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Tanaka M, Szabó Á, Spekker E, Polyák H, Tóth F, Vécsei L. Mitochondrial Impairment: A Common Motif in Neuropsychiatric Presentation? The Link to the Tryptophan-Kynurenine Metabolic System. Cells 2022; 11:cells11162607. [PMID: 36010683 PMCID: PMC9406499 DOI: 10.3390/cells11162607] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/14/2022] [Accepted: 08/19/2022] [Indexed: 02/07/2023] Open
Abstract
Nearly half a century has passed since the discovery of cytoplasmic inheritance of human chloramphenicol resistance. The inheritance was then revealed to take place maternally by mitochondrial DNA (mtDNA). Later, a number of mutations in mtDNA were identified as a cause of severe inheritable metabolic diseases with neurological manifestation, and the impairment of mitochondrial functions has been probed in the pathogenesis of a wide range of illnesses including neurodegenerative diseases. Recently, a growing number of preclinical studies have revealed that animal behaviors are influenced by the impairment of mitochondrial functions and possibly by the loss of mitochondrial stress resilience. Indeed, as high as 54% of patients with one of the most common primary mitochondrial diseases, mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, present psychiatric symptoms including cognitive impairment, mood disorder, anxiety, and psychosis. Mitochondria are multifunctional organelles which produce cellular energy and play a major role in other cellular functions including homeostasis, cellular signaling, and gene expression, among others. Mitochondrial functions are observed to be compromised and to become less resilient under continuous stress. Meanwhile, stress and inflammation have been linked to the activation of the tryptophan (Trp)-kynurenine (KYN) metabolic system, which observably contributes to the development of pathological conditions including neurological and psychiatric disorders. This review discusses the functions of mitochondria and the Trp-KYN system, the interaction of the Trp-KYN system with mitochondria, and the current understanding of the involvement of mitochondria and the Trp-KYN system in preclinical and clinical studies of major neurological and psychiatric diseases.
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Affiliation(s)
- Masaru Tanaka
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Ágnes Szabó
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Doctoral School of Clinical Medicine, University of Szeged, Korányi fasor 6, H-6720 Szeged, Hungary
| | - Eleonóra Spekker
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Helga Polyák
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Doctoral School of Clinical Medicine, University of Szeged, Korányi fasor 6, H-6720 Szeged, Hungary
| | - Fanni Tóth
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - László Vécsei
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-545-351
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Pedersen JH, Skytthe A, Bybjerg-Grauholm J, Kucukyildiz AS, Skov L, Debes NM, Tümer Z. Concordance and comorbidities among monozygotic twins with tic disorders. J Psychiatr Res 2022; 146:297-303. [PMID: 34794811 DOI: 10.1016/j.jpsychires.2021.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/08/2021] [Accepted: 11/06/2021] [Indexed: 11/17/2022]
Abstract
Gilles de la Tourette Syndrome (GTS) is a multifactorial neurodevelopmental disorder characterized by tics and multiple comorbidities. The pathophysiology is not yet fully understood, but both environmental and genetic risk factors seem to be involved. Twin studies provide important knowledge on genetic factors. We assessed the concordance of GTS and chronic tic disorders (CTD) in monozygotic (MZ) twins, and examined tic severity, symptoms of obsessive-compulsive disorder (OCD), attention deficit/hyperactivity disorder and autism spectrum disorder. Twin pairs, where at least one twin was diagnosed with any tic disorder, were identified through Danish Twin Registry, Psychiatric Central Registry, Danish National Patient Registry and National Tourette Clinic, Copenhagen University Hospital, Herlev. Zygosity was tested with single-nucleotide polymorphism (SNP) genotyping and clinical assessment was done with validated tools. 14 MZ twin pairs were included: five were discordant. Seven twin pairs were concordant for GTS, and for two pairs one twin had GTS and the other CTD. Among the twins with CTD or GTS, 50% had at least one comorbidity, which is higher than in background populations. The GTS + OCD-phenotype was significantly more frequent among GTS-concordant than among discordant twins. No statistically significant differences were found between the GTS-concordant and discordant twin pairs regarding tic severity or comorbidities. Thorough clinical assessment and SNP-based genotyping are important when conducting clinical twin studies. We found high concordance of GTS and CTD, which supports the notion that both disorders have common genetic risk factors. Further studies with larger cohorts including dizygotic twins are warranted for more conclusive results.
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Affiliation(s)
| | - Axel Skytthe
- The Danish Twin Registry, Epidemiology, Biostatistics, and Biodemography, Institute of Public Health, University of Southern, Denmark
| | | | - Asli Sena Kucukyildiz
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Liselotte Skov
- Department of Pediatrics, Copenhagen University Hospital, Herlev, Denmark
| | - Nanette Mol Debes
- Department of Pediatrics, Copenhagen University Hospital, Herlev, Denmark
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Meng HR, Suenaga T, Edamura M, Fukuda A, Ishida Y, Nakahara D, Murakami G. Functional MHCI deficiency induces ADHD-like symptoms with increased dopamine D1 receptor expression. Brain Behav Immun 2021; 97:22-31. [PMID: 34022373 DOI: 10.1016/j.bbi.2021.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/23/2021] [Accepted: 05/17/2021] [Indexed: 11/29/2022] Open
Abstract
Inappropriate synaptic development has been proposed as a potential mechanism of neurodevelopmental disorders, including attention-deficit hyperactivity disorder (ADHD). Major histocompatibility complex class I (MHCI), an immunity-associated molecule expressed by neurons in the brain, regulates synaptic development; however, the involvement of MHCI in these disorders remains elusive. We evaluated whether functional MHCI deficiency induced by β2m-/-Tap1-/- double-knockout in mice leads to abnormalities akin to those seen in neurodevelopmental disorders. We found that functional MHCI deficiency induced locomotor hyperactivity, motor impulsivity, and attention deficits, three major symptoms of ADHD. In contrast, these mice showed normal spatial learning, behavioral flexibility, social behavior, and sensorimotor integration. In the analysis of the dopamine system, upregulation of dopamine D1 receptor (D1R) expression in the nucleus accumbens and a greater locomotor response to D1R agonist SKF 81297 were found in the functional MHCI-deficient mice. Low-dose methylphenidate, used for the treatment of ADHD patients, alleviated the three behavioral symptoms and suppressed c-Fos expression in the D1R-expressing medium spiny neurons of the mice. These findings reveal an unexpected role of MHCI in three major symptoms of ADHD and may provide a novel landmark in the pathogenesis of ADHD.
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Affiliation(s)
- Hong-Rui Meng
- Division of Psychology, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Toshiko Suenaga
- Division of Psychology, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; School of Psychology, Tokyo University of Social Welfare, Tokyo 114-0004, Japan
| | - Mitsuhiro Edamura
- Division of Psychology, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; Advanced Research Facilities and Services, Preeminent Medical Photonics Education and Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Yasushi Ishida
- Division of Psychiatry, Department of Clinical Neuroscience, Faculty of Medicine, University of Miyazaki, Miyazaki 889-16, Japan
| | - Daiichiro Nakahara
- Division of Psychology, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; Division of Psychiatry, Department of Clinical Neuroscience, Faculty of Medicine, University of Miyazaki, Miyazaki 889-16, Japan.
| | - Gen Murakami
- Division of Psychology, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; Department of Liberal Arts, Faculty of Medicine, Saitama Medical University, Saitama 350-0495, Japan.
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Xu D, Liu L, Li H, Sun L, Yang L, Qian Q, Wang Y. Potential Role of ADRA2A Genetic Variants in the Etiology of ADHD Comorbid With Tic Disorders. J Atten Disord 2021; 25:33-43. [PMID: 29482474 DOI: 10.1177/1087054718757646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Objective: To evaluate the role of the adrenergic receptor alpha-2A gene (ADRA2A) in the genetic etiology of ADHD comorbid with tic disorders (ADHD+TD). Method: Two single nucleotide polymorphisms (SNPs) of ADRA2A were genotyped and analyzed in 936 normal controls and 1,815 ADHD probands, including 1,249 trios. Approximately 16% of the ADHD probands also had a diagnosis of TD. Results: No significant association was found between ADRA2A and ADHD in general. Case-control analyses indicated different allelic and genotypic distributions of rs553668 between ADHD+TD and controls in males. Family-based association tests showed that the G allele of rs1800544, the A allele of rs553668, and the GA haplotype consisting of these two SNPs were overtransmitted in the ADHD+TD trios, especially in males. Moreover, the allelic/genotypic distribution and allelic transmission were different between ADHD+TD and ADHD without TD. Conclusion:ADRA2A may be associated with ADHD+TD, especially in males.
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Affiliation(s)
- Defeng Xu
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Lu Liu
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Haimei Li
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Li Sun
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Li Yang
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Qiujin Qian
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - Yufeng Wang
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China.,National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
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Mathee K, Cickovski T, Deoraj A, Stollstorff M, Narasimhan G. The gut microbiome and neuropsychiatric disorders: implications for attention deficit hyperactivity disorder (ADHD). J Med Microbiol 2020; 69:14-24. [PMID: 31821133 PMCID: PMC7440676 DOI: 10.1099/jmm.0.001112] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022] Open
Abstract
Neuropsychiatric disorders (NPDs) such as depression, anxiety, bipolar disorder, autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) all relate to behavioural, cognitive and emotional disturbances that are ultimately rooted in disordered brain function. More specifically, these disorders are linked to various neuromodulators (i.e. serotonin and dopamine), as well as dysfunction in both cognitive and socio-affective brain networks. Increasing evidence suggests that the gut environment, and particularly the microbiome, plays a significant role in individual mental health. Although the presence of a gut-brain communication axis has long been established, recent studies argue that the development and regulation of this axis is dictated by the gut microbiome. Many studies involving both animals and humans have connected the gut microbiome with depression, anxiety and ASD. Microbiome-centred treatments for individuals with these same NPDs have yielded promising results. Despite its recent rise and underlying similarities to other NPDs, both biochemically and symptomatically, connections between the gut microbiome and ADHD currently lag behind those for other NPDs. We demonstrate that all evidence points to the importance of, and dire need for, a comprehensive and in-depth analysis of the role of the gut microbiome in ADHD, to deepen our understanding of a condition that affects millions of individuals worldwide.
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Affiliation(s)
- Kalai Mathee
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Florida, USA
| | - Trevor Cickovski
- Bioinformatics Research Group (BioRG), School of Computing and Information Sciences, Florida International University, Florida, USA
| | - Alok Deoraj
- Department of Environmental and Occupational Health, Robert Stempel College of Public Health and Social Work, Florida International University, Florida, USA
| | - Melanie Stollstorff
- Department of Psychology, College of Arts, Science and Education, Florida International University, Florida, USA
| | - Giri Narasimhan
- Bioinformatics Research Group (BioRG), School of Computing and Information Sciences, Florida International University, Florida, USA
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Dow-Edwards D, MacMaster FP, Peterson BS, Niesink R, Andersen S, Braams BR. Experience during adolescence shapes brain development: From synapses and networks to normal and pathological behavior. Neurotoxicol Teratol 2019; 76:106834. [PMID: 31505230 DOI: 10.1016/j.ntt.2019.106834] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 07/27/2019] [Accepted: 09/06/2019] [Indexed: 12/20/2022]
Abstract
Adolescence is a period of dramatic neural reorganization creating a period of vulnerability and the possibility for the development of psychopathology. The maturation of various neural circuits during adolescence depends, to a large degree, on one's experiences both physical and psychosocial. This occurs through a process of plasticity which is the structural and functional adaptation of the nervous system in response to environmental demands, physiological changes and experiences. During adolescence, this adaptation proceeds upon a backdrop of structural and functional alterations imparted by genetic and epigenetic factors and experiences both prior to birth and during the postnatal period. Plasticity entails an altering of connections between neurons through long-term potentiation (LTP) (which alters synaptic efficiency), synaptogenesis, axonal sprouting, dendritic remodeling, neurogenesis and recruitment (Skaper et al., 2017). Although most empirical evidence for plasticity derives from studies of the sensory systems, recent studies have suggested that during adolescence, social, emotional, and cognitive experiences alter the structure and function of the networks subserving these domains of behavior. Each of these neural networks exhibits heightened vulnerability to experience-dependent plasticity during the sensitive periods which occur in different circuits and different brain regions at specific periods of development. This report will summarize some examples of adaptation which occur during adolescence and some evidence that the adolescent brain responds differently to stimuli compared to adults and children. This symposium, "Experience during adolescence shapes brain development: from synapses and networks to normal and pathological behavior" occurred during the Developmental Neurotoxicology Society/Teratology Society Annual Meeting in Clearwater Florida, June 2018. The sections will describe the maturation of the brain during adolescence as studied using imaging technologies, illustrate how plasticity shapes the structure of the brain using examples of pathological conditions such as Tourette's' syndrome and attention deficit hyperactivity disorder, and a review of the key molecular systems involved in this plasticity and how some commonly abused substances alter brain development. The role of stimulants used in the treatment of attention deficit hyperactivity disorder (ADHD) in the plasticity of the reward circuit is then described. Lastly, clinical data promoting an understanding of peer-influences on risky behavior in adolescents provides evidence for the complexity of the roles that peers play in decision making, a phenomenon different from that in the adult. Imaging studies have revealed that activation of the social network by the presence of peers at times of decision making is unique in the adolescent. Since normal brain development relies on experiences which alter the functional and structural connections between cells within circuits and networks to ultimately alter behavior, readers can be made aware of the myriad of ways normal developmental processes can be hijacked. The vulnerability of developing adolescent brain places the adolescent at risk for the development of a life time of abnormal behaviors and mental disorders.
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Affiliation(s)
- Diana Dow-Edwards
- Department of Physiology & Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, NY, United States of America.
| | - Frank P MacMaster
- Departments of Psychiatry & Pediatrics, University of Calgary, Addiction and Mental Health Strategic Clinical Network, Calgary, Alberta, Canada
| | - Bradley S Peterson
- Children's Hospital Los Angeles, The Keck School of Medicine at the University of Southern California, Los Angeles, CA, United States of America
| | - Raymond Niesink
- Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, the Netherlands; Faculty of Management, Science and Technology, School of Science, Open University of the Netherlands, Heerlen, the Netherlands
| | - Susan Andersen
- McLean Hospital, Department of Psychiatry, Harvard Medical School, Boston, MA, United States of America
| | - B R Braams
- Department of Psychology, Center for Brain Science, Harvard University, Cambridge, MA, United States of America
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7
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Blum K, Gondré-Lewis MC, Baron D, Thanos PK, Braverman ER, Neary J, Elman I, Badgaiyan RD. Introducing Precision Addiction Management of Reward Deficiency Syndrome, the Construct That Underpins All Addictive Behaviors. Front Psychiatry 2018; 9:548. [PMID: 30542299 PMCID: PMC6277779 DOI: 10.3389/fpsyt.2018.00548] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022] Open
Affiliation(s)
- Kenneth Blum
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, United States.,Department of Psychiatry, Boonshoft School of Medicine, Dayton VA Medical Center, Wright State University, Dayton, OH, United States.,University of Vermont College of Medicine, Burlington, VM, United States.,Division of Addictive Services, Dominion Diagnostics, LLC, North Kingston, RI, United States.,Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Institute of Psychology, University of Eötvös Loránd, Budapest, Hungary.,Department of Clinical Neurology, Path Foundation, New York, NY, United States.,Division of Neuroscience and Addiction Therapy, Summit Estate Recovery Center, Los Gatos, CA, United States.,Department of Neurogenetics Research and Addiction Therapy, The Florida House Experience, Deerfield Beach, FL, United States.,National Human Genome Center, Howard University, Washington, DC, United States
| | - Marjorie C Gondré-Lewis
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Anatomy, Howard University College of Medicine, Washington, DC, United States.,Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical and Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - David Baron
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, United States.,Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States
| | - Panayotis K Thanos
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical and Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.,Department of Psychology, University at Buffalo, Buffalo, NY, United States
| | - Eric R Braverman
- Department of Clinical Neurology, Path Foundation, New York, NY, United States
| | - Jennifer Neary
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States
| | - Igor Elman
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Psychiatry, Cooper Medical School of Rowan University, Camden, NJ, United States
| | - Rajendra D Badgaiyan
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Chevalier N, Parent V, Rouillard M, Simard F, Guay MC, Verret C. The Impact of a Motor-Cognitive Remediation Program on Attentional Functions of Preschoolers With ADHD Symptoms. J Atten Disord 2017; 21:1121-1129. [PMID: 23269196 DOI: 10.1177/1087054712468485] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE The purpose of this study was to measure the impact of the motor-cognitive remediation program (MCRP) that uses sensorimotor and visual-motor imagery techniques on attentional functions in preschoolers with ADHD symptoms. METHOD A total of 15 high-risk preschoolers were selected based on high ADHD symptoms. An experimental group participated in the MCRP and was compared with a control group. The MCRP consisted of 30 activities, 3 times a week, during 12 weeks. RESULTS Children in the experimental group improved significantly for orienting (selective attention) and executive control (inhibition, stopping, and engaging mental operations) compared with the control group. CONCLUSION These results are a first step to support the postulate that training specific attentional functions by sensorimotor activities and visual-motor imagery has an impact on the cognitive network of attention. This study suggests the potential value of MCRP addressed to preschoolers with ADHD symptoms.
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Sorgdrager FJH, Doornbos B, Penninx BWJH, de Jonge P, Kema IP. The association between the hypothalamic pituitary adrenal axis and tryptophan metabolism in persons with recurrent major depressive disorder and healthy controls. J Affect Disord 2017; 222:32-39. [PMID: 28668713 DOI: 10.1016/j.jad.2017.06.052] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 06/02/2017] [Accepted: 06/23/2017] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Persistent changes in serotonergic and hypothalamic pituitary adrenal (HPA) axis functioning are implicated in recurrent types of major depressive disorder (MDD). Systemic tryptophan levels, which influence the rate of serotonin synthesis, are regulated by glucocorticoids produced along the HPA axis. We investigated tryptophan metabolism and its association with HPA axis functioning in single episode MDD, recurrent MDD and non-depressed individuals. METHODS We included depressed individuals (n = 1320) and controls (n = 406) from the Netherlands Study of Depression and Anxiety (NESDA). The kynurenine to tryptophan ratio (kyn/trp ratio) was established using serum kynurenine and tryptophan levels. Several HPA axis parameters were calculated using salivary cortisol samples. We adjusted the regression analyses for a wide range of potential confounders and differentiated between single episode MDD, recurrent MDD and control. RESULTS Tryptophan, kynurenine and the kyn/trp ratio did not differ between controls and depressed individuals. Increased evening cortisol levels were associated with a decreased kyn/trp ratio in the total sample (Crude: β = -.102, p < .001; Adjusted: β = -.083, p < .001). This association was found to be restricted to recurrently depressed individuals (Crude: β = -.196, p < .001; Adjusted: β = -.145, p = .001). Antidepressant treatment did not affect this association. CONCLUSIONS Our results suggest that an imbalance between HPA axis function and tryptophan metabolism could be involved in recurrent depression.
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Affiliation(s)
- F J H Sorgdrager
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - B Doornbos
- University Center Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Interdisciplinary Center of Psychiatric Epidemiology, Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; GGZ Drenthe Mental Health Center, Department of Affective and Bipolar Disorders, Assen, The Netherlands
| | - B W J H Penninx
- Department of Psychiatry, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands
| | - P de Jonge
- Interdisciplinary Center of Psychiatric Epidemiology, Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - I P Kema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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10
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Sauvé G, Morand-Beaulieu S, O'Connor KP, Blanchet PJ, Lavoie ME. P300 Source Localization Contrasts in Body-Focused Repetitive Behaviors and Tic Disorders. Brain Sci 2017; 7:E76. [PMID: 28671557 PMCID: PMC5532589 DOI: 10.3390/brainsci7070076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/25/2017] [Accepted: 06/27/2017] [Indexed: 11/17/2022] Open
Abstract
Tic disorders (TD) and body-focused repetitive behaviors (BFRB) have similar phenotypes that can be challenging to distinguish in clinical settings. Both disorders show high rates of comorbid psychiatric conditions, dysfunctional basal ganglia activity, atypical cortical functioning in the prefrontal and motor cortical regions, and cognitive deficits. Clinicians frequently confound the two disorders and it is important to find reliable objective methods to discriminate TD and BFRB. Neuropsychological tests and event-related potential (ERP) studies have yielded inconsistent results regarding a possible context updating deficit in TD and BFRB patients. However, most previous studies did not control for the presence of comorbid psychiatric condition and medication status, which might have confounded the findings reported to date. Hence, we aimed to investigate the psychophysiology of working memory using ERP in carefully screened TD and BFRB patients excluding those with psychiatric comorbidity and those taking psychoactive medication. The current study compared 12 TD patients, 12 BRFB patients, and 15 healthy control participants using a motor oddball task (button press). The P300 component was analyzed as an index of working memory functioning. Results showed that BFRB patients had decreased P300 oddball effect amplitudes over the right hemisphere compared to the TD and control groups. Clinical groups presented different scalp distributions compared to controls, which could represent a potential endophenotype candidate of BFRB and TD.
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Affiliation(s)
- Geneviève Sauvé
- Department of Psychiatry, McGill University, Montréal, QC H3A 1A1, Canada.
- Cognitive and Social Psychophysiology Lab, Centre de Recherche de L'Institut Universitaire en Santé Mentale de Montréal, 7331 Hochelaga Street, Montréal, QC H1N 3V2, Canada.
| | - Simon Morand-Beaulieu
- Cognitive and Social Psychophysiology Lab, Centre de Recherche de L'Institut Universitaire en Santé Mentale de Montréal, 7331 Hochelaga Street, Montréal, QC H1N 3V2, Canada.
- Department of Neurosciences, Université de Montréal, Montréal, QC H3T 1J4, Canada.
| | - Kieron P O'Connor
- Department of Psychiatry, Université de Montréal, Montréal, QC H3T 1J4, Canada.
- Centre D'études sur les Troubles Obsessionnels-Compulsifs et les Tics, Centre de Recherche de L'Institut Universitaire en Santé Mentale de Montréal, 7331 Hochelaga Street, Montréal, QC H1N 3V2, Canada.
| | - Pierre J Blanchet
- Department of Neurosciences, Université de Montréal, Montréal, QC H3T 1J4, Canada.
- Centre D'études sur les Troubles Obsessionnels-Compulsifs et les Tics, Centre de Recherche de L'Institut Universitaire en Santé Mentale de Montréal, 7331 Hochelaga Street, Montréal, QC H1N 3V2, Canada.
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada.
| | - Marc E Lavoie
- Cognitive and Social Psychophysiology Lab, Centre de Recherche de L'Institut Universitaire en Santé Mentale de Montréal, 7331 Hochelaga Street, Montréal, QC H1N 3V2, Canada.
- Department of Neurosciences, Université de Montréal, Montréal, QC H3T 1J4, Canada.
- Department of Psychiatry, Université de Montréal, Montréal, QC H3T 1J4, Canada.
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Kim YS, Yoon BE. Altered GABAergic Signaling in Brain Disease at Various Stages of Life. Exp Neurobiol 2017; 26:122-131. [PMID: 28680297 PMCID: PMC5491580 DOI: 10.5607/en.2017.26.3.122] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 05/06/2017] [Accepted: 05/15/2017] [Indexed: 01/21/2023] Open
Abstract
In the healthy brain, gamma-aminobutyric acid (GABA) is regulated by neurons and glia. This begs the question: what happens in the malfunctioning brain? There are many reasons why diseases occur, including genetic mutations, systemic problems, and environmental influences. There are also many ways in which GABA can become dysregulated, such as through alterations in its synthesis or release, and changes in systems that respond to it. Notably, dysregulation of GABA can have a large impact on the brain. To date, few reviews have examined brain diseases in which dysregulation of GABA is implicated as an underlying factor. Accordingly, the time is ripe for investigating alterations in GABAergic signaling that may play a role in changes in neuronal activity observed in the major brain disorders that occur during various stages of life. This review is meant to provide a better understanding of the role of GABA in brain health and contributor to social problems from a scientific perspective.
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Affiliation(s)
- Yoo Sung Kim
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea
| | - Bo-Eun Yoon
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea
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12
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Abstract
Tourette syndrome is a neuropsychiatric condition characterized by both motor and phonic tics over a period of at least 1 year with the onset in childhood or adolescence. Apart from the tics, most of the patients with Tourette syndrome have associated neuropsychiatric comorbidities consisting of attention deficit hyperactivity disorder, obsessive compulsive disorder, rage attacks, sleep issues, depression, and migraine. Patients may also have physical complications directly from violent motor tics which can rarely include cervical myelopathy, arterial dissection, and stroke. The purpose of this article is to review the associated neuropsychiatric comorbidities of Tourette syndrome with emphasis on recent research.
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Zhou R, Han X, Wang J, Sun J. Baicalin may have a therapeutic effect in attention deficit hyperactivity disorder. Med Hypotheses 2016; 85:761-4. [PMID: 26604025 DOI: 10.1016/j.mehy.2015.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/29/2015] [Accepted: 10/11/2015] [Indexed: 11/19/2022]
Abstract
Baicalin is a flavonoid purified from Scutellaria baicalensis Georgi. It possesses a variety of pharmacological properties, such as anti-inflammatory, antioxidant, antiapoptotic, and neuro-protective properties, and provides protection against cerebral hemorrhage. However, it is seldom considered a therapeutic in mental disorders. Recent studies showed that baicalin protects cerebral functions against ischemia and has sedative and anxiolytic-like effects. Animal experiments showed that it protects dopaminergic neurons in the striatum, hippocampus and substantia nigra. It also has effects such as anti-depressive and anti-epileptic and offers resistance to Parkinson's disease. Attention deficit hyperactivity disorder (ADHD) pathogenesis is closely related to dopamine deficiency. However, the therapeutic effect of baicalin in ADHD has not been studied. We hypothesize that baicalin may protect dopaminergic neurons and increase brain dopamine levels, thus serving as an effective novel treatment for ADHD.
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Martínez L, Prada E, Satler C, Tavares MCH, Tomaz C. Executive Dysfunctions: The Role in Attention Deficit Hyperactivity and Post-traumatic Stress Neuropsychiatric Disorders. Front Psychol 2016; 7:1230. [PMID: 27602003 PMCID: PMC4993788 DOI: 10.3389/fpsyg.2016.01230] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
Executive functions (EFs) is an umbrella term for various cognitive processes controlled by a complex neural activity, which allow the production of different types of behaviors seeking to achieve specific objectives, one of them being inhibitory control. There is a wide consensus that clinical and behavioral alterations associated with EF, such as inhibitory control, are present in various neuropsychiatric disorders. This paper reviews the research literature on the relationship between executive dysfunction, frontal-subcortical neural circuit changes, and the psychopathological processes associated with attention deficit hyperactivity disorder (ADHD) and post-traumatic stress disorder (PTSD). A revision on the role of frontal-subcortical neural circuits and their presumable abnormal functioning and the high frequency of neuropsychiatric symptoms could explain the difficulties with putting effector mechanisms into action, giving individuals the necessary tools to act efficiently in their environment. Although, neuronal substrate data about ADHD and PTSD has been reported in the literature, it is isolated. Therefore, this review highlights the overlapping of neural substrates in the symptomatology of ADHD and PTSD disorders concerning EFs, especially in the inhibitory component. Thus, the changes related to impaired EF that accompany disorders like ADHD and PTSD could be explained by disturbances that have a direct or indirect impact on the functioning of these loops. Initially, the theoretical model of EF according to current neuropsychology will be presented, focusing on the inhibitory component. In a second stage, this component will be analyzed for each of the disorders of interest, considering the clinical aspects, the etiology and the neurobiological basis. Additionally, commonalities between the two neuropsychiatric conditions will be taken into consideration from the perspectives of cognitive and emotional inhibition. Finally, the implications and future prospects for research and interventions in the area will be outlined, with the intention of contributing scientific reference information that encompasses the knowledge and understanding of executive dysfunction and its relationship with these treated disorders.
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Affiliation(s)
- Lía Martínez
- Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, University of Brasilia Brasilia, Brazil
| | - Edward Prada
- Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, University of BrasiliaBrasilia, Brazil; Faculty of Psychology, Social Sciences Department, Universidad Pontificia Bolivariana Seccional BucaramangaBucaramanga, Colombia
| | - Corina Satler
- Faculty of Ceilandia, University of Brasilia Brasilia, Brazil
| | - Maria C H Tavares
- Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, University of Brasilia Brasilia, Brazil
| | - Carlos Tomaz
- Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, University of BrasiliaBrasilia, Brazil; Neuroscience Research Program, University CEUMASão Luis, Brazil
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Affiliation(s)
| | - Shun Ting Loy
- Neurosurgery Service, Singapore General Hospital, Singapore.
| | - Arvind Gupta
- Neuro-Ophthalmology Department, Singapore National Eye Centre, Singapore
| | - Ivan Ng
- Neurosurgery Service, Singapore General Hospital, Singapore.
| | - James F Cullen
- Neuro-Ophthalmology Department, Singapore National Eye Centre, Singapore
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O'Farrell K, Harkin A. Stress-related regulation of the kynurenine pathway: Relevance to neuropsychiatric and degenerative disorders. Neuropharmacology 2015; 112:307-323. [PMID: 26690895 DOI: 10.1016/j.neuropharm.2015.12.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/02/2015] [Accepted: 12/08/2015] [Indexed: 02/08/2023]
Abstract
The kynurenine pathway (KP), which is activated in times of stress and infection has been implicated in the pathophysiology of neurodegenerative and psychiatric disorders. Activation of this tryptophan metabolising pathway results in the production of neuroactive metabolites which have the potential to interfere with normal neuronal functioning which may contribute to altered neuronal transmission and the emergence of symptoms of these brain disorders. This review investigates the involvement of the KP in a range of neurological disorders, examining recent in vitro, in vivo and clinical discoveries highlights evidence to indicate that the KP is a potential therapeutic target in both neurodegenerative and stress-related neuropsychiatric disorders. Furthermore, this review identifies gaps in our knowledge with regard to this field which are yet to be examined to lead to a more comprehensive understanding of the role of KP activation in brain health and disease. This article is part of the Special Issue entitled 'The Kynurenine Pathway in Health and Disease'.
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Affiliation(s)
- Katherine O'Farrell
- Neuropsychopharmacology Research Group, School of Pharmacy and Pharmaceutical Sciences & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Andrew Harkin
- Neuropsychopharmacology Research Group, School of Pharmacy and Pharmaceutical Sciences & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland; Neuroimmunology Research Group, Department of Physiology, School of Medicine & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland.
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El Malhany N, Gulisano M, Rizzo R, Curatolo P. Tourette syndrome and comorbid ADHD: causes and consequences. Eur J Pediatr 2015; 174:279-88. [PMID: 25224657 DOI: 10.1007/s00431-014-2417-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/27/2014] [Accepted: 09/01/2014] [Indexed: 12/17/2022]
Abstract
UNLABELLED Attention deficit hyperactivity disorder (ADHD) is the most common comorbid condition in patients with Tourette syndrome (TS). The co-occurrence of ADHD and TS is in most cases associated with a higher social and psychopathological impairment. Comorbidity between Tourette and ADHD appears to have a complex and partially known pathogenesis in which genetic, environmental, and neurobiological factors can be implicated. Genetic studies have revealed an involvement of dopaminergic, catecholaminergic, and GABAergic genes that modulated the activity of neurotransmitters. Furthermore, there are a lot of networks implicated in the development of ADHD and TS, involving cortical and striatal areas and basal ganglia. Although a large number of studies tried to find a common pathogenesis, the complex pathways responsible are not clear. The genes implicated in both disorders are currently unidentified, but it is probable that epigenetic factors associated with neural modifications can represent a substrate for the development of the diseases. CONCLUSION In this paper, recent advances in neurobiology of ADHD and TS are reviewed, providing a basis for understanding the complex common pathogenesis underlying the frequent co-occurrence of the two conditions and the therapeutic choices.
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Affiliation(s)
- N El Malhany
- Section of Child Neuropsychiatry, Department of Neurosciences, Tor Vergata University, Viale Oxford 81, 00133, Rome, Italy,
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Abstract
In addition to the symptoms singled out by the diagnostic criteria for Attention-Deficit Hyperactivity Disorder (ADHD), a comprehensive definition should inform us of the events that trigger ADHD in both its acute and chronic manifestations; the neurobiology that underlies it; and the evolutionary forces that have kept it in the germ line of our species. These factors are organized in terms of Aristotle's four kinds of "causes," or explanations: formal, efficient, material, and final. This framework systematizes the nosology, biology, psychology, and evolutionary pressures that cause ADHD.
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Ferreira BR, Pio-Abreu JL, Januário C. Tourette's syndrome and associated disorders: a systematic review. TRENDS IN PSYCHIATRY AND PSYCHOTHERAPY 2014; 36:123-33. [DOI: 10.1590/2237-6089-2014-1003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Objective: To compile data on Tourette's syndrome (TS), tics and associated disorders.Methods: A systematic review of the literature was conducted using the 5S levels of organization of healthcare research evidence (systems, summaries, synopses, syntheses, studies), based on the model described by Haynes. The search keywords were Tourette, tics and comorbidity, which were cross-referenced. Studies provided by publishers and articles being processed on July 31, 2013, were also included.Results: Of all studies retrieved during the search, 64 were selected because they analyzed the epidemiology, clinical features and etiopathogenesis of TS and its comorbidities. TS is classified as a hyperkinetic movement disorder, and at least 90% of the patients have neuropsychiatric comorbidities, of which attention deficit hyperactivity and obsessive-compulsive disorders are the most common. The syndrome is clinically heterogeneous and has been associated with a dysfunction of cortico-striatal-thalamic-cortical circuits involving various neurotransmitters. Although its genetic etiology has been widely studied, other factors may be important to understand this syndrome and its associated disorders.Conclusions: TS is a neurodevelopmental disorder that results from the impact of stress factors on a vulnerable biological substrate during the critical periods of neurodevelopment. The study of TS and its comorbidities may contribute, at different levels, to the understanding of several neuropsychiatric disorders of clinical and therapeutic relevance.
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Loss of neuronal 3D chromatin organization causes transcriptional and behavioural deficits related to serotonergic dysfunction. Nat Commun 2014; 5:4450. [PMID: 25034090 DOI: 10.1038/ncomms5450] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/18/2014] [Indexed: 12/20/2022] Open
Abstract
The interior of the neuronal cell nucleus is a highly organized three-dimensional (3D) structure where regions of the genome that are linearly millions of bases apart establish sub-structures with specialized functions. To investigate neuronal chromatin organization and dynamics in vivo, we generated bitransgenic mice expressing GFP-tagged histone H2B in principal neurons of the forebrain. Surprisingly, the expression of this chimeric histone in mature neurons caused chromocenter declustering and disrupted the association of heterochromatin with the nuclear lamina. The loss of these structures did not affect neuronal viability but was associated with specific transcriptional and behavioural deficits related to serotonergic dysfunction. Overall, our results demonstrate that the 3D organization of chromatin within neuronal cells provides an additional level of epigenetic regulation of gene expression that critically impacts neuronal function. This in turn suggests that some loci associated with neuropsychiatric disorders may be particularly sensitive to changes in chromatin architecture.
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Vlaikou AM, Manolakos E, Noutsopoulos D, Markopoulos G, Liehr T, Vetro A, Ziegler M, Weise A, Kreskowski K, Papoulidis I, Thomaidis L, Syrrou M. An Interstitial 4q31.21q31.22 Microdeletion Associated with Developmental Delay: Case Report and Literature Review. Cytogenet Genome Res 2014; 142:227-38. [DOI: 10.1159/000361001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2014] [Indexed: 11/19/2022] Open
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Rubin DH, Althoff RR, Ehli EA, Davies GE, Rettew DC, Crehan ET, Walkup JT, Hudziak JJ. Candidate gene associations with withdrawn behavior. J Child Psychol Psychiatry 2013; 54:1337-45. [PMID: 23808549 PMCID: PMC3800258 DOI: 10.1111/jcpp.12108] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/13/2013] [Indexed: 01/03/2023]
Abstract
BACKGROUND Social withdrawal is a core neuropsychiatric phenomenon in developmental psychopathology. Its presence predicts psychopathology across many domains, including depression, psychosis, autism, anxiety, and suicide. Withdrawn behavior is highly heritable, persistent, and characteristically worsens without intervention. To date, few studies have successfully identified genetic associations with withdrawn behavior, despite the abundance of evidence of its heritability. This may be due to reliance of categorical over dimensional measures of the behaviorally inhibited phenotype. The aim of this study is to identify associations between known psychiatric candidate genes and a dimensionally derived measure of withdrawn behavior. METHODS Genetic information was collected on 20 single-nucleotide polymorphisms (SNPs) from a custom-designed SNP chip and TAQMAN arrays of 4 variable number of tandem repeat (VNTR) genes for 551 individuals from 187 families. Linear mixed modeling was employed to examine the relationship between genotypes of interest and Child Behavior Checklist (CBCL) Withdrawn Behavior Subscale Score (WBS) while controlling for gender and age through multiple linear regressions. RESULTS Withdrawn behavior was highly associated with polymorphism rs6314 of the serotonin receptor 2A (HTR2A) [p = .009, estimate = 0.310 (bootstrap 95% CI 0.155-0.448), bootstrap p = .001] and rs1800544 of the alpha 2-adrenergic (ADRA2A) [p = .001, estimate = -0.310 (bootstrap 95% CI -0.479 to -0.126), bootstrap p = .001] genes after correction for gender and age. The association between withdrawn behavior and ADRA2A was stronger for younger children. CONCLUSIONS HTR2A and ADRA2A genes are associated with withdrawn behavior. This reinforces the role of catecholaminergic genes in the heritability of withdrawn behavior.
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Affiliation(s)
- David H. Rubin
- Weill-Cornell Medical College,Correspondence to: David H. Rubin, MD, Weill Cornell Medical College and NewYork-Presbyterian Hospital, 21 Bloomingdale Road, White Plains, NY 10605, Work: 914 997 5991, Fax: 914 682 6988,
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Role of COMT in ADHD: a Systematic Meta-Analysis. Mol Neurobiol 2013; 49:251-61. [DOI: 10.1007/s12035-013-8516-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 07/11/2013] [Indexed: 12/30/2022]
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Yang P, Cai G, Cai Y, Fei J, Liu G. Gamma aminobutyric acid transporter subtype 1 gene knockout mice: a new model for attention deficit/hyperactivity disorder. Acta Biochim Biophys Sin (Shanghai) 2013; 45:578-85. [PMID: 23656791 DOI: 10.1093/abbs/gmt043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Attention deficit/hyperactivity disorder (ADHD) is characterized by hyperactivity, impaired sustained attention, impulsivity, and is usually accompanied by varying degrees of learning difficulties and lack of motor coordination. However, the pathophysiology and etiology of ADHD remain inconclusive so far. Our previous studies have demonstrated that the gamma aminobutyric acid transporter subtype 1 (GAT1) gene knockout (ko) mouse (gat1-/-) is hyperactive and exhibited impaired memory performance in the Morris water maze. In the current study, we found that the gat1-/- mice showed low levels of attentional focusing and increased impulsivity. In addition, the gat1-/- mice displayed ataxia characterized by defects in motor coordination and balance skills. The hyperactivity in the ko mice was reduced by both methylphenidate and amphetamine. Collectively, these results suggest that GAT1 ko mouse is a new animal model for ADHD studying and GAT1 may be a new target to treat ADHD.
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Affiliation(s)
- Ping Yang
- School of Life Sciences and Technology, TongJi University, Shanghai 200092, China
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Sasaki K, Yamasaki T, Omotuyi IO, Mishina M, Ueda H. Age-dependent dystonia in striatal Gγ7 deficient mice is reversed by the dopamine D2 receptor agonist pramipexole. J Neurochem 2013; 124:844-54. [PMID: 23311775 DOI: 10.1111/jnc.12149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/04/2013] [Accepted: 01/04/2013] [Indexed: 01/27/2023]
Abstract
Gγ7 is enriched in striatum and forms a heterotrimeric complex with Gαolf /Gβ, which is coupled to D1 receptor (D1R). Here, we attempted to characterize the pathophysiological, neurochemical, and pharmacological features of mice deficient of Gγ7 gene. Gγ7 knockout mice exhibited age-dependent deficiency in rotarod behavior and increased dystonia-like clasping reflex without loss of striatal neurons. The neurochemical basis for the motor manifestations using immunoblot analysis revealed increased levels of D1R, ChAT and NMDA receptor subunits (NR1 and NR2B) concurrent with decreased levels of D2R and Gαolf , possibly because of the secondary changes of decreased Gαolf /Gγ7-mediated D1R transmission. These behavioral and neurochemical changes are closely related to those observed in Huntington's disease (HD) human subjects and HD model mice. Taking advantage of the finding of D2R down-regulation in Gγ7 knockout mice and the dopamine-mediated synergistic relationship in the control of locomotion between D2R-striatopallidal and D1R-stritonigral neurons, we hypothesized that D2-agonist pramipexole would reverse behavioral dyskinesia caused by defective D1R/Gαolf signaling. Indeed, the rotarod deficiency and clasping reflex were reversed by pramipexole treatment under chronic administration. These findings suggest that Gγ7 knockout mice could be a new type of movement disorders, including HD and useful for the evaluation of therapeutic candidates.
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Affiliation(s)
- Keita Sasaki
- Department of Molecular Pharmacology and Neuroscience, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Gunther J, Tian Y, Stamova B, Lit L, Corbett B, Ander B, Zhan X, Jickling G, Bos-Veneman N, Liu D, Hoekstra P, Sharp F. Catecholamine-related gene expression in blood correlates with tic severity in tourette syndrome. Psychiatry Res 2012; 200:593-601. [PMID: 22648010 DOI: 10.1016/j.psychres.2012.04.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/24/2012] [Accepted: 04/26/2012] [Indexed: 12/24/2022]
Abstract
Tourette syndrome (TS) is a heritable disorder characterized by tics that are decreased in some patients by treatment with alpha adrenergic agonists and dopamine receptor blockers. Thus, this study examines the relationship between catecholamine gene expression in blood and tic severity. TS diagnosis was confirmed using Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria and tic severity measured using the Yale Global Tic Severity Scale (YGTSS) for 26 un-medicated subjects with TS. Whole blood was collected and Ribonucleic acid (RNA) processed on Affymetrix Human Exon 1.0 ST arrays. An Analysis of Covariance (ANCOVA) identified 3627 genes correlated with tic severity (p<0.05). Searches of Medical Subject Headings, Gene Ontology, Allen Mouse Brain Atlas, and PubMed determined genes associated with catecholamines and located in the basal ganglia. Using GeneCards, PubMed, and manual curation, seven genes associated with TS were further examined: DRD2, HRH3, MAOB, BDNF, SNAP25, SLC6A4, and SLC22A3. These genes are highly associated with TS and have also been implicated in other movement disorders, Attention Deficit Hyperactivity Disorder (ADHD), and Obsessive-Compulsive Disorder (OCD). Correlation of gene expression in peripheral blood with tic severity may allow inferences about catecholamine pathway dysfunction in TS subjects. Findings built on previous work suggest that at least some genes expressed peripherally are relevant for central nervous system (CNS) pathology in the brain of individuals with TS.
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Affiliation(s)
- Joan Gunther
- Department of Neurology and MIND Institute, University of California at Davis, 2805 50th Street, Sacramento, CA 95817, USA.
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Correlations of gene expression with ratings of inattention and hyperactivity/impulsivity in Tourette syndrome: a pilot study. BMC Med Genomics 2012; 5:49. [PMID: 23110997 PMCID: PMC3497583 DOI: 10.1186/1755-8794-5-49] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 10/09/2012] [Indexed: 12/04/2022] Open
Abstract
Background Inattentiveness, impulsivity and hyperactivity are the primary behaviors associated with attention-deficit hyperactivity disorder (ADHD). Previous studies showed that peripheral blood gene expression signatures can mirror central nervous system disease. Tourette syndrome (TS) is associated with inattention (IA) and hyperactivity/impulsivity (HI) symptoms over 50% of the time. This study determined if gene expression in blood correlated significantly with IA and/or HI rating scale scores in participants with TS. Methods RNA was isolated from the blood of 21 participants with TS, and gene expression measured on Affymetrix human U133 Plus 2.0 arrays. To identify the genes that correlated with Conners’ Parents Ratings of IA and HI ratings of symptoms, an analysis of covariance (ANCOVA) was performed, controlling for age, gender and batch. Results There were 1201 gene probesets that correlated with IA scales, 1625 that correlated with HI scales, and 262 that correlated with both IA and HI scale scores (P<0.05, |Partial correlation (rp)|>0.4). Immune, catecholamine and other neurotransmitter pathways were associated with IA and HI behaviors. A number of the identified genes (n=27) have previously been reported in ADHD genetic studies. Many more genes correlated with either IA or HI scales alone compared to those that correlated with both IA and HI scales. Conclusions These findings support the concept that the pathophysiology of ADHD and/or its subtypes in TS may involve the interaction of multiple genes. These preliminary data also suggest gene expression may be useful for studying IA and HI symptoms that relate to ADHD in TS and perhaps non-TS participants. These results will need to be confirmed in future studies.
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WANG GUANGXIN, MA YANHUI, WANG SHIFU, REN GUANGFANG, GUO HUI. Association of dopaminergic/GABAergic genes with attention deficit hyperactivity disorder in children. Mol Med Rep 2012; 6:1093-8. [PMID: 22895683 DOI: 10.3892/mmr.2012.1028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 08/01/2012] [Indexed: 11/06/2022] Open
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Murphy T, Muter V. Risk Factors for Comorbidity in ADHD and GTS: Looking Beyond a Single-Deficit Model. APPLIED NEUROPSYCHOLOGY-CHILD 2012; 1:129-36. [DOI: 10.1080/21622965.2012.703889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Tebano MT, Martire A, Popoli P. Adenosine A(2A)-cannabinoid CB(1) receptor interaction: an integrative mechanism in striatal glutamatergic neurotransmission. Brain Res 2012; 1476:108-18. [PMID: 22565012 DOI: 10.1016/j.brainres.2012.04.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 12/12/2022]
Abstract
The striatum is a subcortical area involved in sensorimotor, cognitive and emotional processes. Adenosine A(2A) receptors (A(2A)Rs) are highly expressed in the striatum, and their ability to establish functional and molecular interactions with many other receptors attributes to a pivotal role in the modulation and integration of striatal neurotransmission. This review will focus on the interaction between A(2A)Rs and cannabinoid CB(1) receptors (CB(1)Rs), taking it as a paradigmatic example of synaptic integration. Indeed, A(2A)Rs can exert an opposite (permissive vs. inhibitory) influence on CB1-dependent synaptic effect. These apparently irreconcilable functions could depend on a different role of pre- vs. postsynaptic A(2A)Rs, on their interaction with other receptors (namely adenosine A(1), metabotropic glutamate 5 and dopamine D2 receptors), and on whether A(2A)Rs form or not heteromers with CB(1)Rs. Besides providing a good example of the intricate pattern of events taking place in striatal synapses, the A(2A)/CB(1)R interaction proves very informative to understand the physiology of the basal ganglia and the mechanisms of related diseases. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Maria Teresa Tebano
- Section of Central Nervous System Pharmacology, Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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Fabretto A, Rocca MS, Perrone MD, Skabar A, Pecile V, Gasparini P. De novo 6.9 Mb interstitial deletion on chromosome 4q31.1-q32.1 in a girl with severe speech delay and dysmorphic features. Am J Med Genet A 2012; 158A:882-7. [DOI: 10.1002/ajmg.a.35239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 12/26/2011] [Indexed: 11/05/2022]
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Blum K, Chen ALC, Oscar-Berman M, Chen TJH, Lubar J, White N, Lubar J, Bowirrat A, Braverman E, Schoolfield J, Waite RL, Downs BW, Madigan M, Comings DE, Davis C, Kerner MM, Knopf J, Palomo T, Giordano JJ, Morse SA, Fornari F, Barh D, Femino J, Bailey JA. Generational association studies of dopaminergic genes in reward deficiency syndrome (RDS) subjects: selecting appropriate phenotypes for reward dependence behaviors. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:4425-59. [PMID: 22408582 PMCID: PMC3290972 DOI: 10.3390/ijerph8124425] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 11/23/2011] [Accepted: 11/23/2011] [Indexed: 11/26/2022]
Abstract
UNLABELLED Abnormal behaviors involving dopaminergic gene polymorphisms often reflect an insufficiency of usual feelings of satisfaction, or Reward Deficiency Syndrome (RDS). RDS results from a dysfunction in the "brain reward cascade," a complex interaction among neurotransmitters (primarily dopaminergic and opioidergic). Individuals with a family history of alcoholism or other addictions may be born with a deficiency in the ability to produce or use these neurotransmitters. Exposure to prolonged periods of stress and alcohol or other substances also can lead to a corruption of the brain reward cascade function. We evaluated the potential association of four variants of dopaminergic candidate genes in RDS (dopamine D1 receptor gene [DRD1]; dopamine D2 receptor gene [DRD2]; dopamine transporter gene [DAT1]; dopamine beta-hydroxylase gene [DBH]). METHODOLOGY We genotyped an experimental group of 55 subjects derived from up to five generations of two independent multiple-affected families compared to rigorously screened control subjects (e.g., N = 30 super controls for DRD2 gene polymorphisms). Data related to RDS behaviors were collected on these subjects plus 13 deceased family members. RESULTS Among the genotyped family members, the DRD2 Taq1 and the DAT1 10/10 alleles were significantly (at least p < 0.015) more often found in the RDS families vs. controls. The TaqA1 allele occurred in 100% of Family A individuals (N = 32) and 47.8% of Family B subjects (11 of 23). No significant differences were found between the experimental and control positive rates for the other variants. CONCLUSIONS Although our sample size was limited, and linkage analysis is necessary, the results support the putative role of dopaminergic polymorphisms in RDS behaviors. This study shows the importance of a nonspecific RDS phenotype and informs an understanding of how evaluating single subset behaviors of RDS may lead to spurious results. Utilization of a nonspecific "reward" phenotype may be a paradigm shift in future association and linkage studies involving dopaminergic polymorphisms and other neurotransmitter gene candidates.
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Affiliation(s)
- Kenneth Blum
- Department of Psychiatry, School of Medicine and McKnight Brain Institute, University of Florida, W University Ave., Gainesville, FL 32601, USA;
- Department of Nutrigenomics, LifeGen, Inc., P.O. Box 366, 570 Lederach Stattion Way, Lederach, PA 19450, USA; (R.L.W.); (B.W.D.); (M.M.)
- Department of Integrative Medicine, PATH Medical Research Foundation, 304 Park Ave. South, New York, NY 10010, USA; (M.M.K.); (J.K.)
- Department of Holistic Medicine, G&G Holistic Addiction Treatment, Inc., 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
- Department of Research, National Institute for Holistic Addiction Studies, 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
- Dominion Diagnostics, Inc., 211 Circuit Road, North Kingstown, RI 02852, USA;
- Center for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, Purba Medinipur, West Bengal, India;
| | - Amanda L. C. Chen
- Department of Engineering Management Advanced Technology, Chang Jung Christian University, No. 396, Sec. 1, Changrong Road, Tainan 71101, Taiwan
| | - Marlene Oscar-Berman
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA;
| | - Thomas J. H. Chen
- Department of Occupational Safety and Health, Chang Jung Christian University, No. 396, Sec. 1, Changrong Road, Tainan 71101, Taiwan;
| | - Joel Lubar
- Emeritus, Department of Physiology, University of Tennessee, 719 Andy Holt Tower, Knoxville, TN 37996, USA;
| | - Nancy White
- Unique Mindcare, Inc., 1900 Saint James Place, Houston, TX 77056, USA;
| | - Judith Lubar
- Department of Neurofeedback, Southeastern Biofeedback and Neurobehavioral Clinic, 101 Westwood Road, Knoxville, TN 37919, USA;
| | - Abdalla Bowirrat
- Department of Neuroscience & Population Genetics, EMMS Nazareth Hospital, Nazareth, Israel;
| | - Eric Braverman
- Department of Neurosurgery, Weill Cornell College of Medicine, 1300 York Ave., New York, NY 10065, USA;
- Department of Integrative Medicine, PATH Medical Research Foundation, 304 Park Ave. South, New York, NY 10010, USA; (M.M.K.); (J.K.)
| | - John Schoolfield
- Department of Academic Informatics Services, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA;
| | - Roger L. Waite
- Department of Nutrigenomics, LifeGen, Inc., P.O. Box 366, 570 Lederach Stattion Way, Lederach, PA 19450, USA; (R.L.W.); (B.W.D.); (M.M.)
| | - Bernard W. Downs
- Department of Nutrigenomics, LifeGen, Inc., P.O. Box 366, 570 Lederach Stattion Way, Lederach, PA 19450, USA; (R.L.W.); (B.W.D.); (M.M.)
| | - Margaret Madigan
- Department of Nutrigenomics, LifeGen, Inc., P.O. Box 366, 570 Lederach Stattion Way, Lederach, PA 19450, USA; (R.L.W.); (B.W.D.); (M.M.)
| | - David E. Comings
- Department of Genomic Research, Carlsbad Science Foundation, Department of Medical Genetics, City of Hope National Medical Center, 1500 Duarte Road, Duarte, CA 91010, USA;
| | - Caroline Davis
- Department of Kinesiology and Health Sciences, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada;
| | - Mallory M. Kerner
- Department of Integrative Medicine, PATH Medical Research Foundation, 304 Park Ave. South, New York, NY 10010, USA; (M.M.K.); (J.K.)
| | - Jennifer Knopf
- Department of Integrative Medicine, PATH Medical Research Foundation, 304 Park Ave. South, New York, NY 10010, USA; (M.M.K.); (J.K.)
| | - Tomas Palomo
- Hospital Universitario 12 de Octubre, Servicio de Psiquiatria, Av. Cordoba SN, Madrid 28041, Spain;
| | - John J. Giordano
- Department of Holistic Medicine, G&G Holistic Addiction Treatment, Inc., 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
- Department of Research, National Institute for Holistic Addiction Studies, 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
| | - Siobhan A. Morse
- Department of Holistic Medicine, G&G Holistic Addiction Treatment, Inc., 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
- Department of Research, National Institute for Holistic Addiction Studies, 1590 Northeast 162nd Street, North Miami Beach, FL 33162, USA;
| | - Frank Fornari
- Dominion Diagnostics, Inc., 211 Circuit Road, North Kingstown, RI 02852, USA;
| | - Debmalya Barh
- Center for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, Purba Medinipur, West Bengal, India;
| | - John Femino
- Meadows Edge Recovery Center, 580 10 Rod Road, North Kingstown, RI 02852, USA;
| | - John A. Bailey
- Department of Psychiatry, School of Medicine and McKnight Brain Institute, University of Florida, W University Ave., Gainesville, FL 32601, USA;
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Ena S, de Kerchove d'Exaerde A, Schiffmann SN. Unraveling the differential functions and regulation of striatal neuron sub-populations in motor control, reward, and motivational processes. Front Behav Neurosci 2011; 5:47. [PMID: 21847377 PMCID: PMC3148764 DOI: 10.3389/fnbeh.2011.00047] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/18/2011] [Indexed: 12/15/2022] Open
Abstract
The striatum, the major input structure of the basal ganglia, is critically involved in motor control and learning of habits and skills, and is also involved in motivational and reward processes. The dorsal striatum, caudate–putamen, is primarily implicated in motor functions whereas the ventral striatum, the nucleus accumbens, is essential for motivation and drug reinforcement. Severe basal ganglia dysfunction occurs in movement disorders as Parkinson's and Huntington's disease, and in psychiatric disorders such as schizophrenia and drug addiction. The striatum is essentially composed of GABAergic medium-sized spiny neurons (MSNs) that are output neurons giving rise to the so-called direct and indirect pathways and are targets of the cerebral cortex and mesencephalic dopaminergic neurons. Although the involvement of striatal sub-areas in motor control and motivation has been thoroughly characterized, major issues remained concerning the specific and respective functions of the two MSNs sub-populations, D2R-striatopallidal (dopamine D2 receptor-positive) and D1R-striatonigral (dopamine D1 receptor-positive) neurons, as well as their specific regulation. Here, we review recent advances that gave new insight in the understanding of the differential roles of striatopallidal and striatonigral neurons in the basal ganglia circuit. We discuss innovative techniques developed in the last decade which allowed a much precise evaluation of molecular pathways implicated in motivational processes and functional roles of striatopallidal and striatonigral neurons in motor control and in the establishment of reward-associated behavior.
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Affiliation(s)
- Sabrina Ena
- Laboratory of Neurophysiology, School of Medicine, Université Libre de Bruxelles Brussels, Belgium
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van Loo KMJ, Martens GJM. Genetic and environmental factors in complex neurodevelopmental disorders. Curr Genomics 2011; 8:429-44. [PMID: 19412416 PMCID: PMC2647153 DOI: 10.2174/138920207783591717] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 11/07/2007] [Accepted: 11/09/2007] [Indexed: 12/14/2022] Open
Abstract
Complex neurodevelopmental disorders, such as schizophrenia, autism, attention deficit (hyperactivity) disorder, (manic) depressive illness and addiction, are thought to result from an interaction between genetic and environmental factors. Association studies on candidate genes and genome-wide linkage analyses have identified many susceptibility chromosomal regions and genes, but considerable efforts to replicate association have been surprisingly often disappointing. Here, we summarize the current knowledge of the genetic contribution to complex neurodevelopmental disorders, focusing on the findings from association and linkage studies. Furthermore, the contribution of the interaction of the genetic with environmental and epigenetic factors to the aetiology of complex neurodevelopmental disorders as well as suggestions for future research are discussed.
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Affiliation(s)
- K M J van Loo
- Department of Molecular Animal Physiology, Donders Institute for Neuroscience, Nijmegen Center for Molecular Life Sciences (NCMLS), Faculty of Science, Radboud University Nijmegen, Geert Grooteplein Zuid 28, 6525 GA Nijmegen, The Netherlands
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Funakoshi H, Kanai M, Nakamura T. Modulation of Tryptophan Metabolism, Promotion of Neurogenesis and Alteration of Anxiety-Related Behavior in Tryptophan 2,3-Dioxygenase-Deficient Mice. Int J Tryptophan Res 2011. [PMCID: PMC3195223 DOI: 10.4137/ijtr.s5783] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although tryptophan (Trp) and its metabolites, such as serotonin (5-HT) and kynurenines (KYNs), are strong modulators of emotional behavior, the metabolic pathway(s) responsible for this physiological modulation is not fully understood. Two of the initial rate-limiting enzymes of the kynurenine pathway for Trp metabolism are known: tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO). Based on our comparison of tdo-deficient (Tdo−/−) mice with their wild-type littermates, we report that TDO is the physiological modulator of systemic Trp, brain Trp and serotonin (5-HT), and, therefore, anxiety-related behavior. Tdo−/− mice showed increased plasma concentrations of Trp (about 10-fold) and its metabolites 5-hydroxyindoleacetic acid (5-HIAA) and kynurenine, as well as increased levels of Trp (about 20-fold), 5-HT and 5-HIAA in the hippocampus and midbrain. The Tdo−/− mice also showed anxiolytic modulation in the elevated plus maze and open field tests, and increased neurogenesis during adulthood, as evidenced by double staining with 5-bromo-2′-deoxyuridine (BrdU) and neural progenitor/neuronal markers. TDO also plays a role in the maintenance of brain morphology in adult animals by regulating neurogenesis in the hippocampus and subventricular zone. Collectively, our results in Tdo−/− mice indicate a direct molecular link between Trp metabolism and mental status in mice. Tdo−/− mice will likely prove useful both in identifying the physiological role of Trp metabolism in normal brain function and in psychiatric disorders and in developing new therapeutic interventions for mental disorders. In addition, the potential role(s) and molecular mechanisms of TDO in metabolic mental disease(s) and in emotional behavior are discussed.
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Affiliation(s)
- Hiroshi Funakoshi
- Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- Department of Microbiology and Immunology, Osaka 565-0871, Japan
- Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Midorigaoka, Asahikawa 078-8510, Japan
| | - Masaaki Kanai
- Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- Department of Microbiology and Immunology, Osaka 565-0871, Japan
- Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Midorigaoka, Asahikawa 078-8510, Japan
| | - Toshikazu Nakamura
- Kringle Pharma Joint Research Division for Regenerative Drug Discovery, Osaka University, Osaka 565-0871, Japan
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Liao IH, Corbett BA, Gilbert DL, Bunge SA, Sharp FR. Blood gene expression correlated with tic severity in medicated and unmedicated patients with Tourette Syndrome. Pharmacogenomics 2011; 11:1733-41. [PMID: 21142917 DOI: 10.2217/pgs.10.160] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Tourette Syndrome (TS) has been linked to both genetic and environmental factors. Gene-expression studies provide valuable insight into the causes of TS; however, many studies of gene expression in TS do not account for the effects of medication. MATERIALS & METHODS To investigate the effects of medication on gene expression in TS patients, RNA was isolated from the peripheral blood of 20 medicated TS subjects (MED) and 23 unmedicated TS subjects (UNMED), and quantified using whole-genome Affymetrix microarrays. RESULTS D2 dopamine receptor expression correlated positively with tic severity in MED but not UNMED. GABA(A) receptor ε subunit expression negatively correlated with tic severity in UNMED but not MED. Phenylethanolamine N-methyltransferase expression positively correlated with tic severity in UNMED but not MED. CONCLUSION Modulation of tics by TS medication is associated with changes in dopamine, norepinephrine and GABA pathways.
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Restless legs syndrome mothers and attention–deficit/hyperactivity disorder children: What happened between them? Sleep Med 2011; 12:5-6. [DOI: 10.1016/j.sleep.2010.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 07/01/2010] [Indexed: 11/23/2022]
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Du JC, Chiu TF, Lee KM, Wu HL, Yang YC, Hsu SY, Sun CS, Hwang B, Leckman JF. Tourette syndrome in children: an updated review. Pediatr Neonatol 2010; 51:255-64. [PMID: 20951354 DOI: 10.1016/s1875-9572(10)60050-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/01/2010] [Accepted: 04/21/2010] [Indexed: 10/18/2022] Open
Abstract
Tourette syndrome (TS) is a common neuropsychiatric disorder in children characterized by multiple motor and vocal tics that fluctuate in severity and lasting for at least 1 year. Boys are more commonly affected than girls. Symptoms usually begin with simple motor or vocal tics which then evolve into more complex motor and vocal tics over time. Premonitory sensory urges are common in children over the age of 8 years, and these urges help distinguish tics from symptoms of other movement disorders. Common comorbidities of TS include attention deficit hyperactivity disorder, obsessive-compulsive disorder and learning difficulties. Several genes have been assessed as candidate genes for TS; environmental factors such as stress and streptococcal infections might also contribute to its etiology. The pathophysiology of TS mainly involves dysfunction of basal ganglia-related circuits and hyperactive dopaminergic innervations. A thorough history assessment and neurological examination are important for the correct diagnosis and differentiation from other movement disorders. Treatment for TS should focus on improving the patient's social functioning, minimizing the impairment from cormobid disorders, and controlling tics, if they are severe. Commonly used medications for TS include a2-adrenergic agonists and atypical neuroleptics. Habit reversal therapy is an effective option for TS, and repetitive transcranial magnetic stimulation may be a promising approach for severe cases.
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Affiliation(s)
- Jung-Chieh Du
- Department of Pediatrics, Taipei City Hospital, Zhongxiao Branch, and National Yang-Ming University, Taipei, Taiwan.
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Lentiviral Vector-Mediated Gene Transfer and RNA Silencing Technology in Neuronal Dysfunctions. Mol Biotechnol 2010; 47:169-87. [DOI: 10.1007/s12033-010-9334-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Kanai M, Funakoshi H, Nakamura T. Implication of Tryptophan 2,3-Dioxygenase and its Novel Variants in the Hippocampus and Cerebellum during the Developing and Adult Brain. Int J Tryptophan Res 2010. [DOI: 10.4137/ijtr.s4372] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Tryptophan 2,3-dioxygenase (TDO) is a first and rate-limiting enzyme for the kynurenine pathway of tryptophan metabolism. Using Tdo−/− mice, we have recently shown that TDO plays a pivotal role in systemic tryptophan metabolism and brain serotonin synthesis as well as emotional status and adult neurogenesis. However, the expression of TDO in the brain has not yet been well characterized, in contrast to its predominant expression in the liver. To further examine the possible role of local TDO in the brain, we quantified the levels of tdo mRNA in various nervous tissues, using Northern blot and quantitative real-time RT-PCR. Higher levels of tdo mRNA expression were detected in the cerebellum and hippocampus. We also identified two novel variants of the tdo gene, termed tdo variant1 and variant2, in the brain. Similar to the known TDO form (TDO full-form), tetramer formation and enzymatic activity were obtained when these variant forms were expressed in vitro. While quantitative real-time RT-PCR revealed that the tissue distribution of these variants was similar to that of tdo full-form, the expression patterns of these variants during early postnatal development in the hippocampus and cerebellum differed. Our findings indicate that in addition to hepatic TDO, TDO and its variants in the brain might function in the developing and adult nervous system. Given the previously reported associations of tdo gene polymorphisms in the patients with autism and Tourette syndrome, the expression of TDO in the brain suggests the possible influence of TDO on psychiatric status. Potential functions of TDOs in the cerebellum, hippocampus and cerebral cortex under physiological and pathological conditions are discussed.
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Affiliation(s)
- Masaaki Kanai
- Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Hiroshi Funakoshi
- Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Toshikazu Nakamura
- Kringle Pharma Joint Research Division for Regenerative Drug Discovery, Osaka University, Osaka 565-0871, Japan
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Kang DI, Lee JY, Kim W, Jeong KW, Shin S, Yang J, Park E, Chae YK, Kim Y. Discovery of novel human phenylethanolamine N-methyltransferase (hPNMT) inhibitors using 3D pharmacophore-based in silico, biophysical screening and enzymatic activity assays. Mol Cells 2010; 29:595-602. [PMID: 20496117 DOI: 10.1007/s10059-010-0074-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 03/09/2010] [Indexed: 10/19/2022] Open
Abstract
With the aid of receptor-oriented pharmacophore-based in silico screening, we established three pharmacophore maps explaining the binding model of hPNMT and a known inhibitor, SK&F 29661 (Martin et al., 2001). The compound library was searched using these maps. Nineteen selected candidate inhibitors of hPNMT were screened using STD-NMR and fluorescence experiments. An enzymatic activity assay based on HPLC was additionally performed. Consequently, three potential hPNMT inhibitors were identified, specifically, 4-oxo-1,4-dihydroquinoline-3,7-dicarboxylic acid, 4-(benzo[d][1,3]dioxol-5-ylamino)-4-oxobutanoic acid, and 1,4-diaminonaphthalene-2,6-disulfonic acid. These novel inhibitors were retrieved using Map II comprising one hydrogen bond acceptor, one hydrogen bond donor, one lipophilic feature, and shape constraints, including a hydrogen bond between Lys57 of hPNMT and a hydrogen bond donor of the inhibitor, and stacked hydrophobic interactions between the side-chain of Phe182 and an aromatic region of the inhibitor. Water-mediated interactions between Asn267 and Asn39 of hPNMT and the amide or amine group of three potent inhibitors were additional important features for hPNMT activity. The binding model presented here may be applied to identify inhibitors with higher potency. Moreover, our novel compounds are valuable candidates for further lead optimization of PNMT inhibitors.
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Affiliation(s)
- Dong-Il Kang
- Department of Chemistry, Konkuk University, Seoul, 143-701, Korea
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Nedic G, Pivac N, Hercigonja DK, Jovancevic M, Curkovic KD, Muck-Seler D. Platelet monoamine oxidase activity in children with attention-deficit/hyperactivity disorder. Psychiatry Res 2010; 175:252-5. [PMID: 20022119 DOI: 10.1016/j.psychres.2009.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 07/09/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable developmental disorder characterized by symptoms of impulsivity, hyperactivity and/or inattention, and associated with structural and biochemical abnormalities in cortical and limbic structures innervated by dopamine, noradrenalin and serotonin. The enzyme monoamine oxidase, type B (MAO-B), is expressed in platelets, and metabolizes endogenous amines. Its activity has been proposed to represent a peripheral marker of various traits and forms of psychopathology. This study evaluated platelet MAO activity with a spectrofluorimetric method in 72 boys and 12 girls with predominantly hyperactive, predominantly inattentive, and combined subtype of ADHD (DSM-IV criteria), and in 64 control children. The results showed significantly lower platelet MAO activity in children with hyperactive, inattentive, and combined subtype of ADHD than in control children. There was no significant association between platelet MAO activity and gender or age. The limitation of the study was in the small sample of girls with ADHD (N=12), and in the determination of only one peripheral marker. In line with hypotheses of lower platelet MAO activity in different types of psychopathology, children with different subtypes of ADHD had significantly lower platelet MAO-B activity than control children.
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Affiliation(s)
- Gordana Nedic
- Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
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Dreyer JL. Lentiviral vector-mediated gene transfer and RNA silencing technology in neuronal dysfunctions. Methods Mol Biol 2010; 614:3-35. [PMID: 20225033 DOI: 10.1007/978-1-60761-533-0_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Lentiviral-mediated gene transfer in vivo or in cultured mammalian neurons can be used to address a wide variety of biological questions, to design animal models for specific neurodegenerative pathologies, or to test potential therapeutic approaches in a variety of brain disorders. Lentiviruses can infect nondividing cells, thereby allowing stable gene transfer in postmitotic cells such as mature neurons. An important contribution has been the use of inducible vectors: the same animal can thus be used repeatedly in the doxycycline-on or -off state, providing a powerful mean for assessing the function of a gene candidate in a disorder within a specific neuronal circuit. Furthermore, lentivirus vectors provide a unique tool to integrate siRNA expression constructs with the aim to locally knockdown expression of a specific gene, enabling to assess the function of a gene in a very specific neuronal pathway. Lentiviral vector-mediated delivery of short hairpin RNA results in persistent knockdown of gene expression in the brain. Therefore, the use of lentiviruses for stable expression of siRNA in brain is a powerful aid to probe gene functions in vivo and for gene therapy of diseases of the central nervous system. In this chapter, I review the applications of lentivirus-mediated gene transfer in the investigation of specific gene candidates involved in major brain disorders and neurodegenerative processes. Major applications have been in polyglutamine disorders, such as synucleinopathies and Parkinson's disease, or in investigating gene function in Huntington's disease, dystonia, or muscular dystrophy. Recently, lentivirus gene transfer has been an invaluable tool for evaluation of gene function in behavioral disorders such as drug addiction and attention-deficit hyperactivity disorder or in learning and cognition.
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Affiliation(s)
- Jean-Luc Dreyer
- Division of Biochemistry, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
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Grados MA, Mathews CA. Clinical phenomenology and phenotype variability in Tourette syndrome. J Psychosom Res 2009; 67:491-6. [PMID: 19913653 DOI: 10.1016/j.jpsychores.2009.07.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 07/14/2009] [Accepted: 07/14/2009] [Indexed: 10/20/2022]
Abstract
Tourette syndrome (TS) is a neurodevelopmental disorder with a rich phenomenology that includes simple and complex motor and vocal tics as well as multiple comorbidities. From a nosological perspective, it is evident that a continuum of tic severity exists, of which TS is the most severe and rare form, while transient tics and chronic tics represent milder forms. From a psychopathology perspective, TS is often concurrent with obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD); these disorders appear to define TS "types" TS only, TS+OCD, and TS+OCD+ADHD. Additional clinical aspects of TS include more frequent than expected occurrence of anger episodes, anxiety disorders, mood disorders, impulse control disorders, learning disorders, and pervasive developmental disorders. Data reduction techniques have been used more recently to define a "simple" and "complex" tic symptom clusters or factors. Phenomenologic approaches can be used in TS to guide future pathophysiologic research.
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Affiliation(s)
- Marco A Grados
- Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Pollak Y, Benarroch F, Kanengisser L, Shilon Y, Ben-Pazi H, Shalev RS, Gross-Tsur V. Tourette syndrome-associated psychopathology: roles of comorbid attention-deficit hyperactivity disorder and obsessive-compulsive disorder. J Dev Behav Pediatr 2009; 30:413-9. [PMID: 19827221 DOI: 10.1097/dbp.0b013e3181ba0f89] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Individuals with Tourette syndrome (TS) often display comorbid symptoms of attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD), as well as externalizing and internalizing behaviors. This study was aimed to examine the impacts of tic severity, ADHD symptoms, and OCD on internalizing (e.g., anxiety) and externalizing (e.g., aggression) psychopathology. METHODS Using linear regressions, we examined how tics, ADHD, and OCD symptoms predicted the externalization and internalization behaviors measured by the Child Behavior Checklist in a clinical sample of children and adolescents with TS. In addition, Child Behavior Checklist scales were compared among children with TS without ADHD, TS and ADHD, ADHD without TS, and unaffected control group. RESULTS In the TS group, externalizing behaviors were predicted by tic severity, inattention, and hyperactivity/impulsivity but not by OCD symptoms, whereas internalizing behaviors were predicted by inattention and OCD symptoms but not by tic severity or hyperactivity/impulsivity. Comparison among different clinical groups revealed main effects of TS and ADHD on both externalizing and internalizing behaviors. CONCLUSION These findings suggest that tics, ADHD, and OCD symptoms differentially explain the variance in externalizing and internalizing behavioral problems in individuals with TS. In addition, the data support the notion that TS is itself a risk factor for behavioral problems, mandating that children with TS even without ADHD and OCD still need to be assessed and treated for psychopathology.
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Affiliation(s)
- Yehuda Pollak
- Neuropediatric Unit, Shaare Zedek Medical Center, Jerusalem, Israel.
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Arnsten AF. The Emerging Neurobiology of Attention Deficit Hyperactivity Disorder: The Key Role of the Prefrontal Association Cortex. J Pediatr 2009; 154:I-S43. [PMID: 20596295 PMCID: PMC2894421 DOI: 10.1016/j.jpeds.2009.01.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is characterized by symptoms of inattention, impulsivity, and locomotor hyperactivity. Recent advances in neurobiology, imaging, and genetics have led to a greater understanding of the etiology and treatment of ADHD. Studies have found that ADHD is associated with weaker function and structure of prefrontal cortex (PFC) circuits, especially in the right hemisphere. The prefrontal association cortex plays a crucial role in regulating attention, behavior, and emotion, with the right hemisphere specialized for behavioral inhibition. The PFC is highly dependent on the correct neurochemical environment for proper function: noradrenergic stimulation of postsynaptic alpha-2A adrenoceptors and dopaminergic stimulation of D1 receptors is necessary for optimal prefrontal function. ADHD is associated with genetic changes that weaken catecholamine signaling and, in some patients, with slowed PFC maturation. Effective pharmacologic treatments for ADHD all enhance catecholamine signaling in the PFC and strengthen its regulation of attention and behavior. Recent animal studies show that therapeutic doses of stimulant medications preferentially increase norepinephrine and, to a lesser extent, dopamine, in the PFC. These doses reduce locomotor activity and improve PFC regulation of attention and behavior through enhanced catecholamine stimulation of alpha-2A and D1 receptors. These findings in animals are consistent with improved PFC function in normal human subjects and, more prominently, in patients with ADHD. Thus, a highly cohesive story is emerging regarding the etiology and treatment of ADHD.
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Affiliation(s)
- Amy F.T. Arnsten
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, , PHONE: 203-785-4431, FAX: 203-785-5263
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Kanai M, Funakoshi H, Takahashi H, Hayakawa T, Mizuno S, Matsumoto K, Nakamura T. Tryptophan 2,3-dioxygenase is a key modulator of physiological neurogenesis and anxiety-related behavior in mice. Mol Brain 2009; 2:8. [PMID: 19323847 PMCID: PMC2673217 DOI: 10.1186/1756-6606-2-8] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 03/27/2009] [Indexed: 04/19/2023] Open
Abstract
Although nutrients, including amino acids and their metabolites such as serotonin (5-HT), are strong modulators of anxiety-related behavior, the metabolic pathway(s) responsible for this physiological modulation is not fully understood. Regarding tryptophan (Trp), the initial rate-limiting enzymes for the kynurenine pathway of tryptophan metabolism are tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO). Here, we generated mice deficient for tdo (Tdo-/-). Compared with wild-type littermates, Tdo-/- mice showed increased plasma levels of Trp and its metabolites 5-hydroxyindoleacetic acid (5-HIAA) and kynurenine, as well as increased levels of Trp, 5-HT and 5-HIAA in the hippocampus and midbrain. These mice also showed anxiolytic modulation in the elevated plus maze and open field tests, and increased adult neurogenesis, as evidenced by double staining of BrdU and neural progenitor/neuronal markers. These findings demonstrate a direct molecular link between Trp metabolism and neurogenesis and anxiety-related behavior under physiological conditions.
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Affiliation(s)
- Masaaki Kanai
- Division of Molecular Regenerative Medicine, Department of Biochemistry and Molecular Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
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Blum K, Chen ALC, Braverman ER, Comings DE, Chen TJH, Arcuri V, Blum SH, Downs BW, Waite RL, Notaro A, Lubar J, Williams L, Prihoda TJ, Palomo T, Oscar-Berman M. Attention-deficit-hyperactivity disorder and reward deficiency syndrome. Neuropsychiatr Dis Treat 2008; 4:893-918. [PMID: 19183781 PMCID: PMC2626918 DOI: 10.2147/ndt.s2627] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Molecular genetic studies have identified several genes that may mediate susceptibility to attention deficit hyperactivity disorder (ADHD). A consensus of the literature suggests that when there is a dysfunction in the "brain reward cascade," especially in the dopamine system, causing a low or hypo-dopaminergic trait, the brain may require dopamine for individuals to avoid unpleasant feelings. This high-risk genetic trait leads to multiple drug-seeking behaviors, because the drugs activate release of dopamine, which can diminish abnormal cravings. Moreover, this genetic trait is due in part to a form of a gene (DRD(2) A1 allele) that prevents the expression of the normal laying down of dopamine receptors in brain reward sites. This gene, and others involved in neurophysiological processing of specific neurotransmitters, have been associated with deficient functions and predispose individuals to have a high risk for addictive, impulsive, and compulsive behavioral propensities. It has been proposed that genetic variants of dopaminergic genes and other "reward genes" are important common determinants of reward deficiency syndrome (RDS), which we hypothesize includes ADHD as a behavioral subtype. We further hypothesize that early diagnosis through genetic polymorphic identification in combination with DNA-based customized nutraceutical administration to young children may attenuate behavioral symptoms associated with ADHD. Moreover, it is concluded that dopamine and serotonin releasers might be useful therapeutic adjuncts for the treatment of other RDS behavioral subtypes, including addictions.
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Affiliation(s)
- Kenneth Blum
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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Brennan AR, Arnsten AFT. Neuronal mechanisms underlying attention deficit hyperactivity disorder: the influence of arousal on prefrontal cortical function. Ann N Y Acad Sci 2008; 1129:236-45. [PMID: 18591484 DOI: 10.1196/annals.1417.007] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Neuropsychological and imaging studies indicate that attention deficit hyperactivity disorder (ADHD) is associated with alterations in prefrontal cortex (PFC) and its connections to striatum and cerebellum. Research in animals, in combination with observations of patients with cortical lesions, has shown that the PFC is critical for the regulation of behavior, attention, and affect using representational knowledge. The PFC is important for sustaining attention over a delay, inhibiting distraction, and dividing attention, while more posterior cortical areas are essential for perception and the allocation of attentional resources. The PFC in the right hemisphere is especially important for behavioral inhibition. Lesions to the PFC produce a profile of distractibility, forgetfulness, impulsivity, poor planning, and locomotor hyperactivity. The PFC is very sensitive to its neurochemical environment, and either too little (drowsiness) or too much (stress) catecholamine release in PFC weakens cognitive control of behavior and attention. Recent electrophysiological studies in animals suggest that norepinephrine enhances "signals" through postsynaptic alpha2A adrenoceptors in PFC, while dopamine decreases "noise" through modest levels of D1 receptor stimulation. alpha2A-Adrenoceptor stimulation strengthens the functional connectivity of PFC networks, while blockade of alpha2 receptors in the monkey PFC recreates the symptoms of ADHD, resulting in impaired working memory, increased impulsivity, and locomotor hyperactivity. Genetic alterations in catecholamine pathways may contribute to dysregulation of PFC circuits in this disorder. Medications may have many of their therapeutic effects by optimizing stimulation of alpha2A adrenoceptors and D1 receptors in the PFC, thus strengthening PFC regulation of behavior and attention.
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Affiliation(s)
- Avis R Brennan
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA
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