1
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Kim A, Zisman CR, Holingue C. Influences of the Immune System and Microbiome on the Etiology of ASD and GI Symptomology of Autistic Individuals. Curr Top Behav Neurosci 2022; 61:141-161. [PMID: 35711026 DOI: 10.1007/7854_2022_371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Autism Spectrum Disorder is a developmental condition associated with impairments in communication and social interactions, and repetitive and restricted behavior or interests. Autistic individuals are more likely to experience gastrointestinal (GI) symptoms than neurotypical individuals. This may be partially due to dysbiosis of the gut microbiome. In this article, we describe the interaction of the microbiome and immune system on autism etiology. We also summarize the links between the microbiome and gastrointestinal and related symptoms among autistic individuals. We report that microbial interventions, including diet, probiotics, antibiotics, and fecal transplants, and immune-modulating therapies such as cytokine blockade during the preconception, pregnancy, and postnatal period may impact the neurodevelopment, behavior, and gastrointestinal health of autistic individuals.
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Affiliation(s)
- Amanda Kim
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Corina R Zisman
- Department of Psychology, Pennsylvania State University, University Park, PA, USA
| | - Calliope Holingue
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. .,Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD, USA.
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2
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Woods RM, Lorusso JM, Potter HG, Neill JC, Glazier JD, Hager R. Maternal immune activation in rodent models: A systematic review of neurodevelopmental changes in gene expression and epigenetic modulation in the offspring brain. Neurosci Biobehav Rev 2021; 129:389-421. [PMID: 34280428 DOI: 10.1016/j.neubiorev.2021.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 05/11/2021] [Accepted: 07/11/2021] [Indexed: 01/06/2023]
Abstract
Maternal immune activation (mIA) during pregnancy is hypothesised to disrupt offspring neurodevelopment and predispose offspring to neurodevelopmental disorders such as schizophrenia. Rodent models of mIA have explored possible mechanisms underlying this paradigm and provide a vital tool for preclinical research. However, a comprehensive analysis of the molecular changes that occur in mIA-models is lacking, hindering identification of robust clinical targets. This systematic review assesses mIA-driven transcriptomic and epigenomic alterations in specific offspring brain regions. Across 118 studies, we focus on 88 candidate genes and show replicated changes in expression in critical functional areas, including elevated inflammatory markers, and reduced myelin and GABAergic signalling proteins. Further, disturbed epigenetic markers at nine of these genes support mIA-driven epigenetic modulation of transcription. Overall, our results demonstrate that current outcome measures have direct relevance for the hypothesised pathology of schizophrenia and emphasise the importance of mIA-models in contributing to the understanding of biological pathways impacted by mIA and the discovery of new drug targets.
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Affiliation(s)
- Rebecca M Woods
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PT, United Kingdom.
| | - Jarred M Lorusso
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Harry G Potter
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Joanna C Neill
- Division of Pharmacy & Optometry, School of Health Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Jocelyn D Glazier
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Reinmar Hager
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Manchester Academic Health Science Center, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, M13 9PT, United Kingdom
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3
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Mepham JR, MacFabe DF, Boon FH, Foley KA, Cain DP, Ossenkopp KP. Examining the non-spatial pretraining effect on a water maze spatial learning task in rats treated with multiple intracerebroventricular (ICV) infusions of propionic acid: Contributions to a rodent model of ASD. Behav Brain Res 2021; 403:113140. [PMID: 33508348 DOI: 10.1016/j.bbr.2021.113140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 01/06/2023]
Abstract
Propionic acid (PPA) is produced by enteric gut bacteria and is a dietary short chain fatty acid. Intracerebroventricular (ICV) infusions of PPA in rodents have been shown to produce behavioural changes, including adverse effects on cognition, similar to those seen in autism spectrum disorders (ASD). Previous research has shown that repeated ICV infusions of PPA result in impaired spatial learning in a Morris water maze (MWM) as evidenced by increased search latencies, fewer direct and circle swims, and more time spent in the periphery of the maze than control rats. In the current study rats were first given non-spatial pretraining (NSP) in the water maze in order to familiarize the animals with the general requirements of the non-spatial aspects of the task before spatial training was begun. Then the effects of ICV infusions of PPA on acquisition of spatial learning were examined. PPA treated rats failed to show the positive effects of the non-spatial pretraining procedure, relative to controls, as evidenced by increased search latencies, longer distances travelled, fewer direct and circle swims, and more time spent in the periphery of the maze than PBS controls. Thus, PPA treatment blocked the effects of the pretraining procedure, likely by impairing sensorimotor components or memory of the pretraining.
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Affiliation(s)
- Jennifer R Mepham
- Graduate Program in Neuroscience, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada
| | - Derrick F MacFabe
- Department of Psychology, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada
| | - Francis H Boon
- Department of Psychology, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada
| | - Kelly A Foley
- Graduate Program in Neuroscience, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada
| | - Donald P Cain
- Graduate Program in Neuroscience, Western University, London, Ontario, Canada; Department of Psychology, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada
| | - Klaus-Peter Ossenkopp
- Graduate Program in Neuroscience, Western University, London, Ontario, Canada; Department of Psychology, Western University, London, Ontario, Canada; The Kilee Patchell-Evans Autism Research Group, Department of Psychology, Western University, London, Ontario, Canada.
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4
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Esshili A, Manitz MP, Freund N, Juckel G. Induction of inducible nitric oxide synthase expression in activated microglia and astrocytes following pre- and postnatal immune challenge in an animal model of schizophrenia. Eur Neuropsychopharmacol 2020; 35:100-110. [PMID: 32439226 DOI: 10.1016/j.euroneuro.2020.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 02/24/2020] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
In the central nervous system, activated microglia and astrocytes produce proinflammatory mediators such as inducible nitric oxide (iNOS) and cytokines. Uncontrolled release of these mediators induced by immune challenge can lead to increased vulnerability to complex brain disorders such as schizophrenia. In this study, BALB/c mice were injected intraperitoneally (i.p) with the viral mimetic polyriboinosinic-polyribocytidilic acid (poly(I:C)) or saline. At postnatal day 30 (PND0), the animals were sacrificed and the hippocampus, corpus callosum, striatum, cortex, fimbria and ventricle were immunostained for Iba-1, a microglial marker, glial fibrillary acidic protein (GFAP), an astrocyte marker, and iNOS, an activation marker for NO. Additionally, serum cytokine profiling (Interleukin-2 (IL-2), IL- 4, IL-6, interferon gamma (IFN-γ), tumour necrosis factor (TNF), IL-17A and IL-10) was determined using serum samples from poly(I:C)-treated and control mice. Our results demonstrated that poly(I:C) induced overactivation of differential proinflammatory responses in microglia and astrocytes, which could be strongly enhanced by a postnatal poly(I:C) administration before PND 30 in one part of the animals investigated. Specifically, there was significant iNOS upregulation in hippocampus, cortex and corpus callosum of poly(I:C)-affected off-springs. These inflammatory alterations were accompanied by increased circulating levels of the proinflammatory cytokines tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). This study provides insight into the role of microglia and astrocytes in an animal model of schizophrenia and an understanding of the regulation of iNOS expression in glial cells and cytokine networks. This knowledge could help identify novel targets for anti-oxidative and anti-inflammatory therapeutic schizophrenia intervention.
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Affiliation(s)
- Awatef Esshili
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, LWL-University Hospital, Ruhr University Bochum, Bochum, Germany; Laboratoire de génétique, biodiversité et valorisation des bioressources, Institut supérieur de biotechnologie de Monastir, Université de Monastir, Tunisie
| | - Marie-Pierre Manitz
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, LWL-University Hospital, Ruhr University Bochum, Bochum, Germany
| | - Nadja Freund
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, LWL-University Hospital, Ruhr University Bochum, Bochum, Germany
| | - Georg Juckel
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, LWL-University Hospital, Ruhr University Bochum, Bochum, Germany.
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5
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Kępińska AP, Iyegbe CO, Vernon AC, Yolken R, Murray RM, Pollak TA. Schizophrenia and Influenza at the Centenary of the 1918-1919 Spanish Influenza Pandemic: Mechanisms of Psychosis Risk. Front Psychiatry 2020; 11:72. [PMID: 32174851 PMCID: PMC7054463 DOI: 10.3389/fpsyt.2020.00072] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/28/2020] [Indexed: 12/13/2022] Open
Abstract
Associations between influenza infection and psychosis have been reported since the eighteenth century, with acute "psychoses of influenza" documented during multiple pandemics. In the late 20th century, reports of a season-of-birth effect in schizophrenia were supported by large-scale ecological and sero-epidemiological studies suggesting that maternal influenza infection increases the risk of psychosis in offspring. We examine the evidence for the association between influenza infection and schizophrenia risk, before reviewing possible mechanisms via which this risk may be conferred. Maternal immune activation models implicate placental dysfunction, disruption of cytokine networks, and subsequent microglial activation as potentially important pathogenic processes. More recent neuroimmunological advances focusing on neuronal autoimmunity following infection provide the basis for a model of infection-induced psychosis, potentially implicating autoimmunity to schizophrenia-relevant protein targets including the N-methyl-D-aspartate receptor. Finally, we outline areas for future research and relevant experimental approaches and consider whether the current evidence provides a basis for the rational development of strategies to prevent schizophrenia.
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Affiliation(s)
- Adrianna P. Kępińska
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Conrad O. Iyegbe
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Anthony C. Vernon
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - Robert Yolken
- Stanley Laboratory of Developmental Neurovirology, Johns Hopkins Medical Center, Baltimore, MD, United States
| | - Robin M. Murray
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Thomas A. Pollak
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
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6
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Tellez-Merlo G, Morales-Medina JC, Camacho-Ábrego I, Juárez-Díaz I, Aguilar-Alonso P, de la Cruz F, Iannitti T, Flores G. Prenatal immune challenge induces behavioral deficits, neuronal remodeling, and increases brain nitric oxide and zinc levels in the male rat offspring. Neuroscience 2019; 406:594-605. [DOI: 10.1016/j.neuroscience.2019.02.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 12/11/2018] [Accepted: 02/12/2019] [Indexed: 12/20/2022]
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7
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Impaired Spatial Cognition in Adult Rats Treated with Multiple Intracerebroventricular (ICV) Infusions of the Enteric Bacterial Metabolite, Propionic Acid, and Return to Baseline After 1 Week of No Treatment: Contribution to a Rodent Model of ASD. Neurotox Res 2019; 35:823-837. [DOI: 10.1007/s12640-019-0002-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/23/2018] [Accepted: 01/15/2019] [Indexed: 02/07/2023]
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8
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Zhang J, Jing Y, Zhang H, Bilkey DK, Liu P. Maternal immune activation leads to increased nNOS immunoreactivity in the brain of postnatal day 2 rat offspring. Synapse 2017; 72. [PMID: 28921679 DOI: 10.1002/syn.22011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 01/10/2023]
Abstract
Neuronal nitric oxide synthase (nNOS) is a key arginine metabolising enzyme in the brain, and nNOS-derived nitric oxide (NO) plays an important role in regulating glutamatergic neurotransmission. NO and its related molecules are involved in the pathogenesis of schizophrenia, and human genetic studies have identified schizophrenia risk genes encoding nNOS. This study systematically investigated how maternal immune activation (MIA; a risk factor for schizophrenia) induced by polyinosinic:polycytidylic acid affected nNOS-immunoreactivity in the brain of the resulting male and female offspring at the age of postnatal day (PND) 2. Immunohistochemistry revealed a markedly increased intensity of nNOS-positive cells in the CA3 and dentate gyrus subregions of the hippocampus, the somatosensory cortex, and the striatum, but not the frontal cortex and hippocampal CA1 region, in the MIA offspring when compared to control group animals. There were no sex differences in the effect. Given the role of nNOS in glutamatergic neurotransmission and its functional relationship with glutamate NMDA receptors, increased nNOS immunoreactivity may indicate the up-regulation of NMDA receptor function in MIA rat offspring at an early postnatal age. Future research is required to determine whether these changes contribute to the neuronal and behavioral dysfunction observed in both juvenile and adult MIA rat offspring.
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Affiliation(s)
- Jiaxian Zhang
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Yu Jing
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Hu Zhang
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - David K Bilkey
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Department of Psychology, University of Otago, Dunedin, New Zealand
| | - Ping Liu
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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9
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Dincel GC, Atmaca HT. Nitric oxide production increases during Toxoplasma gondii encephalitis in mice. Exp Parasitol 2015; 156:104-12. [PMID: 26115941 DOI: 10.1016/j.exppara.2015.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/29/2015] [Accepted: 06/15/2015] [Indexed: 11/17/2022]
Abstract
Toxoplasma gondii is an intracellular parasite with the potential of causing severe encephalitis among immunocompromised human and animals. The aim of this experimental study was to investigate the immunomodulatory and immunopathological role of nitric oxide (NO) in central nervous systems and to identify any correlation between toxoplasmosis neuropathology and investigate the consequences of the cellular responses protect against T. gondii. Mice were infected with ME49 strain T. gondii and levels of endothelial, neuronal and inducible nitric oxide synthase (eNOS, nNOS, iNOS), glial fibrillary acidic protein (GFAP) and neurofilament (NF) were examined in brain tissues by immunohistochemistry, during the development and establishment of a chronic infection at 10 30 and 60 days post infection. Results of the study revealed that the levels of eNOS (p < 0.05), nNOS (p < 0.05), iNOS (p < 0.005), GFAP (p < 0.005) and NF (p < 0.005) were remarkably higher in T. gondii-infected mice than in uninfected control. The most prominent finding from our study was 10 and 30 days after inoculation data indicating that increased levels of NO not only a potential neuroprotective role for immunoregulatory and immunopathological but also might be a molecular trigger of bradyzoite development. Furthermore, this findings were shown that high expressed NO origin was not only inducible nitric oxide synthase but also endothelial and neuronal. We demonstrated that activation of astrocytes and microglia/macrophages is a significant event in toxoplasma encephalitis (TE). The results also clearly indicated that increased levels of NO might contribute to neuropathology related with TE. Furthermore, expression of NF might gives an idea of the progress and critical for diagnostic significance of this disease.
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Affiliation(s)
- Gungor Cagdas Dincel
- Gumushane University, Siran Mustafa Beyaz Vocational High School, Siran, Gumushane 29700, Turkey.
| | - Hasan Tarik Atmaca
- Kirikkale University, Faculty of Veterinary Medicine, Department of Pathology, Yahsihan, Kirikkale 71450, Turkey.
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10
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Nakamura Y, Morioka N, Zhang FF, Hisaoka-Nakashima K, Nakata Y. Downregulation of connexin36 in mouse spinal dorsal horn neurons leads to mechanical allodynia. J Neurosci Res 2015; 93:584-91. [PMID: 25400139 DOI: 10.1002/jnr.23515] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/24/2014] [Accepted: 10/13/2014] [Indexed: 11/08/2022]
Abstract
Connexin36 (Cx36), a component of neuronal gap junctions, is crucial for interneuronal communication and regulation. Gap junction dysfunction underlies neurological disorders, including chronic pain. Following a peripheral nerve injury, Cx36 expression in the ipsilateral spinal dorsal horn was markedly decreased over time, which paralleled the time course of hind paw tactile allodynia. Intrathecal (i.t.) injection of Cx36 siRNA (1 and 5 pg) significantly reduced the expression of Cx36 protein in the lumbar spinal cord, peaking 3 days after the injection, which corresponded with the onset of hind paw tactile allodynia. It is possible that some of the tactile allodynia resulting from Cx36 downregulation could be mediated through excitatory neuromodulators, such as glutamate and substance P. The Cx36 knockdown-evoked tactile allodynia was significantly attenuated by i.t. treatment with the N-methyl-D-aspartate glutamate receptor antagonist MK-801 but not the substance P receptor antagonist CP96345. Immunohistochemistry showed that Cx36 was colocalized with glycine transporter-2, a marker for inhibitory glycinergic spinal interneurons, but not with glutamate decarboxylase 67, a marker for inhibitory GABAergic spinal interneurons. The results indicate that spinal inhibition through glycinergic interneurons is reduced, leading to increased glutamatergic neurotransmission, as a result of Cx36 downregulation. The current data suggest that gap junction dysfunction underlies neuropathic pain and further suggest a novel target for the development of analgesics.
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Affiliation(s)
- Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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11
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Maternal immune activation and abnormal brain development across CNS disorders. Nat Rev Neurol 2014; 10:643-60. [PMID: 25311587 DOI: 10.1038/nrneurol.2014.187] [Citation(s) in RCA: 604] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epidemiological studies have shown a clear association between maternal infection and schizophrenia or autism in the progeny. Animal models have revealed maternal immune activation (mIA) to be a profound risk factor for neurochemical and behavioural abnormalities in the offspring. Microglial priming has been proposed as a major consequence of mIA, and represents a critical link in a causal chain that leads to the wide spectrum of neuronal dysfunctions and behavioural phenotypes observed in the juvenile, adult or aged offspring. Such diversity of phenotypic outcomes in the mIA model are mirrored by recent clinical evidence suggesting that infectious exposure during pregnancy is also associated with epilepsy and, to a lesser extent, cerebral palsy in children. Preclinical research also suggests that mIA might precipitate the development of Alzheimer and Parkinson diseases. Here, we summarize and critically review the emerging evidence that mIA is a shared environmental risk factor across CNS disorders that varies as a function of interactions between genetic and additional environmental factors. We also review ongoing clinical trials targeting immune pathways affected by mIA that may play a part in disease manifestation. In addition, future directions and outstanding questions are discussed, including potential symptomatic, disease-modifying and preventive treatment strategies.
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12
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Reyes EP, Cerpa V, Corvalán L, Retamal MA. Cxs and Panx- hemichannels in peripheral and central chemosensing in mammals. Front Cell Neurosci 2014; 8:123. [PMID: 24847209 PMCID: PMC4023181 DOI: 10.3389/fncel.2014.00123] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/18/2014] [Indexed: 01/08/2023] Open
Abstract
Connexins (Cxs) and Pannexins (Panx) form hemichannels at the plasma membrane of animals. Despite their low open probability under physiological conditions, these hemichannels release signaling molecules (i.e., ATP, Glutamate, PGE2) to the extracellular space, thus subserving several important physiological processes. Oxygen and CO2 sensing are fundamental to the normal functioning of vertebrate organisms. Fluctuations in blood PO2, PCO2 and pH are sensed at the carotid bifurcations of adult mammals by glomus cells of the carotid bodies. Likewise, changes in pH and/or PCO2 of cerebrospinal fluid are sensed by central chemoreceptors, a group of specialized neurones distributed in the ventrolateral medulla (VLM), raphe nuclei, and some other brainstem areas. After many years of research, the molecular mechanisms involved in chemosensing process are not completely understood. This manuscript will review data regarding relationships between chemosensitive cells and the expression of channels formed by Cxs and Panx, with special emphasis on hemichannels.
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Affiliation(s)
- Edison Pablo Reyes
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile ; Dirección de Investigación, Universidad Autónoma de Chile Santiago, Chile
| | - Verónica Cerpa
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Liliana Corvalán
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Mauricio Antonio Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
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13
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Question of an infectious etiology or contribution to the pathogenesis of infantile hypertrophic pyloric stenosis. J Pediatr Gastroenterol Nutr 2014; 58:546-8. [PMID: 24345839 DOI: 10.1097/mpg.0000000000000261] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Infantile hypertrophic pyloric stenosis is a concerning cause of nonbilious vomiting in the neonatal population. Although a number of etiological theories exist, its exact cause remains nebulous. The question of an infectious etiology (or contribution) has been previously examined in case reports and case series, with recent support through suggestions of seasonality and familial aggregation with unclear inheritance patterns. The present review discusses the published literature regarding infectious etiologies of infantile hypertrophic pyloric stenosis. Furthermore, it attempts to demonstrate that newer research regarding an NOS1 genetic etiology does not exclude, but rather can be consistent with, an infectious etiology.
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14
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Landreau F, Galeano P, Caltana LR, Masciotra L, Chertcoff A, Pontoriero A, Baumeister E, Amoroso M, Brusco HA, Tous MI, Savy VL, Lores Arnaiz MDR, de Erausquin GA. Effects of two commonly found strains of influenza A virus on developing dopaminergic neurons, in relation to the pathophysiology of schizophrenia. PLoS One 2012; 7:e51068. [PMID: 23251423 PMCID: PMC3519479 DOI: 10.1371/journal.pone.0051068] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 11/01/2012] [Indexed: 12/22/2022] Open
Abstract
Influenza virus (InfV) infection during pregnancy is a known risk factor for neurodevelopment abnormalities in the offspring, including the risk of schizophrenia, and has been shown to result in an abnormal behavioral phenotype in mice. However, previous reports have concentrated on neuroadapted influenza strains, whereas increased schizophrenia risk is associated with common respiratory InfV. In addition, no specific mechanism has been proposed for the actions of maternal infection on the developing brain that could account for schizophrenia risk. We identified two common isolates from the community with antigenic configurations H3N2 and H1N1 and compared their effects on developing brain with a mouse modified-strain A/WSN/33 specifically on the developing of dopaminergic neurons. We found that H1N1 InfV have high affinity for dopaminergic neurons in vitro, leading to nuclear factor kappa B activation and apoptosis. Furthermore, prenatal infection of mothers with the same strains results in loss of dopaminergic neurons in the offspring, and in an abnormal behavioral phenotype. We propose that the well-known contribution of InfV to risk of schizophrenia during development may involve a similar specific mechanism and discuss evidence from the literature in relation to this hypothesis.
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Affiliation(s)
- Fernando Landreau
- Cultivo de Tejidos, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - Pablo Galeano
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Instituto de Investigaciones “Prof. Dr. Alberto C. Taquini” (ININCA), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Laura R. Caltana
- Instituto de Biología Celular y Neurociencia “Profesor E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Luis Masciotra
- Instituto de Biología Celular y Neurociencia “Profesor E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Agustín Chertcoff
- Bioterio Central, Instituto Nacional de Producción de Biológicos, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - A. Pontoriero
- Virus Respiratorios, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - Elsa Baumeister
- Virus Respiratorios, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - Marcela Amoroso
- Microscopía Electrónica, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
- Facultad de Psicología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Herminia A. Brusco
- Bioterio Central, Instituto Nacional de Producción de Biológicos, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - Mónica I. Tous
- Cultivo de Tejidos, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - Vilma L. Savy
- Virus Respiratorios, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
| | - María del Rosario Lores Arnaiz
- Microscopía Electrónica, Departamento Virología, Instituto Nacional de Enfermedades Infecciosas, ANLIS “Dr Carlos G. Malbran”, Buenos Aires, Argentina
- Facultad de Psicología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gabriel A. de Erausquin
- Roskamp Laboratory of Brain Development, Modulation and Repair, Department of Psychiatry and Neurosciences, University of South Florida, Tampa, Florida, United States of America
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15
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Garbett KA, Hsiao EY, Kálmán S, Patterson PH, Mirnics K. Effects of maternal immune activation on gene expression patterns in the fetal brain. Transl Psychiatry 2012; 2:e98. [PMID: 22832908 PMCID: PMC3337077 DOI: 10.1038/tp.2012.24] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We are exploring the mechanisms underlying how maternal infection increases the risk for schizophrenia and autism in the offspring. Several mouse models of maternal immune activation (MIA) were used to examine the immediate effects of MIA induced by influenza virus, poly(I:C) and interleukin IL-6 on the fetal brain transcriptome. Our results indicate that all three MIA treatments lead to strong and common gene expression changes in the embryonic brain. Most notably, there is an acute and transient upregulation of the α, β and γ crystallin gene family. Furthermore, levels of crystallin gene expression are correlated with the severity of MIA as assessed by placental weight. The overall gene expression changes suggest that the response to MIA is a neuroprotective attempt by the developing brain to counteract environmental stress, but at a cost of disrupting typical neuronal differentiation and axonal growth. We propose that this cascade of events might parallel the mechanisms by which environmental insults contribute to the risk of neurodevelopmental disorders such as schizophrenia and autism.
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Affiliation(s)
- K A Garbett
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
| | - E Y Hsiao
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
| | - S Kálmán
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA,Department of Psychiatry, University of Szeged, Szeged, Hungary
| | - P H Patterson
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
| | - K Mirnics
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN, USA,Department of Psychiatry, Vanderbilt University, 8130A MRB III, 465 21st Avenue South, Nashville, TN 37203, USA. E-mail:
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Expression of connexin57 in mouse development and in harmaline-tremor model. Neuroscience 2010; 171:1-11. [PMID: 20849935 DOI: 10.1016/j.neuroscience.2010.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 09/03/2010] [Accepted: 09/08/2010] [Indexed: 11/23/2022]
Abstract
Connexin57 (Cx57) was previously reported in retinal cells but not in brain nerve cells. This occurrence was tested in this study, by searching for the expression of Cx57 RNA and protein transcripts during the postnatal development of the mouse CNS. Both the Cx57 RNA (investigated by reverse transcriptase-polymerase chain reaction (RT-PCR)) and the protein (Western-Blot and immunohistochemistry using a polyclonal antibody generated in chicken) transcripts were firstly expressed in the late postnatal development (P12). The expression of Cx57 in adult life (studied at P28, by in situ hybridization and immunohistochemical analysis) concerned few regions of the brain stem (inferior olive, lateral reticular nucleus and motor trigeminal nucleus), the cerebellum (Purkinje cells and cerebellar nuclei) and the spinal cord (alpha-motoneurons). Double immunohistochemical studies using the Cx57 antibody and antibodies, which specifically labelled neuronal nuclei (NeuN) and astrocyte cells glial fibrillary acidic protein (GFAP), showed the expression of Cx57 segregated in neuronal cells. The study also confirmed the expression of Cx57 in the horizontal cells of the retinal outer plexiform layer, reported in previous investigations. Given the expression of Cx57 in the cerebellum and pre-cerebellar nuclei, such as olivary and lateral reticular nuclei, a possible role of Cx57 was hypothesized in the electrical coupling of the cerebellum. This hypothesis was tested by searching for the expression of the Cx57 transcripts in the mouse cerebellum of the harmaline-tremor model. The up-regulation of the Cx57 transcripts reported in this model suggested a possible involvement of Cx57 in the electrotonic coupling of the cerebellar system.
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Thomas RH, Foley KA, Mepham JR, Tichenoff LJ, Possmayer F, MacFabe DF. Altered brain phospholipid and acylcarnitine profiles in propionic acid infused rodents: further development of a potential model of autism spectrum disorders. J Neurochem 2010; 113:515-29. [PMID: 20405543 DOI: 10.1111/j.1471-4159.2010.06614.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent studies have demonstrated intraventricular infusions of propionic acid (PPA) a dietary and enteric short-chain fatty acid can produce brain and behavioral changes similar to those observed in autism spectrum disorder (ASD). The effects of PPA were further evaluated to determine if there are any alterations in brain lipids associated with the ASD-like behavioral changes observed following intermittent intraventricular infusions of PPA, the related enteric metabolite butyric acid (BUT) or phosphate-buffered saline vehicle. Both PPA and BUT produced significant increases (p < 0.001) in locomotor activity (total distance travelled and stereotypy). PPA and to a lesser extent BUT infusions decreased the levels of total monounsaturates, total omega6 fatty acids, total phosphatidylethanolamine plasmalogens, the ratio of omega6 : omega3 and elevated the levels of total saturates in separated phospholipid species. In addition, total acylcarnitines, total longchain (C12-C24) acylcarnitines, total short-chain (C2 to C9) acylcarnitines, and the ratio of bound to free carnitine were increased following infusions with PPA and BUT. These results provide evidence of a relationship between changes in brain lipid profiles and the occurrence of ASD-like behaviors using the autism rodent model. We propose that altered brain fatty acid metabolism may contribute to ASD.
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Affiliation(s)
- Raymond H Thomas
- The Kilee Patchell-Evans Autism Research Group, Department of Psychology and Biology, University of Western Ontario, London, Ontario, Canada
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Gaspar PA, Bustamante ML, Silva H, Aboitiz F. Molecular mechanisms underlying glutamatergic dysfunction in schizophrenia: therapeutic implications. J Neurochem 2009; 111:891-900. [PMID: 19686383 DOI: 10.1111/j.1471-4159.2009.06325.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Early models for the etiology of schizophrenia focused on dopamine neurotransmission because of the powerful anti-psychotic action of dopamine antagonists. Nevertheless, recent evidence increasingly supports a primarily glutamatergic dysfunction in this condition, where dopaminergic disbalance is a secondary effect. A current model for the pathophysiology of schizophrenia involves a dysfunctional mechanism by which the NMDA receptor (NMDAR) hypofunction leads to a dysregulation of GABA fast- spiking interneurons, consequently disinhibiting pyramidal glutamatergic output and disturbing the signal-to-noise ratio. This mechanism might explain better than other models some cognitive deficits observed in this disease, as well as the dopaminergic alterations and therapeutic effect of anti-psychotics. Although the modulation of glutamate activity has, in principle, great therapeutic potential, a side effect of NMDAR overactivation is neurotoxicity, which accelerates neuropathological alterations in this illness. We propose that metabotropic glutamate receptors can have a modulatory effect over the NMDAR and regulate excitotoxity mechanisms. Therefore, in our view metabotropic glutamate receptors constitute a highly promising target for future drug treatment in this disease.
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Affiliation(s)
- Pablo A Gaspar
- Clínica Psiquiátrica Universitaria, Hospital Clínico de la Universidad de Chile, Casilla, Santiago, Chile.
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Olgiati P, Mandelli L, Lorenzi C, Marino E, Adele P, Ferrari B, De Ronchi D, Serretti A. Schizophrenia: genetics, prevention and rehabilitation. Acta Neuropsychiatr 2009; 21:109-20. [PMID: 26953749 DOI: 10.1111/j.1601-5215.2009.00360.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Genetic factors are largely implicated in predisposing to schizophrenia. Environmental factors contribute to the onset of the disorder in individuals at increased genetic risk. Cognitive deficits have emerged as endophenotypes and potential therapeutic targets for schizophrenia because of their association with functional outcome. The aims of this review were to analyse the joint effect of genetic and environmental (G×E) factors on liability to schizophrenia and to investigate relationships between genes and cognitive endophenotypes focusing on practical applications for prevention and rehabilitation. METHODS Medline search of relevant studies published between 1990 and 2008. RESULTS In schizophrenia, examples of G×E interaction include the catechol-O-methyl transferase (COMT) (Val158Met) polymorphism, which was found to moderate the onset of psychotic manifestations in response to stress and to increase the risk for psychosis related to cannabis use, and neurodevelopmental genes such as AKT1 (serine-threonine kinase), brain-derived neurotrophic factor (BDNF), DTNBP1 (dysbindin) and GRM3 (metabotropic glutamate receptor 3), which were associated with development of schizophrenia in adulthood after exposure to perinatal obstetric complications. Neurocognitive deficits are recognised as core features of schizophrenia that facilitate the onset of the disorder and have a great impact on functional outcome. Neurocognitive deficits are also endophenotypes that have been linked to a variety of genes [COMT, neuregulin (NRG1), BDNF, Disrupted-In-Schizophrenia 1 (DISC1) and dysbindin] conferring susceptibility to schizophrenia. Recently, it has emerged that cognitive improvement during rehabilitation therapy was under control of COMT (Val158Met) polymorphism. CONCLUSION This review could indicate a pivotal role of psychiatric genetics in prevention and rehabilitation of schizophrenic psychoses.
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Affiliation(s)
- Paolo Olgiati
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Laura Mandelli
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Cristina Lorenzi
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Elena Marino
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Pirovano Adele
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Barbara Ferrari
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Diana De Ronchi
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Alessandro Serretti
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
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20
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Abstract
While multiple theories have been put forth regarding the origin of schizophrenia, by far the vast majority of evidence points to the neurodevelopmental model in which developmental insults as early as late first or early second trimester lead to the activation of pathologic neural circuits during adolescence or young adulthood leading to the emergence of positive or negative symptoms. In this report, we examine the evidence from brain pathology (enlargement of the cerebroventricular system, changes in gray and white matters, and abnormal laminar organization), genetics (changes in the normal expression of proteins that are involved in early migration of neurons and glia, cell proliferation, axonal outgrowth, synaptogenesis, and apoptosis), environmental factors (increased frequency of obstetric complications and increased rates of schizophrenic births due to prenatal viral or bacterial infections), and gene-environmental interactions (a disproportionate number of schizophrenia candidate genes are regulated by hypoxia, microdeletions and microduplications, the overrepresentation of pathogen-related genes among schizophrenia candidate genes) in support of the neurodevelopmental model. We relate the neurodevelopmental model to a number of findings about schizophrenia. Finally, we also examine alternate explanations of the origin of schizophrenia including the neurodegenerative model.
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Westberg L, Sawa E, Wang AY, Gunaydin LA, Ribeiro AC, Pfaff DW. Colocalization of connexin 36 and corticotropin-releasing hormone in the mouse brain. BMC Neurosci 2009; 10:41. [PMID: 19405960 PMCID: PMC2688509 DOI: 10.1186/1471-2202-10-41] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 04/30/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gap junction proteins, connexins, are expressed in most endocrine and exocrine glands in the body and are at least in some glands crucial for the hormonal secretion. To what extent connexins are expressed in neurons releasing hormones or neuropeptides from or within the central nervous system is, however, unknown. Previous studies provide indirect evidence for gap junction coupling between subsets of neuropeptide-containing neurons in the paraventricular nucleus (PVN) of the hypothalamus. Here we employ double labeling and retrograde tracing methods to investigate to what extent neuroendocrine and neuropeptide-containing neurons of the hypothalamus and brainstem express the neuronal gap junction protein connexin 36. RESULTS Western blot analysis showed that connexin 36 is expressed in the PVN. In bacterial artificial chromosome transgenic mice, which specifically express the reporter gene Enhanced Green Fluorescent Protein (EGFP) under the control of the connexin 36 gene promoter, EGFP expression was detected in magnocellular (neuroendocrine) and in parvocellular neurons of the PVN. Although no EGFP/connexin36 expression was seen in neurons containing oxytocin or vasopressin, EGFP/connexin36 was found in subsets of PVN neurons containing corticotropin-releasing hormone (CRH), and in somatostatin neurons located along the third ventricle. Moreover, CRH neurons in brainstem areas, including the lateral parabrachial nucleus, also expressed EGFP/connexin 36. CONCLUSION Our data indicate that connexin 36 is expressed in subsets of neuroendocrine and CRH neurons in specific nuclei of the hypothalamus and brainstem.
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Affiliation(s)
- Lars Westberg
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Evelyn Sawa
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Alice Y Wang
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Lisa A Gunaydin
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Ana C Ribeiro
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
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22
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Animal models may help fractionate shared and discrete pathways underpinning schizophrenia and autism. Behav Brain Sci 2008. [DOI: 10.1017/s0140525x08004251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractCrespi & Badcock (C&B) present an appealing and parsimonious synthesis arguing that schizophrenia and autism are differentially regulated by maternal versus paternal genomic imprinting, respectively. We argue that animal models related to schizophrenia and autism provide a useful platform to explore the mechanisms outlined by C&B. We also note that schizophrenia and autism share certain risk factors such as advanced paternal age. Apart from genomic imprinting, copy number variants related to advanced paternal age may also contribute to the differential trajectory of brain development associated with autism and schizophrenia.
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Elsen FP, Shields EJ, Roe MT, Vandam RJ, Kelty JD. Carbenoxolone induced depression of rhythmogenesis in the pre-Bötzinger Complex. BMC Neurosci 2008; 9:46. [PMID: 18500991 PMCID: PMC2413244 DOI: 10.1186/1471-2202-9-46] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 05/23/2008] [Indexed: 12/03/2022] Open
Abstract
Background Carbenoxolone (CBX), a gap junction uncoupler, alters the functioning of the pre-Bötzinger Complex (preBötC), a central pattern generating neuronal network important for the production of respiratory rhythm in mammals. Even when isolated in a 1/2 mm-thick slice of medulla oblongata from neonatal mouse the preBötC continues producing periodic bursts of action potentials, termed population bursts that are thought to be important in generating various patterns of inspiration, in vivo. Whether gap junction communication contributes to preBötC rhythmogenesis remains unresolved, largely because existing gap junction uncouplers exert numerous non-specific effects (e.g., inhibition of active transport, alteration of membrane conductances). Here, we determined whether CBX alters preBötC rhythmogenesis by altering membrane properties including input resistance (Rin), voltage-gated Na+ current (INa), and/or voltage-gated K+ current (IK), rather than by blocking gap junction communication. To do so we used a medullary slice preparation, network-level recordings, whole-cell voltage clamp, and glycyrrhizic acid (GZA; a substance used as a control for CBX, since it is similar in structure and does not block gap junctions). Results Whereas neither of the control treatments [artificial cerebrospinal fluid (aCSF) or GZA (50 μM)] noticeably affected preBötC rhythmogenesis, CBX (50 μM) decreased the frequency, area and amplitude of population bursts, eventually terminating population burst production after 45–60 min. Both CBX and GZA decreased neuronal Rin and induced an outward holding current. Although neither agent altered the steady state component of IK evoked by depolarizing voltage steps, CBX, but not GZA, increased peak INa. Conclusion The data presented herein are consistent with the notion that gap junction communication is important for preBötC rhythmogenesis. By comparing the effects of CBX and GZA on membrane properties our data a) demonstrate that depression of preBötC rhythmogenesis by CBX results from actions on another variable or other variables; and b) show that this comparative approach can be used to evaluate the potential contribution of other non-specific actions (e.g., Ca++ conductances or active transport) of CBX, or other uncouplers, in their alteration of preBötC rhythmogenesis, or the functioning of other networks.
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Affiliation(s)
- Frank P Elsen
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Horowitz SS, Stamper SA, Simmons JA. Neuronal connexin expression in the cochlear nucleus of big brown bats. Brain Res 2008; 1197:76-84. [PMID: 18241843 DOI: 10.1016/j.brainres.2007.12.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 12/12/2007] [Accepted: 12/13/2007] [Indexed: 11/26/2022]
Abstract
We present immunohistochemical data describing the presence and distribution of connexins, structural component of gap junctions, in the cochlear nuclei of adult big brown bats (Eptesicus fuscus). Echolocating big brown bats show microsecond scale echo-delay sensitivity that requires accurate synchronization of neuronal responses to the timing of echoes. Midbrain and auditory cortical neuronal response timing is similar to that observed in other non-echolocating mammals, suggesting that lower auditory processing nuclei may have specialized mechanisms for obtaining the required temporal hyperacuity. Our data shows that connexin 36, a gap junction protein specific to neurons, is most densely expressed in the bat's cochlear nuclear complex, the medullary region that receives and processes first-order afferents from the auditory nerve. Cx36 expression is absent in the cochlear nucleus of normal mice, which have high-frequency hearing sensitivity similar to big brown bats. Glial connexins, Cx26 and Cx43, expressed in astrocytes and several inner ear structures, are also found in the bat cochlear nucleus complex, associated with major fiber tracts in and around the cochlear nuclei. The extensive presence of neuronally-associated Cx36 in brainstem auditory structures of adult bats suggests a possible role for gap junctions in mediating echo-delay hyperacuity.
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Affiliation(s)
- Seth S Horowitz
- Psychology Department, Brown University, Box 1853, Providence RI 02912, USA.
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Immunohistochemical detection of connexin36 in sympathetic preganglionic and somatic motoneurons in the adult rat. Auton Neurosci 2008; 139:15-23. [PMID: 18280223 PMCID: PMC2428072 DOI: 10.1016/j.autneu.2007.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 10/31/2007] [Accepted: 12/13/2007] [Indexed: 11/23/2022]
Abstract
Gap junctional communication in the adult CNS plays an important role in the synchronization of neuronal activities. In vitro studies have shown evidence of electrotonic coupling through gap junctions between sympathetic preganglionic motoneurons and between somatic motoneurons in the neonatal and adult rat spinal cord. Electrotonic transmission of membrane oscillations might be an important mechanism for recruitment of neurons and result in the generation of rhythmic sympathetic and somato-motor activity at the population level. Gap junctions in the adult spinal cord are constituted principally by connexin36 (Cx36). However, the distribution of Cx36 in specific neuronal populations of the spinal cord is unknown. Here, we identify Cx36-like immunoreactivity in sympathetic preganglionic and somatic motoneurons in thoracic spinal cord segments of the adult rat. For this purpose, double immunostaining against Cx36 and choline acetyltransferase (ChAT) was performed on transverse sections (20 μm) taken from spinal segments T6–T8. Cx36 punctate immunostaining was detected in the majority of ChAT-immunoreactive (-ir) neurons from lamina VII [intermediolateral cell column (IML) and intercalated cell group (IC)], lamina X [central autonomic nucleus (CA)] and in ventral horn neurons from laminae VIII and IX. Cx36 puncta were distributed in the neuronal somata and along dendritic processes. The presence of Cx36 in ChAT-ir neurons is consistent with electrical coupling between sympathetic preganglionic motoneurons and between somatic motoneurons through gap junctions in the adult spinal cord.
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Fatemi SH, Reutiman TJ, Folsom TD, Huang H, Oishi K, Mori S, Smee DF, Pearce DA, Winter C, Sohr R, Juckel G. Maternal infection leads to abnormal gene regulation and brain atrophy in mouse offspring: implications for genesis of neurodevelopmental disorders. Schizophr Res 2008; 99:56-70. [PMID: 18248790 PMCID: PMC2312390 DOI: 10.1016/j.schres.2007.11.018] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 10/29/2007] [Accepted: 11/05/2007] [Indexed: 12/15/2022]
Abstract
Prenatal viral infection has been associated with development of schizophrenia and autism. Our laboratory has previously shown that viral infection causes deleterious effects on brain structure and function in mouse offspring following late first trimester (E9) administration of influenza virus. We hypothesized that late second trimester infection (E18) in mice may lead to a different pattern of brain gene expression and structural defects in the developing offspring. C57BL6J mice were infected on E18 with a sublethal dose of human influenza virus or sham-infected using vehicle solution. Male offsping of the infected mice were collected at P0, P14, P35 and P56, their brains removed and prefrontal cortex, hippocampus and cerebellum dissected and flash frozen. Microarray, qRT-PCR, DTI and MRI scanning, western blotting and neurochemical analysis were performed to detect differences in gene expression and brain atrophy. Expression of several genes associated with schizophrenia or autism including Sema3a, Trfr2 and Vldlr were found to be altered as were protein levels of Foxp2. E18 infection of C57BL6J mice with a sublethal dose of human influenza virus led to significant gene alterations in frontal, hippocampal and cerebellar cortices of developing mouse progeny. Brain imaging revealed significant atrophy in several brain areas and white matter thinning in corpus callosum. Finally, neurochemical analysis revealed significantly altered levels of serotonin (P14, P35), 5-Hydroxyindoleacetic acid (P14) and taurine (P35). We propose that maternal infection in mouse provides an heuristic animal model for studying the environmental contributions to genesis of schizophrenia and autism, two important examples of neurodevelopmental disorders.
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Affiliation(s)
- S. Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455,Department of Pharmacology, University of Minnesota Medical School, 310 Church St. SE, Minneapolis, MN 55455,Department of Neuroscience, University of Minnesota Medical School, 310 Church St. SE, Minneapolis, MN 55455
| | - Teri J. Reutiman
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455
| | - Timothy D. Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455
| | - Hao Huang
- Department of Radiology, Division of NMR, Johns Hopkins University, School of Medicine, 720 Rutland Avenue, Baltimore, MD 21287
| | - Kenichi Oishi
- Department of Radiology, Division of NMR, Johns Hopkins University, School of Medicine, 720 Rutland Avenue, Baltimore, MD 21287
| | - Susumu Mori
- Department of Radiology, Division of NMR, Johns Hopkins University, School of Medicine, 720 Rutland Avenue, Baltimore, MD 21287
| | - Donald F. Smee
- Institute for Antiviral Research, Department of Animal, Dairy and Veterinary Sciences, Utah State University, 5600 Old Main Hill, Logan, Utah, 84322
| | - David A. Pearce
- Center for Aging and Developmental Biology, Aab Institute of Biomedical Sciences, Department of Biochemistry and Biophysics, Department of Neurobiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 645, Rochester, NY 14627
| | - Christine Winter
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, University Medicine, Berlin, 10117, Germany
| | - Reinhard Sohr
- Institute of Pharmacology and Toxicology, Charité University Medicine, Dorotheenstrasse 94, D 10117, Berlin, Germany
| | - Georg Juckel
- Department of Psychiatry - Psychotherapy - Psychosomatic Medicine, Ruhr University, 1 Alexandrinenstr. 44791 Bochum, Germany
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Abstract
The basal ganglia (BG) provide a major integrative system of the forebrain involved in the organization of goal-directed behaviour. Pathological alteration of BG function leads to major motor and cognitive impairments such as observed in Parkinson's disease. Recent advances in BG research stress the role of neural oscillations and synchronization in the normal and pathological function of BG. As demonstrated in several brain structures, these patterns of neural activity can emerge from electrically coupled neuronal networks. This review aims at addressing the presence, functionality and putative role of electrical synapses in BG, with a particular emphasis on the striatum and the substantia nigra pars compacta (SNc), two main BG nuclei in which the existence and functional properties of neuronal coupling are best documented.
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Affiliation(s)
- Marie Vandecasteele
- Dynamique et Pathophysiologie des Réseaux Neuronaux, INSERM U667, Collège de France
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28
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Perreault MC, Raastad M. Contribution of morphology and membrane resistance to integration of fast synaptic signals in two thalamic cell types. J Physiol 2006; 577:205-20. [PMID: 16959860 PMCID: PMC2000667 DOI: 10.1113/jphysiol.2006.113043] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Thalamocortical cells (TCs) and interneurons (INs) in the lateral geniculate nucleus process visual information from the retina. The TCs have many short dendrites, whereas the INs have fewer and longer dendrites. Because of these morphological differences, it has been suggested that transmission of synaptic signals from dendritic synapses to soma is more efficient in TCs than in INs. However, a higher membrane resistance (R(m)) for the INs could, in theory, compensate for the attenuating effect of their long dendrites and allow distal synaptic inputs to significantly depolarize the soma. Compartmental models were made from biocytin filled TCs (n = 15) and INs (n = 3) and adjusted to fit the current- and voltage-clamp recordings from the individual cells. The confidence limits for the passive electrical parameters were explored by simulating the influence of noise, morphometric errors and non-uniform and active conductances. One of the useful findings was that R(m) was accurately estimated despite realistic levels of active conductance. Simulations to explore the somatic influence of dendritic synapses showed that a small (0.5 nS) excitatory synapse placed at different dendritic positions gave similar somatic potentials in the individual TCs, within the TC population and also between TCs and INs. A linear increase in the conductance of the synapse gave increases in somatic potentials that were more sublinear in INs than TCs. However, when the total synaptic conductance was increased by simultaneously activating many small, spatially distributed synapses, the INs converted the synaptic signals to soma potentials almost as efficiently as the TCs. Thus, INs can transfer fast synaptic signals to soma as efficiently as TCs except when the focal conductance is large.
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Affiliation(s)
- Marie-Claude Perreault
- University of Oslo, Institute of Basic Medical Sciences, Department of Physiology, Sognsvannsveien 9, PO Box 1103 Blindern, N-0317, Oslo, Norway.
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Zappalà A, Cicero D, Serapide MF, Paz C, Catania MV, Falchi M, Parenti R, Pantò MR, La Delia F, Cicirata F. Expression of pannexin1 in the CNS of adult mouse: cellular localization and effect of 4-aminopyridine-induced seizures. Neuroscience 2006; 141:167-78. [PMID: 16690210 DOI: 10.1016/j.neuroscience.2006.03.053] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 03/23/2006] [Accepted: 03/25/2006] [Indexed: 11/28/2022]
Abstract
The expression pattern of pannexin1, a gene coding for a protein that forms gap junction channels, was studied as both mRNA and protein in the CNS of adult mouse. Pannexin1 was widely expressed in the CNS by neuronal cell types but not glial cells, except for Bergmann glial cells of the cerebellar cortex. Cells positive to Ca-binding proteins, principally parvalbumin, but also calbindin and calretinin, as well as glutamate decarboxylase 67 kDa isoform, were pannexin1-positive. Pannexin1 labeling was found in cells which are known to exhibit spontaneous and synchronous discharge, such as neurons of the inferior olivary complex and the reticular thalamic nucleus, and also in neurons whose electrical activity is not coupled with neighboring cells, such as motoneurons of the spinal cord. The analysis of cellular localization showed puncta that surrounded cell bodies (e.g. the pyramidal cells of hippocampus) or restricted areas inside the cell bodies (e.g. the spinal motoneurons). In Bergmann glial cells the staining was present as fine grains that covered a large part of the cellular surface. Pannexin1 stained cells that previous studies have reported as expressing connexin36, another protein forming gap junction channels. Thus, it was possible that these two proteins could be integrated in the same functions. Since connexin36 expression levels change after seizures, we examined the expression of both pannexin1 and connexin36 in cerebral cortex, hippocampus, cerebellum and brain stem at different time intervals (2, 4 and 8 h) after i.p. injection of 4-aminopyridine, which resulted in systemic seizures. The only modification of the expression levels observed in this study concerned the progressive decrement of the connexin36 in the hippocampus, while pannexin1 expression was unchanged. This finding suggested that pannexin1 and connexin36 are involved in different functional roles or that they are expressed in different cell types and that only those expressing the Cx36 are induced to apoptosis by epileptic seizures.
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Affiliation(s)
- A Zappalà
- Department of Physiological Science, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
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Lauer M, Johannes S, Fritzen S, Senitz D, Riederer P, Reif A. Morphological abnormalities in nitric-oxide-synthase-positive striatal interneurons of schizophrenic patients. Neuropsychobiology 2005; 52:111-7. [PMID: 16110244 DOI: 10.1159/000087555] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Schizophrenia has been suggested to be a neurodevelopmental disorder, and nitric-oxide-synthase (NOS)-positive neurons were shown to be involved in distorted cortical development in schizophrenia. Here we investigated whether nitrinergic neurons in the striatum of schizophrenic patients also display abnormalities regarding distribution or morphology. To do so, postmortem putaminal sections of schizophrenic subjects were examined by means of nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) staining and NOS immunohistochemistry. NOS-positive neurons were counted and analyzed morphologically. Abnormalities regarding morphology or number of NOS-containing neurons could be found in the putamen of schizophrenics (n = 3), but not controls (n = 5). Neurons were either of abnormal size and branching pattern, or they were markedly reduced (130 +/- 44 vs. 54 +/- 62 NADPHd-positive somata/mm(3) putamen; p < 0.0001). Striatal nitrinergic interneurons might thus be involved in the pathogenesis of at least some forms of schizophrenia. Studies on larger samples are however needed to further corroborate this finding.
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Affiliation(s)
- Martin Lauer
- Department of Psychiatry, Julius Maximilian University Würzburg, Füchsleinstrasse 15, DE-97080 Würzburg, Germany
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31
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Bernstein HG, Bogerts B, Keilhoff G. The many faces of nitric oxide in schizophrenia. A review. Schizophr Res 2005; 78:69-86. [PMID: 16005189 DOI: 10.1016/j.schres.2005.05.019] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 05/24/2005] [Accepted: 05/24/2005] [Indexed: 01/16/2023]
Abstract
Intense research has been conducted in an effort to identify specific biological markers of schizophrenia. The gas nitric oxide (NO) is one of the most important signaling molecules involved in a plethora of cellular events that take place in the cardiovascular, immune and nervous systems of animals. This survey aims to demonstrate that NO and its metabolites play important roles in schizophrenia and have a significant influence on our understanding of the development, progression and treatment of the disease. Special emphasis is given to the impact of NO metabolism on processes known to be disturbed in schizophrenia (i.e., cell migration, formation of synapses, NMDA receptor mediated neurotransmission, membrane pathology and cognitive abilities). However, when comparing data on the NO metabolism in the brain tissue and body fluids of schizophrenics with those obtained from patients with other neurological and psychiatric diseases, it becomes clear that alterations of NO metabolism are not unique to, or indicative of, schizophrenia. Thus, NO and its metabolites are not suitable diagnostic tools to distinguish schizophrenia from psychically healthy control cases or from other brain disorders.
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Affiliation(s)
- Hans-Gert Bernstein
- Department of Psychiatry, University of Magdeburg, Leipziger Str.44, D-39120 Magdeburg, Germany.
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Christie JM, Bark C, Hormuzdi SG, Helbig I, Monyer H, Westbrook GL. Connexin36 mediates spike synchrony in olfactory bulb glomeruli. Neuron 2005; 46:761-72. [PMID: 15924862 DOI: 10.1016/j.neuron.2005.04.030] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 03/14/2005] [Accepted: 04/25/2005] [Indexed: 11/16/2022]
Abstract
Neuronal synchrony is important to network behavior in many brain regions. In the olfactory bulb, principal neurons (mitral cells) project apical dendrites to a common glomerulus where they receive a common input. Synchronized activity within a glomerulus depends on chemical transmission but mitral cells are also electrically coupled. We examined the role of connexin-mediated gap junctions in mitral cell coordinated activity. Electrical coupling as well as correlated spiking between mitral cells projecting to the same glomerulus was entirely absent in connexin36 (Cx36) knockout mice. Ultrastructural analysis of glomeruli confirmed that mitral-mitral cell gap junctions on distal apical dendrites contain Cx36. Coupled AMPA responses between mitral cell pairs were absent in the knockout, demonstrating that electrical coupling, not transmitter spillover, is responsible for synchronization. Our results indicate that Cx36-mediated gap junctions between mitral cells orchestrate rapid coordinated signaling via a novel form of electrochemical transmission.
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Shi L, Tu N, Patterson PH. Maternal influenza infection is likely to alter fetal brain development indirectly: the virus is not detected in the fetus. Int J Dev Neurosci 2005; 23:299-305. [PMID: 15749254 DOI: 10.1016/j.ijdevneu.2004.05.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Revised: 05/18/2004] [Accepted: 05/19/2004] [Indexed: 11/24/2022] Open
Abstract
Epidemiological studies have shown that maternal infection can increase the risk for mental illness in the offspring. In a mouse model of maternal respiratory infection with influenza virus, the adult offspring display striking behavioral, pharmacological and histological abnormalities. Although influenza primarily infects the respiratory system, there are reports of viral mRNA and protein in the fetus of infected pregnant animals. To determine the extent of viral spread following maternal respiratory infection, we used RT-PCR to assay various maternal and fetal tissues for influenza A mRNAs coding for neuraminidase, non-structural protein 2, nuclear protein and matrix protein. While infected maternal lungs exhibit uniformly very strong signals, placentae are only rarely positive, and viral RNAs are not detectable in fetal brains from infected mothers. Thus, the effects of maternal infection on fetal brain development are likely to be indirect, probably involving the maternal inflammatory response.
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Affiliation(s)
- Limin Shi
- Biology Division, California Institute of Technology, Pasadena, CA 91125, USA
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Weickert S, Ray A, Zoidl G, Dermietzel R. Expression of neural connexins and pannexin1 in the hippocampus and inferior olive: a quantitative approach. ACTA ACUST UNITED AC 2005; 133:102-9. [PMID: 15661370 DOI: 10.1016/j.molbrainres.2004.09.026] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2004] [Indexed: 11/21/2022]
Abstract
Electrical synapses (or neuronal gap junctions) are thought to be essential for the generation of synchronous oscillatory activities in various areas of the brain. In this study, we quantified the steady state mRNA expression levels of two neuronal gap junction proteins, connexin36 (Cx36) and connexin45 (Cx45), as well as of pannexin1, a member of a novel class of communicative junction forming proteins, and of connexin47 (Cx47) which is expressed in oligodendrocytes. The expression levels of these genes were compared in two regions known for oscillatory activity and which are equipped with electrically coupled neurons. Assessment of the levels of mRNA expression in the hippocampus and the nuclear complex of the inferior olive (IO) was achieved by means of laser microdissection (LMM) in combination with real time RT-PCR. Our results demonstrate the differential expression of Cx36, Cx45, pannexin1 and Cx47 in the hippocampus, with pannexin1 showing the highest level of expression followed by Cx36, Cx47, and Cx45. In the IO, pannexin1 showed a comparable expression level as in the hippocampus, but connexin expression levels were increased. Upon direct comparison, the combination of LMM and real time RT-PCR data generated specific, robust and reproducible results consistent with recent data reported about connexin expression in the nervous system. We conclude that the analytical strategy shown here provides a technological solution to overcome the less sensitive and notoriously less specific analysis of connexin expression by in situ hybridization.
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Affiliation(s)
- Svenja Weickert
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University-Bochum, University Street 150, 44780 Bochum, Germany
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Söhl G, Odermatt B, Maxeiner S, Degen J, Willecke K. New insights into the expression and function of neural connexins with transgenic mouse mutants. ACTA ACUST UNITED AC 2005; 47:245-59. [PMID: 15572175 DOI: 10.1016/j.brainresrev.2004.05.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2004] [Indexed: 10/26/2022]
Abstract
Gap junctions represent direct intercellular conduits between contacting cells. The subunit proteins of these conduits are called connexins. To date, 20 and 21 connexin genes have been described in the mouse and human genome, respectively, many of them represent sequence-orthologous pairs. Targeted deletion of connexin genes in the mouse genome opened new insights into the biological function of these channel forming proteins, which, in some cases, could be correlated to phenotypic abnormalities in humans, suffering from inherited diseases caused by mutations in the corresponding orthologous connexin gene. Replacing the connexin coding DNA by an appropriate reporter gene has clarified in several cases its cell type specific expression in mouse brain. Various studies demonstrated that connexin36 is mainly expressed in interneurons of retina and brain. Targeted deletion of connexin36 evoked a loss of electrical signal transduction and interferes with synchrony which probably leads to defects in visual transmission and memory. Deletion of connexin43 in astrocytes of mouse brain resulted in increased spreading depression consistent with the notion of altered "spatial buffering" of K(+) ions and glutamate secreted by active neurons. General connexin30-deficiency led to hearing impairment and apoptosis of hair cells, similar to that observed in mice with cochlea specific deletion of connexin26. Reporter gene expression in connexin30-deficient mice indicated that astrocytes in certain brain regions and leptomeningeal as well as ependymal cells are labelled. Reporter gene expression in connexin45- and connexin47-deficient mice was used to reassign connexin45 expression to certain CNS neurons and connexin47 expression to oligodendrocytes.
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Affiliation(s)
- Goran Söhl
- Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstr. 164, 53117 Bonn, Germany
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36
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Abbott LC, Nahm SS. Neuronal nitric oxide synthase expression in cerebellar mutant mice. THE CEREBELLUM 2004; 3:141-51. [PMID: 15543804 DOI: 10.1080/14734220410031927] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Nitric oxide (NO) is a diffusible, multifunctional signaling molecule found in many areas of the brain. NO signaling is involved in a wide array of neurophysiological functions including synaptogenesis, modulation of neurotransmitter release, synaptic plasticity, central nervous system blood flow and cell death. NO synthase (NOS) activity regulates the production of NO and the cerebellum expresses high levels of nitric oxide synthase (NOS) in granule, stellate and basket cells. Cerebellar mutant mice provide excellent opportunities to study changes of NO/NOS concentrations and activities to gain a greater understanding of the roles of NO and NOS in cerebellar function. Here, we have reviewed the current understanding of the functional roles of NO and NOS in the cerebellum and present NO/NOS activities that have been described in various cerebellar mutant mice and NOS knockout mice. NO appears to exert neuroprotective effects at low to moderate concentrations, whereas NO becomes neurotoxic as the concentration increases. Excessive NO production can cause oxidative stress to neurons, ultimately impairing neuronal function and result in neuronal cell death. Based on their genetics and cerebellar histopathology, some of cerebellar mutant mice display similarities with human neurological conditions and may prove to be valuable models to study several human neurological disorders, such as autism and schizophrenia.
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Affiliation(s)
- Louise C Abbott
- Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station, Texas 77843-4458, USA.
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Hormuzdi SG, Filippov MA, Mitropoulou G, Monyer H, Bruzzone R. Electrical synapses: a dynamic signaling system that shapes the activity of neuronal networks. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1662:113-37. [PMID: 15033583 DOI: 10.1016/j.bbamem.2003.10.023] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Revised: 10/14/2003] [Accepted: 10/14/2003] [Indexed: 01/25/2023]
Abstract
Gap junctions consist of intercellular channels dedicated to providing a direct pathway for ionic and biochemical communication between contacting cells. After an initial burst of publications describing electrical coupling in the brain, gap junctions progressively became less fashionable among neurobiologists, as the consensus was that this form of synaptic transmission would play a minimal role in shaping neuronal activity in higher vertebrates. Several new findings over the last decade (e.g. the implication of connexins in genetic diseases of the nervous system, in processing sensory information and in synchronizing the activity of neuronal networks) have brought gap junctions back into the spotlight. The appearance of gap junctional coupling in the nervous system is developmentally regulated, restricted to distinct cell types and persists after the establishment of chemical synapses, thus suggesting that this form of cell-cell signaling may be functionally interrelated with, rather than alternative to chemical transmission. This review focuses on gap junctions between neurons and summarizes the available data, derived from molecular, biological, electrophysiological, and genetic approaches, that are contributing to a new appreciation of their role in brain function.
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Affiliation(s)
- Sheriar G Hormuzdi
- Department of Clinical Neurobiology, Interdisciplinary Center for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany
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38
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Abstract
An excess of winter-spring births (and/or a decrease of summer births) has consistently been observed in schizophrenia (SCZ). This observation may provide a significant clue about the causes of the disease if specific factors which cause the phenomenon can be determined. This paper reviews several studies which investigated factors correlated with this observation in SCZ, in an attempt to determine which factors more likely cause the seasonality. Among the candidates of the factors are meteorological variables (such as ambient temperature), several infections, maternal hormones, sperm quality, nutrition and external toxins. A variation of procreation might also have an effect. Among the factors, the most extensively studied are temperature and viral infections. Some of them have appeared promising, but further studies are definitely required. Several challenges, including complicated correlations of the factors and determination of the susceptible period during pregnancy, need to be overcome. Comparisons of the data from areas and cohorts with different patterns of the candidate factors may be helpful. Animal studies may also help investigate the molecular and physiological mechanisms of the phenomenon.
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Affiliation(s)
- Mamoru Tochigi
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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39
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Cicirata F, Nicotra A, Cicero D, Parenti R, Zappalà A. Cloning and expression pattern of connexin39, a new member of the gap junction gene family isolated from the neural tube of chicken embryos. Gene 2004; 328:121-6. [PMID: 15019991 DOI: 10.1016/j.gene.2003.11.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Revised: 11/07/2003] [Accepted: 11/24/2003] [Indexed: 11/23/2022]
Abstract
In this study, a new gap junction (GJ) connexin (Cx) gene was isolated from the neural tube of chicken (c) embryos (HH21) and cloned by degenerate reverse transcription-polymerase chain reaction (RT-PCR). The open reading frame of the gene encodes for a protein of 343 amino acid residues with strong similarity to highly conserved connexin sequences. On the basis of the predicted molecular mass of 39144 kDa, we denominated it as cCx39. Sequence analysis allocated the cCx39 to the alpha-group of connexin gene family. The mRNA expression of cCx39 was detected by RT-PCR and Northern blot in several tissues of chicken, including different parts of central nervous system, heart, liver, kidney, aorta and ovary. In situ hybridisation analysis of chicken brain showed strong expression in neurons of granular layers of cerebellum, optic tectum and ectostriatum. The in situ hybridisation of extracererebral tissues revealed strong expression of cCx39 in the atrium of the heart, the external layer of the aorta and endothelium of biliary vessels; moderate expression was found in the endothelium of the aorta.
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Affiliation(s)
- Federico Cicirata
- Dipartimento di Scienze Fisiologiche, Università di Catania, V.le A. Doria 6, 95125 Catania, Italy.
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40
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Solomon IC. Connexin36 distribution in putative CO2-chemosensitive brainstem regions in rat. Respir Physiol Neurobiol 2003; 139:1-20. [PMID: 14637306 DOI: 10.1016/j.resp.2003.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Recent work from our laboratory has demonstrated that the gap junction proteins connexin26 (Cx26) and connexin32 (Cx32) are expressed in neurons in putative CO2-chemosensitive brainstem regions in both neonatal and adult rats. Whether the recently identified neuron-specific gap junction protein connexin36 (Cx36) is also present in these brainstem regions remains to be determined. Therefore, in the current experiments, immunoblot and immunohistochemical protocols were used to investigate the regional distribution and cellular localization of Cx36 in putative CO2-chemosensitive brainstem regions in both neonatal and adult rats. Immunoblot analyses revealed Cx36 expression in putative CO2-chemosensitive brainstem regions in each of the age groups examined, although both regional and developmental differences in the relative expression levels were detected. Immunohistochemical analyses confirmed Cx36 expression in neurons in each of the putative CO2-chemosensitive brainstem regions and revealed both somal and dendritic labeling patterns. These findings provide additional morphological evidence supporting the potential for gap junctional communication in these regions in both neonatal and adult rats. We propose that the gap junction protein Cx36 also contributes to the neuroanatomical substrate for gap junctional communication, which is hypothesized to play a role in central CO2 chemoreception.
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Affiliation(s)
- Irene C Solomon
- Department of Physiology and Biophysics, State University of New York at Stony Brook, Basic Science Tower, Health Science Center, Level 6, Rm. 140, Stony Brook, NY 11794-8661, USA.
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41
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Winmill RE, Hedrick MS. Gap junction blockade with carbenoxolone differentially affects fictive breathing in larval and adult bullfrogs. Respir Physiol Neurobiol 2003; 138:239-51. [PMID: 14609513 DOI: 10.1016/j.resp.2003.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study examined the role of gap junctional communication in the modulation of respiratory related motor output using in vitro brainstem preparations of larval (N=14) and adult (N=14) bullfrogs (Rana catesbeiana). Superfusion of the isolated brainstem for at least 1 h with the gap junction blocker carbenoxolone (CBX; 100 microM and 1 mM) dissolved in artificial cerebrospinal fluid (aCSF) elicited significant changes in respiratory-related burst frequency in both larval and adult preparations. In tadpole preparations, both concentrations of CBX significantly decreased gill and lung burst frequency over 20-40 min, with 1 mM CBX producing complete cessation of gill and lung burst activity by 40 min in all preparations. There was little or no change in other burst characteristics such as burst amplitude or duration. By contrast, superfusion of the adult brainstem preparation with CBX significantly increased lung burst frequency over 10-20 min, and caused cessation of lung burst activity with 100 microM CBX (five of seven preparations) and with 1 mM CBX (seven of seven preparations). Adult preparations that ceased activity with 100 microM CBX recovered in control aCSF, but those in 1 mM did not recover, despite up to 3 h superfusion with control aCSF. In two additional adult preparations, 1 h exposure to hypercapnic aCSF (7-10% CO2) following the cessation of fictive breathing with 1 mM CBX failed to evoke respiratory activity. The inhibition of fictive breathing in tadpoles suggests that gap junctional communication may be important for respiratory rhythmogenesis prior to the development of central CO2 chemosensitivity. Following metamorphosis to the terrestrial adult, however, gap junctional communication may contribute to regulation of respiratory frequency and possibly the transduction of central CO2 chemosensitivity.
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Affiliation(s)
- Rachel E Winmill
- Department of Biological Sciences, California State University, Hayward, Hayward, CA 94542, USA
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Maxeiner S, Krüger O, Schilling K, Traub O, Urschel S, Willecke K. Spatiotemporal transcription of connexin45 during brain development results in neuronal expression in adult mice. Neuroscience 2003; 119:689-700. [PMID: 12809690 DOI: 10.1016/s0306-4522(03)00077-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Characterization of the expression pattern of connexins in neural tissue is a necessary prerequisite for understanding the functional relevance of the corresponding gap junction channels in brain. Here we describe the cell type-specific expression of connexin45 in the CNS and the spatiotemporal expression pattern from embryonic day 19.5 to adult brain using a recently described connexin45 LacZ-reporter mouse. The connexin45 gene is highly expressed during embryogenesis and up to 2 weeks after birth in nearly all brain regions. Afterward its expression is restricted to the thalamus, the CA3 region of hippocampus and the cerebellum. In adult mouse brain, the pattern of LacZ-staining in combination with the analysis of different neuronal and glial marker proteins strongly suggests that connexin45 is expressed in neurons, but presumably not in astrocytes or mature oligodendrocytes. Expression of the LacZ/connexin45 reporter gene in subsets of neurons, such as cerebral cortical, hippocampal and thalamic neurons as well as basket and stellate cells of cerebellum should be corroborated by functional investigations of connexin45 protein in electrical synapses. Based on its expression pattern during development, we suggest that the connexin45-containing gap junction channels have a rather ubiquitous role during brain development and may contribute to functional specification in certain subsets of neurons in the adult brain.
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Affiliation(s)
- S Maxeiner
- Institut für Genetik, Abteilung fur Molekulargenetik, Rheinische Friedrich-Wilhelms Universität Bonn, Römerstrasse 164, D-53117, Bonn, Germany
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43
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2003; 11:1059-1063. [DOI: 10.11569/wcjd.v11.i7.1059] [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] [Indexed: 02/06/2023] Open
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Zoroğlu SS, Yürekli M, Meram I, Söğüt S, Tutkun H, Yetkin O, Sivasli E, Savaş HA, Yanik M, Herken H, Akyol O. Pathophysiological role of nitric oxide and adrenomedullin in autism. Cell Biochem Funct 2003; 21:55-60. [PMID: 12579522 DOI: 10.1002/cbf.989] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Several studies indicate that nitric oxide (NO) is involved in the aetiopathogenesis of many neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, Alzheimer's disease, Hungtington disease and stroke. Although it has not been investigated yet, several recent studies proposed that NO may have a pathophysiological role in autism. Adrenomedullin (AM), a recently discovered 52-amino acid peptide hormone, induces vasorelaxation by activating adenylate cyclase and also by stimulating NO release. AM immune reactivity is present in the brain consistent with a role as a neurotransmitter. It has been stated that NO and AM do function in the regulation of many neurodevelopmental processes. We hypothesized that NO and AM activities have been affected in autistic patients and aimed to examine these molecules. Twenty-six autistic patients and 22 healthy control subjects were included in this study. AM and total nitrite (a metabolite of NO) levels have been measured in plasma. The mean values of plasma total nitrite and AM levels in the autistic group were significantly higher than control values, respectively (p < 0.001, p = 0.028). There is no correlation between total nitrite and AM levels (r = 0.11, p = 0.31). Certainly, this subject needs much further research investigating autistic patients in earlier periods of life and with subtypes of the disorder.
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Affiliation(s)
- Süleyman Salih Zoroğlu
- Department of Child and Adolescent Psychiatry, Gaziantep University Medical School, Gaziantep, Turkey.
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Abstract
Recent evidence indicates that gap junctions play a more prominent role in normal functioning of the mammalian central nervous system (CNS) than was once believed. Accumulating evidence from both neonatal and adult rodents indicates that gap junctions participate in multiple aspects of respiratory control, including central CO(2) chemoreception, respiratory rhythmogenesis, and respiratory motoneuron output. This review provides an overview of gap junction neurobiology in the mammalian CNS and presents the anatomical and electrophysiological evidence for gap junctions in CO(2) chemoreception and respiratory control.
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Affiliation(s)
- Irene C Solomon
- Department of Physiology and Biophysics, State University of New York at Stony Brook, , Stony Brook, NY 11794-8661, USA.
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46
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Ramirez JM, Zuperku EJ, Alheid GF, Lieske SP, Ptak K, McCrimmon DR. Respiratory rhythm generation: converging concepts from in vitro and in vivo approaches? Respir Physiol Neurobiol 2002; 131:43-56. [PMID: 12106994 DOI: 10.1016/s1569-9048(02)00036-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The timing and activation pattern of breathing movements are determined by the respiratory network. This network is amenable to a variety of in vivo and in vitro approaches, which offers a unique opportunity to investigate multiple organizational levels. It is only recently, however, that concepts obtained under in vivo and in vitro conditions are being integrated into a coherent model of breathing behavior. For example, the pre-Bötzinger complex as an essential site for rhythm generation was first identified in vitro, but has since been verified in vivo. Conversely, timing signals provided by other central and peripheral neuronal areas have so far been investigated in vivo, but it is now possible to address these issues with more complex in vitro preparations. Several key issues remain unresolved. For example, to what extent is the respiratory pattern controlled independently of the underlying rhythm? Answers to this and other questions require a dissection of mechanisms that is only possible through a complementary combination of experimental approaches.
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Affiliation(s)
- Jan-Marino Ramirez
- Department of Organismal Biology and Anatomy, Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
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Hughes SW, Blethyn KL, Cope DW, Crunelli V. Properties and origin of spikelets in thalamocortical neurones in vitro. Neuroscience 2002; 110:395-401. [PMID: 11906781 DOI: 10.1016/s0306-4522(01)00577-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Spikelets, or fast prepotentials as they are frequently referred to, are a common feature of the electrophysiology of central neurones and are invariably correlated with the presence of electrotonic coupling via gap junctions. Here we report that in the presence of the metabotropic glutamate receptor agonists, trans-ACPD or DHPG, thalamocortical neurones of the cat dorsal lateral geniculate nucleus maintained in vitro exhibit stereotypical spikelets that possess similar properties to those described in other brain areas. These spikelets were routinely observed in the presence of antagonists of fast chemical synaptic transmission, were resistant to the application of a variety of voltage-dependent Ca(2+) channel blockers but were abolished by tetrodotoxin. In addition, spikelets were reversibly blocked by the putative gap junction blocker carbenoxolone and were nearly always accompanied by dye-coupling. These results indicate that thalamocortical neurones may be electrotonically coupled via gap junctions with spikelets representing attenuated action potentials from adjoining cells. We suggest that the presence of electrotonic communication between thalamocortical neurones would have major implications for the understanding of both physiological (Steriade et al., 1993; Sillito et al., 1994; Alonso et al., 1996; Neuenschwander and Singer, 1996; Weliky and Katz, 1999) and pathological (Steriade and Contreras, 1995; Pinault et al., 1998) synchronised electrical activity in the thalamus.
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Affiliation(s)
- S W Hughes
- School of Biosciences, Cardiff University, Museum Avenue, CF10 3US, Cardiff, UK
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Hidaka S, Kato T, Miyachi EI. Expression of gap junction connexin36 in adult rat retinal ganglion cells. J Integr Neurosci 2002; 1:3-22. [PMID: 15011262 DOI: 10.1142/s0219635202000025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2002] [Accepted: 04/29/2002] [Indexed: 11/18/2022] Open
Abstract
Electrophysiological and ultrastructural studies have demonstrated that gap junctions connect diverse types of neurons in the central nervous system, permitting direct electrical and metabolic coupling. A member of gap junction channel subunit connexin36 (Cx36), is probed for the location of cell-to-cell communication in the mammalian retina, where gap junction networks of major classes of neurons are present. We present an analysis of the expression and localization of Cx36 protein in adult Wistar rat retina, using a newly generated polyclonal antibody against a sequence in the predicted cytoplasmic loop of the Cx36 amino acid alignment, deduced from the cDNA sequence. The affinity-purified antibody, recognizing a single 36-kDa protein, consistently labeled discrete puncta of subcellular structures likely to be associated with gap junctions in the inner plexiform layer, and also cytoplasm within somata and dendrites of retinal amacrine and ganglion cells, following examination with various fixation protocols and double labeling immuno-fluorescence. These results provide that prominent cell-to-cell communication appears in mature excitatory neurons such as retinal ganglion cells, in addition to inhibitory amacrine cells, mediated by gap junctions in the adult retina.
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Affiliation(s)
- Soh Hidaka
- Department of Physiology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192 Japan.
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Hormuzdi SG, Pais I, LeBeau FE, Towers SK, Rozov A, Buhl EH, Whittington MA, Monyer H. Impaired electrical signaling disrupts gamma frequency oscillations in connexin 36-deficient mice. Neuron 2001; 31:487-95. [PMID: 11516404 DOI: 10.1016/s0896-6273(01)00387-7] [Citation(s) in RCA: 393] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neural processing occurs in parallel in distant cortical areas even for simple perceptual tasks. Associated cognitive binding is believed to occur through the interareal synchronization of rhythmic activity in the gamma (30-80 Hz) range. Such oscillations arise as an emergent property of the neuronal network and require conventional chemical neurotransmission. To test the potential role of gap junction-mediated electrical signaling in this network property, we generated mice lacking connexin 36, the major neuronal connexin. Here we show that the loss of this protein disrupts gamma frequency network oscillations in vitro but leaves high frequency (150 Hz) rhythms, which may involve gap junctions between principal cells (Schmitz et al., 2001), unaffected. Thus, specific connexins differentially deployed throughout cortical networks are likely to regulate different functional aspects of neuronal information processing in the mature brain.
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Affiliation(s)
- S G Hormuzdi
- Department of Clinical Neurobiology, University Hospital of Neurology, Im Neuenheimer Feld 364, Heidelberg, Germany
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Fatemi SH. Reelin mutations in mouse and man: from reeler mouse to schizophrenia, mood disorders, autism and lissencephaly. Mol Psychiatry 2001; 6:129-33. [PMID: 11317213 DOI: 10.1038/sj.mp.4000129] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- S H Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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