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Dougnon G, Matsui H. Modelling Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) Using Mice and Zebrafish. Int J Mol Sci 2022; 23:ijms23147550. [PMID: 35886894 PMCID: PMC9319972 DOI: 10.3390/ijms23147550] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) are two debilitating neurodevelopmental disorders. The former is associated with social impairments whereas the latter is associated with inattentiveness, hyperactivity, and impulsivity. There is recent evidence that both disorders are somehow related and that genes may play a large role in these disorders. Despite mounting human and animal research, the neurological pathways underlying ASD and ADHD are still not well understood. Scientists investigate neurodevelopmental disorders by using animal models that have high similarities in genetics and behaviours with humans. Mice have been utilized in neuroscience research as an excellent animal model for a long time; however, the zebrafish has attracted much attention recently, with an increasingly large number of studies using this model. In this review, we first discuss ASD and ADHD aetiology from a general point of view to their characteristics and treatments. We also compare mice and zebrafish for their similarities and discuss their advantages and limitations in neuroscience. Finally, we summarize the most recent and existing research on zebrafish and mouse models of ASD and ADHD. We believe that this review will serve as a unique document providing interesting information to date about these models, thus facilitating research on ASD and ADHD.
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Chen F, Chen H, Chen Y, Wei W, Sun Y, Zhang L, Cui L, Wang Y. Dysfunction of the SNARE complex in neurological and psychiatric disorders. Pharmacol Res 2021; 165:105469. [PMID: 33524541 DOI: 10.1016/j.phrs.2021.105469] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/30/2020] [Accepted: 01/24/2021] [Indexed: 02/07/2023]
Abstract
The communication between neurons constitutes the basis of all neural activities, and synaptic vesicle exocytosis is the fundamental biological event that mediates most communication between neurons in the central nervous system. The SNARE complex is the core component of the protein machinery that facilitates the fusion of synaptic vesicles with presynaptic terminals and thereby the release of neurotransmitters. In synapses, each release event is dependent on the assembly of the SNARE complex. In recent years, basic research on the SNARE complex has provided a clearer understanding of the mechanism underlying the formation of the SNARE complex and its role in vesicle formation. Emerging evidence indicates that abnormal expression or dysfunction of the SNARE complex in synapse physiology might contribute to abnormal neurotransmission and ultimately to synaptic dysfunction. Clinical research using postmortem tissues suggests that SNARE complex dysfunction is correlated with various neurological diseases, and some basic research has also confirmed the important role of the SNARE complex in the pathology of these diseases. Genetic and pharmacogenetic studies suggest that the SNARE complex and individual proteins might represent important molecular targets in neurological disease. In this review, we summarize the recent progress toward understanding the SNARE complex in regulating membrane fusion events and provide an update of the recent discoveries from clinical and basic research on the SNARE complex in neurodegenerative, neuropsychiatric, and neurodevelopmental diseases.
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Affiliation(s)
- Feng Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Huiyi Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yanting Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Wenyan Wei
- Department of Gerontology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yuanhong Sun
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Lu Zhang
- The First Clinical College, Guangdong Medical University, Zhanjiang, China
| | - Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China.
| | - Yan Wang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China; Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Xi'an Jiao tong University, Xi'an, China.
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Vester A, Caudle WM. The Synapse as a Central Target for Neurodevelopmental Susceptibility to Pesticides. TOXICS 2016; 4:toxics4030018. [PMID: 29051423 PMCID: PMC5606656 DOI: 10.3390/toxics4030018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/07/2016] [Accepted: 08/17/2016] [Indexed: 12/12/2022]
Abstract
The developmental period of the nervous system is carefully orchestrated and highly vulnerable to alterations. One crucial factor of a properly-functioning nervous system is the synapse, as synaptic signaling is critical for the formation and maturation of neural circuits. Studies show that genetic and environmental impacts can affect diverse components of synaptic function. Importantly, synaptic dysfunction is known to be associated with neurologic and psychiatric disorders, as well as more subtle cognitive, psychomotor, and sensory defects. Given the importance of the synapse in numerous domains, we wanted to delineate the effects of pesticide exposure on synaptic function. In this review, we summarize current epidemiologic and molecular studies that demonstrate organochlorine, organophosphate, and pyrethroid pesticide exposures target the developing synapse. We postulate that the synapse plays a central role in synaptic vulnerability to pesticide exposure during neurodevelopment, and the synapse is a worthy candidate for investigating more subtle effects of chronic pesticide exposure in future studies.
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Affiliation(s)
- Aimee Vester
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | - W Michael Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
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Liu YS, Dai X, Wu W, Yuan FF, Gu X, Chen JG, Zhu LQ, Wu J. The Association of SNAP25 Gene Polymorphisms in Attention Deficit/Hyperactivity Disorder: a Systematic Review and Meta-Analysis. Mol Neurobiol 2016; 54:2189-2200. [PMID: 26941099 DOI: 10.1007/s12035-016-9810-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/22/2016] [Indexed: 11/30/2022]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is one of the most highly heritable psychiatric disorders in childhood. The risk gene mutation accounts for about 60 to 90 % cases. Synaptosomal-associated protein of 25 kDa (SNAP-25) is a presynaptic plasma membrane protein which is expressed highly and specifically in the neuronal cells. A number of evidences have suggested the role of SNAP-25 in the etiology of ADHD. Notably, the animal model of coloboma mouse mutant bears a ∼2-cM deletion encompassing genes including SNAP25 and displays spontaneous hyperkinetic behavior. Previous investigators have reported association between SNPs in SNAP25 and ADHD, and controversial results were observed. In this study, we analyzed the possible association between six polymorphisms (rs3746544, rs363006, rs1051312, rs8636, rs362549, and rs362998) of SNAP25 and ADHD in a pooled sample of ten family-based studies and four case-control studies by using meta-analysis. The combined analysis results were significant only for rs3746544 (P = 0.010) with mild association (odds ratio (OR) = 1.14). And, the meta-analysis data for rs8636, rs362549, and rs362998 are the first time to be reported; however, no positive association was detected. In conclusion, we report some evidence supporting the association of SNAP25 to ADHD. Future research should emphasize genome-wide association studies in more specific subgroups and larger independent samples.
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Affiliation(s)
- Yun-Sheng Liu
- Key Laboratory of Environment and Health, Ministry of Education & Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Xuan Dai
- Key Laboratory of Environment and Health, Ministry of Education & Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Wei Wu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Fang-Fen Yuan
- Key Laboratory of Environment and Health, Ministry of Education & Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Xue Gu
- Key Laboratory of Environment and Health, Ministry of Education & Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Jian-Guo Chen
- Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.,Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Ling-Qiang Zhu
- Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China. .,Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
| | - Jing Wu
- Key Laboratory of Environment and Health, Ministry of Education & Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
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Evidence of association between SNAP25 gene and attention deficit hyperactivity disorder in a Latin American sample. ACTA ACUST UNITED AC 2013; 6:19-23. [PMID: 24362847 DOI: 10.1007/s12402-013-0123-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 12/09/2013] [Indexed: 12/31/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is one of the most highly heritable behavioral disorders in childhood, with heritability estimates between 60 and 90 %. Family, twin and adoption studies have indicated a strong genetic component in the susceptibility to ADHD. The synaptosomal-associated protein of molecular weight 25 kDa (SNAP25) is a plasma membrane protein known to be involved in synaptic and neural plasticity. Animal model studies have shown that SNAP25 gene is responsible for hyperkinetic behavior in the coloboma mouse. In recent studies, several authors reported an association between SNAP25 and ADHD. In this study, we used a case-control approach to analyze the possible association of two polymorphisms of SNAP25 for possible association with ADHD in a sample of 73 cases and 152 controls in a Colombian children population. Polymorphisms are located in 3' untranslated region of SNAP25, positions T1065G and T1069C. We found a significant association with the GT haplotype (rs3746554|rs1051312) of SNAP25 (p = 0.001). Evidence of association was also found for the G/G genotype of rs3746554 (p = 0.002) and C/C genotype of rs1051312 (p = 0.009). This is the first study in a Latin American population. Similar to other studies, we found evidence of the association of SNAP25 and ADHD.
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Sontag TA, Tucha O, Walitza S, Lange KW. Animal models of attention deficit/hyperactivity disorder (ADHD): a critical review. ACTA ACUST UNITED AC 2010; 2:1-20. [DOI: 10.1007/s12402-010-0019-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 01/02/2010] [Indexed: 01/04/2023]
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Lit L, Schweitzer JB, Iosif AM, Oberbauer AM. Owner reports of attention, activity, and impulsivity in dogs: a replication study. Behav Brain Funct 2010; 6:1. [PMID: 20047681 PMCID: PMC2823640 DOI: 10.1186/1744-9081-6-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 01/04/2010] [Indexed: 01/21/2023] Open
Abstract
Background When developing behaviour measurement tools that use third party assessments, such as parent report, it is important to demonstrate reliability of resulting scales through replication using novel cohorts. The domestic dog has been suggested as a model to investigate normal variation in attention, hyperactivity, and impulsive behaviours impaired in Attention Deficit Hyperactive Disorder (ADHD). The human ADHD Rating Scale, modified for dogs and using owner-directed surveys, was applied in a European sample. We asked whether findings would be replicated utilizing an Internet survey in a novel sample, where unassisted survey completion, participant attitudes and breeds might affect previous findings. Methods Using a slightly modified version of the prior survey, we collected responses (n = 1030, 118 breeds representing 7 breed groups) primarily in the United States and Canada. This study was conducted using an Internet survey mechanism. Results Reliability analyses confirmed two scales previously identified for dogs (inattention [IA], hyperactivity-impulsivity [HA-IM]). Models including age, training status, and breed group accounted for very little variance in subscales, with no effect of gender. Conclusions The factor invariance demonstrated in these findings confirms that owner report, using this modified human questionnaire, provides dog scores according to "inattention" and "hyperactivity-impulsivity" axes. Further characterization of naturally occurring variability of attention, activity, and impulsivity in domestic dogs may provide insight into genetic backgrounds underlying behaviours impaired in attention and associated disorders.
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Affiliation(s)
- Lisa Lit
- MIND Institute and Department of Neurology, University of California at Davis, Sacramento, CA, USA.
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Szklarczyk A, Conant K, Owens DF, Ravin R, McKay RD, Gerfen C. Matrix metalloproteinase-7 modulates synaptic vesicle recycling and induces atrophy of neuronal synapses. Neuroscience 2007; 149:87-98. [PMID: 17826919 DOI: 10.1016/j.neuroscience.2007.07.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 07/02/2007] [Accepted: 08/02/2007] [Indexed: 12/01/2022]
Abstract
Matrix metalloproteinase-7 (MMP-7) belongs to a family of zinc dependent endopeptidases that are expressed in a variety of tissues including the brain. MMPs are known to be potent mediators of pericellular proteolysis and likely mediators of dynamic remodelling of neuronal connections. While an association between proteases and the neuronal synapse is emerging, a full understanding of this relationship is lacking. Here, we show that MMP-7 alters the structure and function of presynaptic terminals without affecting neuronal survival. Bath application of recombinant MMP-7 to cultured rat neurons induced long-lasting inhibition of vesicular recycling as measured by synaptotagmin 1 antibody uptake assays and FM4-64 optical imaging. MMP-7 application resulted in reduced abundance of vesicular and active zone proteins locally within synaptic terminals although their general levels remained unaltered. Finally, chronic application of the protease resulted in synaptic atrophy, including smaller terminals and fewer synaptic vesicles, as determined by electron microscopy. Together these results suggest that MMP-7 is a potent modulator of synaptic vesicle recycling and synaptic ultrastructure and that elevated levels of the enzyme, as may occur with brain inflammation, may adversely influence neurotransmission.
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Affiliation(s)
- A Szklarczyk
- Laboratory of Systems Neuroscience, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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Gosso MF, de Geus EJC, van Belzen MJ, Polderman TJC, Heutink P, Boomsma DI, Posthuma D. The SNAP-25 gene is associated with cognitive ability: evidence from a family-based study in two independent Dutch cohorts. Mol Psychiatry 2006; 11:878-86. [PMID: 16801949 DOI: 10.1038/sj.mp.4001868] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The synaptosomal-associated protein of 25 kDa (SNAP-25) gene plays an integral role in synaptic transmission, and is differentially expressed in the mammalian brain in the neocortex, hippocampus, anterior thalamic nuclei, substantia nigra and cerebellar granular cells. Recent studies have suggested a possible involvement of SNAP-25 in learning and memory, both of which are key components of human intelligence. In addition, the SNAP-25 gene lies in a linkage area implicated previously in human intelligence. In two independent family-based Dutch samples of 391 (mean age 12.4 years) and 276 (mean age 37.3 years) subjects, respectively, we genotyped 12 single-nucleotide polymorphisms (SNPs) in the SNAP-25 gene on 20p12-20p11.2. From all individuals, standardized intelligence measures were available. Using a family-based association test, a strong association was found between three SNPs in the SNAP-25 gene and intelligence, two of which showed association in both independent samples. The strongest, replicated association was found between SNP rs363050 and performance IQ (PIQ), where the A allele was associated with an increase of 2.84 PIQ points (P=0.0002). Variance in this SNP accounts for 3.4% of the phenotypic variance in PIQ.
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Affiliation(s)
- M F Gosso
- Department of Biological Psychology, Vrije Universiteit, Amsterdam, The Netherlands.
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Abstract
The study of human behavioural and psychiatric disorders benefits from the development of genetic models in mice and other organisms. Mouse mutants allow one to investigate the molecular basis of disease progression and to develop novel therapies. The number of potential mouse models is increasing dramatically through the implementation of mutagenesis screens for aberrant behavioural phenotypes. The alkylating agent N-ethyl-N-nitrosourea ENU is the mutagen of choice in these screens as it induces mutations at a very high rate. Progeny of chemically-mutagenised animals are screened either in systematic high-throughput test batteries or in specific low-throughput tests. Both approaches have been highly successful with large numbers of novel loci being identified and characterised. Many mutant lines are available for general research with phenotypes and genetic map positions on public websites. Of the mutant genes characterised, the majority have contributed to our knowledge of gene function in physiology and disease. The 'mutagenesis screening' approach continues to evolve through the design of new phenotyping strategies. The development of modifier screens in mice shows promise in the elucidation of complex phenotypes whereas the use of mutagenesis in combination with pharmacological agents targets specific neurochemical systems. Finally, the systematic screening approach has demonstrated that mutations are likely to affect more than one biological process.
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Affiliation(s)
- Sofia I H Godinho
- MRC Mammalian Genetics Unit, Harwell, Didcot, Oxfordshire OX11 0RD, UK
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Keays DA, Nolan PM. N-ethyl-N-nitrosourea mouse mutants in the dissection of behavioural and psychiatric disorders. Eur J Pharmacol 2004; 480:205-17. [PMID: 14623363 DOI: 10.1016/j.ejphar.2003.08.107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Twin and adoption studies have consistently implicated genetics in the aetiology of psychiatric and behavioural disorders. The identification of the genes and molecular pathways that are associated with these traits using linkage studies has been difficult because psychiatric disorders are almost always non-mendelian, heterogeneous, involve multiple genetic loci and are influenced significantly by environmental factors. Mouse models that are based on intermediate signatures of psychiatric disease and pharmacological responsiveness hold promise as a complementary approach to dissecting the molecular basis of neurobehavioural disorders. This has been made possible by the development and refinement of gene targeting technologies and the use of super-efficient chemical mutagens. N-ethyl-N-nitrosourea (ENU) mutagenesis in the mouse, when coupled to a battery of sensitive behavioural screens, is an effective way of creating and identifying novel mouse behavioural mutants. Here, the concept of screening for ENU mutants is introduced while progress with two behavioural screens, an "anxiety" screen and a circadian screen, are presented. It is hoped that the study of mouse mutants that have arisen from these screens will provide new insights into the genetic basis of abnormal behaviour and that they might lead to the development of novel therapeutic compounds for human psychiatric disease.
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Affiliation(s)
- David A Keays
- MRC Mammalian Genetics Unit, Harwell, Didcot, OX11 0RD, Oxfordshire, UK
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Acosta MT, Arcos-Burgos M, Muenke M. Attention deficit/hyperactivity disorder (ADHD): complex phenotype, simple genotype? Genet Med 2004; 6:1-15. [PMID: 14726804 DOI: 10.1097/01.gim.0000110413.07490.0b] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Complex genetic traits refer to those phenotypes not fitting patterns of Mendelian segregation and/or assortment but exhibiting a preferential familial clustering that cannot be explained by cultural or environmental causes. Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood and probably the most controversial. ADHD has been considered a complex genetic trait based upon the absence of a clear-cut boundary between affected and unaffected status. Furthermore, its high comorbidity with other disorders strongly suggests complex epistatic or pleiotropic effects acting in common with the environmental influences. This implies that the same gene or genes is or are associated with different and concurrently occurring phenotypes. In this study, we will review clinical and epidemiological aspects related to the ADHD phenotype, which are considered either as categorical or continuous traits. We also will discuss genetic models underlying the complexity of this behavioral phenotype and the probable role of epistatic interactions between major genes contributing to the ADHD phenotype.
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Affiliation(s)
- Maria Teresa Acosta
- Department of Neurology, Children's National Medical Center, Washington, DC, USA
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Davids E, Zhang K, Tarazi FI, Baldessarini RJ. Animal models of attention-deficit hyperactivity disorder. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2003; 42:1-21. [PMID: 12668288 DOI: 10.1016/s0165-0173(02)00274-6] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) involves clinically heterogeneous dysfunctions of sustained attention, with behavioral overactivity and impulsivity, of juvenile onset. Experimental models, in addition to mimicking syndromal features, should resemble the clinical condition in pathophysiology, and predict potential new treatments. One of the most extensively evaluated animal models of ADHD is the spontaneously hypertensive rat. Other models include additional genetic variants (dopamine transporter gene knock-out mouse, coloboma mouse, Naples hyperexcitable rat, acallosal mouse, hyposexual rat, and population-extreme rodents), neonatal lesioning of dopamine neurons with 6-hydroxydopamine, and exposure to other neurotoxins or hippocampal irradiation. None is fully comparable to clinical ADHD. The pathophysiology involved varies, including both deficient and excessive dopaminergic functioning, and probable involvement of other monoamine neurotransmitters. Improved models as well as further testing of their ability to predict treatment responses are required.
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Affiliation(s)
- Eugen Davids
- Department of Psychiatry and Neuroscience Program, Harvard Medical School, and Mailman Research Center, McLean Division of Massachusetts General Hospital, 115 Mill Street, Belmont, MA 02478-9106, USA
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Fatemi SH, Earle JA, Stary JM, Lee S, Sedgewick J. Altered levels of the synaptosomal associated protein SNAP-25 in hippocampus of subjects with mood disorders and schizophrenia. Neuroreport 2001; 12:3257-62. [PMID: 11711867 DOI: 10.1097/00001756-200110290-00023] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
SNAP-25 levels were measured in ventral hippocampus in subjects with unipolar depression (n = 12), bipolar disorder (n = 13), schizophrenia (n = 15) and controls (n = 15) using quantitative immunocytochemistry. SNAP-25 levels were reduced significantly in stratum oriens of bipolar patients compared with controls (p < 0.05); they were also reduced significantly in st. oriens (p < 0.01 vs schizophrenia), in alveous (p < 0.01 vs schizophrenia) and in presubiculum (p < 0.05 vs depressed). SNAP-25 levels were also reduced in several layers of schizophrenics, only significantly so in st. granulosum (p < 0.05 vs controls). In contrast, depressed SNAP-25 levels increased in st. moleculare (p < 0.01 vs schizophrenics) and presubiculum (p < 0.05 vs controls and bipolars; p < 0.01 vs schizophrenics). SNAP-25 values were not affected by age, sex, race, post-mortem interval, brain pH, side of brain, age of onset of disease, family history of psychiatric disease, drug or alcohol use, antipsychotic drug treatment, or mode of death. The reported changes in SNAP-25 levels appear to be disease specific, separating synaptic pathology in unipolar depression from that observed in schizophrenia and bipolar disorders.
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Affiliation(s)
- S H Fatemi
- Department of Psychiatry, University of Minnesota Medical School, Box 392, Mayo Building, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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Chin LS, Nugent RD, Raynor MC, Vavalle JP, Li L. SNIP, a novel SNAP-25-interacting protein implicated in regulated exocytosis. J Biol Chem 2000; 275:1191-200. [PMID: 10625663 DOI: 10.1074/jbc.275.2.1191] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Synaptosome-associated protein of 25 kDa (SNAP-25) is a presynaptic membrane protein that has been clearly implicated in membrane fusion in both developing and mature neurons, although its mechanisms of action are unclear. We have now identified a novel SNAP-25-interacting protein named SNIP. SNIP is a hydrophilic, 145-kDa protein that comprises two predicted coiled-coil domains, two highly charged regions, and two proline-rich domains with multiple PPXY and PXXP motifs. SNIP is selectively expressed in brain where it co-distributes with SNAP-25 in most brain regions. Biochemical studies have revealed that SNIP is tightly associated with the brain cytoskeleton. Subcellular fractionation and immunofluorescence localization studies have demonstrated that SNIP co-localizes with SNAP-25 as well as the cortical actin cytoskeleton, suggesting that SNIP serves as a linker protein connecting SNAP-25 to the submembranous cytoskeleton. By using deletion analysis, we have mapped the binding domains of SNIP and SNAP-25, and we have demonstrated that the SNIP-SNAP-25 association is mediated via coiled-coil interactions. Moreover, we have shown that overexpression of SNIP or its SNAP-25-interacting domain inhibits Ca(2+)-dependent exocytosis from PC12 cells. These results indicate that SNIP is involved in regulation of neurosecretion, perhaps via its interaction with SNAP-25 and the cytoskeleton.
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Affiliation(s)
- L S Chin
- Departments of Pharmacology and Physiology, Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Wilson MC. Coloboma mouse mutant as an animal model of hyperkinesis and attention deficit hyperactivity disorder. Neurosci Biobehav Rev 2000; 24:51-7. [PMID: 10654661 DOI: 10.1016/s0149-7634(99)00064-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hyperkinesis and developmental behavioral deficiencies are cardinal signs of attention-deficit hyperactivity disorder. In mice, the mutation coloboma (Cm) corresponds to a contiguous gene defect that results in phenotypic abnormalities including spontaneous hyperactivity, head-bobbing, and ocular dysmorphology. In addition, coloboma mutant mice exhibit delays in achieving complex neonatal motor abilities and deficits in hippocampal physiology, which may contribute to learning deficiencies. The hyperkinesis is ameliorated by low doses of the psychostimulant D-amphetamine and can be rescued genetically by a transgene encoding SNAP-25, located within the Cm deletion. Together with syntaxin and synaptobrevin/VAMP, SNAP-25 constitutes a core protein complex integral to synaptic vesicle fusion and neurotransmitter release. Despite the ubiquitous role of SNAP-25 in synaptic transmission, and uniformly decreased expression in the mutants, coloboma mice show marked deficits in Ca2+-dependent dopamine release selectively in dorsal but not ventral striatum. This suggests that haploinsufficiency of SNAP-25 reveals a specific vulnerability of the nigrostriatal pathway which regulates motor activity and may provide a model for impaired striatal input into executive functions encoded by the prefrontal cortex associated with ADHD.
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Affiliation(s)
- M C Wilson
- Department of Neurosciences, University of New Mexico, Health Sciences Center, Albuquerque 87131-5223, USA.
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Abstract
The mouse mutants mocha (mh) and mocha2J (mh2J) result from separate mutations in the same gene (AP-3 delta) that arose independently on different backgrounds of inbred strains. They exhibit a neurological phenotype that includes hyperactivity, an epileptiform EEG and changes in the basic function of the hippocampus. Depth electrode recordings of hippocampal auditory evoked potentials revealed that the response to the first of two paired tones was significantly enhanced in mocha and mocha2J, as compared with littermate controls. The pronounced theta rhythm characteristic of unanesthetized mocha mice was not observed in these chloral-hydrate anesthetized mice, whereas spike discharge activity was frequently present in the recordings.
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Affiliation(s)
- C L Miller
- Mental Health Research Institute, University of Michigan, Ann Arbor 48109, USA.
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18
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Steffensen SC, Henriksen SJ, Wilson MC. Transgenic rescue of SNAP-25 restores dopamine-modulated synaptic transmission in the coloboma mutant. Brain Res 1999; 847:186-95. [PMID: 10575087 DOI: 10.1016/s0006-8993(99)02023-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many of the molecular components constituting the exocytotic machinery responsible for neurotransmitter release have been identified, yet the precise role played by these proteins in synaptic transmission, and their impact on neural function, has not been resolved. The mouse mutation coloboma is a contiguous gene defect that leads to electrophysiological and behavioral deficits and includes the gene-encoding SNAP-25, an integral component of the synaptic vesicle-docking/fusion core complex. The involvement of SNAP-25 in the hyperactive behavior of coloboma mice, which can be ameliorated by the indirect dopaminergic agonist, amphetamine, has been demonstrated by genetic rescue using a SNAP-25 transgene. Coloboma mice also exhibit increased recurrent inhibition, reduced theta rhythm by tail-pinch and reduced long-term potentiation in the hippocampal dentate gyrus that, as the hyperkinesis seen in these mutants suggests, may reflect impaired monoaminergic modulation. We sought to identify neurophysiological correlates of the rescued hyperactivity within hippocampal synaptic circuitry of SNAP-25 transgenic coloboma mutant mice. In contrast to the differences between coloboma and wild-type mice, there was no significant difference in the duration or amplitude of theta rhythmic activity (4-6 Hz) induced by tail-pinch (10 s), afferent-evoked field potentials, or paired-pulse responses recorded in the dentate gyrus of SNAP-25 transgenic coloboma and wild-type mice. Amphetamine (3.0 mg/kg, i.p.) produced disinhibition of dentate paired-pulse responses in both SNAP-25 transgenic and wild-type mice but increased inhibition in non-transgenic coloboma mice. These findings support the hypothesis that alteration of monoaminergic neurotransmission, which can be reversed by the indirect agonist, amphetamine, is particularly sensitive to alterations in the expression of SNAP-25.
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Affiliation(s)
- S C Steffensen
- Department of Neuropharmacology, Scripps Research Institute, La Jolla, CA 92037, USA
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