent analysis of the same cKO mice, we showed that female cKO mice were more affected their male counterparts, and we also found that female schizophrenia patients, but not male patients, had increased Vglut2 levels in the cortex. Second, we produced and analysed cKO mice in which Vglut2 was deleted in the cortex, amygdala and hippocampus already from midgestation, and could show that this deletion affected emotional, but not cognitive, function. Third, we addressed the role of VGLUT2 in midbrain dopamine neurons by targeting Vglut2 specifically in these neurons. These cKO mice showed a blunted activational response to the psychostimulant amphetamine and increased operant self-administration of both sugar and cocaine reinforcers. Further, the cKO mice displayed strongly enhanced cocaine-seeking in response to cocaine-associated cues, a behaviour of relevance for addiction in humans. In summary, this thesis work has addressed the role of the presynaptic glutamatergic neuron in different neuronal circuits and shown that the temporal and spatial distribution of VGLUT2 is of great significance for normal brain function.
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| 12. |
- Nordenankar, Karin, et al.
(författare)
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Increased hippocampal excitability and impaired spatial memory function in mice lacking VGLUT2 selectively in neurons defined by tyrosine hydroxylase promoter activity
- 2015
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Ingår i: Brain Structure and Function. - : Springer Science and Business Media LLC. - 1863-2653 .- 1863-2661. ; 220:4, s. 2171-2190
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Tidskriftsartikel (refereegranskat)abstract
- Three populations of neurons expressing the vesicular glutamate transporter 2 (Vglut2) were recently described in the A10 area of the mouse midbrain, of which two populations were shown to express the gene encoding, the rate-limiting enzyme for catecholamine synthesis, tyrosine hydroxylase (TH).One of these populations ("TH-Vglut2 Class1") also expressed the dopamine transporter (DAT) gene while one did not ("TH-Vglut2 Class2"), and the remaining population did not express TH at all ("Vglut2-only"). TH is known to be expressed by a promoter which shows two phases of activation, a transient one early during embryonal development, and a later one which gives rise to stable endogenous expression of the TH gene. The transient phase is, however, not specific to catecholaminergic neurons, a feature taken to advantage here as it enabled Vglut2 gene targeting within all three A10 populations expressing this gene, thus creating a new conditional knockout. These knockout mice showed impairment in spatial memory function. Electrophysiological analyses revealed a profound alteration of oscillatory activity in the CA3 region of the hippocampus. In addition to identifying a novel role for Vglut2 in hippocampus function, this study points to the need for improved genetic tools for targeting of the diversity of subpopulations of the A10 area.
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| 13. |
- Nordenankar, Karin, et al.
(författare)
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Targeted deletion of Vglut2 expression in the embryonal telencephalon promotes an anxiolytic phenotype of the adult mouse
- 2015
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 120:3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anxiety is a natural emotion experienced by all individuals. However, when anxiety becomes excessive, it contributes to the substantial group of anxiety disorders that affect one in three people and thus are among the most common psychiatric disorders. Anxiolysis, the reduction of anxiety, is mediated via several large groups of therapeutical compounds, but the relief is often only temporary, and increased knowledge of the neurobiology underlying anxiety is needed in order to improve future therapies.AIM: We previously demonstrated that mice lacking forebrain expression of the Vesicular glutamate transporter 2 (Vglut2) from adolescence showed a strong anxiolytic behaviour as adults. In the current study, we wished to analyse if removal of Vglut2 expression already from mid-gestation of the mouse embryo would give rise to similar anxiolysis in the adult mouse.METHODS: We produced transgenic mice lacking Vglut2 from mid-gestation and analysed their affective behaviour, including anxiety, when they had reached adulthood.RESULTS: The transgenic mice lacking Vglut2 expression from mid-gestation showed certain signs of anxiolytic behaviour, but this phenotype was not as prominent as when Vglut2 was removed during adolescence.CONCLUSION: Our results suggest that both embryonal and adolescent forebrain expression of Vglut2 normally contributes to balancing the level of anxiety. As the neurobiological basis for anxiety is similar across species, our results in mice may help improve the current understanding of the neurocircuitry of anxiety, and hence anxiolysis, also in humans.
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| 14. |
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| 15. |
- Nordström, Eva, et al.
(författare)
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ABBV-0805, a novel antibody selective for soluble aggregated alpha-synuclein, prolongs lifespan and prevents buildup of alpha-synuclein pathology in mouse models of Parkinson's disease
- 2021
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Ingår i: Neurobiology of Disease. - : Elsevier. - 0969-9961 .- 1095-953X. ; 161
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Tidskriftsartikel (refereegranskat)abstract
- A growing body of evidence suggests that aggregated alpha-synuclein, the major constituent of Lewy bodies, plays a key role in the pathogenesis of Parkinson's disease and related alpha-synucleinopathies. Immunotherapies, both active and passive, against alpha-synuclein have been developed and are promising novel treatment strategies for such disorders. Here, we report on the humanization and pharmacological characteristics of ABBV-0805, a monoclonal antibody that exhibits a high selectivity for human aggregated alpha-synuclein and very low affinity for monomers. ABBV-0805 binds to a broad spectrum of soluble aggregated alpha-synuclein, including small and large aggregates of different conformations. Binding of ABBV-0805 to pathological alpha-synuclein was demonstrated in Lewy body-positive post mortem brains of Parkinson's disease patients. The functional potency of ABBV-0805 was demonstrated in several cellular assays, including Fc gamma-receptor mediated uptake of soluble aggregated alpha-synuclein in microglia and inhibition of neurotoxicity in primary neurons. In vivo, the murine version of ABBV-0805 (mAb47) displayed significant dose dependent decrease of alpha-synuclein aggregates in brain in several mouse models, both in prophylactic and therapeutic settings. In addition, mAb47 treatment of alpha-synuclein transgenic mice resulted in a significantly prolonged survival. ABBV-0805 selectively targets soluble toxic alpha-synuclein aggregates with a picomolar affinity and demonstrates excellent in vivo efficacy. Based on the strong preclinical findings described herein, ABBV-0805 has been progressed into clinical development as a potential disease-modifying treatment for Parkinson's disease.
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| 16. |
- Rajagopalan, Aparna, et al.
(författare)
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Reduced Gene Expression Levels of Munc13-1 and Additional Components of the Presynaptic Exocytosis Machinery Upon Conditional Targeting of Vglut2 in the Adolescent Mouse
- 2014
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Ingår i: Synapse. - : Wiley. - 0887-4476 .- 1098-2396. ; 68:12, s. 624-633
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Tidskriftsartikel (refereegranskat)abstract
- Presynaptic proteins orchestrate an intricate interplay of dynamic interactions in order to regulate quantal exocytosis of transmitter-filled vesicles, and their dysregulation might cause neurological and neuropsychiatric dysfunction. Mice carrying a spatiotemporal restriction in the expression of the Vesicular glutamate transporter 2 (Vglut2; aka Slc17a6) in the cortex, amygdala and hippocampal subiculum from the third postnatal week show a strong anxiolytic phenotype and certain behavioral correlates of schizophrenia. To further understand the molecular consequences of this targeted deletion of Vglut2, we performed an unbiased microarray analysis comparing gene expression levels in the subiculum of these conditional Vglut2 knockout mice (Vglut2(f/f;CamKII) cKO) to those in control littermates. Expression of Unc13C (Munc13-3), a member of the Unc/Munc family, previously shown to be important for glutamatergic transmission, was identified to be significantly down-regulated. Subsequent analysis by quantitative RT-PCR revealed a 50% down-regulation of Munc 13-1, the gene encoding the Unc/Munc subtype described as an essential component in the majority of glutamtergic synapses in the hippocampus. Genes encoding additional components of the presynaptic machinery were also found regulated, including Rab3A, RIM1, as well as Syntaxin1 and Synaptobrevin. Altered expression levels of these genes were further found in the amygdala and in the retrosplenial group of the cortex, additional regions in which Vglut2 was conditionally targeted. These findings suggest that expression levels of Vglut2 might be important for the maintenance of gene expression in the presynaptic machinery in the adult mouse brain. Synapse 68:624-633, 2014.
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| 17. |
- Schweizer, Nadine, et al.
(författare)
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Limiting glutamate transmission in a Vglut2-expressing subpopulation of the subthalamic nucleus is sufficient to cause hyperlocomotion
- 2014
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 111:21, s. 7837-7842
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Tidskriftsartikel (refereegranskat)abstract
- The subthalamic nucleus (STN) is a key area of the basal ganglia circuitry regulating movement. We identified a subpopulation of neurons within this structure that coexpresses Vglut2 and Pitx2, and by conditional targeting of this subpopulation we reduced Vglut2 expression levels in the STN by 40%, leaving Pitx2 expression intact. This reduction diminished, yet did not eliminate, glutamatergic transmission in the substantia nigra pars reticulata and entopeduncular nucleus, two major targets of the STN. The knockout mice displayed hyperlocomotion and decreased latency in the initiation of movement while preserving normal gait and balance. Spatial cognition, social function, and level of impulsive choice also remained undisturbed. Furthermore, these mice showed reduced dopamine transporter binding and slower dopamine clearance in vivo, suggesting that Vglut2-expressing cells in the STN regulate dopaminergic transmission. Our results demonstrate that altering the contribution of a limited population within the STN is sufficient to achieve results similar to STN lesions and high-frequency stimulation, but with fewer side effects.
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| 18. |
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| 19. |
- Schweizer, Nadine, et al.
(författare)
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Reduced Vglut2/Slc17a6 Gene Expression Levels throughout the Mouse Subthalamic Nucleus Cause Cell Loss and Structural Disorganization Followed by Increased Motor Activity and Decreased Sugar Consumption
- 2016
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Ingår i: eNeuro. - 2373-2822. ; 3:5
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Tidskriftsartikel (refereegranskat)abstract
- The subthalamic nucleus (STN) plays a central role in motor, cognitive, and affective behavior. Deep brain stimulation (DBS) of the STN is the most common surgical intervention for advanced Parkinson's disease (PD), and STN has lately gained attention as target for DBS in neuropsychiatric disorders, including obsessive compulsive disorder, eating disorders, and addiction. Animal studies using STN-DBS, lesioning, or inactivation of STN neurons have been used extensively alongside clinical studies to unravel the structural organization, circuitry, and function of the STN. Recent studies in rodent STN models have exposed different roles for STN neurons in reward-related functions. We have previously shown that the majority of STN neurons express the vesicular glutamate transporter 2 gene (Vglut2/Slc17a6) and that reduction of Vglut2 mRNA levels within the STN of mice [conditional knockout (cKO)] causes reduced postsynaptic activity and behavioral hyperlocomotion. The cKO mice showed less interest in fatty rewards, which motivated analysis of reward-response. The current results demonstrate decreased sugar consumption and strong rearing behavior, whereas biochemical analyses show altered dopaminergic and peptidergic activity in the striatum. The behavioral alterations were in fact correlated with opposite effects in the dorsal versus the ventral striatum. Significant cell loss and disorganization of the STN structure was identified, which likely accounts for the observed alterations. Rare genetic variants of the human VGLUT2 gene exist, and this study shows that reduced Vglut2/Slc17a6 gene expression levels exclusively within the STN of mice is sufficient to cause strong modifications in both the STN and the mesostriatal dopamine system.
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| 20. |
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| 21. |
- Wallén-Mackenzie, Åsa, et al.
(författare)
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Restricted cortical and amygdaloid removal of vesicular glutamate transporter 2 in preadolescent mice impacts dopaminergic activity and neuronal circuitry of higher brain function.
- 2009
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Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401 .- 0270-6474. ; 29:7, s. 2238-51
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Tidskriftsartikel (refereegranskat)abstract
- A major challenge in neuroscience is to resolve the connection between gene functionality, neuronal circuits, and behavior. Most, if not all, neuronal circuits of the adult brain contain a glutamatergic component, the nature of which has been difficult to assess because of the vast cellular abundance of glutamate. In this study, we wanted to determine the role of a restricted subpopulation of glutamatergic neurons within the forebrain, the Vglut2-expressing neurons, in neuronal circuitry of higher brain function. Vglut2 expression was selectively deleted in the cortex, hippocampus, and amygdala of preadolescent mice, which resulted in increased locomotor activity, altered social dominance and risk assessment, decreased sensorimotor gating, and impaired long-term spatial memory. Presynaptic VGLUT2-positive terminals were lost in the cortex, striatum, nucleus accumbens, and hippocampus, and a downstream effect on dopamine binding site availability in the striatum was evident. A connection between the induced late-onset, chronic reduction of glutamatergic neurotransmission and dopamine signaling within the circuitry was further substantiated by a partial attenuation of the deficits in sensorimotor gating by the dopamine-stabilizing antipsychotic drug aripiprazole and an increased sensitivity to amphetamine. Somewhat surprisingly, given the restricted expression of Vglut2 in regions responsible for higher brain function, our analyses show that VGLUT2-mediated neurotransmission is required for certain aspects of cognitive, emotional, and social behavior. The present study provides support for the existence of a neurocircuitry that connects changes in VGLUT2-mediated neurotransmission to alterations in the dopaminergic system with schizophrenia-like behavioral deficits as a major outcome.
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| 22. |
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