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Yde Ohki CM, McNeill RV, Nieberler M, Radtke F, Kittel-Schneider S, Grünblatt E. Promising Developments in the Use of Induced Pluripotent Stem Cells in Research of ADHD. Curr Top Behav Neurosci 2022; 57:483-501. [PMID: 35543866 DOI: 10.1007/7854_2022_346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Although research using animal models, peripheral and clinical biomarkers, multimodal neuroimaging techniques and (epi)genetic information has advanced our understanding of Attention-Deficit Hyperactivity Disorder (ADHD), the aetiopathology of this neurodevelopmental disorder has still not been elucidated. Moreover, as the primary affected tissue is the brain, access to samples is problematic. Alternative models are therefore required, facilitating cellular and molecular analysis. Recent developments in stem cell research have introduced the possibility to reprogram somatic cells from patients, in this case ADHD, and healthy controls back into their pluripotent state, meaning that they can then be differentiated into any cell or tissue type. The potential to translate patients' somatic cells into stem cells, and thereafter to use 2- and 3-dimensional (2D and 3D) neuronal cells to model neurodevelopmental disorders and/or test novel drug therapeutics, is discussed in this chapter.
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Affiliation(s)
- Cristine Marie Yde Ohki
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital Zurich (PUK), University of Zurich, Zürich, Switzerland
| | - Rhiannon V McNeill
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Matthias Nieberler
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Franziska Radtke
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, Würzburg, Germany
| | - Sarah Kittel-Schneider
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Edna Grünblatt
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital Zurich (PUK), University of Zurich, Zürich, Switzerland.
- Neuroscience Center Zurich, University of Zurich and the ETH Zurich, Zürich, Switzerland.
- Zurich Center for Integrative Human Physiology, University of Zurich, Zürich, Switzerland.
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ADHD-like behaviors caused by inactivation of a transcription factor controlling the balance of inhibitory and excitatory neuron development in the mouse anterior brainstem. Transl Psychiatry 2020; 10:357. [PMID: 33087695 PMCID: PMC7578792 DOI: 10.1038/s41398-020-01033-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 07/28/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022] Open
Abstract
The neural circuits regulating motivation and movement include midbrain dopaminergic neurons and associated inhibitory GABAergic and excitatory glutamatergic neurons in the anterior brainstem. Differentiation of specific subtypes of GABAergic and glutamatergic neurons in the mouse embryonic brainstem is controlled by a transcription factor Tal1. This study characterizes the behavioral and neurochemical changes caused by the absence of Tal1 function. The Tal1cko mutant mice are hyperactive, impulsive, hypersensitive to reward, have learning deficits and a habituation defect in a novel environment. Only minor changes in their dopaminergic system were detected. Amphetamine induced striatal dopamine release and amphetamine induced place preference were normal in Tal1cko mice. Increased dopamine signaling failed to stimulate the locomotor activity of the Tal1cko mice, but instead alleviated their hyperactivity. Altogether, the Tal1cko mice recapitulate many features of the attention and hyperactivity disorders, suggesting a role for Tal1 regulated developmental pathways and neural structures in the control of motivation and movement.
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Areal LB, Blakely RD. Neurobehavioral changes arising from early life dopamine signaling perturbations. Neurochem Int 2020; 137:104747. [PMID: 32325191 PMCID: PMC7261509 DOI: 10.1016/j.neuint.2020.104747] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022]
Abstract
Dopamine (DA) signaling is critical to the modulation of multiple brain functions including locomotion, reinforcement, attention and cognition. The literature provides strong evidence that altered DA availability and actions can impact normal neurodevelopment, with both early and enduring consequences on anatomy, physiology and behavior. An appreciation for the developmental contributions of DA signaling to brain development is needed to guide efforts to preclude and remedy neurobehavioral disorders, such as attention-deficit/hyperactivity disorder, addiction, bipolar disorder, schizophrenia and autism spectrum disorder, each of which exhibits links to DA via genetic, cellular and/or pharmacological findings. In this review, we highlight research pursued in preclinical models that use genetic and pharmacological approaches to manipulate DA signaling at sensitive developmental stages, leading to changes at molecular, circuit and/or behavioral levels. We discuss how these alterations can be aligned with traits displayed by neuropsychiatric diseases. Lastly, we review human studies that evaluate contributions of developmental perturbations of DA systems to increased risk for neuropsychiatric disorders.
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Affiliation(s)
- Lorena B Areal
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA.
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Davis GL, Stewart A, Stanwood GD, Gowrishankar R, Hahn MK, Blakely RD. Functional coding variation in the presynaptic dopamine transporter associated with neuropsychiatric disorders drives enhanced motivation and context-dependent impulsivity in mice. Behav Brain Res 2017; 337:61-69. [PMID: 28964912 DOI: 10.1016/j.bbr.2017.09.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/18/2017] [Accepted: 09/27/2017] [Indexed: 10/18/2022]
Abstract
Recent genetic analyses have provided evidence that clinical commonalities associated with different psychiatric diagnoses often have shared mechanistic underpinnings. The development of animal models expressing functional genetic variation attributed to multiple disorders offers a salient opportunity to capture molecular, circuit and behavioral alterations underlying this hypothesis. In keeping with studies suggesting dopaminergic contributions to attention-deficit hyperactivity disorder (ADHD), bipolar disorder (BPD) and autism spectrum disorder (ASD), subjects with these diagnoses have been found to express a rare, functional coding substitution in the dopamine (DA) transporter (DAT), Ala559Val. We developed DAT Val559 knock-in mice as a construct valid model of dopaminergic alterations that drive multiple clinical phenotypes, and here evaluate the impact of lifelong expression of the variant on impulsivity and motivation utilizing the 5- choice serial reaction time task (5-CSRTT) and Go/NoGo as well as tests of time estimation (peak interval analysis), reward salience (sucrose preference), and motivation (progressive ratio test). Our findings indicate that the DAT Val559 variant induces impulsivity behaviors that are dependent upon the reward context, with increased impulsive action observed when mice are required to delay responding for a reward, whereas mice are able to withhold responding if there is a probability of reward for a correct rejection. Utilizing peak interval and progressive ratio tests, we provide evidence that impulsivity is likely driven by an enhanced motivational phenotype that also may drive faster task acquisition in operant tasks. These data provide critical validation that DAT, and more generally, DA signaling perturbations can drive impulsivity that can manifest in specific contexts and not others, and may rely on motivational alterations, which may also drive increased maladaptive reward seeking.
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Affiliation(s)
- Gwynne L Davis
- Department of Pharmacology, Vanderbilt University, 2220 Pierce Ave, Nashville, TN 37232, United States; Department of Biomedical Science, Charles E. Schmidt College of Medicine, United States.
| | - Adele Stewart
- Department of Pharmacology, Vanderbilt University, 2220 Pierce Ave, Nashville, TN 37232, United States; Department of Biomedical Science, Charles E. Schmidt College of Medicine, United States; Brain Institute, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, United States.
| | - Gregg D Stanwood
- Biomedical Sciences, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, United States.
| | - Raajaram Gowrishankar
- Department of Pharmacology, Vanderbilt University, 2220 Pierce Ave, Nashville, TN 37232, United States; Department of Biomedical Science, Charles E. Schmidt College of Medicine, United States.
| | - Maureen K Hahn
- Department of Pharmacology, Vanderbilt University, 2220 Pierce Ave, Nashville, TN 37232, United States; Department of Biomedical Science, Charles E. Schmidt College of Medicine, United States; Brain Institute, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, United States.
| | - Randy D Blakely
- Department of Pharmacology, Vanderbilt University, 2220 Pierce Ave, Nashville, TN 37232, United States; Department of Biomedical Science, Charles E. Schmidt College of Medicine, United States; Brain Institute, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, United States.
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Majdak P, Grogan EL, Gogola JV, Sorokina A, Tse S, Rhodes JS. The impact of maternal neglect on genetic hyperactivity. Behav Brain Res 2016; 313:282-292. [PMID: 27449202 DOI: 10.1016/j.bbr.2016.07.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/14/2016] [Accepted: 07/18/2016] [Indexed: 10/21/2022]
Abstract
Early environmental conditions are increasingly appreciated as critical in shaping behavior and cognition. Evidence suggests that stressful rearing environments can have an enduring impact on behaviors in adulthood, but few studies have explored the possibility that rearing environment could exacerbate genetic hyperactivity disorders. Uncovering a strong environmental influence on the transmission of hyperactivity could provide novel avenues for translational research. Recently we developed a selectively bred High-Active line of mice to model ADHD, providing a unique resource to address the question of environmental transmission. The High-Active line demonstrates transgenerational hyperactivity, but the influence of the postnatal environment (i.e. maternal care provided by dams) on hyperactivity had not been systemically quantified. This study employed a cross-fostering method to simultaneously address 1) whether High-Active and Control pups are provided with similar levels of care in the early environment, and 2) whether any differences in rearing environment influence hyperactive behavior. High-Active dams demonstrated impairment in all measures of maternal competence relative to Controls, which reduced survival rates and significantly reduced the body mass of offspring in early life and at weaning. While the deteriorated postnatal environment provided by High-Active dams was ultimately sufficient to depress Control activity, the hyperactivity of High-Active offspring remained unaffected by fostering condition. These data not only confirm the power of genetics to influence hyperactivity across generations, but also provide evidence that early rearing environments may not have a significant impact on the extreme end of hyperactive phenotypes.
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Affiliation(s)
- Petra Majdak
- The Neuroscience Program, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA; The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA.
| | - Elizabeth L Grogan
- The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA
| | - Joseph V Gogola
- The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA
| | - Anastassia Sorokina
- The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA
| | - Stephen Tse
- The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA
| | - Justin S Rhodes
- The Neuroscience Program, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA; The Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, IL 61801, USA; Department of Psychology, University of Illinois, 603 E. Daniel Street, Champaign, IL 61820, USA
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Attention-Deficit/Hyperactivity Disorder-like Phenotype in a Mouse Model with Impaired Actin Dynamics. Biol Psychiatry 2015; 78:95-106. [PMID: 24768258 DOI: 10.1016/j.biopsych.2014.03.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 11/23/2022]
Abstract
BACKGROUND Actin depolymerizing proteins of the actin depolymerizing factor (ADF)/cofilin family are essential for actin dynamics, which is critical for synaptic function. Two ADF/cofilin family members, ADF and n-cofilin, are highly abundant in the brain, where they are present in excitatory synapses. Previous studies demonstrated the relevance of n-cofilin for postsynaptic plasticity, associative learning, and anxiety. These studies also suggested overlapping functions for ADF and n-cofilin. METHODS We performed pharmacobehavioral, electrophysiologic, and electron microscopic studies on ADF and n-cofilin single mutants and double mutants (named ACC mice) to characterize the importance of ADF/cofilin activity for synapse physiology and mouse behavior. RESULTS The ACC mice, but not single mutants, exhibited hyperlocomotion, impulsivity, and impaired working memory. Hyperlocomotion and impulsive behavior were reversed by methylphenidate, a psychostimulant commonly used for the treatment of attention-deficit/hyperactivity disorder (ADHD). Also, ACC mice displayed a disturbed morphology of striatal excitatory synapses, accompanied by strongly increased glutamate release. Blockade of dopamine or glutamate transmission resulted in normal locomotion. CONCLUSIONS Our study reveals that ADHD can result from a disturbed balance between excitation and inhibition in striatal circuits, providing novel insights into the mechanisms underlying this neurobehavioral disorder. Our results link actin dynamics to ADHD, suggesting that mutations in actin regulatory proteins may contribute to the etiology of ADHD in humans.
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Mergy MA, Gowrishankar R, Davis GL, Jessen TN, Wright J, Stanwood GD, Hahn MK, Blakely RD. Genetic targeting of the amphetamine and methylphenidate-sensitive dopamine transporter: on the path to an animal model of attention-deficit hyperactivity disorder. Neurochem Int 2014; 73:56-70. [PMID: 24332984 PMCID: PMC4177817 DOI: 10.1016/j.neuint.2013.11.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 11/20/2013] [Accepted: 11/23/2013] [Indexed: 12/20/2022]
Abstract
Alterations in dopamine (DA) signaling underlie the most widely held theories of molecular and circuit level perturbations that lead to risk for attention-deficit hyperactivity disorder (ADHD). The DA transporter (DAT), a presynaptic reuptake protein whose activity provides critical support for DA signaling by limiting DA action at pre- and postsynaptic receptors, has been consistently associated with ADHD through pharmacological, behavioral, brain imaging and genetic studies. Currently, the animal models of ADHD exhibit significant limitations, stemming in large part from their lack of construct validity. To remedy this situation, we have pursued the creation of a mouse model derived from a functional nonsynonymous variant in the DAT gene (SLC6A3) of ADHD probands. We trace our path from the identification of these variants to in vitro biochemical and physiological studies to the production of the DAT Val559 mouse model. We discuss our initial findings with these animals and their promise in the context of existing rodent models of ADHD.
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Affiliation(s)
- Marc A Mergy
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Raajaram Gowrishankar
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gwynne L Davis
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Tammy N Jessen
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jane Wright
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gregg D Stanwood
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Maureen K Hahn
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Randy D Blakely
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA.
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Hansen FH, Skjørringe T, Yasmeen S, Arends NV, Sahai MA, Erreger K, Andreassen TF, Holy M, Hamilton PJ, Neergheen V, Karlsborg M, Newman AH, Pope S, Heales SJR, Friberg L, Law I, Pinborg LH, Sitte HH, Loland C, Shi L, Weinstein H, Galli A, Hjermind LE, Møller LB, Gether U. Missense dopamine transporter mutations associate with adult parkinsonism and ADHD. J Clin Invest 2014; 124:3107-20. [PMID: 24911152 DOI: 10.1172/jci73778] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 04/24/2014] [Indexed: 11/17/2022] Open
Abstract
Parkinsonism and attention deficit hyperactivity disorder (ADHD) are widespread brain disorders that involve disturbances of dopaminergic signaling. The sodium-coupled dopamine transporter (DAT) controls dopamine homeostasis, but its contribution to disease remains poorly understood. Here, we analyzed a cohort of patients with atypical movement disorder and identified 2 DAT coding variants, DAT-Ile312Phe and a presumed de novo mutant DAT-Asp421Asn, in an adult male with early-onset parkinsonism and ADHD. According to DAT single-photon emission computed tomography (DAT-SPECT) scans and a fluoro-deoxy-glucose-PET/MRI (FDG-PET/MRI) scan, the patient suffered from progressive dopaminergic neurodegeneration. In heterologous cells, both DAT variants exhibited markedly reduced dopamine uptake capacity but preserved membrane targeting, consistent with impaired catalytic activity. Computational simulations and uptake experiments suggested that the disrupted function of the DAT-Asp421Asn mutant is the result of compromised sodium binding, in agreement with Asp421 coordinating sodium at the second sodium site. For DAT-Asp421Asn, substrate efflux experiments revealed a constitutive, anomalous efflux of dopamine, and electrophysiological analyses identified a large cation leak that might further perturb dopaminergic neurotransmission. Our results link specific DAT missense mutations to neurodegenerative early-onset parkinsonism. Moreover, the neuropsychiatric comorbidity provides additional support for the idea that DAT missense mutations are an ADHD risk factor and suggests that complex DAT genotype and phenotype correlations contribute to different dopaminergic pathologies.
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Dolan J, Mitchell KJ. Mutation of Elfn1 in mice causes seizures and hyperactivity. PLoS One 2013; 8:e80491. [PMID: 24312227 PMCID: PMC3842350 DOI: 10.1371/journal.pone.0080491] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 10/12/2013] [Indexed: 02/02/2023] Open
Abstract
A growing number of proteins with extracellular leucine-rich repeats (eLRRs) have been implicated in directing neuronal connectivity. We previously identified a novel family of eLRR proteins in mammals: the Elfns are transmembrane proteins with 6 LRRs, a fibronectin type-3 domain and a long cytoplasmic tail. The recent discovery that Elfn1 protein, expressed postsynaptically, can direct the elaboration of specific electrochemical properties of synapses between particular cell types in the hippocampus strongly reinforces this hypothesis. Here, we present analyses of an Elfn1 mutant mouse line and demonstrate a functional requirement for this gene in vivo. We first carried out detailed expression analysis of Elfn1 using a β-galactosidase reporter gene in the knockout line. Elfn1 is expressed in distinct subsets of interneurons of the hippocampus and cortex, and also in discrete subsets of cells in the habenula, septum, globus pallidus, dorsal subiculum, amygdala and several other regions. Elfn1 is expressed in diverse cell types, including local GABAergic interneurons as well as long-range projecting GABAergic and glutamatergic neurons. Elfn1 protein localises to axons of excitatory neurons in the habenula, and long-range GABAergic neurons of the globus pallidus, suggesting the possibility of additional roles for Elfn1 in axons or presynaptically. While gross anatomical analyses did not reveal any obvious neuroanatomical abnormalities, behavioural analyses clearly illustrate functional effects of Elfn1 mutation. Elfn1 mutant mice exhibit seizures, subtle motor abnormalities, reduced thigmotaxis and hyperactivity. The hyperactivity is paradoxically reversible by treatment with the stimulant amphetamine, consistent with phenotypes observed in animals with habenular lesions. These analyses reveal a requirement for Elfn1 in brain function and are suggestive of possible relevance to the etiology and pathophysiology of epilepsy and attention-deficit hyperactivity disorder.
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Affiliation(s)
- Jackie Dolan
- Smurfit Institute of Genetics and Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Kevin J. Mitchell
- Smurfit Institute of Genetics and Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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Leo D, Gainetdinov RR. Transgenic mouse models for ADHD. Cell Tissue Res 2013; 354:259-71. [PMID: 23681253 PMCID: PMC3785710 DOI: 10.1007/s00441-013-1639-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/15/2013] [Indexed: 12/20/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a developmental disorder characterized by symptoms of inattention, impulsivity and hyperactivity that adversely affect many aspects of life. Whereas the etiology of ADHD remains unknown, growing evidence indicates a genetic involvement in the development of this disorder. The brain circuits associated with ADHD are rich in monoamines, which are involved in the mechanism of action of psychostimulants and other medications used to treat this disorder. Dopamine (DA) is believed to play a major role in ADHD but other neurotransmitters are certainly also involved. Genetically modified mice have become an indispensable tool used to analyze the contribution of genetic factors in the pathogenesis of human disorders. Although rodent models cannot fully recapitulate complex human psychiatric disorders such as ADHD, transgenic mice offer an opportunity to directly investigate in vivo the specific roles of novel candidate genes identified in ADHD patients. Several knock-out and transgenic mouse models have been proposed as ADHD models, mostly based on targeting genes involved in DA transmission, including the gene encoding the dopamine transporter (DAT1). These mutant models provided an opportunity to evaluate the contribution of dopamine-related processes to brain pathology, to dissect the neuronal circuitry and molecular mechanisms involved in the antihyperkinetic action of psychostimulants and to evaluate novel treatments for ADHD. New transgenic models mouse models targeting other genes have recently been proposed for ADHD. Here, we discuss the recent advances and pitfalls in modeling ADHD endophenotypes in genetically altered animals.
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Affiliation(s)
- Damiana Leo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Via Morego 30, Genoa, Italy,
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Is the treatment with psychostimulants in children and adolescents with attention deficit hyperactivity disorder harmful for the dopaminergic system? ACTA ACUST UNITED AC 2013; 5:71-81. [PMID: 23605387 DOI: 10.1007/s12402-013-0105-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 03/09/2013] [Indexed: 12/13/2022]
Abstract
A major concern regarding psychostimulant medication (amphetamine and methylphenidate) in the treatment of children and adolescents with attention deficit/hyperactivity disorder (ADHD) are the potential adverse effects to the developing brain, particularly in regard to dopaminergic brain function. The present review focuses on the pharmacology of these psychostimulants, their mode of action in the human brain and their potential neurotoxic effects to the developing brain in animals, particularly concerning DA brain function. The potential clinical significance of these findings for the treatment of ADHD in children and adolescents is discussed. Studies on sensitization to psychostimulants' rewarding effects, which is a process expected to increase the risk of substance abuse in humans, are not included. The available findings in non-human primates support the notion that the administration of amphetamine and methylphenidate with procedures simulating clinical treatment conditions does not lead to long-term adverse effects in regard to development, neurobiology or behaviour as related to the central dopaminergic system.
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Dervola KS, Roberg BA, Wøien G, Bogen IL, Sandvik TH, Sagvolden T, Drevon CA, Johansen EB, Walaas SI. Marine Ο-3 polyunsaturated fatty acids induce sex-specific changes in reinforcer-controlled behaviour and neurotransmitter metabolism in a spontaneously hypertensive rat model of ADHD. Behav Brain Funct 2012; 8:56. [PMID: 23228189 PMCID: PMC3573936 DOI: 10.1186/1744-9081-8-56] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 11/28/2012] [Indexed: 01/19/2023] Open
Abstract
Background Previous reports suggest that omega-3 (n-3) polyunsaturated fatty acids (PUFA) supplements may reduce ADHD-like behaviour. Our aim was to investigate potential effects of n-3 PUFA supplementation in an animal model of ADHD. Methods We used spontaneously hypertensive rats (SHR). SHR dams were given n-3 PUFA (EPA and DHA)-enriched feed (n-6/n-3 of 1:2.7) during pregnancy, with their offspring continuing on this diet until sacrificed. The SHR controls and Wistar Kyoto (WKY) control rats were given control-feed (n-6/n-3 of 7:1). During postnatal days (PND) 25–50, offspring were tested for reinforcement-dependent attention, impulsivity and hyperactivity as well as spontaneous locomotion. The animals were then sacrificed at PND 55–60 and their neostriata were analysed for monoamine and amino acid neurotransmitters with high performance liquid chromatography. Results n-3 PUFA supplementation significantly enhanced reinforcement-controlled attention and reduced lever-directed hyperactivity and impulsiveness in SHR males whereas the opposite or no effects were observed in females. Analysis of neostriata from the same animals showed significantly enhanced dopamine and serotonin turnover ratios in the male SHRs, whereas female SHRs showed no change, except for an intermediate increase in serotonin catabolism. In contrast, both male and female SHRs showed n-3 PUFA-induced reduction in non-reinforced spontaneous locomotion, and sex-independent changes in glycine levels and glutamate turnover. Conclusions Feeding n-3 PUFAs to the ADHD model rats induced sex-specific changes in reinforcement-motivated behaviour and a sex-independent change in non-reinforcement-associated behaviour, which correlated with changes in presynaptic striatal monoamine and amino acid signalling, respectively. Thus, dietary n-3 PUFAs may partly ameliorate ADHD-like behaviour by reinforcement-induced mechanisms in males and partly via reinforcement-insensitive mechanisms in both sexes.
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Affiliation(s)
- Kine S Dervola
- Department of Biochemistry, Institute of Basic Medical Science, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Dichter GS, Damiano CA, Allen JA. Reward circuitry dysfunction in psychiatric and neurodevelopmental disorders and genetic syndromes: animal models and clinical findings. J Neurodev Disord 2012; 4:19. [PMID: 22958744 PMCID: PMC3464940 DOI: 10.1186/1866-1955-4-19] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/02/2012] [Indexed: 02/07/2023] Open
Abstract
This review summarizes evidence of dysregulated reward circuitry function in a range of neurodevelopmental and psychiatric disorders and genetic syndromes. First, the contribution of identifying a core mechanistic process across disparate disorders to disease classification is discussed, followed by a review of the neurobiology of reward circuitry. We next consider preclinical animal models and clinical evidence of reward-pathway dysfunction in a range of disorders, including psychiatric disorders (i.e., substance-use disorders, affective disorders, eating disorders, and obsessive compulsive disorders), neurodevelopmental disorders (i.e., schizophrenia, attention-deficit/hyperactivity disorder, autism spectrum disorders, Tourette's syndrome, conduct disorder/oppositional defiant disorder), and genetic syndromes (i.e., Fragile X syndrome, Prader-Willi syndrome, Williams syndrome, Angelman syndrome, and Rett syndrome). We also provide brief overviews of effective psychopharmacologic agents that have an effect on the dopamine system in these disorders. This review concludes with methodological considerations for future research designed to more clearly probe reward-circuitry dysfunction, with the ultimate goal of improved intervention strategies.
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Affiliation(s)
- Gabriel S Dichter
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina School of Medicine, CB# 7255, 101 Manning Drive, Chapel Hill, NC, 275997255, USA
| | - Cara A Damiano
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - John A Allen
- Neuroscience Research Unit Pfizer Global Research and Development, Groton, CT 06340, USA
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Thome J, Ehlis AC, Fallgatter AJ, Krauel K, Lange KW, Riederer P, Romanos M, Taurines R, Tucha O, Uzbekov M, Gerlach M. Biomarkers for attention-deficit/hyperactivity disorder (ADHD). A consensus report of the WFSBP task force on biological markers and the World Federation of ADHD. World J Biol Psychiatry 2012; 13:379-400. [PMID: 22834452 DOI: 10.3109/15622975.2012.690535] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Psychiatric "nosology" is largely based on clinical phenomenology using convention-based diagnostic systems not necessarily reflecting neurobiological pathomechanisms. While progress has been made regarding its molecular biology and neuropathology, the phenotypic characterization of ADHD has not improved. Thus, validated biomarkers, more directly linked to the underlying pathology, could constitute an objective measure for the condition. METHOD The task force on biological markers of the World Federation of Societies of Biological Psychiatry (WFSBP) and the World Federation of ADHD commissioned this paper to develop a consensus report on potential biomarkers of ADHD. The criteria for biomarker-candidate evaluation were: (1) sensitivity >80%, (2) specificity >80%, (3) the candidate is reliable, reproducible, inexpensive, non-invasive, easy to use, and (4) confirmed by at least two independent studies in peer-reviewed journals conducted by qualified investigators. RESULTS No reliable ADHD biomarker has been described to date, but some promising candidates (e.g., olfactory sensitivity, substantial echogenicity) exist. A problem in the development of ADHD markers is sample heterogeneity due to aetiological and phenotypic complexity and age-dependent co-morbidities. CONCLUSIONS Most likely, no single ADHD biomarker can be identified. However, the use of a combination of markers may help to reduce heterogeneity and to identify homogeneous subtypes of ADHD.
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Affiliation(s)
- Johannes Thome
- Department of Psychiatry and Psychotherapy, University of Rostock, Rostock, Germany.
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Adult attention deficit hyperactivity disorder: translating research into practice. ACTA ACUST UNITED AC 2012; 4:41-51. [DOI: 10.1007/s12402-012-0073-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 02/07/2012] [Indexed: 02/02/2023]
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Trent S, Dennehy A, Richardson H, Ojarikre OA, Burgoyne PS, Humby T, Davies W. Steroid sulfatase-deficient mice exhibit endophenotypes relevant to attention deficit hyperactivity disorder. Psychoneuroendocrinology 2012; 37:221-9. [PMID: 21723668 PMCID: PMC3242075 DOI: 10.1016/j.psyneuen.2011.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/10/2011] [Accepted: 06/06/2011] [Indexed: 12/18/2022]
Abstract
Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition characterised by inattention, impulsivity and hyperactivity; it is frequently co-morbid with anxiety and conduct disorders, sleep perturbation and abnormal consummatory behaviours. Recent studies have implicated the neurosteroid-modulating enzyme steroid sulfatase (STS) as a modulator of ADHD-related endophenotypes. The effects of steroid sulfatase deficiency on homecage activity, feeding/drinking behaviours, anxiety-related behaviours (assayed in light-dark box and open field paradigms), social dominance and serum steroid hormone levels were determined by comparing 40,XY and 39,X(Y*)O mice. Subsequently, mice administered the steroid sulfatase inhibitor COUMATE acutely were compared to vehicle-treated mice on behavioural tasks sensitive to enzyme deficiency to dissociate between its developmental and ongoing effects. 39,X(Y*)O mice exhibited heightened reactivity to a novel environment, hyperactivity in the active phase, and increased water (but not food) consumption relative to 40,XY mice during a 24h period; the former group also demonstrated evidence for heightened emotional reactivity. There was no difference in social dominance between the 40,XY and 39,X(Y*)O mice. COUMATE administration had no effect on homecage activity, water consumption or anxiety measures in the open field. 39,X(Y*)O mice exhibited significantly lower dehydroepiandrosterone (DHEA) serum levels than 40,XY mice, but equivalent corticosterone levels. Together with previous data, the present results suggest that steroid sulfatase may influence core and associated ADHD behavioural endophenotypes via both developmental and ongoing mechanisms, and that the 39,X(Y*)O model may represent a useful tool for elucidating the neurobiological basis of these endophenotypes.
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Affiliation(s)
- Simon Trent
- Behavioural Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics and Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | | | | | | | | | - Trevor Humby
- Behavioural Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics and Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - William Davies
- Behavioural Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics and Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
- Corresponding author at: Henry Wellcome Building, Heath Park Campus, Cardiff CF14 4XN, UK. Tel.: +44 0 29 2068 7047; fax: +44 0 29 2068 7068.
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