1
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Knockout or Knock-in? A Truncated D2 Receptor Protein Is Expressed in the Brain of Functional D2 Receptor Knockout Mice. NEUROSCI 2021. [DOI: 10.3390/neurosci2020014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Null mice for the dopamine D2 receptor (D2R) have been instrumental in understanding the function of this protein. For our research, we obtained the functional D2R knockout mouse strain described initially in 1997. Surprisingly, our biochemical characterization showed that this mouse strain is not a true knockout. We determined by sequence analysis of the rapid 3′ amplification of cDNA ends that functional D2R knockout mice express transcripts that lack only the eighth exon. Furthermore, immunofluorescence assays showed a D2R-like protein in the brain of functional D2R knockout mice. We verified by immunofluorescence that the recombinant truncated D2R is expressed in HEK293T cells, showing intracellular localization, colocalizing in the Golgi apparatus and the endoplasmic reticulum, but with less presence in the Golgi apparatus compared to the native D2R. As previously reported, functional D2R knockout mice are hypoactive and insensitive to the D2R agonist quinpirole. Concordantly, microdialysis studies confirmed that functional D2R knockout mice have lower extracellular dopamine levels in the striatum than the native mice. In conclusion, functional D2R knockout mice express transcripts that lead to a truncated D2R protein lacking from the sixth transmembrane domain to the C-terminus. We share these findings to avoid future confusion and the community considers this mouse strain in D2R traffic and protein–protein interaction studies.
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2
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Yang P, Knight WC, Li H, Guo Y, Perlmutter JS, Benzinger TLS, Morris JC, Xu J. Dopamine D1 + D3 receptor density may correlate with parkinson disease clinical features. Ann Clin Transl Neurol 2020; 8:224-237. [PMID: 33348472 PMCID: PMC7818081 DOI: 10.1002/acn3.51274] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/11/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Objective Dopamine D2‐like receptors – mainly dopamine D2 receptors (D2R) and dopamine D3 receptors (D3R) – are believed to be greatly involved in the pathology of Parkinson disease (PD) progression. However, these receptors have not been precisely examined in PD patients. Our aim was to quantitatively calculate the exact densities of dopamine D1 receptors (D1R), D2R, and D3R in control, Alzheimer disease (AD), and Lewy body disease (LBD) patients (including PD, Dementia with Lewy bodies, and Parkinson disease dementia); and analyze the relationship between dopamine receptors and clinical PD manifestations. Methods We analyzed the densities of D1R, D2R, and D3R in the striatum and substantia nigra (SN) using a novel quantitative autoradiography procedure previously developed by our group. We also examined the expression of D2R and D3R mRNA in the striatum by in situ hybridization. Results The results showed that although no differences of striatal D1R were found among all groups; D2R was significantly decreased in the striatum of PD patients when compared with control and AD patients. Some clinical manifestations: age of onset, PD stage, dopamine responsiveness, and survival time after onset; showed a better correlation with striatal D1R + D3R densities combined compared to D1R or D3R alone. Interpretation There is a possibility that we may infer the results in diagnosis, treatment, and prognosis of PD by detecting D1R + D3R as opposed to using dopamine D1 or D3 receptors alone. This is especially true for elderly patients with low D2R expression as is common in this disease.
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Affiliation(s)
- Pengfei Yang
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - William C Knight
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Huifangjie Li
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Yingqiu Guo
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA.,Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, 63110, USA.,Department of Physical Therapy, Washington University School of Medicine, St. Louis, Missouri, 63110, USA.,Department of Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Tammie L S Benzinger
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - John C Morris
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Jinbin Xu
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
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3
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Farino ZJ, Morgenstern TJ, Maffei A, Quick M, De Solis AJ, Wiriyasermkul P, Freyberg RJ, Aslanoglou D, Sorisio D, Inbar BP, Free RB, Donthamsetti P, Mosharov EV, Kellendonk C, Schwartz GJ, Sibley DR, Schmauss C, Zeltser LM, Moore H, Harris PE, Javitch JA, Freyberg Z. New roles for dopamine D 2 and D 3 receptors in pancreatic beta cell insulin secretion. Mol Psychiatry 2020; 25:2070-2085. [PMID: 30626912 PMCID: PMC6616020 DOI: 10.1038/s41380-018-0344-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/17/2018] [Accepted: 12/10/2018] [Indexed: 01/11/2023]
Abstract
Although long-studied in the central nervous system, there is increasing evidence that dopamine (DA) has important roles in the periphery including in metabolic regulation. Insulin-secreting pancreatic β-cells express the machinery for DA synthesis and catabolism, as well as all five DA receptors. In these cells, DA functions as a negative regulator of glucose-stimulated insulin secretion (GSIS), which is mediated by DA D2-like receptors including D2 (D2R) and D3 (D3R) receptors. However, the fundamental mechanisms of DA synthesis, storage, release, and signaling in pancreatic β-cells and their functional relevance in vivo remain poorly understood. Here, we assessed the roles of the DA precursor L-DOPA in β-cell DA synthesis and release in conjunction with the signaling mechanisms underlying DA's inhibition of GSIS. Our results show that the uptake of L-DOPA is essential for establishing intracellular DA stores in β-cells. Glucose stimulation significantly enhances L-DOPA uptake, leading to increased DA release and GSIS reduction in an autocrine/paracrine manner. Furthermore, D2R and D3R act in combination to mediate dopaminergic inhibition of GSIS. Transgenic knockout mice in which β-cell D2R or D3R expression is eliminated exhibit diminished DA secretion during glucose stimulation, suggesting a new mechanism where D2-like receptors modify DA release to modulate GSIS. Lastly, β-cell-selective D2R knockout mice exhibit marked postprandial hyperinsulinemia in vivo. These results reveal that peripheral D2R and D3R receptors play important roles in metabolism through their inhibitory effects on GSIS. This opens the possibility that blockade of peripheral D2-like receptors by drugs including antipsychotic medications may significantly contribute to the metabolic disturbances observed clinically.
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Affiliation(s)
- Zachary J. Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Travis J. Morgenstern
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Antonella Maffei
- Division of Endocrinology, Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Matthias Quick
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Alain J. De Solis
- Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA
| | - Pattama Wiriyasermkul
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Current address: Department of Collaborative Research, Nara Medical University, Kashihara, Nara, Japan
| | - Robin J. Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Denise Sorisio
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Benjamin P. Inbar
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - R. Benjamin Free
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Prashant Donthamsetti
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Current address: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Eugene V. Mosharov
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Neurology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Christoph Kellendonk
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Pharmacology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Gary J. Schwartz
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Claudia Schmauss
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Lori M. Zeltser
- Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Holly Moore
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY, USA
| | - Paul E. Harris
- Division of Endocrinology, Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Jonathan A. Javitch
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Pharmacology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
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4
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Martin TA, Smith HR, Luessen DJ, Chen R, Porrino LJ. Functional brain activity is globally elevated by dopamine D2 receptor knockdown in the ventral tegmental area. Brain Res 2020; 1727:146552. [PMID: 31726041 PMCID: PMC6941665 DOI: 10.1016/j.brainres.2019.146552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/07/2019] [Accepted: 11/10/2019] [Indexed: 12/14/2022]
Abstract
The mesocorticolimbic system is comprised of dopaminergic neurons in the ventral tegmental area (VTA) and their projection targets in the ventral striatum, amygdala, prefrontal cortex, and hippocampus, among others. Regulation of dopamine transmission within this system is achieved in part through a negative feedback mechanism via dopamine D2 autoreceptors located on somatodendrites and terminals of VTA dopaminergic neurons. Dysregulation of this mechanism has been implicated in addiction and other psychiatric disorders, although the biological bases for these associations are unclear. In order to elucidate the functional consequences of VTA D2 receptor dysregulation, this study investigated alterations in local cerebral glucose utilization throughout the brain following Drd2 knockdown in the VTA. Male Sprague-Dawley rats received bilateral injections of lentivirus encoding shRNAs against the rat dopamine D2 receptor, scrambled shRNA or phosphate buffered saline. The autoradiographic 2-[14C]deoxyglucose metabolic mapping procedure was conducted 22 days post-infection. Brains were sectioned for autoradiography and glucose utilization was measured across distinct regions throughout the brain. Local cerebral glucose utilization was found to be elevated in the Drd2 knockdown group as compared to control groups. These greater levels of metabolic activity following Drd2 knockdown in the VTA were observed not only in the mesocorticolimbic system and associated dopamine pathways, but also in a global pattern that included many areas with far less concentrated VTA dopamine inputs. This suggests that even a partial Drd2 deletion in the VTA can have widespread consequences and impact information flow in diverse networks that process sensory, cognitive, motor and emotional information.
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Affiliation(s)
- Tamriage A Martin
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Hilary R Smith
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Deborah J Luessen
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Rong Chen
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Linda J Porrino
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
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5
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The effect of anti-emetic drugs on rat embryonic heart activity. Reprod Toxicol 2019; 87:140-145. [PMID: 31199962 DOI: 10.1016/j.reprotox.2019.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023]
Abstract
Nausea and vomiting of pregnancy (NVP) is the most common medical complaint during pregnancy affecting up to 70% of pregnant women worldwide. Some antiemetic medications (AEM) (droperidol, domperidone, granisetron, metoclopramide and trifluoperazine) used to treat NVP have the unwanted side effect of hERG blockade. The hERG potassium channel is essential for normal heart rhythm in both the adult human and the human and rat embryo. Animal studies show hERG blockade in the embryo causes bradycardia and arrhythmia leading to cardiovascular malformations and other birth defects. Whole rat embryo in vitro culture was used to determine the effect of the above listed AEM and meclizine on the heart rate of Gestational day 13 rat embryos. These embryos are similar in size and heart development to 5-6-week human embryo. The results showed that all of the AEMs caused a concentration-dependent bradycardia. Droperidol had the lowest margin of safety.
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6
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Gallo EF. Disentangling the diverse roles of dopamine D2 receptors in striatal function and behavior. Neurochem Int 2019; 125:35-46. [PMID: 30716356 DOI: 10.1016/j.neuint.2019.01.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/21/2019] [Accepted: 01/27/2019] [Indexed: 02/07/2023]
Abstract
Dopamine D2 receptors (D2Rs) mediate many of the actions of dopamine in the striatum, ranging from movement to the effortful pursuit of reward. Yet despite significant advances in linking D2Rs to striatal functions with pharmacological and genetic strategies in animals, how dopamine orchestrates its myriad actions on different cell populations -each expressing D2Rs- remains unclear. Furthermore, brain imaging and genetic studies in humans have consistently associated striatal D2R alterations with various neurological and neuropsychiatric disorders, but how and which D2Rs are involved in each case is poorly understood. Therefore, a critical first step is to engage in a refined and systematic investigation of the impact of D2R function on specific striatal cells, circuits, and behaviors. Here, I will review recent efforts, primarily in animal models, aimed at unlocking the complex and heterogeneous roles of D2Rs in striatum.
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Affiliation(s)
- Eduardo F Gallo
- Department of Biological Sciences, Fordham University, Bronx, NY, USA.
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7
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Antihypertensive effect of etamicastat in dopamine D2 receptor-deficient mice. Hypertens Res 2018; 41:489-498. [PMID: 29654295 DOI: 10.1038/s41440-018-0041-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/23/2017] [Accepted: 11/30/2017] [Indexed: 12/21/2022]
Abstract
Abnormalities of the D2R gene (DRD2) play a role in the pathogenesis of human essential hypertension; variants of the DRD2 have been reported to be associated with hypertension. Disruption of Drd2 (D2-/-) in mice increases blood pressure. The hypertension of D2-/- mice has been related, in part, to increased sympathetic activity, renal oxidative stress, and renal endothelin B receptor (ETBR) expression. We tested in D2-/- mice the effect of etamicastat, a reversible peripheral inhibitor of dopamine-β-hydroxylase that reduces the biosynthesis of norepinephrine from dopamine and decreases sympathetic nerve activity. Blood pressure was measured in anesthetized D2-/- mice treated with etamicastat by gavage, (10 mg/kg), conscious D2-/- mice, and D2+/+ littermates, and mice with the D2R selectively silenced in the kidney, treated with etamicastat in the drinking water (10 mg/kg per day). Tissue and urinary catecholamines and renal expression of selected G protein-coupled receptors, enzymes related to the production of reactive oxygen species, and sodium transporters were also measured. Etamicastat decreased blood pressure both in anesthetized and conscious D2-/- mice and mice with renal-selective silencing of D2R to levels similar or close to those measured in D2+/+ littermates. Etamicastat decreased cardiac and renal norepinephrine and increased cardiac and urinary dopamine levels in D2-/- mice. It also normalized the increased renal protein expressions of ETBR, NADPH oxidase isoenzymes, and urinary 8-isoprostane, as well as renal NHE3 and NCC, and increased the renal expression of D1R but not D5R in D2-/- mice. In conclusion, etamicastat is effective in normalizing the increased blood pressure and some of the abnormal renal biochemical alterations of D2-/- mice.
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8
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Abstract
Dopamine receptors are targets for drugs with antipsychotic potency, and they are also the primary target in the treatment of Parkinson’s disease. Molecular cloning has identified five genes that code for dopamine receptors. These receptors belong in two functionally distinct classes of G-protein-coupled receptors, known as the D1 class of receptors (D1 and D5) and the D2 class of receptors (D2, D3, and D4). The diversity of dopamine receptor subtypes that belong to the same functional class, their high degree of structural similarity, and the lack of antagonists with selectivity for each of the individual subtypes have challenged studies on the function of the individual receptor subtypes. This review focuses on the recent progress made with studies on the expression and function of D1, D2, and D3 receptors. It summarizes results of studies that suggest that these receptor proteins are expressed in monomeric and oligomeric forms and reviews results of a growing number of gene-targeting studies that begin to illustrate major differences in the phenotypes of D1-, D2-, and D3-mutant mice.
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Affiliation(s)
- Claudia Schmauss
- Department of Psychiatry/Neuroscience, Columbia University, New York, NY
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9
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Soto PL, Hiranita T, Xu M, Hursh SR, Grandy DK, Katz JL. Dopamine D₂-Like Receptors and Behavioral Economics of Food Reinforcement. Neuropsychopharmacology 2016. [PMID: 26205210 PMCID: PMC4748422 DOI: 10.1038/npp.2015.223] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies suggest dopamine (DA) D2-like receptor involvement in the reinforcing effects of food. To determine contributions of the three D2-like receptor subtypes, knockout (KO) mice completely lacking DA D2, D3, or D4 receptors (D2R, D3R, or D4R KO mice) and their wild-type (WT) littermates were exposed to a series of fixed-ratio (FR) food-reinforcement schedules in two contexts: an open economy with additional food provided outside the experimental setting and a closed economy with all food earned within the experimental setting. A behavioral economic model was used to quantify reinforcer effectiveness with food pellets obtained as a function of price (FR schedule value) plotted to assess elasticity of demand. Under both economies, as price increased, food pellets obtained decreased more rapidly (ie, food demand was more elastic) in DA D2R KO mice compared with WT littermates. Extinction of responding was studied in two contexts: by eliminating food deliveries and by delivering food independently of responding. A hyperbolic model quantified rates of extinction. Extinction in DA D2R KO mice occurred less rapidly compared with WT mice in both contexts. Elasticity of food demand was higher in DA D4R KO than WT mice in the open, but not closed, economy. Extinction of responding in DA D4R KO mice was not different from that in WT littermates in either context. No differences in elasticity of food demand or extinction rate were obtained in D3R KO mice and WT littermates. These results indicate that the D2R is the primary DA D2-like receptor subtype mediating the reinforcing effectiveness of food.
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Affiliation(s)
- Paul L Soto
- Department of Educational Psychology & Leadership, Texas Tech University, Lubbock, TX, USA,Department of Educational Psychology & Leadership, Texas Tech University, 3008 18th Street, Lubbock, TX 79410, USA, Tel: +1 806 834 0734, Fax: +1 806 742 1840, E-mail:
| | - Takato Hiranita
- Psychobiology Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Ming Xu
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL, USA
| | | | - David K Grandy
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Jonathan L Katz
- Psychobiology Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
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10
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Frederick AL, Yano H, Trifilieff P, Vishwasrao HD, Biezonski D, Mészáros J, Sibley DR, Kellendonk C, Sonntag KC, Graham DL, Colbran RJ, Stanwood GD, Javitch JA, Javitch JA. Evidence against dopamine D1/D2 receptor heteromers. Mol Psychiatry 2015; 20:1373-85. [PMID: 25560761 PMCID: PMC4492915 DOI: 10.1038/mp.2014.166] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 02/07/2023]
Abstract
Hetero-oligomers of G-protein-coupled receptors have become the subject of intense investigation, because their purported potential to manifest signaling and pharmacological properties that differ from the component receptors makes them highly attractive for the development of more selective pharmacological treatments. In particular, dopamine D1 and D2 receptors have been proposed to form hetero-oligomers that couple to Gαq proteins, and SKF83959 has been proposed to act as a biased agonist that selectively engages these receptor complexes to activate Gαq and thus phospholipase C. D1/D2 heteromers have been proposed as relevant to the pathophysiology and treatment of depression and schizophrenia. We used in vitro bioluminescence resonance energy transfer, ex vivo analyses of receptor localization and proximity in brain slices, and behavioral assays in mice to characterize signaling from these putative dimers/oligomers. We were unable to detect Gαq or Gα11 protein coupling to homomers or heteromers of D1 or D2 receptors using a variety of biosensors. SKF83959-induced locomotor and grooming behaviors were eliminated in D1 receptor knockout (KO) mice, verifying a key role for D1-like receptor activation. In contrast, SKF83959-induced motor responses were intact in D2 receptor and Gαq KO mice, as well as in knock-in mice expressing a mutant Ala(286)-CaMKIIα that cannot autophosphorylate to become active. Moreover, we found that, in the shell of the nucleus accumbens, even in neurons in which D1 and D2 receptor promoters are both active, the receptor proteins are segregated and do not form complexes. These data are not compatible with SKF83959 signaling through Gαq or through a D1/D2 heteromer and challenge the existence of such a signaling complex in the adult animals that we used for our studies.
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Affiliation(s)
- Aliya L. Frederick
- Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Hideaki Yano
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Pierre Trifilieff
- Nutrition and Integrative Neurobiology, INRA UMR 1286; University of Bordeaux, F-33076, Bordeaux, France,Center for Neuroscience. Columbia University, Kolb Research Building, New York, NY10032, USA
| | - Harshad D. Vishwasrao
- Center for Neuroscience. Columbia University, Kolb Research Building, New York, NY10032, USA
| | - Dominik Biezonski
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - József Mészáros
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Christoph Kellendonk
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Kai C. Sonntag
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, USA
| | - Devon L. Graham
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Roger J. Colbran
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA,Vanderbilt Kennedy Center and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gregg D. Stanwood
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA,Vanderbilt Kennedy Center and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jonathan A. Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - J A Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
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11
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Moraga-Amaro R, Gonzalez H, Pacheco R, Stehberg J. Dopamine receptor D3 deficiency results in chronic depression and anxiety. Behav Brain Res 2014; 274:186-93. [PMID: 25110304 DOI: 10.1016/j.bbr.2014.07.055] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 07/26/2014] [Accepted: 07/31/2014] [Indexed: 01/17/2023]
Abstract
Over the last decade accumulating evidence suggests that brain dopamine (DA) has a role in depression, particularly given the high comorbidity of depression with Parkinson's Disease (PD) and the antidepressant effects of the DA receptor subtype 3 (D3R) agonist pramipexole. The present study assesses the role of D3R in depression. Here we hypothesized that D3R mediates the antidepressant effects of DA. Thus, genetic deficiency of D3R in D3R knockout (D3RKO) mice would yield animals with chronic depressive symptoms. Whereas D3R deficient mice did not show significant alterations in locomotion when tested in the openfield, these animals showed anxiety-like symptoms measured as a significant increase in thigmotaxis at the openfield and a significantly lower time spent in the lit compartment at the light/dark exploration test. D3RKO animals also showed depressive-like symptoms as measured by increased immobility time in the Porsolt forced swim test and the tail suspension test, as well as anhedonia measured in the non-motor dependent sucrose test. In conclusion, D3R deficiency results in anxiety-like and depressive-like symptoms that cannot be attributed to motor dysfunction.
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Affiliation(s)
- Rodrigo Moraga-Amaro
- Laboratorio de Neurobiología, Centro de Investigaciones Biomédicas, Universidad Andres Bello, Santiago, Chile
| | - Hugo Gonzalez
- Laboratorio of Neuroinmunología, Fundación Ciencia & Vida, Av. Zañartu 1482, Ñuñoa (7780272), Santiago, Chile
| | - Rodrigo Pacheco
- Laboratorio of Neuroinmunología, Fundación Ciencia & Vida, Av. Zañartu 1482, Ñuñoa (7780272), Santiago, Chile; Programa de Biomedicina, Universidad San Sebastián, Av. Zañartu 1482, Ñuñoa (7780272), Santiago, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Centro de Investigaciones Biomédicas, Universidad Andres Bello, Santiago, Chile.
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Nakamura T, Sato A, Kitsukawa T, Momiyama T, Yamamori T, Sasaoka T. Distinct motor impairments of dopamine D1 and D2 receptor knockout mice revealed by three types of motor behavior. Front Integr Neurosci 2014; 8:56. [PMID: 25076876 PMCID: PMC4097398 DOI: 10.3389/fnint.2014.00056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 06/20/2014] [Indexed: 11/13/2022] Open
Abstract
Both D1R and D2R knock out (KO) mice of the major dopamine receptors show significant motor impairments. However, there are some discrepant reports, which may be due to the differences in genetic background and experimental procedures. In addition, only few studies directly compared the motor performance of D1R and D2R KO mice. In this paper, we examined the behavioral difference among N10 congenic D1R and D2R KO, and wild type (WT) mice. First, we examined spontaneous motor activity in the home cage environment for consecutive 5 days. Second, we examined motor performance using the rota-rod task, a standard motor task in rodents. Third, we examined motor ability with the Step-Wheel task in which mice were trained to run in a motor-driven turning wheel adjusting their steps on foothold pegs to drink water. The results showed clear differences among the mice of three genotypes in three different types of behavior. In monitoring spontaneous motor activities, D1R and D2R KO mice showed higher and lower 24 h activities, respectively, than WT mice. In the rota-rod tasks, at a low speed, D1R KO mice showed poor performance but later improved, whereas D2R KO mice showed a good performance at early days without further improvement. When first subjected to a high speed task, the D2R KO mice showed poorer rota-rod performance at a low speed than the D1R KO mice. In the Step-Wheel task, across daily sessions, D2R KO mice increased the duration that mice run sufficiently close to the spout to drink water, and decreased time to touch the floor due to missing the peg steps and number of times the wheel was stopped, which performance was much better than that of D1R KO mice. These incongruent results between the two tasks for D1R and D2R KO mice may be due to the differences in the motivation for the rota-rod and Step-Wheel tasks, aversion- and reward-driven, respectively. The Step-Wheel system may become a useful tool for assessing the motor ability of WT and mutant mice.
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Affiliation(s)
- Toru Nakamura
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI) Okazaki, Japan
| | - Asako Sato
- Laboratory of Neurochemistry, National Institute for Basic Biology Okazaki, Japan ; Department of Laboratory Animal Science, Kitasato University School of Medicine Sagamihara, Japan
| | - Takashi Kitsukawa
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University Osaka, Japan
| | - Toshihiko Momiyama
- Department of Pharmacology, Jikei University School of Medicine Tokyo, Japan
| | - Tetsuo Yamamori
- Division of Brain Biology, National Institute for Basic Biology Okazaki, Japan ; Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI) Okazaki, Japan
| | - Toshikuni Sasaoka
- Laboratory of Neurochemistry, National Institute for Basic Biology Okazaki, Japan ; Department of Laboratory Animal Science, Kitasato University School of Medicine Sagamihara, Japan ; Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University Niigata, Japan
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13
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Increasing dopamine D2 receptor expression in the adult nucleus accumbens enhances motivation. Mol Psychiatry 2013; 18:1025-33. [PMID: 23711983 PMCID: PMC4030518 DOI: 10.1038/mp.2013.57] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/21/2013] [Accepted: 04/02/2013] [Indexed: 01/24/2023]
Abstract
A decrease in dopamine D2 receptor (D2R) binding in the striatum is one of the most common findings in disorders that involve a dysregulation of motivation, including obesity, addiction and attention deficit hyperactivity disorder. As disruption of D2R signaling in the ventral striatum--including the nucleus accumbens (NAc)--impairs motivation, we sought to determine whether potentiating postsynaptic D2R-dependent signaling in the NAc would improve motivation. In this study, we used a viral vector strategy to overexpress postsynaptic D2Rs in either the NAc or the dorsal striatum. We investigated the effects of D2R overexpression on instrumental learning, willingness to work, use of reward value representations and modulation of motivation by reward associated cues. Overexpression of postsynaptic D2R in the NAc selectively increased motivation without altering consummatory behavior, the representation of the value of the reinforcer, or the capacity to use reward associated cues in flexible ways. In contrast, D2R overexpression in the dorsal striatum did not alter performance on any of the tasks. Thus, consistent with numerous studies showing that reduced D2R signaling impairs motivated behavior, our data show that postsynaptic D2R overexpression in the NAc specifically increases an animal's willingness to expend effort to obtain a goal. Taken together, these results provide insight into the potential impact of future therapeutic strategies that enhance D2R signaling in the NAc.
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Wang X, Escano CS, Asico L, Jones JE, Barte A, Lau YS, Jose PA, Armando I. Upregulation of renal D5 dopamine receptor ameliorates the hypertension in D3 dopamine receptor-deficient mice. Hypertension 2013; 62:295-301. [PMID: 23753418 DOI: 10.1161/hypertensionaha.113.01483] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
D3 dopamine receptor (D3R)-deficient mice have renin-dependent hypertension associated with sodium retention, but the hypertension is mild. To determine whether any compensatory mechanisms in the kidney are involved in the regulation of blood pressure with disruption of Drd3, we measured the renal protein expression of all dopamine receptor subtypes (D1R, D2R, D4R, and D5R) in D3R homozygous (D3(-/-)) and heterozygous (D3(+/-)) knockout mice and their wild-type (D3(+/+)) littermates. The renal immunohistochemistry and protein expression of D5R were increased (n=5/group) in D3(-/-) mice; renal D4R protein expression was decreased, whereas renal protein expressions of D1R and D2R were similar in both groups. Renal D5R protein expression was also increased in D3(+/-) (n=5/group) relative to D3(+/+) mice, whereas D1R, D2R, and D4R protein expressions were similar in D3(+/-) and D3(+/+) mice. The increase in renal D5R protein expression was abolished when D3(-/-) mice were fed a high-salt diet. Treatment with the D1-like receptor antagonist, SCH23390, increased the blood pressure in anesthetized D3(-/-) but not D3(+/+) mice (n=4/group), suggesting that the renal upregulation of D5R may have minimized the hypertension in D3(-/-) mice. The renal D5R protein upregulation was not caused by increased transcription because renal mRNA expression of D5R was similar in D3(-/-) and D3(+/+) mice. Our findings suggest that the renal upregulation of D5R may have minimized the hypertension that developed in D3(-/-) mice.
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Affiliation(s)
- Xiaoyan Wang
- Department of Medicine, University of Maryland, School of Medicine, 20 Penn St, Baltimore, MD 21201, USA.
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15
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Zimnisky R, Chang G, Gyertyán I, Kiss B, Adham N, Schmauss C. Cariprazine, a dopamine D(3)-receptor-preferring partial agonist, blocks phencyclidine-induced impairments of working memory, attention set-shifting, and recognition memory in the mouse. Psychopharmacology (Berl) 2013; 226:91-100. [PMID: 23079899 PMCID: PMC3572273 DOI: 10.1007/s00213-012-2896-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 09/19/2012] [Indexed: 01/02/2023]
Abstract
RATIONALE A major challenge in the pharmacological treatment of psychotic disorders is the effective management of the associated cognitive dysfunctions. Novel concepts emphasize a potential benefit of partial agonists acting upon dopamine D(2)-like receptors in ameliorating these cognitive deficits, and pre-clinical studies suggest that D(3)-receptor-preferring compounds can exert pro-cognitive effects. OBJECTIVE The objective of the study was to use acute phencyclidine (PCP) treatment to model the cognitive deficits of schizophrenia in mice, and to test the efficacy of the novel, dopamine D(3)-receptor-preferring drug cariprazine in ameliorating the severity of PCP-triggered cognitive deficits. METHODS One group of wild-type or D(3)-receptor knockout mice was acutely treated with either saline or phencyclidine (PCP, 1 mg/kg). A separate group of mice was treated with cariprazine prior to PCP administration. Both groups were then tested in three cognitive tasks: social interaction/recognition and recognition memory, spatial working memory, and attention-set-shifting. RESULTS PCP effectively disrupted social recognition and social recognition memory, spatial working memory, and extradimensional attention set-shifting. Cariprazine pretreatment significantly attenuated the emergence of these cognitive deficits in PCP-treated wild-type mice, but not in PCP-treated D(3)-receptor knockout mice. CONCLUSIONS In an animal model of PCP-induced cognitive impairment, cariprazine pretreatment significantly diminished PCP-triggered cognitive deficits, and studies on knockout mice show that dopamine D(3) receptors contribute to this effect.
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Affiliation(s)
- Ross Zimnisky
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - Gloria Chang
- Department of Psychiatry, Columbia University, New York, NY, USA
| | | | - Béla Kiss
- New York State Psychiatric Institute, New York, NY, USA
| | - Nika Adham
- Forest Research Institute, Jersey City, NJ, USA
| | - Claudia Schmauss
- Department of Psychiatry, Columbia University, New York, NY, USA
- New York State Psychiatric Institute, New York, NY, USA
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16
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Caine SB, Thomsen M, Barrett AC, Collins GT, Grundt P, Newman AH, Butler P, Xu M. Cocaine self-administration in dopamine D₃ receptor knockout mice. Exp Clin Psychopharmacol 2012; 20:352-63. [PMID: 22867038 PMCID: PMC3587777 DOI: 10.1037/a0029135] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The dopamine D₃ receptor has received attention over the last two decades as a target for medications development for substance abuse disorders. Results have remained mixed. Despite emergence of more D₃-selective ligands, possible attribution of observed effects to D₂ receptors remains a concern. Knockout mice may help shed light on mechanisms. Here we evaluated the effect of constitutive D₃ receptor inactivation ("knockout") on the reinforcing effects of cocaine. We tested D₃ wild-type (WT), heterozygous (D₃⁺/⁻), and knockout (D₃⁻/⁻), mice in acquisition and maintenance of intravenous self-administration across a broad range of cocaine doses, using a fixed ratio (FR) 1 and a progressive ratio (PR) schedule of reinforcement, along with parallel food-reinforced studies. Generally, D₃⁻/⁻ mice showed cocaine self-administration comparable to WT controls across assays. Moderate and nonsignificant trends toward lesser reinforcing effects of a low cocaine dose (0.32 mg/kg) were apparent in acquisition and PR studies, consistent with the idea that the D₃ receptor may play a subtle role in the reinforcing effects of low cocaine doses under low FR conditions. However, those effects with cocaine self-administration were more subtle than the lower responding of D₃ knockout mice observed with food-maintained behavior. In addition, the D₃ antagonist PG01037 failed to affect cocaine self-administration under an FR 1 schedule in WT mice. The present data do not support a necessary role for the D₃ receptor in the direct reinforcing effects of cocaine.
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Affiliation(s)
- S Barak Caine
- Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, MA 02478, USA.
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17
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Dual control of dopamine synthesis and release by presynaptic and postsynaptic dopamine D2 receptors. J Neurosci 2012; 32:9023-34. [PMID: 22745501 DOI: 10.1523/jneurosci.0918-12.2012] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Dysfunctions of dopaminergic homeostasis leading to either low or high dopamine (DA) levels are causally linked to Parkinson's disease, schizophrenia, and addiction. Major sites of DA synthesis are the mesencephalic neurons originating in the substantia nigra and ventral tegmental area; these structures send major projections to the dorsal striatum (DSt) and nucleus accumbens (NAcc), respectively. DA finely tunes its own synthesis and release by activating DA D2 receptors (D2R). To date, this critical D2R-dependent function was thought to be solely due to activation of D2Rs on dopaminergic neurons (D2 autoreceptors); instead, using site-specific D2R knock-out mice, we uncover that D2 heteroreceptors located on non-DAergic medium spiny neurons participate in the control of DA levels. This D2 heteroreceptor-mediated mechanism is more efficient in the DSt than in NAcc, indicating that D2R signaling differentially regulates mesolimbic- versus nigrostriatal-mediated functions. This study reveals previously unappreciated control of DA signaling, shedding new light on region-specific regulation of DA-mediated effects.
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18
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Xing B, Guo J, Meng X, Wei SG, Li SB. The dopamine D1 but not D3 receptor plays a fundamental role in spatial working memory and BDNF expression in prefrontal cortex of mice. Behav Brain Res 2012; 235:36-41. [PMID: 22776159 DOI: 10.1016/j.bbr.2012.06.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 06/24/2012] [Accepted: 06/30/2012] [Indexed: 01/09/2023]
Abstract
Although dopamine within the prefrontal cortex has been implicated in working memory, how different dopamine receptor subtypes contribute to this process need to be further characterized. Previous studies have suggest the importance of dopamine receptors signaling in regulating the brain-derived neurotrophic factor (BDNF) function that is associated with synaptic plasticity underlying normal memory formation. Changes in BDNF expression through the dopamine receptors within the prefrontal cortex may accompany and mediate the spatial working memory. To test the possibility, dopamine D1 and D3 receptor mutant mice were tested in Morris water maze for spatial working memory. We found that trial-dependent, matching-to-sample, learning of the platform location, an index of short-term spatial working memory in mice, was significantly impaired in D1 receptor knockout mice compared to wild-type mice, and regular performance of D3 receptor mutants was observed in the similar working memory task. BDNF protein was significantly decreased in prefrontal cortex, though not in hippocampus, of the D1 receptor knockout mice, whereas no changes were found in both prefrontal cortex and hippocampus of D3 receptor knockout mice. These data suggest that dopamine D1 but not D3 receptors are critical for prefrontal cortex BDNF expression which may be related to spatial working memory processes.
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Affiliation(s)
- Bo Xing
- Xi'an Mental Health Center, Xi'an, Shaanxi, PR China
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19
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Fernandes AR, Easton AC, De Souza Silva MA, Schumann G, Müller CP, Desrivières S. Lentiviral-mediated gene delivery reveals distinct roles of nucleus accumbens dopamine D2 and D3 receptors in novelty- and light-induced locomotor activity. Eur J Neurosci 2012; 35:1344-53. [DOI: 10.1111/j.1460-9568.2012.08028.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Cuevas S, Zhang Y, Yang Y, Escano C, Asico L, Jones JE, Armando I, Jose PA. Role of renal DJ-1 in the pathogenesis of hypertension associated with increased reactive oxygen species production. Hypertension 2012; 59:446-52. [PMID: 22215708 DOI: 10.1161/hypertensionaha.111.185744] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The D(2) dopamine receptor (D(2)R) is important in the pathogenesis of essential hypertension. We have already reported that systemic deletion of the D(2)R gene in mice results in reactive oxygen species (ROS)-dependent hypertension, suggesting that the D(2)R has antioxidant effects. However, the mechanism of this effect is unknown. DJ-1 is a protein that has antioxidant properties. D(2)R and DJ-1 are expressed in the mouse kidney and colocalize and coimunoprecipitate in mouse renal proximal tubule cells. We hypothesized that D(2)Rs regulate renal ROS production in the kidney through regulation of DJ-1 expression or function. Heterozygous D(2)(+/-) mice have increased blood pressure, urinary 8-isoprostanes, and renal Nox 4 expression, but decreased renal DJ-1 expression. Silencing D(2)R expression in mouse renal proximal tubule cells increases ROS production and decreases the expression of DJ-1. Conversely, treatment of these cells with a D(2)R agonist increases DJ-1 expression and decreases Nox 4 expression and NADPH oxidase activity, effects that are partially blocked by a D(2)R antagonist. Silencing DJ-1 expression in mouse renal proximal tubule cells increases ROS production and Nox 4 expression. Selective renal DJ-1 silencing by the subcapsular infusion of DJ-1 siRNA in mice increases blood pressure, renal Nox4 expression, and NADPH oxidase activity. These results suggest that the inhibitory effects of D(2)R on renal ROS production are at least, in part, mediated by a positive regulation of DJ-1 expression/function and that DJ-1 may have a role in the prevention of hypertension associated with increased ROS production.
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Affiliation(s)
- Santiago Cuevas
- Center for Molecular Physiology Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA.
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21
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Detection of antigen interactions ex vivo by proximity ligation assay: endogenous dopamine D2-adenosine A2A receptor complexes in the striatum. Biotechniques 2011; 51:111-8. [PMID: 21806555 DOI: 10.2144/000113719] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 06/16/2011] [Indexed: 01/31/2023] Open
Abstract
The existence of G protein-coupled receptor (GPCR) dimers and/or oligomers has been demonstrated in heterologous systems using a variety of biochemical and biophysical assays. While these interactions are the subject of intense research because of their potential role in modulating signaling and altering pharmacology, evidence for the existence of receptor interactions in vivo is still elusive because of a lack of appropriate methods to detect them. Here, we adapted and optimized a proximity ligation assay (PLA) for the detection in brain slices of molecular proximity of two antigens located on either the same or two different GPCRs. Using this approach, we were able to confirm the existence of dopamine D2 and adenosine A2A receptor complexes in the striatum of mice ex vivo.
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β-arrestin2 plays permissive roles in the inhibitory activities of RGS9-2 on G protein-coupled receptors by maintaining RGS9-2 in the open conformation. Mol Cell Biol 2011; 31:4887-901. [PMID: 22006018 DOI: 10.1128/mcb.05690-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Together with G protein-coupled receptor (GPCR) kinases (GRKs) and β-arrestins, RGS proteins are the major family of molecules that control the signaling of GPCRs. The expression pattern of one of these RGS family members, RGS9-2, coincides with that of the dopamine D(3) receptor (D(3)R) in the brain, and in vivo studies have shown that RGS9-2 regulates the signaling of D2-like receptors. In this study, β-arrestin2 was found to be required for scaffolding of the intricate interactions among the dishevelled-EGL10-pleckstrin (DEP) domain of RGS9-2, Gβ5, R7-binding protein (R7BP), and D(3)R. The DEP domain of RGS9-2, under the permission of β-arrestin2, inhibited the signaling of D(3)R in collaboration with Gβ5. β-Arrestin2 competed with R7BP and Gβ5 so that RGS9-2 is placed in the cytosolic region in an open conformation which is able to inhibit the signaling of GPCRs. The affinity of the receptor protein for β-arrestin2 was a critical factor that determined the selectivity of RGS9-2 for the receptor it regulates. These results show that β-arrestins function not only as mediators of receptor-G protein uncoupling and initiators of receptor endocytosis but also as scaffolding proteins that control and coordinate the inhibitory effects of RGS proteins on the signaling of certain GPCRs.
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Inta D, Meyer-Lindenberg A, Gass P. Alterations in postnatal neurogenesis and dopamine dysregulation in schizophrenia: a hypothesis. Schizophr Bull 2011; 37:674-80. [PMID: 21097511 PMCID: PMC3122276 DOI: 10.1093/schbul/sbq134] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An increasing number of studies demonstrate the important role of several susceptibility genes for schizophrenia, such as neuregulin-1 and DISC1, in early postnatal and adult neurogenesis. Its significance for the pathophysiology of the disease, including its relation to neurotransmitter systems implicated in schizophrenia (like the dopamine system), remains, however, unknown. Here, we review molecular and cellular components of the dopamine system associated with postnatal neurogenesis and plasticity, both in rodents and in primates, and discuss their possible implication in schizophrenia. We focus mainly on the islands of Calleja, complex aggregations of granule cells in the ventral striatum, generated early postnatally in the subventricular zone. In contrast to the involution of the primate olfactory bulb, the islands of Calleja attain their maximal development in humans, an evolution paralleled by a larger ventral subventricular zone and more connections with other structures, including temporal cortical areas. The islands of Calleja express high levels of neuronal nitric oxide (NO) synthase and D3 dopamine receptors and are densely interconnected by dopaminergic projections with the ventral tegmental area. D3 receptors modulate subventricular zone neurogenesis and dopamine release. Their genetic deletion induces striatal hyperdopaminergia. We review data indicating a high plasticity of postnatal islands of Calleja, potentially facilitating susceptibility to schizophrenia-related risk factors. In this context, we propose a new pathophysiological model, where altered neurogenesis of the islands of Calleja may contribute to dysfunction of the dopamine and NO systems and psychosis through convergence of genetic and environmental disease-associated factors.
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Affiliation(s)
- Dragos Inta
- Department for Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim, University of Heidelberg, Mannheim, Germany.
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Dopamine receptors and Parkinson's disease. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2011; 2011:403039. [PMID: 25954517 PMCID: PMC4411877 DOI: 10.1155/2011/403039] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 03/04/2011] [Accepted: 04/12/2011] [Indexed: 01/03/2023]
Abstract
Parkinson's disease (PD) is a progressive extrapyramidal motor
disorder. Pathologically, this disease is characterized by the selective dopaminergic (DAergic) neuronal degeneration in the substantia nigra. Correcting the DA deficiency in PD with levodopa (L-dopa) significantly attenuates the motor symptoms; however, its effectiveness often declines, and L-dopa-related adverse effects emerge after long-term treatment. Nowadays, DA receptor agonists are useful medication even regarded as first choice to delay the starting of L-dopa therapy. In advanced stage of PD, they are also used as adjunct therapy together with L-dopa. DA receptor agonists act by stimulation of presynaptic and postsynaptic DA receptors. Despite the usefulness, they could be causative drugs for valvulopathy and nonmotor complication such as DA dysregulation syndrome (DDS). In this paper, physiological characteristics of DA receptor familyare discussed. We also discuss the validity, benefits, and specific adverse effects of pharmaceutical DA receptor agonist.
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25
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Papaleo F, Lipska BK, Weinberger DR. Mouse models of genetic effects on cognition: relevance to schizophrenia. Neuropharmacology 2011; 62:1204-20. [PMID: 21557953 DOI: 10.1016/j.neuropharm.2011.04.025] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 04/08/2011] [Accepted: 04/20/2011] [Indexed: 01/27/2023]
Abstract
Cognitive dysfunction is a core feature of schizophrenia. Growing evidence indicates that a wide variety of genetic mutations and polymorphisms impact cognition and may thus be implicated in various aspects of this mental disorder. Despite differences between human and rodent brain structure and function, genetic mouse models have contributed critical information about brain mechanisms involved in cognitive processes. Here, we summarize discoveries of genetic modifications in mice that impact cognition. Based on functional hypotheses, gene modifications within five model systems are described: 1) dopamine (D1, D2, D3, D4, D5, DAT, COMT, MAO); 2) glutamate (GluR-A, NR1, NR2A, NR2B, GRM2, GRM3, GLAST); 3) GABA (α(5), γ(2), α(4), δGABA(A), GABA(B(1)), GAT1); 4) acetylcholine (nAChRβ2, α7, CHRM1); and 5) calcium (CaMKII-α, neurogranin, CaMKKβ, CaMKIV). We also consider other risk-associated genes for schizophrenia such as dysbindin (DTNBP1), neuregulin (NRG1), disrupted-in-schizophrenia1 (DISC1), reelin and proline dehydrogenase (PRODH). Because of the presumed importance of environmental factors, we further consider genetic modifications within the stress-sensitive systems of corticotropin-releasing factor (CRF), brain-derived neurotrophic factor (BDNF) and the endocannabinoid systems. We highlight the missing information and limitations of cognitive assays in genetically modified mice models relevant to schizophrenia pathology.
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Affiliation(s)
- Francesco Papaleo
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy.
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26
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Klinker F, Hasan K, Dowling P, Paulus W, Liebetanz D. Dopamine D(3) receptor deficiency sensitizes mice to iron deficiency-related deficits in motor learning. Behav Brain Res 2011; 220:358-61. [PMID: 21354213 DOI: 10.1016/j.bbr.2011.02.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/21/2011] [Accepted: 02/16/2011] [Indexed: 12/26/2022]
Abstract
Iron deficiency is a widespread form of malnutrition and is known to interfere with cognitive performance and development. To elucidate the role of dopamine D3 and iron deficiency (ID) in inducing cognitive deficits, we studied wildtype and D3 knockout mice on normal or iron-deficient diets subjected to a running wheel-based motor skill sequence. Surprisingly, ID alone had no effect on motor learning in this study, whereas combined ID and dopamine D(3) receptor (D3R)-deficiency significantly interfered with the acquisition of motor skills. Reduced D3R function may serve as a predisposing factor towards ID-related effects on motor learning.
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Affiliation(s)
- F Klinker
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Georg August University, Robert-Koch-Strasse 40, Göttingen, Germany.
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27
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Zhang Y, Fu C, Ren H, He D, Wang X, Asico LD, Jose PA, Zeng C. Impaired stimulatory effect of ETB receptor on D₃ receptor in immortalized renal proximal tubule cells of spontaneously hypertensive rats. Kidney Blood Press Res 2011; 34:75-82. [PMID: 21228598 DOI: 10.1159/000323135] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 11/23/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Activation of renal D₃ receptor induces natriuresis and diuresis in Wistar-Kyoto (WKY) rats; in the presence of ETB receptor antagonist, the natriuretic effect of D₃ receptor in WKY rats is reduced. We hypothesize that ETB receptor activation may regulate D₃ receptor expression in renal proximal tubule (RPT) cells from WKY rats, which is impaired in RPT cells from spontaneously hypertensive rats (SHRs). METHODS D₃ receptor expression was determined by immunoblotting; the D₃/ETB receptor linkage was checked by coimmunoprecipitation; Na(+)-K(+)-ATPase activity was determined as the rate of inorganic phosphate released in the presence or absence of ouabain. RESULTS In RPT cells from WKY rats, the ETB receptor agonist BQ3020 increased D₃ receptor protein. In contrast, in RPT cells from SHRs, BQ3020 did not increase D₃ receptor. There was coimmunoprecipitation between D₃ and ETB receptors in RPT cells from WKY and SHRs. Activation of ETB receptor increased D₃/ETB coimmunoprecipitation in RPT cells from WKY rats, but not from SHRs. The basal levels of D₃/ETB receptor coimmunoprecipitation were greater in RPT cells from WKY rats than in those from SHRs. Stimulation of D₃ receptor inhibited Na(+)-K(+)-ATPase activity, which was augmented by the pretreatment with the ETB receptor agonist BQ3020 in WKY RPT cells, but not in SHR RPT cells. CONCLUSION ETB receptors regulate and physically interact with D₃ receptors differently in WKY rats and SHRs. The impaired natriuretic effect in SHRs may be, in part, related to impaired ETB and D₃ receptor interactions.
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Affiliation(s)
- Ye Zhang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
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28
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Current perspectives on the selective regulation of dopamine D2 and D3 receptors. Arch Pharm Res 2010; 33:1521-38. [DOI: 10.1007/s12272-010-1005-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 08/20/2010] [Accepted: 08/20/2010] [Indexed: 01/07/2023]
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29
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van den Buuse M. Modeling the positive symptoms of schizophrenia in genetically modified mice: pharmacology and methodology aspects. Schizophr Bull 2010; 36:246-70. [PMID: 19900963 PMCID: PMC2833124 DOI: 10.1093/schbul/sbp132] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, there have been huge advances in the use of genetically modified mice to study pathophysiological mechanisms involved in schizophrenia. This has allowed rapid progress in our understanding of the role of several proposed gene mechanisms in schizophrenia, and yet this research has also revealed how much still remains unresolved. Behavioral studies in genetically modified mice are reviewed with special emphasis on modeling psychotic-like behavior. I will particularly focus on observations on locomotor hyperactivity and disruptions of prepulse inhibition (PPI). Recommendations are included to address pharmacological and methodological aspects in future studies. Mouse models of dopaminergic and glutamatergic dysfunction are then discussed, reflecting the most important and widely studied neurotransmitter systems in schizophrenia. Subsequently, psychosis-like behavior in mice with modifications in the most widely studied schizophrenia susceptibility genes is reviewed. Taken together, the available studies reveal a wealth of available data which have already provided crucial new insight and mechanistic clues which could lead to new treatments or even prevention strategies for schizophrenia.
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Affiliation(s)
- Maarten van den Buuse
- Mental Health Research Institute of Victoria, Parkville, Melbourne, Victoria 3052, Australia.
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Yarkov AV, Der TC, Joyce JN. Locomotor activity induced by MK-801 is enhanced in dopamine D3 receptor knockout mice but suppression by dopamine D3/D2 antagonists does not occur through the dopamine D3 receptor. Eur J Pharmacol 2010; 627:167-72. [DOI: 10.1016/j.ejphar.2009.10.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2009] [Revised: 09/21/2009] [Accepted: 10/14/2009] [Indexed: 11/28/2022]
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31
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Iarkov AV, Der TC, Joyce JN. Age-related differences in MK-801 induced behaviors in dopamine D3 receptor knock out mice. Eur J Pharmacol 2010; 627:177-84. [DOI: 10.1016/j.ejphar.2009.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 10/16/2009] [Accepted: 11/03/2009] [Indexed: 11/16/2022]
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32
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De Steno DA, Schmauss C. A role for dopamine D2 receptors in reversal learning. Neuroscience 2009; 162:118-27. [PMID: 19401217 DOI: 10.1016/j.neuroscience.2009.04.052] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 04/08/2009] [Accepted: 04/20/2009] [Indexed: 11/15/2022]
Abstract
Reversal learning has been shown to require intact serotonergic innervation of the forebrain neocortex. Whether dopamine acting through D2 receptors plays a complementary role in this anatomic area is still unclear. Here we show that mice lacking dopamine D2 receptors exhibited significantly impaired performance in the reversal learning phase of an attention-set-shifting task (ASST) and that wild type mice treated chronically with the D2-like receptor antagonist haloperidol exhibited the same cognitive deficit. The test-phase-specific deficits of D2 mutants and haloperidol-treated mice were also accompanied by deficits in the induction of expression of early growth response gene 2 (egr-2), a regulatory transcription factor previously shown to be selectively induced in the ventrolateral orbital frontal cortex and the pre- and infralimbic medial prefrontal cortex of ASST-tested mice. D2-receptor knockout mice and haloperidol-treated wild type, however, exhibited lower egr-2 expression in these anatomic regions after completion of an ASST-test phase that required reversal learning but not after completion of set-shifting phases without rule reversals. In contrast, mice treated chronically with clozapine, an atypical neuroleptic drug with lower D2-receptor affinity and broader pharmacological effects, had deficits in compound discrimination phases of the ASST, but also these deficits were accompanied by lower egr-2 expression in the same anatomic subregions. Thus, the findings indicate that egr-2 expression is a sensitive indicator of test-phase-specific performance in the ASST and that normal function of D2 receptors in subregions of the orbital frontal and the medial prefrontal cortex is required for cognitive flexibility in tests involving rule reversals.
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Affiliation(s)
- D A De Steno
- Department of Pharmacology, Columbia University, New York, NY 10032, USA
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Harrison SJ, Nobrega JN. Differential susceptibility to ethanol and amphetamine sensitization in dopamine D3 receptor-deficient mice. Psychopharmacology (Berl) 2009; 204:49-59. [PMID: 19096829 DOI: 10.1007/s00213-008-1435-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 12/02/2008] [Indexed: 11/30/2022]
Abstract
RATIONALE Dopamine D3 receptors (D3Rs) have been implicated in behavioral sensitization to various drugs of abuse, but their role in ethanol (EtOH) sensitization has not been directly examined. We used D3R knockout (D3 KO) mice to examine whether the D3R plays a permissive role in EtOH and amphetamine (AMPH) sensitization. We also investigated whether EtOH sensitization is accompanied by alterations in D3R mRNA expression or binding. MATERIALS AND METHODS After comparing EtOH sensitization in C57Bl/6 mice and DBA/2 mice, D3 KO, wild type (WT), and for comparison, D1 and D2 KOs received five biweekly injections of EtOH (2.2 g/kg, i.p.) or saline. Another group of D3 KOs and WT controls received six times AMPH (1.5 mg/kg, i.p.). D3R mRNA and binding were measured in EtOH-sensitized DBA/2 mice with in situ hybridization and [(125)I]-7-OH-PIPAT autoradiography, respectively. RESULTS C57Bl/6 mice expressed EtOH sensitization albeit to a lesser extent than DBA/2 mice. Compared to WT mice, D3 KOs were resistant to EtOH sensitization. The behavioral profile of D3 KOs was more similar to D1 KOs than D2 KOs, which also failed to develop EtOH sensitization. However, D3 KOs developed AMPH sensitization normally. EtOH sensitization was not accompanied by changes in either D3R mRNA or D3R binding in the islands of Calleja, nucleus accumbens, dorsal striatum, or cerebellum. CONCLUSIONS These results suggest a necessary role for the D3R in EtOH but not AMPH sensitization, possibly through postreceptor intracellular mechanisms. Results also suggest that different neurochemical mechanisms underlie sensitization to different drugs of abuse.
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De Mei C, Ramos M, Iitaka C, Borrelli E. Getting specialized: presynaptic and postsynaptic dopamine D2 receptors. Curr Opin Pharmacol 2009. [PMID: 19138563 DOI: 10.1016/j.coph.2008.12.002.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dopamine (DA) signaling controls many physiological functions ranging from locomotion to hormone secretion, and plays a critical role in addiction. DA elevation, for instance in response to drugs of abuse, simultaneously activates neurons expressing different DA receptors; how responses from diverse neurons/receptors are orchestrated in the generation of behavioral and cellular outcomes, is still not completely defined. Signaling from D2 receptors (D2Rs) is a good example to illustrate this complexity. D2Rs have presynaptic and postsynaptic localization and functions, which are shared by two isoforms in vivo. Recent results from knockout mice are clarifying the role of site and D2 isoform-specific effects thereby increasing our understanding of how DA modulates neuronal physiology.
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Affiliation(s)
- Claudia De Mei
- University of California Irvine, Department of Microbiology and Molecular Genetics, 3113 Gillespie NRF, Irvine, CA 92617 USA
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35
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De Mei C, Ramos M, Iitaka C, Borrelli E. Getting specialized: presynaptic and postsynaptic dopamine D2 receptors. Curr Opin Pharmacol 2009; 9:53-8. [PMID: 19138563 DOI: 10.1016/j.coph.2008.12.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 11/21/2008] [Accepted: 12/01/2008] [Indexed: 11/25/2022]
Abstract
Dopamine (DA) signaling controls many physiological functions ranging from locomotion to hormone secretion, and plays a critical role in addiction. DA elevation, for instance in response to drugs of abuse, simultaneously activates neurons expressing different DA receptors; how responses from diverse neurons/receptors are orchestrated in the generation of behavioral and cellular outcomes, is still not completely defined. Signaling from D2 receptors (D2Rs) is a good example to illustrate this complexity. D2Rs have presynaptic and postsynaptic localization and functions, which are shared by two isoforms in vivo. Recent results from knockout mice are clarifying the role of site and D2 isoform-specific effects thereby increasing our understanding of how DA modulates neuronal physiology.
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Affiliation(s)
- Claudia De Mei
- University of California Irvine, Department of Microbiology and Molecular Genetics, 3113 Gillespie NRF, Irvine, CA 92617 USA
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36
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Zhu H, Clemens S, Sawchuk M, Hochman S. Unaltered D1, D2, D4, and D5 dopamine receptor mRNA expression and distribution in the spinal cord of the D3 receptor knockout mouse. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2008; 194:957-62. [PMID: 18797877 DOI: 10.1007/s00359-008-0368-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 09/02/2008] [Accepted: 09/03/2008] [Indexed: 01/24/2023]
Abstract
Dopamine (DA) acts through five receptor subtypes (D1-D5). We compared expression levels and distribution patterns of all DA mRNA receptors in the spinal cord of wild-type (WT) and loss of function D3 receptor knockout (D3KO) animals. D3 mRNA expression was increased in D3KO, but no D3 receptor protein was associated with cell membranes, supporting the previously reported lack of function. In contrast, mRNA expression levels and distribution patterns of D1, D2, D4, and D5 receptors were similar between WT and D3KO animals. We conclude that D3KO spinal neurons do not compensate for the loss of function of the D3 receptor with changes in the other DA receptor subtypes. This supports use of D3KO animals as a model to provide insight into D3 receptor dysfunction in the spinal cord.
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Affiliation(s)
- Hong Zhu
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
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37
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Léna I, Bradshaw S, Pintar J, Kitchen I. Adaptive changes in the expression of central opioid receptors in mice lacking the dopamine D2 receptor gene. Neuroscience 2008; 153:773-88. [DOI: 10.1016/j.neuroscience.2008.02.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 02/22/2008] [Accepted: 02/23/2008] [Indexed: 10/22/2022]
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Abstract
Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport, vascular smooth muscle contractility and production of reactive oxygen species and by interacting with the renin–angiotensin and sympathetic nervous systems. Dopamine receptors are classified into D1-like (D1 and D5) and D2-like (D2, D3 and D4) subtypes based on their structure and pharmacology. Each of the dopamine receptor subtypes participates in the regulation of blood pressure by mechanisms specific for the subtype. Some receptors regulate blood pressure by influencing the central and/or peripheral nervous system; others influence epithelial transport and regulate the secretion and receptors of several humoral agents. This review summarizes the physiology of the different dopamine receptors in the regulation of blood pressure, and the relationship between dopamine receptor subtypes and hypertension.
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MESH Headings
- Blood Pressure/physiology
- Dopamine/metabolism
- Gastrointestinal Tract/metabolism
- Gastrointestinal Tract/physiopathology
- Humans
- Hypertension/metabolism
- Hypertension/physiopathology
- Kidney/metabolism
- Kidney/physiopathology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Receptors, Dopamine/metabolism
- Receptors, Dopamine/physiology
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3/metabolism
- Receptors, Dopamine D3/physiology
- Receptors, Dopamine D4/metabolism
- Receptors, Dopamine D4/physiology
- Receptors, Dopamine D5/metabolism
- Receptors, Dopamine D5/physiology
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City, People's Republic of China.
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39
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Mizuno T, Schmauss C, Rayport S. Distinct roles of presynaptic dopamine receptors in the differential modulation of the intrinsic synapses of medium-spiny neurons in the nucleus accumbens. BMC Neurosci 2007; 8:8. [PMID: 17239247 PMCID: PMC1783657 DOI: 10.1186/1471-2202-8-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Accepted: 01/19/2007] [Indexed: 11/21/2022] Open
Abstract
Background In both schizophrenia and addiction, pathological changes in dopamine release appear to induce alterations in the circuitry of the nucleus accumbens that affect coordinated thought and motivation. Dopamine acts principally on medium-spiny GABA neurons, which comprise 95% of accumbens neurons and give rise to the majority of inhibitory synapses in the nucleus. To examine dopamine action at single medium-spiny neuron synapses, we imaged Ca2+ levels in their presynaptic varicosities in the acute brain slice using two-photon microscopy. Results Presynaptic Ca2+ rises were differentially modulated by dopamine. The D1/D5 selective agonist SKF81297 was exclusively facilitatory. The D2/D3 selective agonist quinpirole was predominantly inhibitory, but in some instances it was facilitatory. Studies using D2 and D3 receptor knockout mice revealed that quinpirole inhibition was either D2 or D3 receptor-mediated, while facilitation was mainly D3 receptor-mediated. Subsets of varicosities responded to both D1 and D2 agonists, showing that there was significant co-expression of these receptor families in single medium-spiny neurons. Neighboring presynaptic varicosities showed strikingly heterogeneous responses to DA agonists, suggesting that DA receptors may be differentially trafficked to individual varicosities on the same medium-spiny neuron axon. Conclusion Dopamine receptors are present on the presynaptic varicosities of medium-spiny neurons, where they potently control GABAergic synaptic transmission. While there is significant coexpression of D1 and D2 family dopamine receptors in individual neurons, at the subcellular level, these receptors appear to be heterogeneously distributed, potentially explaining the considerable controversy regarding dopamine action in the striatum, and in particular the degree of dopamine receptor segregation on these neurons. Assuming that post-receptor signaling is restricted to the microdomains of medium-spiny neuron varicosities, the heterogeneous distribution of dopamine receptors on individual varicosities is likely to encode patterns in striatal information processing.
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Affiliation(s)
- Takeo Mizuno
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
- Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
| | - Claudia Schmauss
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
- Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
| | - Stephen Rayport
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
- Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 62, New York, NY 10032, USA
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40
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Chen PC, Lao CL, Chen JC. Dual alteration of limbic dopamine D1receptor-mediated signalling and the Akt/GSK3 pathway in dopamine D3receptor mutants during the development of methamphetamine sensitization. J Neurochem 2007; 100:225-41. [PMID: 17101033 DOI: 10.1111/j.1471-4159.2006.04203.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The central dopamine system plays significant roles in motor activity and drug-induced behavioural sensitization. Our goal was to determine the significance of dopamine D(3) receptors in the development of behavioural sensitization to methamphetamine, assessed with D(3) receptor mutant mice. The absence of D(3) receptors significantly increased the behavioural responses to acute methamphetamine and evoked a faster rate of behavioural sensitization to chronic methamphetamine. In addition, both D(3) receptor protein and mRNA levels in the limbic forebrain decreased in sensitized wild-type mice. Further analyses indicated that D(1)-dependent behavioural sensitization and the number of limbic D(1) receptors increased in sensitized D(3) mutants as compared with sensitized wild-type mice. Consistent with this finding, we observed higher levels of D(1) receptor-evoked cAMP accumulation and basal phosphoDARPP-32/Thr34 in the limbic forebrain of D(3) mutants than wild-type mice and the difference was more pronounced after chronic methamphetamine treatment. We also observed an increase in phospho-extracellular signal-regulated kinase 2 but a decrease in phosphoAkt/Ser473 and phosphoglycogen synthase kinase 3 (GSK3)-alpha/beta in the limbic forebrain of D(3) mutants compared with wild-type mice after methamphetamine treatment. The convergent results implicate D(3) receptors as a negative regulator of the development of methamphetamine sensitization. A compensatory up-regulation of D(1) receptor-mediated signals, in addition to an altered Akt/GSK3 pathway, could contribute to the accelerated development of behavioural sensitization.
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Affiliation(s)
- Pei-Chun Chen
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, Chang-Gung University, Kwei-Shan, Tao-Yuan, Taiwan
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41
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McNamara RK, Logue A, Stanford K, Xu M, Zhang J, Richtand NM. Dose-response analysis of locomotor activity and stereotypy in dopamine D3 receptor mutant mice following acute amphetamine. Synapse 2006; 60:399-405. [PMID: 16856172 PMCID: PMC1815379 DOI: 10.1002/syn.20315] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Accumulating evidence suggests that dopamine D3 receptor (D3R) stimulation is inhibitory to spontaneous and psychostimulant-induced locomotion through opposition of concurrent D1R and D2R-mediated signaling. To evaluate this model, we used homozygous D3R mutant mice and wild-type controls to investigate the role of the D3R in locomotor activity and stereotypy stimulated by acute amphetamine (AMPH) (0.2, 2.5, 5.0, 10.0 mg/kg). At the lowest dose tested (0.2 mg/kg), neither D3R mutant mice nor wild-type mice exhibited measurable change in locomotor activity or stereotypy relative to their respective saline-treated controls. D3R mutant mice exhibited a significantly greater increase in locomotor activity, but not stereotypy, relative to wild-type mice in response to treatment with AMPH 2.5 mg/kg. AMPH-induced locomotor activity and stereotypy were similar in both wild-type and D3R mutant mice at both the 5.0 and 10 mg/kg AMPH doses. These findings provide further support for an inhibitory role for the D3R in AMPH-induced locomotor activity, and demonstrate a more limited role for the D3R in modulating AMPH-induced stereotypy.
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Affiliation(s)
- Robert K McNamara
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
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42
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Leonard SK, Ferry-Leeper P, Mailman RB. Low affinity binding of the classical D1 antagonist SCH23390 in rodent brain: potential interaction with A2A and D2-like receptors. Brain Res 2006; 1117:25-37. [PMID: 16962565 PMCID: PMC1945230 DOI: 10.1016/j.brainres.2006.08.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 08/04/2006] [Indexed: 11/19/2022]
Abstract
Whereas structurally dissimilar D(1) antagonists competing for [(3)H]-SCH23390 binding recognize primarily one site in striatum, two distinct affinity states are observed in both amygdala and hippocampus. The binding profile of SCH23390 is similar in both of these regions, with the high affinity site (K(D) approximately 0.4 nM) consistent with D(1)/D(5) receptors. The appearance of the low affinity site (K(D) approximately 300 nM) is dependent upon the absence of MgCl(2), but independent of D(1) expression (i.e., still present in D(1) knockout mice). Although the density of high affinity state receptor is lower in hippocampus or amygdala of D(1) knockout mice, some residual binding remains, consistent with the known expression of D(5) receptors in these regions. Remarkably, in hippocampus, the affinity of the low affinity site is shifted rightward in the presence of the D(2) antagonist domperidone and is largely absent in the hippocampus of D(2) knockout animals. Additionally, this site is also shifted rightward in the presence of the A(2A) ligands SCH58261, CSC, or NECA, or in the absence of A(2A) receptors. The affinity of SCH23390 for this low affinity site is greater than seen for SCH23390 binding to D(2) receptors in heterologous expression systems, consistent with the hypothesis that both D(2) and A(2A) receptors are involved in the low affinity binding site. Therefore, we suggest that the heteromerization of D(2) and A(2A) receptors reported previously in vitro also may occur in the brain of both rats and mice.
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MESH Headings
- Adenosine/metabolism
- Animals
- Benzazepines/metabolism
- Benzazepines/pharmacology
- Binding Sites/drug effects
- Binding Sites/genetics
- Binding, Competitive/drug effects
- Binding, Competitive/genetics
- Brain/anatomy & histology
- Brain/drug effects
- Brain/metabolism
- Domperidone/pharmacology
- Dopamine/metabolism
- Dopamine/pharmacology
- Dopamine Antagonists/metabolism
- Dopamine Antagonists/pharmacology
- Female
- HeLa Cells
- Humans
- Magnesium Chloride/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Radioligand Assay
- Rats
- Receptor Aggregation/drug effects
- Receptor Aggregation/genetics
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2A/genetics
- Receptor, Adenosine A2A/metabolism
- Receptors, Dopamine D1/drug effects
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/drug effects
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/metabolism
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Affiliation(s)
| | | | - Richard B. Mailman
- * Corresponding author. Fax: +1 919 966 9604. E-mail address: (R.B. Mailman)
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43
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Abstract
Voluntary movement in animals is modulated by a number of subcortical systems. One of these resides in the basal nuclei and their associated projections and utilizes dopamine as a neurotransmitter. Apart from regulating movement, the dopaminergic axis is also involved in the control of goal-oriented behavior, cognition, and mood. Disorders of this system result in common human neurologic disorders such as Parkinson's and Huntington's diseases, as well contributing to a host of behavioral conditions, such as schizophrenia, attention deficit hyperactivity disorder, and addiction. Many individual mouse models of human dopaminergic dysfunction have been described in varying degrees of detail. However, when evaluating this region of the brain, the veterinary pathologist is confronted by a paucity of information summarizing the comparative aspects of the anatomy, physiology, and pathology of the central dopaminergic system. In this review, a systematic approach to anatomic phenotyping of the central dopaminergic system in the mouse is described and illustrated using tyrosine hydroxylase immunohistochemistry. Differences between murine neuroanatomy and comparable regions of the nonhuman primate brain are highlighted. Although the mouse is the focus of this review, conditions in domestic animals characterized by lesions within the basal nuclei and its projections are also briefly described. Murine behavioral and motor tests that accompany abnormalities of specific anatomic regions of the dopaminergic axis are summarized. Finally, we review mouse models of Parkinson's and Huntington's diseases, as well as those genetically altered mice that elucidate aspects of dopamine metabolism and receptor function.
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Affiliation(s)
- C J Zeiss
- Comparative Medicine, Yale University School of Medicine, 375 Congress Avenue, New Haven, CT 06437, USA.
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44
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Li ZS, Schmauss C, Cuenca A, Ratcliffe E, Gershon MD. Physiological modulation of intestinal motility by enteric dopaminergic neurons and the D2 receptor: analysis of dopamine receptor expression, location, development, and function in wild-type and knock-out mice. J Neurosci 2006; 26:2798-807. [PMID: 16525059 PMCID: PMC6675162 DOI: 10.1523/jneurosci.4720-05.2006] [Citation(s) in RCA: 196] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dopaminergic neurons are present in both plexuses of the murine bowel and are upregulated after extrinsic denervation but play unknown roles in enteric nervous system (ENS) physiology. Transcripts encoding dopamine (DA) receptors D1-D5 were analyzed by reverse transcription-PCR in stomach approximately duodenum approximately ileum approximately proximal > > distal colon. Dissected muscle and myenteric plexus contained transcripts encoding D1-D3 and D5, whereas mucosa contained D1 and D3-D5. D1-D5 expression began in fetal gut [embryonic day 10 (E10)], before the appearance of neurons (E12), and was sustained without developmental regulation through postnatal day 1. In situ hybridization revealed that subsets of submucosal and myenteric neurons contained mRNA encoding D2 or D3. Immunoblots confirmed that D1, D2, and D5 receptor proteins were present from stomach through distal colon. Subsets of submucosal and myenteric neurons were also D1, D2, or D3 immunoreactive. When double labeled by in situ hybridization, these neurons contained mRNA encoding the respective receptors. Total gastrointestinal transit time (TGTT) and colonic transit time (CTT) were measured in mice lacking D2, D3, or D2 plus D3. Both TGTT and CTT were decreased significantly (motility increased) in D2 and D2 plus D3, but not D3, knock-out animals. Mice lacking D2 and D2 plus D3 but not D3 were smaller than wild-type littermates, yet ate significantly more and had greater stool frequency, water content, and mass. Because motility is abnormal when D2 is absent, the net inhibitory DA effect on motility is physiologically significant. The early expression of DA receptors is also consistent with the possibility that DA affects ENS development.
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MESH Headings
- Analysis of Variance
- Animals
- Animals, Newborn
- Blotting, Western/methods
- Dopamine/metabolism
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Drinking/genetics
- Eating/genetics
- Embryo, Mammalian
- Gastrointestinal Motility/genetics
- Gastrointestinal Motility/physiology
- Gastrointestinal Tract/cytology
- Gastrointestinal Tract/growth & development
- Gene Expression/physiology
- Gene Expression Regulation, Developmental/genetics
- Immunoprecipitation/methods
- In Situ Hybridization/methods
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neurons/metabolism
- RNA, Messenger/biosynthesis
- Receptors, Dopamine D2/deficiency
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D3/deficiency
- Receptors, Dopamine D3/genetics
- Receptors, Dopamine D3/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Time Factors
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Affiliation(s)
- Zhi Shan Li
- Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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45
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Job MO, Ramachandra V, Anders S, Low MJ, Gonzales RA. Reduced basal and ethanol stimulation of striatal extracellular dopamine concentrations in dopamine D2 receptor knockout mice. Synapse 2006; 60:158-64. [PMID: 16715495 DOI: 10.1002/syn.20283] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The present study was undertaken to examine the role of the dopamine (DA) D2 receptor in the ethanol-evoked DA response in the ventral striatum. We performed microdialysis experiments using the D2 null mutant and wild-type controls and measured the effect of an intraperitoneal (i.p.) injection of either saline or ethanol (2 g/kg) on dialysate DA concentrations in the ventral striatum. Dialysate ethanol concentrations were also determined in the samples from the ventral striatum. In addition, the effects of quinpirole, a D2/D3 agonist, were examined in both the ventral and dorsal striatum. Basal dialysate concentrations of DA were significantly reduced in both the ventral and dorsal striatum of the D2 knockouts compared with wild-type controls. Ethanol administration significantly enhanced ventral striatal DA in both groups, but the increase in dialysate DA concentration was 3.5-fold higher in the wild-type controls. The time course of dialysate ethanol concentrations was similar in the two groups. Saline injection did not alter DA concentrations in either the ventral or dorsal striatum. However, quinpirole (0.3 mg/kg) administration significantly depressed striatal dialysate DA concentrations in the wild-type mice, but not in the D2 knockouts. The results suggest that the D2 receptor is necessary for normal development and regulation of striatal extracellular DA concentrations, but the mechanism for this alteration is unclear. In addition, the blunted ethanol-evoked DA response in the D2 knockouts may contribute, in part, to some of the behavioral deficits previously observed in response to ethanol.
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Affiliation(s)
- Martin O Job
- The University of Texas at Austin, PHAR-Pharmacology, Austin, Texas 78712, USA
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46
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Waddington JL, O'Tuathaigh C, O'Sullivan G, Tomiyama K, Koshikawa N, Croke DT. Phenotypic studies on dopamine receptor subtype and associated signal transduction mutants: insights and challenges from 10 years at the psychopharmacology-molecular biology interface. Psychopharmacology (Berl) 2005; 181:611-38. [PMID: 16041535 DOI: 10.1007/s00213-005-0058-8] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 04/27/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Mutants with targeted gene deletion ('knockout') or insertion (transgenic) of D1, D2, D3, D4 and D5 dopamine (DA) receptor subtypes are complemented by an increasing variety of double knockout and transgenic-'knockout' models, together with knockout of critical components of DA receptor signalling cascades such as G alpha(olf)[G gamma7], adenylyl cyclase type 5, PKA [RIIbeta] and DARPP-32. However, it is increasingly recognised that these molecular techniques have a number of inherent limitations. Furthermore, there are poorly understood methodological factors that contribute to inconsistent phenotypic findings between laboratories. OBJECTIVE This review seeks to document the impact of DA receptor subtype and related transduction mutants on our understanding of the behavioural roles of these entities, primarily at the level of unconditioned psychomotor behaviour. METHODS It includes ethologically based and orofacial movement studies in our own laboratories, since these are the only studies to systematically compare each of the D1, D2, D3, D4 and D5 receptor and DARPP-32 signal transduction 'knockouts'. DISCUSSION There is a particular emphasis on identifying methodological factors that might influence phenotypic effects and account for inconsistencies. The findings are offered empirically to (1) specify the extent of phenotypic diversity among individual DA receptor subtypes and transduction components and (2) indicate relationships between D1, D2, D3, D4 and D5 receptor subtype proteins, associated G alpha(i)/G alpha(s)/G alpha(olf)[G gamma7]-adenylyl cyclase type 5-PKA [RIIbeta]-DARPP-32 signalling cascades and behaviour. The findings are also offered heuristically as a base for such phenotypic comparisons at additional levels of behaviour so that a yet more complete phenotypic profile might emerge.
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Affiliation(s)
- John L Waddington
- Institute of Biopharmaceutical Sciences, Royal College of Surgeons in Ireland, St. Stephen's Green, Dublin 2, Ireland.
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47
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Zeng C, Hopfer U, Asico LD, Eisner GM, Felder RA, Jose PA. Altered AT
1
Receptor Regulation of ETB Receptors in Renal Proximal Tubule Cells of Spontaneously Hypertensive Rats. Hypertension 2005; 46:926-31. [PMID: 16144989 DOI: 10.1161/01.hyp.0000174595.41637.13] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The renin-angiotensin and endothelin systems regulate blood pressure, in part, by affecting renal tubular sodium transport. In rodents, ETB receptors decrease proximal tubular reabsorption, whereas AT
1
receptors produce the opposite effect. We hypothesize that ETB and AT
1
receptors interact at the receptor level, and that the interaction is altered in spontaneously hypertensive rats (SHRs). In immortalized renal proximal tubule (RPT) cells from Wistar-Kyoto (WKY) rats, angiotensin II, via AT
1
receptors, increased ETB receptor protein in a time- and concentration-dependent manner. In contrast, in SHR RPT cells, angiotensin II (10
−8
M/24 hours) had no effect on ETB receptor protein. AT
1
/ETB receptors colocalized and co-immunoprecipitated in both rat strains but long-term angiotensin II (10
−8
M/24 hours) treatment increased AT
1
/ETB co-immunoprecipitation in WKY but not in SHR cells. Short-term angiotensin II (10
−8
M/15 minutes) treatment decreased ETB receptor phosphorylation in both WKY and SHR cells, and increased ETB receptors in RPT cell surface membranes of RPT cells in WKY but not SHRs. Basal cell surface membrane ETB receptor expression was also higher in WKY than in SHRs. We conclude that AT
1
receptors regulate ETB receptors by receptor interaction and modulation of receptor expression. The altered AT
1
receptor regulation of ETB receptors in SHRs may play a role in the pathogenesis of hypertension.
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, PR China.
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48
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Clemens S, Hochman S. Conversion of the modulatory actions of dopamine on spinal reflexes from depression to facilitation in D3 receptor knock-out mice. J Neurosci 2005; 24:11337-45. [PMID: 15601940 PMCID: PMC2731231 DOI: 10.1523/jneurosci.3698-04.2004] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Descending monoaminergic systems modulate spinal cord function, yet spinal dopaminergic actions are poorly understood. Using the in vitro lumbar cord, we studied the effects of dopamine and D2-like receptor ligands on spinal reflexes in wild-type (WT) and D3-receptor knock-out mice (D3KO). Low dopamine levels (1 microM) decreased the monosynaptic "stretch" reflex (MSR) amplitude in WT animals and increased it in D3KO animals. Higher dopamine concentrations (10-100 microM) decreased MSR amplitudes in both groups, but always more strongly in WT. Like low dopamine, the D3 receptor agonists pergolide and PD 128907 reduced MSR amplitude in WT but not D3KO mice. Conversely, D3 receptor antagonists (GR 103691 and nafadotride) increased the MSR in WT but not in D3KO mice. In comparison, D2-preferring agonists bromocriptine and quinpirole depressed the MSR in both groups. Low dopamine (1-5 microM) also depressed longer-latency (presumably polysynaptic) reflexes in WT but facilitated responses in D3KO mice. Additionally, in some experiments (e.g., during 10 microM dopamine or pergolide in WT), polysynaptic reflexes were facilitated in parallel to MSR depression, demonstrating differential modulatory control of these reflex circuits. Thus, low dopamine activates D3 receptors to limit reflex excitability. Moreover, in D3 ligand-insensitive mice, excitatory actions are unmasked, functionally converting the modulatory action of dopamine from depression to facilitation. Restless legs syndrome (RLS) is a CNS disorder involving abnormal limb sensations. Because RLS symptoms peak at night when dopamine levels are lowest, are relieved by D3 agonists, and likely involve increased reflex excitability, the D3KO mouse putatively explains how impaired D3 activity could contribute to this sleep disorder.
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Affiliation(s)
- Stefan Clemens
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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49
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Goldberg MS, Pisani A, Haburcak M, Vortherms TA, Kitada T, Costa C, Tong Y, Martella G, Tscherter A, Martins A, Bernardi G, Roth BL, Pothos EN, Calabresi P, Shen J. Nigrostriatal dopaminergic deficits and hypokinesia caused by inactivation of the familial Parkinsonism-linked gene DJ-1. Neuron 2005; 45:489-96. [PMID: 15721235 DOI: 10.1016/j.neuron.2005.01.041] [Citation(s) in RCA: 382] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 01/05/2005] [Accepted: 01/26/2005] [Indexed: 11/16/2022]
Abstract
The manifestations of Parkinson's disease are caused by reduced dopaminergic innervation of the striatum. Loss-of-function mutations in the DJ-1 gene cause early-onset familial parkinsonism. To investigate a possible role for DJ-1 in the dopaminergic system, we generated a mouse model bearing a germline disruption of DJ-1. Although DJ-1(-/-) mice had normal numbers of dopaminergic neurons in the substantia nigra, evoked dopamine overflow in the striatum was markedly reduced, primarily as a result of increased reuptake. Nigral neurons lacking DJ-1 were less sensitive to the inhibitory effects of D2 autoreceptor stimulation. Corticostriatal long-term potentiation was normal in medium spiny neurons of DJ-1(-/-) mice, but long-term depression (LTD) was absent. The LTD deficit was reversed by treatment with D2 but not D1 receptor agonists. Furthermore, DJ-1(-/-) mice displayed hypoactivity in the open field. Collectively, our findings suggest an essential role for DJ-1 in dopaminergic physiology and D2 receptor-mediated functions.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Age Factors
- Animals
- Behavior, Animal
- Blotting, Southern/methods
- Blotting, Western/methods
- Cell Count
- Cerebral Cortex/cytology
- Cerebral Cortex/physiology
- Disease Models, Animal
- Dopamine/deficiency
- Dopamine Agonists/pharmacology
- Dopamine Plasma Membrane Transport Proteins
- Electric Stimulation/methods
- Electrochemistry/methods
- Excitatory Postsynaptic Potentials/drug effects
- Excitatory Postsynaptic Potentials/physiology
- Germ-Line Mutation
- Humans
- Hypokinesia/physiopathology
- Immunohistochemistry/methods
- In Vitro Techniques
- Intracellular Signaling Peptides and Proteins
- Membrane Glycoproteins/metabolism
- Membrane Transport Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Nerve Tissue Proteins/metabolism
- Neurons/physiology
- Oncogene Proteins/physiology
- Parkinsonian Disorders/genetics
- Parkinsonian Disorders/metabolism
- Protein Deglycase DJ-1
- Quinpirole/pharmacology
- RNA, Messenger/biosynthesis
- Radioligand Assay/methods
- Receptors, Dopamine D2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Substantia Nigra/cytology
- Substantia Nigra/drug effects
- Substantia Nigra/metabolism
- Tyrosine 3-Monooxygenase/metabolism
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Affiliation(s)
- Matthew S Goldberg
- Center for Neurologic Diseases, Brigham & Women's Hospital, Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, USA
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50
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Abstract
Specific protein G-coupled receptors mediate the effects of dopamine in its projection areas. Five dopaminergic receptors have been cloned, characterized and classified in two families, the D1-like family (D1- and D5-receptor subtypes) and the D2-like family (D2-, D3- and D4-receptor subtypes). These five dopamine receptor subtypes are characterized by their diversity in terms of transduction, distribution, pharmacology, functions, and regulation, leading to pleiotropic pathophysiological and pharmacological involvements in neuropsychiatric disorders underlain by a deregulation of the dopaminergic system.
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Affiliation(s)
- R Bordet
- EA1046, Laboratoire de Pharmacologie, Faculté de Médecine, Université de Lille 2, Lille
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