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Mandeville JB, Weigand-Whittier J, Wey HY, Chen YCI. Amphetamine pretreatment blunts dopamine-induced D2/D3-receptor occupancy by an arrestin-mediated mechanism: A PET study in internalization compromised mice. Neuroimage 2023; 283:120416. [PMID: 37866759 PMCID: PMC10841768 DOI: 10.1016/j.neuroimage.2023.120416] [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: 08/22/2023] [Revised: 09/29/2023] [Accepted: 10/19/2023] [Indexed: 10/24/2023] Open
Abstract
While all reversible receptor-targeting radioligands for positron emission tomography (PET) can be displaced by competition with an antagonist at the receptor, many radiotracers show limited occupancies using agonists even at high doses. [11C]Raclopride, a D2/D3 receptor radiotracer with rapid kinetics, can identify the direction of changes in the neurotransmitter dopamine, but quantitative interpretation of the relationship between dopamine levels and radiotracer binding has proven elusive. Agonist-induced receptor desensitization and internalization, a homeostatic mechanism to downregulate neurotransmitter-mediated function, can shift radioligand-receptor binding affinity and confound PET interpretations of receptor occupancy. In this study, we compared occupancies induced by amphetamine (AMP) in drug-naive wild-type (WT) and internalization-compromised β-arrestin-2 knockout (KO) mice using a within-scan drug infusion to modulate the kinetics of [11C]raclopride. We additionally performed studies at 3 h following AMP pretreatment, with the hypothesis that receptor internalization should markedly attenuate occupancy on the second challenge, because dopamine cannot access internalized receptors. Without prior AMP treatment, WT mice exhibited somewhat larger binding potential than KO mice but similar AMP-induced occupancy. At 3 h after AMP treatment, WT mice exhibited binding potentials that were 15 % lower than KO mice. At this time point, occupancy was preserved in KO mice but suppressed by 60 % in WT animals, consistent with a model in which most receptors contributing to binding potential in WT animals were not functional. These results demonstrate that arrestin-mediated receptor desensitization and internalization produce large effects in PET [11C]raclopride occupancy studies using agonist challenges.
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Affiliation(s)
- Joseph B Mandeville
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Jonah Weigand-Whittier
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Department of Bioengineering, University of California, Berkeley, CA, USA
| | - Hsiao-Ying Wey
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Yin-Ching I Chen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
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Gao N, Liu Z, Wang H, Shen C, Dong Z, Cui W, Xiong WC, Mei L. Deficiency of Cullin 3, a Protein Encoded by a Schizophrenia and Autism Risk Gene, Impairs Behaviors by Enhancing the Excitability of Ventral Tegmental Area (VTA) DA Neurons. J Neurosci 2023; 43:6249-6267. [PMID: 37558490 PMCID: PMC10490515 DOI: 10.1523/jneurosci.0247-23.2023] [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: 02/09/2023] [Revised: 07/09/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023] Open
Abstract
The dopaminergic neuromodulator system is fundamental to brain functions. Abnormal dopamine (DA) pathway is implicated in psychiatric disorders, including schizophrenia (SZ) and autism spectrum disorder (ASD). Mutations in Cullin 3 (CUL3), a core component of the Cullin-RING ubiquitin E3 ligase complex, have been associated with SZ and ASD. However, little is known about the function and mechanism of CUL3 in the DA system. Here, we show that CUL3 is critical for the function of DA neurons and DA-relevant behaviors in male mice. CUL3-deficient mice exhibited hyperactive locomotion, deficits in working memory and sensorimotor gating, and increased sensitivity to psychostimulants. In addition, enhanced DA signaling and elevated excitability of the VTA DA neurons were observed in CUL3-deficient animals. Behavioral impairments were attenuated by dopamine D2 receptor antagonist haloperidol and chemogenetic inhibition of DA neurons. Furthermore, we identified HCN2, a hyperpolarization-activated and cyclic nucleotide-gated channel, as a potential target of CUL3 in DA neurons. Our study indicates that CUL3 controls DA neuronal activity by maintaining ion channel homeostasis and provides insight into the role of CUL3 in the pathogenesis of psychiatric disorders.SIGNIFICANCE STATEMENT This study provides evidence that Cullin 3 (CUL3), a core component of the Cullin-RING ubiquitin E3 ligase complex that has been associated with autism spectrum disorder and schizophrenia, controls the excitability of dopamine (DA) neurons in mice. Its DA-specific heterozygous deficiency increased spontaneous locomotion, impaired working memory and sensorimotor gating, and elevated response to psychostimulants. We showed that CUL3 deficiency increased the excitability of VTA DA neurons, and inhibiting D2 receptor or DA neuronal activity attenuated behavioral deficits of CUL3-deficient mice. We found HCN2, a hyperpolarization-activated channel, as a target of CUL3 in DA neurons. Our findings reveal CUL3's role in DA neurons and offer insights into the pathogenic mechanisms of autism spectrum disorder and schizophrenia.
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Affiliation(s)
- Nannan Gao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Zhipeng Liu
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Hongsheng Wang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Chen Shen
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Zhaoqi Dong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Wanpeng Cui
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106
- Chinese Institutes for Medical Research, Beijing, China 100069
- Capital Medical University, Beijing, China 100069
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Delignat-Lavaud B, Kano J, Ducrot C, Massé I, Mukherjee S, Giguère N, Moquin L, Lévesque C, Burke S, Denis R, Bourque MJ, Tchung A, Rosa-Neto P, Lévesque D, De Beaumont L, Trudeau LÉ. Synaptotagmin-1-dependent phasic axonal dopamine release is dispensable for basic motor behaviors in mice. Nat Commun 2023; 14:4120. [PMID: 37433762 PMCID: PMC10336101 DOI: 10.1038/s41467-023-39805-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 06/27/2023] [Indexed: 07/13/2023] Open
Abstract
In Parkinson's disease (PD), motor dysfunctions only become apparent after extensive loss of DA innervation. This resilience has been hypothesized to be due to the ability of many motor behaviors to be sustained through a diffuse basal tone of DA; but experimental evidence for this is limited. Here we show that conditional deletion of the calcium sensor synaptotagmin-1 (Syt1) in DA neurons (Syt1 cKODA mice) abrogates most activity-dependent axonal DA release in the striatum and mesencephalon, leaving somatodendritic (STD) DA release intact. Strikingly, Syt1 cKODA mice showed intact performance in multiple unconditioned DA-dependent motor tasks and even in a task evaluating conditioned motivation for food. Considering that basal extracellular DA levels in the striatum were unchanged, our findings suggest that activity-dependent DA release is dispensable for such tasks and that they can be sustained by a basal tone of extracellular DA. Taken together, our findings reveal the striking resilience of DA-dependent motor functions in the context of a near-abolition of phasic DA release, shedding new light on why extensive loss of DA innervation is required to reveal motor dysfunctions in PD.
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Affiliation(s)
- Benoît Delignat-Lavaud
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Jana Kano
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Charles Ducrot
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Ian Massé
- Hôpital du Sacré-Cœur-de-Montréal, CIUSSS NIM, Université de Montréal, Montreal, QC, Canada
| | - Sriparna Mukherjee
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Nicolas Giguère
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Luc Moquin
- Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l'Ouest-de-l'Île-de-Montréal; Department of Neurology and Neurosurgery, Psychiatry and Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | | | - Samuel Burke
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Raphaëlle Denis
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Marie-Josée Bourque
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Alex Tchung
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada
| | - Pedro Rosa-Neto
- Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l'Ouest-de-l'Île-de-Montréal; Department of Neurology and Neurosurgery, Psychiatry and Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Daniel Lévesque
- Faculty of Pharmacy, Université de Montréal, Montreal, QC, Canada
| | - Louis De Beaumont
- Hôpital du Sacré-Cœur-de-Montréal, CIUSSS NIM, Université de Montréal, Montreal, QC, Canada
| | - Louis-Éric Trudeau
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada.
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada.
- SNC and CIRCA Research Groups, Université de Montréal, Montréal, QC, Canada.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA.
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Sexual satiety modifies methamphetamine-induced locomotor and rewarding effects and dopamine-related protein levels in the striatum of male rats. Psychopharmacology (Berl) 2023; 240:797-812. [PMID: 36745226 DOI: 10.1007/s00213-023-06322-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/18/2023] [Indexed: 02/07/2023]
Abstract
RATIONALE Drug and natural rewarding stimuli activate the mesolimbic dopaminergic system. Both methamphetamine (Meth) and copulation to satiety importantly increase dopamine (DA) release in the nucleus accumbens (NAc), but with differences in magnitude. This paper analyzes the interaction between Meth administration and the intense sexual activity associated with sexual satiety. OBJECTIVES To evaluate possible changes in Meth-induced behavioral effects and striatal DA-related protein expression due to sexual satiety. METHODS Meth-induced locomotor activity and conditioned place preference (CPP) were tested in sexually experienced male rats that copulated to satiety (S-S) or ejaculated once (1E) the day before or displayed no sexual activity (control group; C). DA receptors and DA transporter expression were determined by western blot in the striatum of animals of all sexual conditions treated with specific Meth doses. RESULTS Meth's locomotor and rewarding effects were exacerbated in S-S animals, while in 1E rats, only locomotor effects were enhanced. Sexual activity, by itself, modified DA-related protein expression in the NAc core and in the caudate-putamen (CPu), while Meth treatment alone changed their expression only in the NAc shell. Meth-induced changes in the NAc shell turned in the opposite direction when animals had sexual activity, and additional changes appeared in the NAc core and CPu of S-S rats. CONCLUSION Sexual satiety sensitizes rats to Meth's behavioral effects and the Meth-induced striatal DA-related protein adaptations are modified by sexual activity, evidencing cross-sensitization between both stimuli.
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Kovalev G, Sukhorukova N, Vasileva E, Kondrakhin E, Salimov R, Narkevich V, Kudrin V. Behavioral and neuroreceptor effects of the racetam derivative GIZh-290 in mouse experimental attention deficit model. BIOMEDITSINSKAYA KHIMIYA 2022; 68:367-374. [DOI: 10.18097/pbmc20226805367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Behavioral and neurochemical effects of the new racetam derivative GIZh-290 were studied in a mouse attention deficit model (the ED-Low animals subpopulation selected during preliminary behavioral typing in the “closed enriched cross maze” test). Subchronic administration of GIZh-290 (1 mg/kg, 3 mg/kg and 5 mg/kg, intraperitoneally, for 6 days), increased the initially low level of attention in ED-Low animals; the highest selectivity was observed at a dose of 3 mg/kg. Radioligand analysis showed that at this dose, the drug changed density (Bmax) of D2 and GABAB receptors as markers in the pre-frontal cortex of the ED-Low subpopulation to Bmax values observed in the ED-High subpopulation. In the prefrontal cortex of the ED-Low rodents treated with GIZh-290 in dose of 3 mg/kg, there was a normalization of tissue concentrations of both dopamine itself (DA) and its intra- and extracellular metabolites (DOPA/DA and HVA/DA). The obtained results indicate the effectiveness of the studied drug for pharmacotherapy of attention deficit in experimental modeling and impact on potential molecular targets identified in the study.
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Affiliation(s)
- G.I. Kovalev
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | | | - E.V. Vasileva
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | | | - R.M. Salimov
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - V.B. Narkevich
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - V.S. Kudrin
- Zakusov Research Institute of Pharmacology, Moscow, Russia
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6
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Influence of Piracetam on Brain Receptor Systems in CD-1 Mice with Different Attention Stability Phenotypes. Pharm Chem J 2021. [DOI: 10.1007/s11094-021-02489-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Kovalev GI, Sukhorukova NA, Vasileva EV, Kondrakhin EA, Salimov RM. [Influence of pantogam and atomoxetine on attention stability and distribution of dopamine D2 and GABAB receptors in the attention deficit mouse model]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2021; 67:402-410. [PMID: 34730553 DOI: 10.18097/pbmc20216705402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The closed enriched cross maze test was employed as a new experimental model of the attention deficit disorder (ADD) for evaluation of the behavioral and neurochemical effects of the nootropic drug pantogam (100 mg/kg, intraperitoneally) and atomoxetine hydrochloride (3 mg/kg, intraperitoneally) administered subchronically to CD-1 outbred mice. Two subpopulations of rodents differed spontaneously in attention to enriched compartments (ED-Low and ED-High), were estimated on the basis of time spent by the mice in the empty or enriched compartments. The ED-Low and ED-High mice insignificantly differed in parameters associated with anxiety, exploratory efficacy and motor activity. Subchronic administration of both drugs in selected doses produced corrective effect on animal behavior seen as a selective increase in the ED-ratio values in the ED-Low subpopulation. Differences in the distribution of dopamine D2 and GABAB receptors (Bmax) between placebo-treated ED-Low and ED-High mice were found in the prefrontal cortex using the radioligand binding method. The neuroreceptor effects of atomoxetine were seen in prefrontal cortex of ED-Low mice as decrease in the Bmax values of D2 receptors by 14%. Pantogam in the prefrontal cortex of ED-Low subpopulation showed a decrease in the Bmax values of D2 receptors by 22% and an increase for GABAB receptors by 44%. Therefore, subchronic administration of pantogam had a positive corrective effect on the behavior parameters and the density of the studied receptor subtypes in animals with severe attention deficit.
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Affiliation(s)
- G I Kovalev
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | | | - E V Vasileva
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - E A Kondrakhin
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - R M Salimov
- Zakusov Research Institute of Pharmacology, Moscow, Russia
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8
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Kubota M, Kimura Y, Shimojo M, Takado Y, Duarte JMN, Takuwa H, Seki C, Shimada H, Shinotoh H, Takahata K, Kitamura S, Moriguchi S, Tagai K, Obata T, Nakahara J, Tomita Y, Tokunaga M, Maeda J, Kawamura K, Zhang MR, Ichise M, Suhara T, Higuchi M. Dynamic alterations in the central glutamatergic status following food and glucose intake: in vivo multimodal assessments in humans and animal models. J Cereb Blood Flow Metab 2021; 41:2928-2943. [PMID: 34039039 PMCID: PMC8545038 DOI: 10.1177/0271678x211004150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/24/2021] [Accepted: 02/28/2021] [Indexed: 11/17/2022]
Abstract
Fluctuations of neuronal activities in the brain may underlie relatively slow components of neurofunctional alterations, which can be modulated by food intake and related systemic metabolic statuses. Glutamatergic neurotransmission plays a major role in the regulation of excitatory tones in the central nervous system, although just how dietary elements contribute to the tuning of this system remains elusive. Here, we provide the first demonstration by bimodal positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) that metabotropic glutamate receptor subtype 5 (mGluR5) ligand binding and glutamate levels in human brains are dynamically altered in a manner dependent on food intake and consequent changes in plasma glucose levels. The brain-wide modulations of central mGluR5 ligand binding and glutamate levels and profound neuronal activations following systemic glucose administration were further proven by PET, MRS, and intravital two-photon microscopy, respectively, in living rodents. The present findings consistently support the notion that food-associated glucose intake is mechanistically linked to glutamatergic tones in the brain, which are translationally accessible in vivo by bimodal PET and MRS measurements in both clinical and non-clinical settings.
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Affiliation(s)
- Manabu Kubota
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
- Department of Psychiatry, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yasuyuki Kimura
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Masafumi Shimojo
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Yuhei Takado
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Joao MN Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Hiroyuki Takuwa
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Chie Seki
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Hitoshi Shimada
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Hitoshi Shinotoh
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Keisuke Takahata
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Soichiro Kitamura
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
- Department of Psychiatry, Nara Medical University, Nara, Japan
| | - Sho Moriguchi
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Kenji Tagai
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Takayuki Obata
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Jin Nakahara
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Yutaka Tomita
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
- Tomita Hospital, Aichi, Japan
| | - Masaki Tokunaga
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Jun Maeda
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Kazunori Kawamura
- Department of Radiopharmaceutics Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Ming-Rong Zhang
- Department of Radiopharmaceutics Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Masanori Ichise
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tetsuya Suhara
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
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Alpha-Synuclein PET Tracer Development-An Overview about Current Efforts. Pharmaceuticals (Basel) 2021; 14:ph14090847. [PMID: 34577548 PMCID: PMC8466155 DOI: 10.3390/ph14090847] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 12/18/2022] Open
Abstract
Neurodegenerative diseases such as Parkinson’s disease (PD) are manifested by inclusion bodies of alpha-synuclein (α-syn) also called α-synucleinopathies. Detection of these inclusions is thus far only possible by histological examination of postmortem brain tissue. The possibility of non-invasively detecting α-syn will therefore provide valuable insights into the disease progression of α-synucleinopathies. In particular, α-syn imaging can quantify changes in monomeric, oligomeric, and fibrillic α-syn over time and improve early diagnosis of various α-synucleinopathies or monitor treatment progress. Positron emission tomography (PET) is a non-invasive in vivo imaging technique that can quantify target expression and drug occupancies when a suitable tracer exists. As such, novel α-syn PET tracers are highly sought after. The development of an α-syn PET tracer faces several challenges. For example, the low abundance of α-syn within the brain necessitates the development of a high-affinity ligand. Moreover, α-syn depositions are, in contrast to amyloid proteins, predominantly localized intracellularly, limiting their accessibility. Furthermore, another challenge is the ligand selectivity over structurally similar amyloids such as amyloid-beta or tau, which are often co-localized with α-syn pathology. The lack of a defined crystal structure of α-syn has also hindered rational drug and tracer design efforts. Our objective for this review is to provide a comprehensive overview of current efforts in the development of selective α-syn PET tracers.
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10
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Nawaratne V, McLaughlin SP, Mayer FP, Gichi Z, Mastriano A, Carvelli L. Prolonged Amphetamine Exposures Increase the Endogenous Human Dopamine Receptors 2 at the Cellular Membrane in Cells Lacking the Dopamine Transporter. Front Cell Neurosci 2021; 15:681539. [PMID: 34512264 PMCID: PMC8427050 DOI: 10.3389/fncel.2021.681539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/03/2021] [Indexed: 11/30/2022] Open
Abstract
The dopamine 2 receptors (D2R) are G-protein coupled receptors expressed both in pre- and post-synaptic terminals that play an important role in mediating the physiological and behavioral effects of amphetamine (Amph). Previous studies have indicated that the effects of Amph at the D2R mainly rely on the ability of Amph to robustly increase extracellular dopamine through the dopamine transporter (DAT). This implies that the effects of Amph on D2R require the neurotransmitter dopamine. However, because of its lipophilic nature, Amph can cross the cellular membrane and thus potentially affect D2R expression independently of dopamine and DAT, e.g., in post-synaptic terminals. Here we used an in vitro system to study whether Amph affects total expression, cellular distribution, and function of the human D2R (hD2R), endogenously expressed in HEK293 cells. By performing Western blot experiments, we found that prolonged treatments with 1 or 50 μM Amph cause a significant decrease of the endogenous hD2R in cells transfected with human DAT (hDAT). On the other hand, in cells lacking expression of DAT, quantification of the hD2R-mediated changes in cAMP, biotinylation assays, Western blots and imaging experiments demonstrated an increase of hD2R at the cellular membrane after 15-h treatments with Amph. Moreover, imaging data suggested that barbadin, a specific inhibitor of the βarrestin-βadaptin interaction, blocked the Amph-induced increase of hD2R. Taken together our data suggest that prolonged exposures to Amph decrease or increase the endogenous hD2R at the cellular membrane in HEK293 cells expressing or lacking hDAT, respectively. Considering that this drug is often consumed for prolonged periods, during which tolerance develops, our data suggest that even in absence of DAT or dopamine, Amph can still alter D2R distribution and function.
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Affiliation(s)
- Vindhya Nawaratne
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
| | - Sean P. McLaughlin
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Felix P. Mayer
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Zayna Gichi
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Alyssa Mastriano
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
| | - Lucia Carvelli
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
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11
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ERK1/2 kinases and dopamine D2 receptors participate in the anticonvulsant effects of a new derivative of benzoylpyridine oxime and valproic acid. Eur J Pharmacol 2021; 903:174150. [PMID: 33961874 DOI: 10.1016/j.ejphar.2021.174150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 01/11/2023]
Abstract
Inhibition of the activity of extracellular signal-regulated kinases (ERK1/2) induced by the activation of the dopamine D2 receptor signalling cascade may be a promising pharmacological target. The aim of this work was to study the involvement of ERK1/2 and dopamine D2 receptor in the mechanism of the anticonvulsant action of valproic acid (VA) and a new benzoylpyridine oxime derivative (GIZH-298), which showed antiepileptic activity in different models of epilepsy. We showed that subchronic exposure to maximal electroshock seizures (MES) for 5 days reduced the density of dopamine D2 receptors in the striatum of mice. GIZH-298 counteracted the decrease in the number of dopamine D2 receptors associated with MES and increased the number of ligand binding sites of dopamine D2 receptors in mice without MES. The affinity of dopamine D2 receptors to the ligand was not changed by GIZH-298. MES caused an increase in ERK1/2 and synapsin I phosphorylation in the striatum while GIZH-298, similar to VA, reduced the levels of both phospho-ERK1/2 and phosphosynapsin I after MES, which correlated with the decrease in the intensity of seizure in mice. In addition, GIZH-298 suppressed ERK1/2 phosphorylation in SH-SY5Y human neuroblastoma cells at therapeutic concentrations, while VA inhibited ERK1/2 phosphorylation in vivo but not in vitro. The data obtained expand the understanding of the mechanisms of action of VA and GIZH-298, which involve regulating the activity of ERK1/2 kinases, probably by modulating dopamine D2 receptors in limbic structures, as well as (in the case of GIZH-298) directly inhibiting of the ERK1/2 cascade.
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12
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Caravaggio F, Porco N, Kim J, Torres-Carmona E, Brown E, Iwata Y, Nakajima S, Gerretsen P, Remington G, Graff-Guerrero A. Measuring amphetamine-induced dopamine release in humans: A comparative meta-analysis of [ 11 C]-raclopride and [ 11 C]-(+)-PHNO studies. Synapse 2021; 75:e22195. [PMID: 33471400 DOI: 10.1002/syn.22195] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/02/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
The radiotracers [11 C]-raclopride and [11 C]-(+)-PHNO are commonly used to measure differences in amphetamine-induced dopamine release between healthy persons and persons with neuropsychiatric diseases. As an agonist radiotracer, [11 C]-(+)-PHNO should theoretically be roughly 2.7 times more sensitive to displacement by endogenous dopamine than [11 C]raclopride. To date, only one study has been published comparing the sensitivity of these two radiotracers to amphetamine-induced dopamine release in healthy persons. Unfortunately, conflicting findings in the literature suggests that the dose of amphetamine they employed (0.3 mg/kg, p.o.) may not reliably reduce [11 C]-raclopride binding in the caudate. Thus, it is unclear whether the preponderance of evidence supports the theory that [11 C]-(+)-PHNO is more sensitive to displacement by amphetamine in humans than [11 C]-raclopride. In order to clarify these issues, we conducted a comparative meta-analysis summarizing the effects of amphetamine on [11 C]-raclopride and [11 C]-(+)-PHNO binding in healthy humans. Our analysis indicates that amphetamine given at 0.3 mg/kg, p.o. does not reliably reduce [11 C]-raclopride binding in the caudate. Second, the greater sensitivity of [11 C]-(+)-PHNO is evidenced at 0.5 mg/kg, p.o., but not at lower doses of amphetamine. Third, our analysis suggests that [11 C]-(+)-PHNO may be roughly 1.5 to 2.5 times more sensitive to displacement by amphetamine than [11 C]-raclopride in healthy persons. We recommend that future displacement studies with these radiotracers employ 0.5 mg/kg, p.o. of amphetamine with a dose, post-scan interval of at least 3 hr. Using this dose of amphetamine, [11 C]-raclopride studies should employ at least n = 34 participants per group, while [11 C]-(+)-PHNO studies should employ at least n = 6 participants per group, in order to be sufficiently powered (80%) to detect changes in radiotracer binding within the caudate.
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Affiliation(s)
- Fernando Caravaggio
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Natasha Porco
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Julia Kim
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Edgardo Torres-Carmona
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Eric Brown
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Yusuke Iwata
- Department of Neuropsychiatry, University of Yamanashi, Chuo, Japan
| | | | - Philip Gerretsen
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gary Remington
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Ariel Graff-Guerrero
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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13
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Cumming P, Gründer G, Brinson Z, Wong DF. Applications, Advances, and Limitations of Molecular Imaging of Brain Receptors. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00063-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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14
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Kreisler AD, Terranova MJ, Somkuwar SS, Purohit DC, Wang S, Head BP, Mandyam CD. In vivo reduction of striatal D1R by RNA interference alters expression of D1R signaling-related proteins and enhances methamphetamine addiction in male rats. Brain Struct Funct 2020; 225:1073-1088. [PMID: 32246242 DOI: 10.1007/s00429-020-02059-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 03/18/2020] [Indexed: 01/06/2023]
Abstract
This study sought to determine if reducing dopamine D1 receptor (D1R) expression in the dorsal striatum (DS) via RNA-interference alters methamphetamine self-administration. A lentiviral construct containing a short hairpin RNA (shRNA) was used to knock down D1R expression (D1RshRNA). D1RshRNA in male rats increased responding for methamphetamine (i.v.) under a fixed-ratio schedule in an extended access paradigm, compared to D1R-intact rats. D1RshRNA also produced a vertical shift in a dose-response paradigm and enhanced responding for methamphetamine in a progressive-ratio schedule, generating a drug-vulnerable phenotype. D1RshRNA did not alter responding for sucrose (oral) under a fixed-ratio schedule compared to D1R-intact rats. Western blotting confirmed reduced D1R expression in methamphetamine and sucrose D1RshRNA rats. D1RshRNA reduced the expression of PSD-95 and MAPK-1 and increased the expression of dopamine transporter (DAT) in the DS from methamphetamine, but not sucrose rats. Sucrose density gradient fractionation was performed in behavior-naïve controls, D1RshRNA- and D1R-intact rats to determine the subcellular localization of D1Rs, DAT and D1R signaling proteins. D1Rs, DAT, MAPK-1 and PSD-95 predominantly localized to heavy fractions, and the membrane/lipid raft protein caveolin-1 (Cav-1) and flotillin-1 were distributed equally between buoyant and heavy fractions in controls. Methamphetamine increased localization of PSD-95, Cav-1, and flotillin-1 in D1RshRNA and D1R-intact rats to buoyant fractions. Our studies indicate that reduced D1R expression in the DS increases vulnerability to methamphetamine addiction-like behavior, and this is accompanied by striatal alterations in the expression of DAT and D1R signaling proteins and is independent of the subcellular localization of these proteins.
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Affiliation(s)
| | | | | | | | - Shanshan Wang
- VA San Diego Healthcare System, San Diego, CA, 92161, USA
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA
| | - Brian P Head
- VA San Diego Healthcare System, San Diego, CA, 92161, USA
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA
| | - Chitra D Mandyam
- VA San Diego Healthcare System, San Diego, CA, 92161, USA.
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA.
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15
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Ziffert I, Kaiser A, Babilon S, Mörl K, Beck-Sickinger AG. Unusually persistent Gα i-signaling of the neuropeptide Y 2 receptor depletes cellular G i/o pools and leads to a G i-refractory state. Cell Commun Signal 2020; 18:49. [PMID: 32223755 PMCID: PMC7104545 DOI: 10.1186/s12964-020-00537-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 02/19/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND A sensitive balance between receptor activation and desensitization is crucial for cellular homeostasis. Like many other GPCR, the human neuropeptide Y2 receptor (hY2R) undergoes ligand dependent activation and internalization into intracellular compartments, followed by recycling to the plasma membrane. This receptor is involved in the pathophysiology of distinct diseases e.g. epilepsy and cancer progression and conveys anorexigenic signals which makes it an interesting and promising anti-obesity target. However, Y2R desensitization was observed after daily treatment with a selective PYY13-36 analog in vivo by a yet unknown mechanism. MATERIALS We studied the desensitization and activatability of recycled Y2R in transiently transfected HEK293 cells as well as in endogenously Y2R expressing SH-SY5Y and SMS-KAN cells. Results were evaluated by one-way ANOVA and Tukey post test. RESULTS We observed strong desensitization of the Y2R in a second round of stimulation despite its reappearance at the membrane. Already the first activation of the Y2R leads to depletion of the functional cellular Gαi/o protein pool and consequently desensitizes the linked signal transduction pathways, independent of receptor internalization. This desensitization also extends to other Gαi/o-coupled GPCR and can be detected in transfected HEK293 as well as in SH-SY5Y and SMS-KAN cell lines, both expressing the Y2R endogenously. By overexpression of chimeric Gαqi proteins in a model system, activation has been rescued, which identifies a critical role of the G protein status for cellular signaling. Furthermore, Y2R displays strong allosteric coupling to inhibitory G proteins in radioligand binding assays, and loses 10-fold affinity in the G protein-depleted state observed after activation, which can be largely abrogated by overexpression of the Gαi-subunit. CONCLUSION The unusually persistent Gαi-signaling of the Y2R leads to a state of cellular desensitization of the inhibitory Gαi-pathway. The strong allosteric effects of the Y2R-Gαi-interaction might be a mechanism that contributes to the burst of Gαi-signaling, but also serves as a mechanism to limit the Y2-mediated signaling after recycling. Thus, the cell is left in a refractory state, preventing further Gαi-signaling of the Y2R itself but also other Gαi/o-coupled receptors by simply controlling the repertoire of downstream effectors. Video abstract.
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Affiliation(s)
- Isabelle Ziffert
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Anette Kaiser
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Stefanie Babilon
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Karin Mörl
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany.
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16
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McCutcheon RA, Krystal JH, Howes OD. Dopamine and glutamate in schizophrenia: biology, symptoms and treatment. World Psychiatry 2020; 19:15-33. [PMID: 31922684 PMCID: PMC6953551 DOI: 10.1002/wps.20693] [Citation(s) in RCA: 252] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glutamate and dopamine systems play distinct roles in terms of neuronal signalling, yet both have been proposed to contribute significantly to the pathophysiology of schizophrenia. In this paper we assess research that has implicated both systems in the aetiology of this disorder. We examine evidence from post-mortem, preclinical, pharmacological and in vivo neuroimaging studies. Pharmacological and preclinical studies implicate both systems, and in vivo imaging of the dopamine system has consistently identified elevated striatal dopamine synthesis and release capacity in schizophrenia. Imaging of the glutamate system and other aspects of research on the dopamine system have produced less consistent findings, potentially due to methodological limitations and the heterogeneity of the disorder. Converging evidence indicates that genetic and environmental risk factors for schizophrenia underlie disruption of glutamatergic and dopaminergic function. However, while genetic influences may directly underlie glutamatergic dysfunction, few genetic risk variants directly implicate the dopamine system, indicating that aberrant dopamine signalling is likely to be predominantly due to other factors. We discuss the neural circuits through which the two systems interact, and how their disruption may cause psychotic symptoms. We also discuss mechanisms through which existing treatments operate, and how recent research has highlighted opportunities for the development of novel pharmacological therapies. Finally, we consider outstanding questions for the field, including what remains unknown regarding the nature of glutamate and dopamine function in schizophrenia, and what needs to be achieved to make progress in developing new treatments.
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Affiliation(s)
- Robert A McCutcheon
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
| | - John H Krystal
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Oliver D Howes
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
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17
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Hansson AC, Gründer G, Hirth N, Noori HR, Spanagel R, Sommer WH. Dopamine and opioid systems adaptation in alcoholism revisited: Convergent evidence from positron emission tomography and postmortem studies. Neurosci Biobehav Rev 2019; 106:141-164. [DOI: 10.1016/j.neubiorev.2018.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 09/08/2018] [Accepted: 09/14/2018] [Indexed: 12/20/2022]
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18
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Effect of amphetamine dose on wheel-running functioning as reinforcement or operant behavior on a multiple schedule of reinforcement. Behav Pharmacol 2019; 30:588-595. [PMID: 31206370 DOI: 10.1097/fbp.0000000000000493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Does the effect of amphetamine on behavior (wheel running) differ depending on the functional role (operant, reinforcement) of that behavior? This study addressed this question using a multiple schedule of reinforcement in which wheel running served as reinforcement for lever pressing in one component and as operant behavior for sucrose reinforcement in the other component. Seven female Long-Evans rats were exposed to a multiple schedule in which pressing a lever on a variable ratio 10 schedule produced the opportunity to run for 15 revolutions in one component and running 15 revolutions produced a drop of 15% sucrose solution in the other component. Doses of 0.5, 1.0, and 2.0 mg/kg D-amphetamine were administered by intraperitoneal injection 20 min prior to a session. As amphetamine dose increased, wheel running decreased in both components - showing no evidence that the effect of the drug on wheel running depended on the function of wheel activity. Notably, lever pressing for wheel-running reinforcement also decreased with amphetamine dose. Drug dose increased the initiation of operant lever pressing, but not the initiation of operant wheel running. We propose that amphetamine dose had common effects on wheel running regardless of its function (reinforcement vs. operant) because wheel-running generates automatic reinforcement and the automatic-reinforcement value of wheel activity is modulated by drug dose.
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Shalgunov V, van Waarde A, Booij J, Michel MC, Dierckx RAJO, Elsinga PH. Hunting for the high-affinity state of G-protein-coupled receptors with agonist tracers: Theoretical and practical considerations for positron emission tomography imaging. Med Res Rev 2018; 39:1014-1052. [PMID: 30450619 PMCID: PMC6587759 DOI: 10.1002/med.21552] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/02/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022]
Abstract
The concept of the high‐affinity state postulates that a certain subset of G‐protein‐coupled receptors is primarily responsible for receptor signaling in the living brain. Assessing the abundance of this subset is thus potentially highly relevant for studies concerning the responses of neurotransmission to pharmacological or physiological stimuli and the dysregulation of neurotransmission in neurological or psychiatric disorders. The high‐affinity state is preferentially recognized by agonists in vitro. For this reason, agonist tracers have been developed as tools for the noninvasive imaging of the high‐affinity state with positron emission tomography (PET). This review provides an overview of agonist tracers that have been developed for PET imaging of the brain, and the experimental paradigms that have been developed for the estimation of the relative abundance of receptors configured in the high‐affinity state. Agonist tracers appear to be more sensitive to endogenous neurotransmitter challenge than antagonists, as was originally expected. However, other expectations regarding agonist tracers have not been fulfilled. Potential reasons for difficulties in detecting the high‐affinity state in vivo are discussed.
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Affiliation(s)
- Vladimir Shalgunov
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Nuclear Medicine, Ghent University, University Hospital, Ghent, Belgium
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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20
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Caynas-Rojas S, Rodríguez-García G, Delint-Ramírez I, Miranda MI. Differential function of medial prefrontal cortex catecholaminergic receptors after long-term sugar consumption. Behav Brain Res 2018; 356:495-503. [PMID: 29920309 DOI: 10.1016/j.bbr.2018.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/07/2018] [Accepted: 06/08/2018] [Indexed: 12/18/2022]
Abstract
The medial prefrontal cortex (mPFC) has reciprocal projections with many cerebral structures that are crucial in the control of food ingestion behavior and reward processing; Thus the mPFC has an important function in taste memory recognition. Previous results indicate that long-term consumption of sugar produces changes in appetitive re-learning and suggest that this could trigger an escalating consumption due to the inability to learn new negative consequences related to the same taste. Further evidence suggests that general identity reward value could be encoded in the mPFC. Therefore, the purpose of this study was to evaluate in rats whether after 21 days of sugar consumption the increase in sweet taste preference and latent inhibition of conditioned taste aversion (CTA) were affected differentially by pharmacological activation or blockage of dopaminergic and β-adrenergic receptors, in the mPFC, during CTA acquisition. Results showed that after long-term sugar exposure, mPFC activation of β-adrenergic receptors with clenbuterol delayed aversive memory extinction, but the blockade with propranolol or activation of dopaminergic receptors with apomorphine increased CTA latent inhibition and accelerated aversive memory extinction only after acute sugar exposure. Only dopaminergic blockade with haloperidol prevented sweet taste preference expression after long-term sugar consumption, increased CTA latent inhibition and accelerated extinction after acute sugar exposure. Taken together, the present data provide evidence that catecholaminergic receptors in the mPFC after prolonged sugar consumption underwent functional changes related to re-learning and new aversive taste learning.
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Affiliation(s)
- Seraid Caynas-Rojas
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, UNAM, Campus Juriquilla, Querétaro, 76230, Mexico
| | - Gabriela Rodríguez-García
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, UNAM, Campus Juriquilla, Querétaro, 76230, Mexico
| | - Ilse Delint-Ramírez
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, 64460, Mexico
| | - María Isabel Miranda
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, UNAM, Campus Juriquilla, Querétaro, 76230, Mexico.
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21
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Faraone SV. The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities. Neurosci Biobehav Rev 2018; 87:255-270. [PMID: 29428394 DOI: 10.1016/j.neubiorev.2018.02.001] [Citation(s) in RCA: 291] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 02/05/2018] [Indexed: 12/20/2022]
Abstract
Psychostimulants, including amphetamines and methylphenidate, are first-line pharmacotherapies for individuals with attention-deficit/hyperactivity disorder (ADHD). This review aims to educate physicians regarding differences in pharmacology and mechanisms of action between amphetamine and methylphenidate, thus enhancing physician understanding of psychostimulants and their use in managing individuals with ADHD who may have comorbid psychiatric conditions. A systematic literature review of PubMed was conducted in April 2017, focusing on cellular- and brain system-level effects of amphetamine and methylphenidate. The primary pharmacologic effect of both amphetamine and methylphenidate is to increase central dopamine and norepinephrine activity, which impacts executive and attentional function. Amphetamine actions include dopamine and norepinephrine transporter inhibition, vesicular monoamine transporter 2 (VMAT-2) inhibition, and monoamine oxidase activity inhibition. Methylphenidate actions include dopamine and norepinephrine transporter inhibition, agonist activity at the serotonin type 1A receptor, and redistribution of the VMAT-2. There is also evidence for interactions with glutamate and opioid systems. Clinical implications of these actions in individuals with ADHD with comorbid depression, anxiety, substance use disorder, and sleep disturbances are discussed.
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Affiliation(s)
- Stephen V Faraone
- Departments of Psychiatry and of Neuroscience and Physiology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States; K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.
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22
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Ashok AH, Mizuno Y, Volkow ND, Howes OD. Association of Stimulant Use With Dopaminergic Alterations in Users of Cocaine, Amphetamine, or Methamphetamine: A Systematic Review and Meta-analysis. JAMA Psychiatry 2017; 74:511-519. [PMID: 28297025 PMCID: PMC5419581 DOI: 10.1001/jamapsychiatry.2017.0135] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Importance Stimulant use disorder is common, affecting between 0.3% and 1.1% of the population, and costs more than $85 billion per year globally. There are no licensed treatments to date. Several lines of evidence implicate the dopamine system in the pathogenesis of substance use disorder. Therefore, understanding the nature of dopamine dysfunction seen in stimulant users has the potential to aid the development of new therapeutics. Objective To comprehensively review the in vivo imaging evidence for dopaminergic alterations in stimulant (cocaine, amphetamine, or methamphetamine) abuse or dependence. Data Sources The entire PubMed, EMBASE, and PsycINFO databases were searched for studies from inception date to May 14, 2016. Study Selection Case-control studies were identified that compared dopaminergic measures between stimulant users and healthy controls using positron emission tomography or single-photon emission computed tomography to measure striatal dopamine synthesis or release or to assess dopamine transporter availability or dopamine receptor availability. Data Extraction and Synthesis Demographic, clinical, and imaging measures were extracted from each study, and meta-analyses and sensitivity analyses were conducted for stimulants combined, as well as for cocaine and for amphetamine and methamphetamine separately if there were sufficient studies. Main Outcomes and Measures Differences were measured in dopamine release (assessed using change in the D2/D3 receptor availability after administration of amphetamine or methylphenidate), dopamine transporter availability, and dopamine receptor availability in cocaine users, amphetamine and methamphetamine users, and healthy controls. Results A total of 31 studies that compared dopaminergic measures between 519 stimulant users and 512 healthy controls were included in the final analysis. In most of the studies, the duration of abstinence varied from 5 days to 3 weeks. There was a significant decrease in striatal dopamine release in stimulant users compared with healthy controls: the effect size was -0.84 (95% CI, -1.08 to -0.60; P < .001) for stimulants combined and -0.87 (95% CI, -1.15 to -0.60; P < .001) for cocaine. In addition, there was a significant decrease in dopamine transporter availability: the effect size was -0.91 (95% CI, -1.50 to -0.32; P < .01) for stimulants combined and -1.47 (95% CI, -1.83 to -1.10; P < .001) for amphetamine and methamphetamine. There was also a significant decrease in D2/D3 receptor availability: the effect size was -0.76 (95% CI, -0.92 to -0.60; P < .001) for stimulants combined, -0.73 (95% CI, -0.94 to -0.53; P < .001) for cocaine, and -0.81 (95% CI, -1.12 to -0.49; P < .001) for amphetamine and methamphetamine. Consistent alterations were not found in vesicular monoamine transporter, dopamine synthesis, or D1 receptor studies. Conclusions and Relevance Data suggest that both presynaptic and postsynaptic aspects of the dopamine system in the striatum are down-regulated in stimulant users. The commonality and differences between these findings and the discrepancies with the preclinical literature and models of drug addiction are discussed, as well as their implications for future drug development.
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Affiliation(s)
- Abhishekh H Ashok
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences Centre (LMS), Du Cane Road, London, UK
- Psychiatric Imaging Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London, UK
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Yuya Mizuno
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Nora D Volkow
- National Institute on Alcohol Abuse and Alcoholism and National Institute on Drug Abuse, Bethesda, USA
| | - Oliver D Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences Centre (LMS), Du Cane Road, London, UK
- Psychiatric Imaging Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London, UK
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
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A single-scan protocol for absolute D2/3 receptor quantification with [123I]IBZM SPECT. Neuroimage 2017; 147:461-472. [DOI: 10.1016/j.neuroimage.2016.12.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/24/2016] [Accepted: 12/18/2016] [Indexed: 11/19/2022] Open
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Sander CY, Hooker JM, Catana C, Rosen BR, Mandeville JB. Imaging Agonist-Induced D2/D3 Receptor Desensitization and Internalization In Vivo with PET/fMRI. Neuropsychopharmacology 2016; 41:1427-36. [PMID: 26388148 PMCID: PMC4793127 DOI: 10.1038/npp.2015.296] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 09/14/2015] [Accepted: 09/14/2015] [Indexed: 12/23/2022]
Abstract
This study investigated the dynamics of dopamine receptor desensitization and internalization, thereby proposing a new technique for non-invasive, in vivo measurements of receptor adaptations. The D2/D3 agonist quinpirole, which induces receptor internalization in vitro, was administered at graded doses in non-human primates while imaging with simultaneous positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). A pronounced temporal divergence between receptor occupancy and fMRI signal was observed: occupancy remained elevated while fMRI responded transiently. Analogous experiments with an antagonist (prochlorperazine) and a lower-affinity agonist (ropinirole) exhibited reduced temporal dissociation between occupancy and function, consistent with a mechanism of desensitization and internalization that depends upon drug efficacy and affinity. We postulated a model that incorporates internalization into a neurovascular-coupling relationship. This model yielded in vivo desensitization/internalization rates (0.2/min for quinpirole) consistent with published in vitro measurements. Overall, these results suggest that simultaneous PET/fMRI enables characterization of dynamic neuroreceptor adaptations in vivo, and may offer a first non-invasive method for assessing receptor desensitization and internalization.
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Affiliation(s)
- Christin Y Sander
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA,Harvard Medical School, Boston, MA, USA,A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Room 2301, Charlestown, MA 02129, USA, Tel: +617 724 1839, Fax: +617 726 7422, E-mail:
| | - Jacob M Hooker
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA,Harvard Medical School, Boston, MA, USA
| | - Ciprian Catana
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA,Harvard Medical School, Boston, MA, USA
| | - Bruce R Rosen
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA,Harvard Medical School, Boston, MA, USA,Health Sciences and Technology, Harvard-MIT, Cambridge, MA, USA
| | - Joseph B Mandeville
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA,Harvard Medical School, Boston, MA, USA
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Wulff S, Pinborg LH, Svarer C, Jensen LT, Nielsen MØ, Allerup P, Bak N, Rasmussen H, Frandsen E, Rostrup E, Glenthøj BY. Striatal D(2/3) Binding Potential Values in Drug-Naïve First-Episode Schizophrenia Patients Correlate With Treatment Outcome. Schizophr Bull 2015; 41:1143-52. [PMID: 25698711 PMCID: PMC4535636 DOI: 10.1093/schbul/sbu220] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
One of best validated findings in schizophrenia research is the association between blockade of dopamine D2 receptors and the effects of antipsychotics on positive psychotic symptoms. The aim of the present study was to examine correlations between baseline striatal D(2/3) receptor binding potential (BP(p)) values and treatment outcome in a cohort of antipsychotic-naïve first-episode schizophrenia patients. Additionally, we wished to investigate associations between striatal dopamine D(2/3) receptor blockade and alterations of negative symptoms as well as functioning and subjective well-being. Twenty-eight antipsychotic-naïve schizophrenia patients and 26 controls were included in the study. Single-photon emission computed tomography (SPECT) with [(123)I]iodobenzamide ([(123)I]-IBZM) was used to examine striatal D(2/3) receptor BP(p). Patients were examined before and after 6 weeks of treatment with the D(2/3) receptor antagonist amisulpride. There was a significant negative correlation between striatal D(2/3) receptor BP(p) at baseline and improvement of positive symptoms in the total group of patients. Comparing patients responding to treatment to nonresponders further showed significantly lower baseline BP(p) in the responders. At follow-up, the patients demonstrated a negative correlation between the blockade and functioning, whereas no associations between blockade and negative symptoms or subjective well-being were observed. The results show an association between striatal BP(p) of dopamine D(2/3) receptors in antipsychotic-naïve first-episode patients with schizophrenia and treatment response. Patients with a low BP(p) have a better treatment response than patients with a high BP(p). The results further suggest that functioning may decline at high levels of dopamine receptor blockade.
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Affiliation(s)
- Sanne Wulff
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences University of Copenhagen, Denmark;
| | - Lars Hageman Pinborg
- Neurobiology Research Unit (NRU), Rigshospitalet, University of Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit (NRU), Rigshospitalet, University of Copenhagen, Denmark
| | - Lars Thorbjørn Jensen
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Denmark
| | - Mette Ødegaard Nielsen
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Peter Allerup
- Department of Education, Centre for Research in Compulsory Schooling, Aarhus University, Denmark
| | - Nikolaj Bak
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Hans Rasmussen
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Erik Frandsen
- Department of Diagnostics, Functional Imaging Unit and Section of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Denmark
| | - Egill Rostrup
- Department of Diagnostics, Functional Imaging Unit and Section of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Denmark
| | - Birte Yding Glenthøj
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark;,Department of Clinical Medicine, Faculty of Health and Medical Sciences University of Copenhagen, Denmark
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Tyurenkov IN, Bagmetova VV, Merkushenkova OV, Markina YV, Klodt PM, Narkevich VB, Kudrin VS, Kondrakhin EA, Vasil’eva EV, Kovalev GI. An analysis of the involvement of monoaminergic mechanisms in the neuropsychotropic effects of neuroglutam. NEUROCHEM J+ 2015. [DOI: 10.1134/s1819712415010122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Finnema SJ, Scheinin M, Shahid M, Lehto J, Borroni E, Bang-Andersen B, Sallinen J, Wong E, Farde L, Halldin C, Grimwood S. Application of cross-species PET imaging to assess neurotransmitter release in brain. Psychopharmacology (Berl) 2015; 232:4129-57. [PMID: 25921033 PMCID: PMC4600473 DOI: 10.1007/s00213-015-3938-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/09/2015] [Indexed: 01/03/2023]
Abstract
RATIONALE This review attempts to summarize the current status in relation to the use of positron emission tomography (PET) imaging in the assessment of synaptic concentrations of endogenous mediators in the living brain. OBJECTIVES Although PET radioligands are now available for more than 40 CNS targets, at the initiation of the Innovative Medicines Initiative (IMI) "Novel Methods leading to New Medications in Depression and Schizophrenia" (NEWMEDS) in 2009, PET radioligands sensitive to an endogenous neurotransmitter were only validated for dopamine. NEWMEDS work-package 5, "Cross-species and neurochemical imaging (PET) methods for drug discovery", commenced with a focus on developing methods enabling assessment of changes in extracellular concentrations of serotonin and noradrenaline in the brain. RESULTS Sharing the workload across institutions, we utilized in vitro techniques with cells and tissues, in vivo receptor binding and microdialysis techniques in rodents, and in vivo PET imaging in non-human primates and humans. Here, we discuss these efforts and review other recently published reports on the use of radioligands to assess changes in endogenous levels of dopamine, serotonin, noradrenaline, γ-aminobutyric acid, glutamate, acetylcholine, and opioid peptides. The emphasis is on assessment of the availability of appropriate translational tools (PET radioligands, pharmacological challenge agents) and on studies in non-human primates and human subjects, as well as current challenges and future directions. CONCLUSIONS PET imaging directed at investigating changes in endogenous neurochemicals, including the work done in NEWMEDS, have highlighted an opportunity to further extend the capability and application of this technology in drug development.
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Affiliation(s)
- Sjoerd J. Finnema
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden
| | - Mika Scheinin
- />Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland , />Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| | - Mohammed Shahid
- />Research and Development, Orion Corporation, Orion Pharma, Turku, Finland
| | - Jussi Lehto
- />Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Edilio Borroni
- />Neuroscience Department, Hoffman-La Roche, Basel, Switzerland
| | | | - Jukka Sallinen
- />Research and Development, Orion Corporation, Orion Pharma, Turku, Finland
| | - Erik Wong
- />Neuroscience Innovative Medicine Unit, AstraZeneca, Wilmington, DE USA
| | - Lars Farde
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden , />Translational Science Center at Karolinska Institutet, AstraZeneca, Stockholm, Sweden
| | - Christer Halldin
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden
| | - Sarah Grimwood
- Neuroscience Research Unit, Pfizer Inc, Cambridge, MA, USA. .,, 610 Main Street, Cambridge, MA, 02139, USA.
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Craig-McQuaide A, Akram H, Zrinzo L, Tripoliti E. A review of brain circuitries involved in stuttering. Front Hum Neurosci 2014; 8:884. [PMID: 25452719 PMCID: PMC4233907 DOI: 10.3389/fnhum.2014.00884] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/14/2014] [Indexed: 11/13/2022] Open
Abstract
Stuttering has been the subject of much research, nevertheless its etiology remains incompletely understood. This article presents a critical review of the literature on stuttering, with particular reference to the role of the basal ganglia (BG). Neuroimaging and lesion studies of developmental and acquired stuttering, as well as pharmacological and genetic studies are discussed. Evidence of structural and functional changes in the BG in those who stutter indicates that this motor speech disorder is due, at least in part, to abnormal BG cues for the initiation and termination of articulatory movements. Studies discussed provide evidence of a dysfunctional hyperdopaminergic state of the thalamocortical pathways underlying speech motor control in stuttering. Evidence that stuttering can improve, worsen or recur following deep brain stimulation for other indications is presented in order to emphasize the role of BG in stuttering. Further research is needed to fully elucidate the pathophysiology of this speech disorder, which is associated with significant social isolation.
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Affiliation(s)
| | - Harith Akram
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London London, UK ; Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery London, UK
| | - Ludvic Zrinzo
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London London, UK ; Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery London, UK
| | - Elina Tripoliti
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London London, UK ; Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery London, UK
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The influence of different cellular environments on PET radioligand binding: an application to D2/3-dopamine receptor imaging. Neuropharmacology 2014; 85:305-13. [PMID: 24910074 PMCID: PMC4109028 DOI: 10.1016/j.neuropharm.2014.05.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 05/01/2014] [Accepted: 05/26/2014] [Indexed: 01/10/2023]
Abstract
Various D2/3 receptor PET radioligands are sensitive to endogenous dopamine release in vivo. The Occupancy Model is generally used to interpret changes in binding observed in in vivo competition binding studies; an Internalisation Hypothesis may also contribute to these changes in signal. Extension of in vivo competition imaging to other receptor systems has been relatively unsuccessful. A greater understanding of the cellular processes underlying signal changes following endogenous neurotransmitter release may help translate this imaging paradigm to other receptor systems. To investigate the Internalisation Hypothesis we assessed the effects of different cellular environments, representative of those experienced by a receptor following agonist-induced internalisation, on the binding of three D2/3 PET ligands with previously reported sensitivities to endogenous dopamine in vivo, namely [3H]spiperone, [3H]raclopride and [3H]PhNO. Furthermore, we determined the contribution of each cellular compartment to total striatal binding for these D2/3 ligands. These studies suggest that sensitivity to endogenous dopamine release in vivo is related to a decrease in affinity in the endosomal environment compared with those found at the cell surface. In agreement with these findings we also demonstrate that ∼25% of total striatal binding for [3H]spiperone originates from sub-cellular, microsomal receptors, whereas for [3H]raclopride and [3H]PhNO, this fraction is lower, representing ∼14% and 17%, respectively. This pharmacological approach is fully translatable to other receptor systems. Assessment of affinity shifts in different cellular compartments may play a crucial role for understanding if a radioligand is sensitive to endogenous release in vivo, for not just the D2/3, but other receptor systems. The internalisation hypothesis was investigated in relation to D2/3 receptor PET ligand binding. KD and Bmax were determined for [3H]Raclopride, PhNO and Spiperone in different cellular buffers. The cellular distribution of [3H]Raclopride, PhNO and Spiperone binding was also determined. Reductions in KD were observed in the endosomal condition in the following order PhNO > Raclopride > Spiperone. KD shifts in different cellular compartments may predict sensitivity to neurotransmitter release in vivo.
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Single and binge methamphetamine administrations have different effects on the levels of dopamine D2 autoreceptor and dopamine transporter in rat striatum. Int J Mol Sci 2014; 15:5884-906. [PMID: 24717411 PMCID: PMC4013602 DOI: 10.3390/ijms15045884] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/15/2014] [Accepted: 03/25/2014] [Indexed: 01/17/2023] Open
Abstract
Methamphetamine (METH) is a central nervous system psychostimulant with a high potential for abuse. At high doses, METH causes a selective degeneration of dopaminergic terminals in the striatum. Dopamine D2 receptor antagonists and dopamine transporter (DAT) inhibitors protect against neurotoxicity of the drug by decreasing intracellular dopamine content and, consequently, dopamine autoxidation and production of reactive oxygen species. In vitro, amphetamines regulate D2 receptor and DAT functions via regulation of their intracellular trafficking. No data exists on axonal transport of both proteins and there is limited data on their interactions in vivo. The aim of the present investigation was to examine synaptosomal levels of presynaptic D2 autoreceptor and DAT after two different regimens of METH and to determine whether METH affects the D2 autoreceptor-DAT interaction in the rat striatum. We found that, as compared to saline controls, administration of single high-dose METH decreased D2 autoreceptor immunoreactivity and increased DAT immunoreactivity in rat striatal synaptosomes whereas binge high-dose METH increased immunoreactivity of D2 autoreceptor and had no effect on DAT immunoreactivity. Single METH had no effect on D2 autoreceptor-DAT interaction whereas binge METH increased the interaction between the two proteins in the striatum. Our results suggest that METH can affect axonal transport of both the D2 autoreceptor and DAT in an interaction-dependent and -independent manner.
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Agonist high- and low-affinity states of dopamine D₂ receptors: methods of detection and clinical implications. Naunyn Schmiedebergs Arch Pharmacol 2012; 386:135-54. [PMID: 23224422 DOI: 10.1007/s00210-012-0817-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 11/22/2012] [Indexed: 01/10/2023]
Abstract
Dopamine D(2) receptors, similar to other G-protein-coupled receptors, exist in a high- and low-affinity state for agonists. Based upon a review of the methods for detecting D(2) receptor agonist high-affinity states, we discuss alterations of such states in animal models of disease and the implications of such alterations for their labelling with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers. The classic approach of detecting agonist high-affinity states compares agonist competition for antagonist radioligands, in most cases using [(3)H]-spiperone as the radioligand; alternative approaches and radioligands have been proposed, but their claimed advantages have not been substantiated by other investigators. In view of the advantages and disadvantages of various techniques, we critically have reviewed reported findings on the detection of D(2) receptor agonist high-affinity states in a variety of animal models. These data are compared to the less numerous findings from human in vivo studies based on PET and SPECT tracers; they are interpreted in light of the finding that D(2) receptor agonist high-affinity states under control conditions may differ between rodent and human brain. The potential advantages of agonist ligands in studies of pathophysiology and as diagnostics are being discussed.
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Diet-induced obesity: dopamine transporter function, impulsivity and motivation. Int J Obes (Lond) 2012; 37:1095-103. [PMID: 23164701 DOI: 10.1038/ijo.2012.178] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/26/2012] [Accepted: 10/06/2012] [Indexed: 12/28/2022]
Abstract
OBJECTIVE A rat model of diet-induced obesity (DIO) was used to determine dopamine transporter (DAT) function, impulsivity and motivation as neurobehavioral outcomes and predictors of obesity. DESIGN To evaluate neurobehavioral alterations following the development of DIO induced by an 8-week high-fat diet (HF) exposure, striatal D2-receptor density, DAT function and expression, extracellular dopamine concentrations, impulsivity, and motivation for high- and low-fat reinforcers were determined. To determine predictors of DIO, neurobehavioral antecedents including impulsivity, motivation for high-fat reinforcers, DAT function and extracellular dopamine were evaluated before the 8-week HF exposure. METHODS Striatal D2-receptor density was determined by in vitro kinetic analysis of [(3)H]raclopride binding. DAT function was determined using in vitro kinetic analysis of [(3)H]dopamine uptake, methamphetamine-evoked [(3)H]dopamine overflow and no-net flux in vivo microdialysis. DAT cell-surface expression was determined using biotinylation and western blotting. Impulsivity and food-motivated behavior were determined using a delay discounting task and progressive ratio schedule, respectively. RESULTS Relative to obesity-resistant (OR) rats, obesity-prone (OP) rats exhibited 18% greater body weight following an 8-week HF-diet exposure, 42% lower striatal D2-receptor density, 30% lower total DAT expression, 40% lower in vitro and in vivo DAT function, 45% greater extracellular dopamine and twofold greater methamphetamine-evoked [(3)H]dopamine overflow. OP rats exhibited higher motivation for food, and surprisingly, were less impulsive relative to OR rats. Impulsivity, in vivo DAT function and extracellular dopamine concentration did not predict DIO. Importantly, motivation for high-fat reinforcers predicted the development of DIO. CONCLUSION Human studies are limited by their ability to determine if impulsivity, motivation and DAT function are causes or consequences of DIO. The current animal model shows that motivation for high-fat food, but not impulsive behavior, predicts the development of obesity, whereas decreases in striatal DAT function are exhibited only after the development of obesity.
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Howes OD, Kambeitz J, Kim E, Stahl D, Slifstein M, Abi-Dargham A, Kapur S. The nature of dopamine dysfunction in schizophrenia and what this means for treatment. ACTA ACUST UNITED AC 2012; 69:776-86. [PMID: 22474070 DOI: 10.1001/archgenpsychiatry.2012.169] [Citation(s) in RCA: 645] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Current drug treatments for schizophrenia are inadequate for many patients, and despite 5 decades of drug discovery, all of the treatments rely on the same mechanism: dopamine D(2) receptor blockade. Understanding the pathophysiology of the disorder is thus likely to be critical to the rational development of new treatments for schizophrenia. OBJECTIVE To investigate the nature of the dopaminergic dysfunction in schizophrenia using meta-analysis of in vivo studies. DATA SOURCES The MEDLINE, EMBASE, and PsycINFO databases were searched for studies from January 1, 1960, to July 1, 2011. STUDY SELECTION A total of 44 studies were identified that compared 618 patients with schizophrenia with 606 controls, using positron emission tomography or single-photon emission computed tomography to measure in vivo striatal dopaminergic function. DATA EXTRACTION Demographic, clinical, and imaging variables were extracted from each study, and effect sizes were determined for the measures of dopaminergic function. Studies were grouped into those of presynaptic function and those of dopamine transporter and receptor availability. Sensitivity analyses were conducted to explore the consistency of effects and the effect of clinical and imaging variables. DATA SYNTHESIS There was a highly significant elevation (P.<001) in presynaptic dopaminergic function in schizophrenia with a large effect size (Cohen d=0.79). There was no evidence of alterations in dopamine transporter availability. There was a small elevation in D(2/3) receptor availability (Cohen d=0.26), but this was not evident in drug-naive patients and was influenced by the imaging approach used. CONCLUSIONS The locus of the largest dopaminergic abnormality in schizophrenia is presynaptic, which affects dopamine synthesis capacity, baseline synaptic dopamine levels, and dopamine release. Current drug treatments, which primarily act at D(2/3) receptors, fail to target these abnormalities. Future drug development should focus on the control of presynaptic dopamine synthesis and release capacity.
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Affiliation(s)
- Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, King's College London, Camberwell, UK.
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Evidence that sleep deprivation downregulates dopamine D2R in ventral striatum in the human brain. J Neurosci 2012; 32:6711-7. [PMID: 22573693 DOI: 10.1523/jneurosci.0045-12.2012] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dopamine D2 receptors are involved with wakefulness, but their role in the decreased alertness associated with sleep deprivation is unclear. We had shown that sleep deprivation reduced dopamine D2/D3 receptor availability (measured with PET and [(11)C]raclopride in controls) in striatum, but could not determine whether this reflected dopamine increases ([(11)C]raclopride competes with dopamine for D2/D3 receptor binding) or receptor downregulation. To clarify this, we compared the dopamine increases induced by methylphenidate (a drug that increases dopamine by blocking dopamine transporters) during sleep deprivation versus rested sleep, with the assumption that methylphenidate's effects would be greater if, indeed, dopamine release was increased during sleep deprivation. We scanned 20 controls with [(11)C]raclopride after rested sleep and after 1 night of sleep deprivation; both after placebo and after methylphenidate. We corroborated a decrease in D2/D3 receptor availability in the ventral striatum with sleep deprivation (compared with rested sleep) that was associated with reduced alertness and increased sleepiness. However, the dopamine increases induced by methylphenidate (measured as decreases in D2/D3 receptor availability compared with placebo) did not differ between rested sleep and sleep deprivation, and were associated with the increased alertness and reduced sleepiness when methylphenidate was administered after sleep deprivation. Similar findings were obtained by microdialysis in rodents subjected to 1 night of paradoxical sleep deprivation. These findings are consistent with a downregulation of D2/D3 receptors in ventral striatum with sleep deprivation that may contribute to the associated decreased wakefulness and also corroborate an enhancement of D2 receptor signaling in the arousing effects of methylphenidate in humans.
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Measuring Dopamine Synaptic Transmission with Molecular Imaging and Pharmacological Challenges: The State of the Art. MOLECULAR IMAGING IN THE CLINICAL NEUROSCIENCES 2012. [DOI: 10.1007/7657_2012_45] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Firstova YY, Abaimov DA, Kapitsa IG, Voronina TA, Kovalev GI. The effects of scopolamine and the nootropic drug phenotropil on rat brain neurotransmitter receptors during testing of the conditioned passive avoidance task. NEUROCHEM J+ 2011. [DOI: 10.1134/s1819712411020048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Cumming P. Absolute abundances and affinity states of dopamine receptors in mammalian brain: A review. Synapse 2011; 65:892-909. [DOI: 10.1002/syn.20916] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 01/14/2011] [Indexed: 12/14/2022]
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Voulalas PJ, Schetz J, Undieh AS. Differential subcellular distribution of rat brain dopamine receptors and subtype-specific redistribution induced by cocaine. Mol Cell Neurosci 2011; 46:645-54. [PMID: 21236347 PMCID: PMC3055788 DOI: 10.1016/j.mcn.2011.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 12/07/2010] [Accepted: 01/04/2011] [Indexed: 12/01/2022] Open
Abstract
We investigated the subcellular distribution of dopamine D(1), D(2) and D(5) receptor subtypes in rat frontal cortex, and examined whether psychostimulant-induced elevation of synaptic dopamine could alter the receptor distribution. Differential detergent solubilization and density gradient centrifugation were used to separate various subcellular fractions, followed by semi-quantitative determination of the relative abundance of specific receptor proteins in each fraction. D(1) receptors were predominantly localized to detergent-resistant membranes, and a portion of these receptors also floated on sucrose gradients. These properties are characteristic of proteins found in lipid rafts and caveolae. D(2) receptors exhibited variable distribution between cytoplasmic, detergent-soluble and detergent-resistant membrane fractions, yet were not present in buoyant membranes. Most D(5) receptor immunoreactivity was distributed into the cytoplasmic fraction, failing to sediment at forces up to 300,000g, while the remainder was localized to detergent-soluble membranes in cortex. D(5) receptors were undetectable in detergent-resistant fractions or raft-like subdomains. Following daily cocaine administration for seven days, a significant portion of D(1) receptors translocated from detergent-resistant membranes to detergent-soluble membranes and the cytoplasmic fraction. The distributions of D(5) and D(2) receptor subtypes were not significantly altered by cocaine treatment. These data imply that D(5) receptors are predominantly cytoplasmic, D(2) receptors are diffusely distributed within the cell, whereas D(1) receptors are mostly localized to lipid rafts within the rat frontal cortex. Dopamine receptor subtype localization is susceptible to modulation by pharmacological manipulations that elevate synaptic dopamine, however the functional implications of such drug-induced receptor warrant further investigation.
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Affiliation(s)
- Pamela J Voulalas
- Pharmacokinetics-Biopharmaceutics Laboratory, Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, USA.
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Crawford CA, Akopian G, Ring J, Jakowec MW, Petzinger GM, Andersen JK, Vittozzi-Wong P, Wang K, Farley CM, Charntikov S, Mitroi D, Beal MF, Chow R, Walsh JP. Acute and long-term response of dopamine nigrostriatal synapses to a single, low-dose episode of 3-nitropropionic acid-mediated chemical hypoxia. Synapse 2010; 65:339-50. [PMID: 20730800 DOI: 10.1002/syn.20852] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 07/26/2010] [Indexed: 11/11/2022]
Abstract
The goal of the present investigation was to determine the persistence of striatal (DA) dopaminergic dysfunction after a mild chemically induced hypoxic event in Fisher 344 rats. To this end, we gave a single injection of the mitochondrial complex II inhibitor 3-nitropropionic acid (3-NP; 16.5 mg/kg, i.p.) to 2-month old male F344 rats and measured various indices of striatal DA functioning and lipid peroxidation over a 3-month span. Separate groups of rats were used to measure rod walking, evoked DA release, DA content, malondialdehyde (MDA) accumulation, DA receptor binding, and tyrosine hydroxylase (TH) activity. The results showed that 3-NP exposure reduced most measures of DA functioning including motoric ability, DA release, and D(2) receptor densities for 1 to 3 months postdrug administration. Interestingly, DA content was reduced 1 week after 3-NP exposure, but rose to 147% of control values 1 month after 3-NP treatment. MDA accumulation, a measure of lipid peroxidation activity, was increased 24 h and 1 month after 3-NP treatment. 3-NP did not affect TH activity, suggesting that alterations in DA functioning were not the result of nigrostriatal terminal loss. These data demonstrate that a brief mild hypoxic episode caused by 3-NP exposure has long-term detrimental effects on the functioning of the nigrostriatal DA system.
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Affiliation(s)
- Cynthia A Crawford
- Department of Psychology, California State University, San Bernardino, California 92407, USA.
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Skinbjerg M, Liow JS, Seneca N, Hong J, Lu S, Thorsell A, Heilig M, Pike VW, Halldin C, Sibley DR, Innis RB. D2 dopamine receptor internalization prolongs the decrease of radioligand binding after amphetamine: a PET study in a receptor internalization-deficient mouse model. Neuroimage 2010; 50:1402-7. [PMID: 20097293 PMCID: PMC2838946 DOI: 10.1016/j.neuroimage.2010.01.055] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 11/14/2009] [Accepted: 01/14/2010] [Indexed: 11/18/2022] Open
Abstract
Dopamine released by amphetamine decreases the in vivo binding of PET radioligands to the dopamine D(2) receptor. Although concentrations of extracellular dopamine largely return to baseline within 1 to 2 h after amphetamine treatment, radioligand binding remains decreased for several hours. The purpose of this study was to determine whether the prolonged decrease of radioligand binding after amphetamine administration is caused by receptor internalization. To distinguish dopamine displacement from receptor internalization, we used wild-type and arrestin3 (arr3) knockout mice, which are incapable of internalizing D(2) receptors. In addition, we used both the D(2) selective agonist [(11)C]MNPA (which is thought to bind to the high affinity state of the receptor) and the D(2) selective antagonist [(18)F]fallypride (which does not differentiate between high and low affinity state). After an initial baseline scan, animals were divided in three groups for a second scan: either 30 min or 4 h after amphetamine administration (3 mg/kg, i.p.) or as retest. At 30 min, [(11)C]MNPA showed greater displacement than [(18)F]fallypride, but each radioligand gave similar displacement in knockout and wild-type mice. At 4 h, the binding of both radioligands returned to baseline in arr3 knockout mice, but remained decreased in wild-type mice. Radioligand binding was unaltered on retest scanning. Our results suggest that the prolonged decrease of radioligand binding after amphetamine is mainly due to internalization of the D(2) receptor rather than dopamine displacement. In addition, this study demonstrates the utility of small animal PET to study receptor trafficking in vivo in genetically modified mice.
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Affiliation(s)
- Mette Skinbjerg
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
- Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Stockholm, Sweden
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Nicholas Seneca
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Jinsoo Hong
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Annika Thorsell
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA
| | - Markus Heilig
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Christer Halldin
- Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Stockholm, Sweden
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
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Xiao MF, Xu JC, Tereshchenko Y, Novak D, Schachner M, Kleene R. Neural cell adhesion molecule modulates dopaminergic signaling and behavior by regulating dopamine D2 receptor internalization. J Neurosci 2009; 29:14752-63. [PMID: 19940170 PMCID: PMC6666007 DOI: 10.1523/jneurosci.4860-09.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 10/01/2009] [Indexed: 12/15/2022] Open
Abstract
The dopaminergic system plays an important role in the etiology of schizophrenia, and most antipsychotic drugs exert their functions by blocking dopamine D(2) receptors (D(2)Rs). Since the signaling strength mediated by D(2)Rs is regulated by internalization and degradation processes, it is crucial to identify molecules that modulate D(2)R localization at the cell surface. Here, we show that the neural cell adhesion molecule (NCAM) promotes D(2)R internalization/desensitization and subsequent degradation via direct interaction with a short peptide in the third intracellular loop of the D(2)R. NCAM deficiency in mice leads to increased numbers of D(2)Rs at the cell surface and augmented D(2)R signaling as a result of impaired D(2)R internalization. Furthermore, NCAM-deficient mice show higher sensitivity to the psychostimulant apomorphine and exaggerated activity of dopamine-related locomotor behavior. These results demonstrate that, in addition to its classical function in cell adhesion, NCAM is involved in regulating the trafficking of the neurotransmitter receptor D(2)R as well as receptor-mediated signaling and behavior, thus implicating NCAM as modulator of the dopaminergic system and a potential pharmacological target for dopamine-related neurological and psychiatric disorders.
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Affiliation(s)
- Mei-Fang Xiao
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Jin-Chong Xu
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Yuliya Tereshchenko
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Daniel Novak
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Melitta Schachner
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854, and
- Center for Neuroscience, Shantou University Medical College, Shantou 515041, China
| | - Ralf Kleene
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
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Franklin KM, Engleman EA, Ingraham CM, McClaren JA, Keith CM, McBride WJ, Murphy JM. A single, moderate ethanol exposure alters extracellular dopamine levels and dopamine d receptor function in the nucleus accumbens of wistar rats. Alcohol Clin Exp Res 2009; 33:1721-30. [PMID: 19572982 PMCID: PMC2858589 DOI: 10.1111/j.1530-0277.2009.01009.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The nucleus accumbens (NAc) has been implicated in the neurochemical effects of ethanol (EtOH). Evidence suggests that repeated EtOH exposures and chronic EtOH drinking increase dopamine (DA) neurotransmission in the NAc due, in part, to a reduction in D(2) autoreceptor function. The objectives of the current study were to evaluate the effects of a single EtOH pretreatment and repeated EtOH pretreatments on DA neurotransmission and D(2) autoreceptor function in the NAc of Wistar rats. METHODS Experiment 1 examined D(2) receptor function after a single intraperitoneal (i.p.) injection or repeated i.p. injections of 0.0, 0.5, 1.0, or 2.0 g/kg EtOH to female Wistar rats. Single EtOH pretreatment groups received 1 daily i.p. injection of 0.9% NaCl (saline) for 4 days, followed by 1 day of saline or EtOH administration; repeated EtOH pretreatment groups received 5 days of saline or EtOH injections. Reverse microdialysis experiments were conducted to determine the effects of local perfusion with the D(2)-like receptor antagonist (-)sulpiride (SUL; 100 uM), on extracellular DA levels in the NAc. Experiment 2 evaluated if pretreatment with a single, moderate (1.0 g/kg) dose of EtOH would alter levels and clearance of extracellular DA in the NAc, as measured by no-net-flux (NNF) microdialysis. Subjects were divided into the EtOH-naïve and the single EtOH pretreated groups from Experiment 1. RESULTS Experiment 1: Changes in extracellular DA levels induced with SUL perfusion were altered by the EtOH dose (p < 0.001), but not the number of EtOH pretreatments (p > 0.05). Post-hoc analyses indicated that groups pretreated with single or repeated 1.0 g/kg EtOH showed significantly attenuated DA response to SUL, compared with all other groups (p < 0.001). Experiment 2: Multiple linear regression analyses yielded significantly (p < 0.05) higher extracellular DA concentrations in the NAc of rats receiving EtOH pretreatment, compared with their EtOH-naïve counterparts (3.96 +/- 0.42 nM and 3.25 +/- 0.23 nM, respectively). Extraction fractions were not significantly different between the 2 groups. CONCLUSIONS The present results indicate that a single EtOH pretreatment at a moderate dose can increase DA neurotransmission in the NAc due, in part, to reduced D(2) autoreceptor function.
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Affiliation(s)
- Kelle M Franklin
- Department of Psychology, Purdue School of Science, IUPUI, Indianapolis, Indiana 46202, USA
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43
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Guo Q, Brady M, Gunn RN. A Biomathematical Modeling Approach to Central Nervous System Radioligand Discovery and Development. J Nucl Med 2009; 50:1715-23. [DOI: 10.2967/jnumed.109.063800] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Ellis J, Nathan P, Villemagne V, Mulligan R, Ellis K, Tochon-Danguy H, Chan J, O'keefe G, Bradley J, Savage G, Rowe C. The relationship between nicotinic receptors and cognitive functioning in healthy aging: An in vivo positron emission tomography (PET) study with 2-[18F]fluoro-A-85380. Synapse 2009; 63:752-63. [DOI: 10.1002/syn.20642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Finnema SJ, Halldin C, Bang-Andersen B, Gulyás B, Bundgaard C, Wikström HV, Farde L. Dopamine D(2/3) receptor occupancy of apomorphine in the nonhuman primate brain--a comparative PET study with [11C]raclopride and [11C]MNPA. Synapse 2009; 63:378-89. [PMID: 19173265 DOI: 10.1002/syn.20615] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Binding studies in vitro have demonstrated that the dopamine D2 receptor may exist in two affinity states for agonists. The high affinity state is thought to represent the functional state of the receptor and proportions might alter during disease. In vitro studies further indicate that agonists induce measurable D(2) receptor occupancy at clinically relevant concentrations but only when measured at the high affinity state. Recently developed PET-radioligands, such as [11C]MNPA, have now made it possible to directly study agonist binding in vivo. The aim of this study was to compare the inhibition by apomorphine of agonist and antagonist radioligand binding to D(2/3) receptors in vivo. A total of 36 PET measurements were performed with the D(2/3) antagonist [11C]raclopride or the D(2/3) agonist [11C]MNPA in two cynomolgus monkeys. On each study day, a baseline measurement was followed by two consecutive pretreatment studies with rising doses of apomorphine (0.01, 0.05, 0.15, 0.5, 1.0, and 3.0 mg/kg). Binding potential (BP(ND)) values were calculated for the striatum with cerebellum as reference region. Apomorphine inhibited [11C]raclopride and [11C]MNPA binding in a dose-dependent manner and to a similar extent. ID(50) and K(i) values were 0.26 mg/kg and 29 ng/ml for [11C]raclopride and 0.50 mg/kg and 31 ng/ml for [11C]MNPA. The present observations do not support the existence of two affinity states in vivo. It might thus be speculated that all D(2/3) receptors are in the high affinity state at in vivo conditions.
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Affiliation(s)
- Sjoerd J Finnema
- Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Stockholm, Sweden.
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Testing for radioligand sensitivity to endogenous neurotransmitter release. Eur J Nucl Med Mol Imaging 2009; 36:472-4. [PMID: 19172267 DOI: 10.1007/s00259-009-1067-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Egerton A, Mehta MA, Montgomery AJ, Lappin JM, Howes OD, Reeves SJ, Cunningham VJ, Grasby PM. The dopaminergic basis of human behaviors: A review of molecular imaging studies. Neurosci Biobehav Rev 2009; 33:1109-32. [PMID: 19481108 DOI: 10.1016/j.neubiorev.2009.05.005] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/14/2009] [Accepted: 05/18/2009] [Indexed: 11/16/2022]
Abstract
This systematic review describes human molecular imaging studies which have investigated alterations in extracellular DA levels during performance of behavioral tasks. Whilst heterogeneity in experimental methods limits meta-analysis, we describe the advantages and limitations of different methodological approaches. Interpretation of experimental results may be limited by regional cerebral blood flow (rCBF) changes, head movement and choice of control conditions. We revisit our original study of striatal DA release during video-game playing [Koepp, M.J., Gunn, R.N., Lawrence, A.D., Cunningham, V.J., Dagher, A., Jones, T., Brooks, D.J., Bench, C.J., Grasby, P.M., 1998. Evidence for striatal dopamine release during a video game. Nature 393, 266-268] to illustrate the potentially confounding influences of head movement and alterations in rCBF. Changes in [(11)C]raclopride binding may be detected in extrastriatal as well as striatal brain regions-however we review evidence which suggests that extrastriatal changes may not be clearly interpreted in terms of DA release. Whilst several investigations have detected increases in striatal extracellular DA concentrations during task components such as motor learning and execution, reward-related processes, stress and cognitive performance, the presence of potentially biasing factors should be carefully considered (and, where possible, accounted for) when designing and interpreting future studies.
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Affiliation(s)
- Alice Egerton
- Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, United Kingdom.
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Leri F, Zhou Y, Goddard B, Levy A, Jacklin D, Kreek MJ. Steady-state methadone blocks cocaine seeking and cocaine-induced gene expression alterations in the rat brain. Eur Neuropsychopharmacol 2009; 19:238-49. [PMID: 18990547 PMCID: PMC2900837 DOI: 10.1016/j.euroneuro.2008.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/22/2008] [Accepted: 09/30/2008] [Indexed: 11/26/2022]
Abstract
To elucidate the effects of steady-state methadone exposure on responding to cocaine conditioned stimuli and on cocaine-induced alterations in central opioid, hypocretin/orexin, and D2 receptor systems, male Sprague-Dawley rats received intravenous infusions of 1 mg/kg/inf cocaine paired with an audiovisual stimulus over three days of conditioning. Then, mini pumps releasing vehicle or 30 mg/kg/day methadone were implanted (SC), and lever pressing for the stimulus was assessed in the absence of cocaine and after a cocaine prime (20 mg/kg, IP). It was found that rats treated with vehicle, but not methadone, responded for the cocaine conditioned stimulus and displayed elevated mu-opioid receptor mRNA expression in the nucleus accumbens core and basolateral amygdala, reduced hypocretin/orexin mRNA in the lateral hypothalamus, and reduced D2 receptor mRNA in the caudate-putamen. This is the first demonstration that steady-state methadone administered after cocaine exposure blocks cocaine-induced behavioral and neural adaptations.
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MESH Headings
- Acoustic Stimulation/methods
- Analgesics, Opioid/administration & dosage
- Analysis of Variance
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Cocaine/pharmacology
- Cocaine-Related Disorders/drug therapy
- Cocaine-Related Disorders/metabolism
- Conditioning, Classical/drug effects
- Conditioning, Operant/drug effects
- Dopamine Uptake Inhibitors/pharmacology
- Drug Administration Schedule
- Drug Delivery Systems/methods
- Dynorphins/genetics
- Dynorphins/metabolism
- Gene Expression Regulation/drug effects
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Locomotion/drug effects
- Male
- Methadone/administration & dosage
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Orexins
- Photic Stimulation/methods
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Francesco Leri
- Department of Psychology, University of Guelph, Guelph, Canada.
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Positron emission tomography imaging demonstrates correlation between behavioral recovery and correction of dopamine neurotransmission after gene therapy. J Neurosci 2009; 29:1544-53. [PMID: 19193901 DOI: 10.1523/jneurosci.4491-08.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In vivo gene transfer using viral vectors is an emerging therapy for neurodegenerative diseases with a clinical impact recently demonstrated in Parkinson's disease patients. Recombinant adeno-associated viral (rAAV) vectors, in particular, provide an excellent tool for long-term expression of therapeutic genes in the brain. Here we used the [(11)C]raclopride [(S)-(-)-3,5-dichloro-N-((1-ethyl-2-pyrrolidinyl)methyl)-2-hydroxy-6-methoxybenzamide] micro-positron emission tomography (PET) technique to demonstrate that delivery of the tyrosine hydroxylase (TH) and GTP cyclohydrolase 1 (GCH1) enzymes using an rAAV5 vector normalizes the increased [(11)C]raclopride binding in hemiparkinsonian rats. Importantly, we show in vivo by microPET imaging and postmortem by classical binding assays performed in the very same animals that the changes in [(11)C]raclopride after viral vector-based enzyme replacement therapy is attributable to a decrease in the affinity of the tracer binding to the D(2) receptors, providing evidence for reconstitution of a functional pool of endogenous dopamine in the striatum. Moreover, the extent of the normalization in this non-invasive imaging measure was highly correlated with the functional recovery in motor behavior. The PET imaging protocol used in this study is fully adaptable to humans and thus can serve as an in vivo imaging technique to follow TH + GCH1 gene therapy in PD patients and provide an additional objective measure to a potential clinical trial using rAAV vectors to deliver l-3,4-dihydroxyphenylanaline in the brain.
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Ellis JR, Nathan PJ, Villemagne VL, Mulligan RS, Saunder T, Young K, Smith CL, Welch J, Woodward M, Wesnes KA, Savage G, Rowe CC. Galantamine-induced improvements in cognitive function are not related to alterations in alpha(4)beta (2) nicotinic receptors in early Alzheimer's disease as measured in vivo by 2-[18F]fluoro-A-85380 PET. Psychopharmacology (Berl) 2009; 202:79-91. [PMID: 18949462 DOI: 10.1007/s00213-008-1347-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 09/19/2008] [Indexed: 01/25/2023]
Abstract
INTRODUCTION The nicotinic acetylcholine receptor (nAChR) system plays a regulatory role in a number of cognitive processes. Cholinesterase inhibitors (i.e., galantamine) that potentiate cholinergic neurotransmission improve cognitive function in Alzheimer's disease (AD); however, the relationship between these effects and associated changes in nAChRs are yet to be established in vivo. MATERIALS AND METHODS 2-[18F]Fluoro-A-85380 (2-FA) binds to nAChRs and with positron emission tomography (PET) imaging provides a composite measure of receptor density and ligand affinity. This study aimed to: (1) quantify nAChRs in vivo in 15 drug-naïve patients with mild AD before and after chronic treatment with galantamine, using 2-FA and PET, and (2) examine the relationship between treatment-induced changes in nAChRs and improvements in cognitive function. Participants were nonsmokers and underwent extensive cognitive testing and a PET scan after injection of approximately 200 MBq of 2-FA on two occasions (before and after 12 weeks, galantamine treatment). A 3-day washout period preceded the second scan. Brain regional 2-FA binding was assessed through a simplified estimation of distribution volume (DV(S)). RESULTS Performance on global measures of cognition significantly improved following galantamine treatment (p < 0.05). This improvement extended to specific cognitive measures of language and verbal learning. No significant differences in nAChR DV(S) before and after galantamine treatment were found. The treatment-induced improvement in cognition was not correlated with regional or global nAChR DV(S), suggesting that changes in nAChRs may not be responsible for the improvements in cognition following galantamine in patients with mild AD.
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Affiliation(s)
- J R Ellis
- School of Psychology, Psychiatry, and Psychological Medicine, Monash University, Melbourne, Victoria, Australia.
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