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Cellular and neuronal mechanisms that underlie addiction - literature review. CURRENT PROBLEMS OF PSYCHIATRY 2022. [DOI: 10.2478/cpp-2022-0016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Introduction: Addictive substances act on a number of neurotransmitter systems, and the end result of this action is the activation of the reward system in the brain. The cellular and neuronal mechanisms that underlie addiction have long been searched for. One of such neurotransmitters is dopamine, a catecholamine synthesized in neurons located mainly in the midbrain.
Material and method: The available literature was reviewed on the Pubmed platform and from other sources. The analysis included original studies, reviews.
The aim of the study was to review the literature on the relationship between the DRD2 gene and the occurrence of substance addiction.
Discussion: This work presents several currently discussed biological mechanisms, especially at the molecular and genetic level, involved in the process of addiction to various psychoactive substances. They discovered the brain structures that are most at risk, as well as other neurotransmitter systems and receptor proteins through which they can exert their pathological effects. It has also been established that exposure to psychoactive substances causes significant changes in expression in over 100 genes (including genes for dopaminergic, serotonergic and signaling pathways). The DRD2 receptor (present, among others, in the nucleus accumbens) plays an important role in the reward system, in the transmission of information. The weakening of this conductivity is a significant risk factor for the onset of clinical features that are associated with reward system deficiency syndrome. The expression of the D2 receptor gene may take up to 2 isoforms: short D2S and long D2L.
Conclusions: Further research at the molecular level may result in the modification of psychotherapy and pharmacotherapy in terms of their personalization.
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Huang XF, Song X. Effects of antipsychotic drugs on neurites relevant to schizophrenia treatment. Med Res Rev 2018; 39:386-403. [PMID: 29785841 DOI: 10.1002/med.21512] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/06/2018] [Accepted: 04/30/2018] [Indexed: 12/31/2022]
Abstract
Although antipsychotic drugs are mainly used for treating schizophrenia, they are widely used for treating various psychiatric diseases in adults, the elderly, adolescents and even children. Today, about 1.2% of the worldwide population suffers from psychosis and related disorders, which translates to about 7.5 million subjects potentially targeted by antipsychotic drugs. Neurites project from the cell body of neurons and connect neurons to each other to form neural networks. Deficits in neurite outgrowth and integrity are implicated in psychiatric diseases including schizophrenia. Neurite deficits contribute to altered brain development, neural networking and connectivity as well as symptoms including psychosis and altered cognitive function. This review revealed that (1) antipsychotic drugs could have profound effects on neurites, synaptic spines and synapse, by which they may influence and regulate neural networking and plasticity; (2) antipsychotic drugs target not only neurotransmitter receptors but also intracellular signaling molecules regulating the signaling pathways responsible for neurite outgrowth and maintenance; (3) high doses and chronic administration of antipsychotic drugs may cause some loss of neurites, synaptic spines, or synapsis in the cortical structures. In addition, confounding effects causing neurite deficits may include elevated inflammatory cytokines and antipsychotic drug-induced metabolic side effects in patients on chronic antipsychotic therapy. Unraveling how antipsychotic drugs affect neurites and neural connectivity is essential for improving therapeutic outcomes and preventing aversive effects for patients on antipsychotic drug treatment.
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Affiliation(s)
- Xu-Feng Huang
- Henan Medical Key Laboratory of Translational Research on Psychiatric Diseases, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.,The Illawarra Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, Australia
| | - Xueqin Song
- Henan Medical Key Laboratory of Translational Research on Psychiatric Diseases, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
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Sedlak TW, Nucifora LG, Koga M, Shaffer LS, Higgs C, Tanaka T, Wang AM, Coughlin JM, Barker PB, Fahey JW, Sawa A. Sulforaphane Augments Glutathione and Influences Brain Metabolites in Human Subjects: A Clinical Pilot Study. MOLECULAR NEUROPSYCHIATRY 2018; 3:214-222. [PMID: 29888232 PMCID: PMC5981770 DOI: 10.1159/000487639] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/12/2018] [Indexed: 12/17/2022]
Abstract
Schizophrenia and other neuropsychiatric disorders await mechanism-associated interventions. Excess oxidative stress is increasingly appreciated to participate in the pathophysiology of brain disorders, and decreases in the major antioxidant, glutathione (GSH), have been reported in multiple studies. Technical cautions regarding the estimation of oxidative stress-related changes in the brain via imaging techniques have led investigators to explore peripheral GSH as a possible pathological signature of oxidative stress-associated brain changes. In a preclinical model of GSH deficiency, we found a correlation between whole brain and peripheral GSH levels. We found that the naturally occurring isothiocyanate sulforaphane increased blood GSH levels in healthy human subjects following 7 days of daily oral administration. In parallel, we explored the potential influence of sulforaphane on brain GSH levels in the anterior cingulate cortex, hippocampus, and thalamus via 7-T magnetic resonance spectroscopy. A significant positive correlation between blood and thalamic GSH post- and pre-sulforaphane treatment ratios was observed, in addition to a consistent increase in brain GSH levels in response to treatment. This clinical pilot study suggests the value of exploring relationships between peripheral GSH and clinical/neuropsychological measures, as well as the influences sulforaphane has on functional measures that are altered in neuropsychiatric disorders.
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Affiliation(s)
- Thomas W. Sedlak
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Leslie G. Nucifora
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Minori Koga
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lindsay S. Shaffer
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Cecilia Higgs
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Teppei Tanaka
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Anna M. Wang
- Department of Radiology and Radiological Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jennifer M. Coughlin
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter B. Barker
- Department of Radiology and Radiological Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jed W. Fahey
- Department of Clinical Pharmacology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Clark AM, Leroy F, Martyniuk KM, Feng W, McManus E, Bailey MR, Javitch JA, Balsam PD, Kellendonk C. Dopamine D2 Receptors in the Paraventricular Thalamus Attenuate Cocaine Locomotor Sensitization. eNeuro 2017; 4:ENEURO.0227-17.2017. [PMID: 29071300 PMCID: PMC5654238 DOI: 10.1523/eneuro.0227-17.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 12/21/2022] Open
Abstract
Alterations in thalamic dopamine (DA) or DA D2 receptors (D2Rs) have been measured in drug addiction and schizophrenia, but the relevance of thalamic D2Rs for behavior is largely unknown. Using in situ hybridization and mice expressing green fluorescent protein (GFP) under the Drd2 promoter, we found that D2R expression within the thalamus is enriched in the paraventricular nucleus (PVT) as well as in more ventral midline thalamic nuclei. Within the PVT, D2Rs are inhibitory as their activation inhibits neuronal action potentials in brain slices. Using Cre-dependent anterograde and retrograde viral tracers, we further determined that PVT neurons are reciprocally interconnected with multiple areas of the limbic system including the amygdala and the nucleus accumbens (NAc). Based on these anatomical findings, we analyzed the role of D2Rs in the PVT in behaviors that are supported by these areas and that also have relevance for schizophrenia and drug addiction. Male and female mice with selective overexpression of D2Rs in the PVT showed attenuated cocaine locomotor sensitization, whereas anxiety levels, fear conditioning, sensorimotor gating, and food-motivated behaviors were not affected. These findings suggest the importance of PVT inhibition by D2Rs in modulating the sensitivity to cocaine, a finding that may have novel implications for human drug use.
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Affiliation(s)
- Abigail M. Clark
- Graduate Program in Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Felix Leroy
- Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Kelly M. Martyniuk
- Graduate Program in Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Wendy Feng
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Erika McManus
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Matthew R. Bailey
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Jonathan A. Javitch
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032
| | - Peter D. Balsam
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Department of Psychology, Barnard College Columbia University, New York, NY 10027
| | - Christoph Kellendonk
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032
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Blum K, Atzmon G, Baron D, Badgaiyan RD. Hypothesizing Molecular Genetics of the Holocaust: Were Dopaminergic Genes Involved or Brain Wash? SOJ PSYCHOLOGY 2016; 3:1-5. [PMID: 34708151 PMCID: PMC8547313 DOI: 10.15226/2374-6874/3/2/00129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Numerous studies indicated that the prevalence of certain alleles of the dopamine D2 receptor gene (DRD2) vary across different ethnic groups. Under adverse environmental conditions, these alleles can increase the risk of developing psychiatric symptoms. Thus, we hypothesized that the prevalence of the DRD2 gene Taq IA allele may serve to explain the horrific behaviours practiced by the Nazi regime. Hitler's 'Brain Washing' methods goaded his followers to carry out genocide at a time when carriers of the DRD2 TaqIA allele (the so called 'aggressive--genotype') were significantly higher among the Aryan Germans compared to resident German Jews. It would be of interest, to genotype the Jewish Holocaust survivors, to determine whether those with the Taq AI allele survived in greater numbers. The hypothesis being that, greater survival may result in enhanced frequency of not only the DRD2 AI allele but other reward gene polymorphisms among survivors. Understanding the molecular genetics of any population in terms of reward dependence and subsequent behaviours will be most beneficial in future human interaction whether negative (war) or positive (peace) in nature.
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Affiliation(s)
- Kenneth Blum
- Departments of Psychiatry and Behavioural Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
- Department of Psychiatry, Wright State University Boonshoft School of Medicine and Dayton VA Medical Center, Dayton, OH (IE)
| | - Gil Atzmon
- Departments of Medicine and Genetics, Albert Einstein School of Medicine, Bronx, New York, USA and Departments of Medical Sciences and Human biology Haifa University, Haifa, Israel
| | - David Baron
- Departments of Psychiatry and Behavioural Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - RD Badgaiyan
- Department of Psychiatry, Wright State University Boonshoft School of Medicine and Dayton VA Medical Center, Dayton, OH (IE)
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Bolkan SS, Carvalho Poyraz F, Kellendonk C. Using human brain imaging studies as a guide toward animal models of schizophrenia. Neuroscience 2016; 321:77-98. [PMID: 26037801 PMCID: PMC4664583 DOI: 10.1016/j.neuroscience.2015.05.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/15/2015] [Accepted: 05/21/2015] [Indexed: 12/17/2022]
Abstract
Schizophrenia is a heterogeneous and poorly understood mental disorder that is presently defined solely by its behavioral symptoms. Advances in genetic, epidemiological and brain imaging techniques in the past half century, however, have significantly advanced our understanding of the underlying biology of the disorder. In spite of these advances clinical research remains limited in its power to establish the causal relationships that link etiology with pathophysiology and symptoms. In this context, animal models provide an important tool for causally testing hypotheses about biological processes postulated to be disrupted in the disorder. While animal models can exploit a variety of entry points toward the study of schizophrenia, here we describe an approach that seeks to closely approximate functional alterations observed with brain imaging techniques in patients. By modeling these intermediate pathophysiological alterations in animals, this approach offers an opportunity to (1) tightly link a single functional brain abnormality with its behavioral consequences, and (2) to determine whether a single pathophysiology can causally produce alterations in other brain areas that have been described in patients. In this review we first summarize a selection of well-replicated biological abnormalities described in the schizophrenia literature. We then provide examples of animal models that were studied in the context of patient imaging findings describing enhanced striatal dopamine D2 receptor function, alterations in thalamo-prefrontal circuit function, and metabolic hyperfunction of the hippocampus. Lastly, we discuss the implications of findings from these animal models for our present understanding of schizophrenia, and consider key unanswered questions for future research in animal models and human patients.
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Affiliation(s)
- S S Bolkan
- Department of Pharmacology, Columbia University, New York, NY 10032, USA; Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - F Carvalho Poyraz
- Department of Pharmacology, Columbia University, New York, NY 10032, USA; Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - C Kellendonk
- Department of Pharmacology, Columbia University, New York, NY 10032, USA; Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA.
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The role of the thalamus in schizophrenia from a neuroimaging perspective. Neurosci Biobehav Rev 2015; 54:57-75. [DOI: 10.1016/j.neubiorev.2015.01.013] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 12/19/2014] [Accepted: 01/12/2015] [Indexed: 02/06/2023]
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Seeman MV, Seeman P. Is schizophrenia a dopamine supersensitivity psychotic reaction? Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:155-60. [PMID: 24128684 PMCID: PMC3858317 DOI: 10.1016/j.pnpbp.2013.10.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/03/2013] [Accepted: 10/03/2013] [Indexed: 12/22/2022]
Abstract
Adolf Meyer (1866-1950) did not see schizophrenia as a discrete disorder with a specific etiology but, rather, as a reaction to a wide variety of biopsychosocial factors. He may have been right. Today, we have evidence that gene mutations, brain injury, drug use (cocaine, amphetamine, marijuana, phencyclidine, and steroids), prenatal infection and malnutrition, social isolation and marginalization, can all result in the signs and symptoms of schizophrenia. This clinical picture is generally associated with supersensitivity to dopamine, and activates dopamine neurotransmission that is usually alleviated or blocked by drugs that block dopamine D2 receptors. While the dopamine neural pathway may be a final common route to many of the clinical symptoms, the components of this pathway, such as dopamine release and number of D2 receptors, are approximately normal in schizophrenia patients who are in remission. Postmortem findings, however, reveal more dimers of D1D2 and D2D2 receptors in both human schizophrenia brains and in animal models of schizophrenia. Another finding in animal models is an elevation of high-affinity state D2High receptors, but no radioactive ligand is yet available to selectively label D2High receptors in humans. It is suggested that synaptic dopamine supersensitivity in schizophrenia is an attempt at compensation for the original damage by heightening dopamine neurotransmission pathways (preparing the organism for fight or flight). The dopamine overactivity is experienced subjectively as overstimulation, which accounts for some of the clinical symptoms, with attempts at dampening down the stimulation leading to still other symptoms. Reaction and counter-reaction may explain the symptoms of schizophrenia.
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Affiliation(s)
- Mary V. Seeman
- Departments of Psychiatry, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada
| | - Philip Seeman
- Departments of Pharmacology, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada,Corresponding author. Tel.: +1 416 486 3456. (P. Seeman)
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