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Methylmercury Causes Neurodegeneration and Downregulation of Myelin Basic Protein in the Spinal Cord of Offspring Rats after Maternal Exposure. Int J Mol Sci 2022; 23:ijms23073777. [PMID: 35409136 PMCID: PMC8998727 DOI: 10.3390/ijms23073777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/23/2022] [Accepted: 01/26/2022] [Indexed: 02/06/2023] Open
Abstract
Methylmercury (MeHg) is one of the most dangerous toxic pollutants spread throughout the earth. Chronic MeHg intoxication by contaminated food ingestion is the most common threat to human health, including impairment to the developing fetus. The present study aims at investigating the effects of maternal exposure to MeHg during gestation and lactation on the spinal cord of offspring. Pregnant rats received oral doses of MeHg (40 μg/kg/day) over a period of 42 days (21 gestation and 21 lactation). Control animals received the vehicle only. Total mercury concentration was measured in blood samples from offspring collected at the 41st postnatal day. Counting of motor neurons and immunoreactivity for myelin basic protein (MBP) were assessed in the spinal cords in both control and MeHg-intoxicated animals. Our results showed that MeHg promoted an increase in blood Hg levels. In addition, it caused a reduction in the number of spinal cord motor neurons as well as decreased MBP immunoreactivity in the cervical, thoracic and lumbar segments. Our present findings suggest that MeHg intoxication during rat pregnancy and lactation is associated with a pattern of motor neuron degeneration and downregulation of myelin basic protein in different segments of a developing spinal cord. Further studies are needed to establish the effect of MeHg intoxication in both young and adult rats.
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Methylmercury exposure during prenatal and postnatal neurodevelopment promotes oxidative stress associated with motor and cognitive damages in rats: an environmental-experimental toxicology study. Toxicol Rep 2022; 9:563-574. [PMID: 35392159 PMCID: PMC8980556 DOI: 10.1016/j.toxrep.2022.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/29/2022] [Accepted: 02/25/2022] [Indexed: 12/11/2022] Open
Abstract
The environmental contamination by methylmercury (MeHg) is a major concern for public health. The effects of MeHg in the central nervous system (CNS) of adult animals have been extensively investigated; however, little is known about the effects of MeHg exposure during intrauterine and lactation periods on motor and cognitive functions of adolescent rats. Therefore, this study aimed to investigate the effect of MeHg exposure during intrauterine life and lactation on both motor and cognitive functions of offspring rats. Ten female Wistar rats were exposed to 40 μg/kg/day of MeHg through cookie treats from the first day of pregnancy until the last day of breastfeeding. Both motor and cognitive functions of offspring male rats were assessed by open field, rotarod, and step-down inhibitory avoidance tests. Forty-one days after birth, the hippocampus and cerebellum were collected to determine total Hg content, antioxidant capacity against peroxyl radicals (ACAP), reduced glutathione (GSH) levels, lipid peroxidation (LPO), and nitrite levels. MeHg exposure during CNS development increased Hg levels in both hippocampal and cerebellar parenchymas, triggered oxidative stress throughout ACAP and GSH decrease, increased LPO and nitrite levels. These alterations resulted in reduced spontaneous and stimulated locomotion and short- and long-term memory deficits. Therefore, damages triggered by MeHg exposure during intrauterine life and lactation had detrimental effects on oxidative biochemistry and motor and cognitive functions of offspring rats. The MeHg exposure during CNS development increased mercury levels in hippocampal and cerebellar parenchyma. The MeHg intoxication during pregnancy and lactation impairs the redox status of hippocampus and cerebellum of the offspring. MeHg exposure causes behavioral effects in motor ability and cognition of offspring rats.
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Freire MAM, Lima RR, Nascimento PC, Gomes-Leal W, Pereira A. Effects of methylmercury on the pattern of NADPH diaphorase expression and astrocytic activation in the rat. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110799. [PMID: 32544743 DOI: 10.1016/j.ecoenv.2020.110799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is an environmental contaminant that poses great risk to human health. However, it is still widely used in artisanal gold-mining enterprises around the world, especially in developing countries. Methylmercury (MeHg) is produced environmentally by biomethylation of inorganic Hg present in water sediments, leading to its subsequent accumulation in the aquatic food chain. Due to its high metabolic rate, the Central Nervous System (CNS) is one of the main targets of MeHg. In the present study, we investigate the impact of chronic MeHg intoxication on NADPH diaphorase (NADPH-d) activity and astrocyte mobilization in the visual cortex of the rat. After 60 days of MeHg administration by oral gavage (0.04 mg/kg/day), tissue samples containing the visual cortex were submitted to measurements of Hg levels, NADPH-d activity, and GFAP immunohistochemistry for identification of astrocytes. MeHg intoxication was associated with increased Hg deposits and with reduced NADPH-d neuropil reactivity in the visual cortex. A morphometric analysis suggested that NADPH-d-positive neurons were mostly spared from MeHg harmful action and intoxicated animals had astrocytic activation similar to the control group. The decrease in NADPH-d neuropil reactivity may be due to the negative effect of chronic MeHg poisoning on both the synthesis and transport of this enzyme in afferent pathways to the visual cortex. The relative resistance of NADPH-d-reactive neurons to chronic MeHg intoxication may be associated with peculiarities in cell metabolism or to a protective role of nitric oxide, safeguarding those neurons from Hg deleterious effects.
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Affiliation(s)
- Marco Aurelio M Freire
- Graduate Program in Health and Society, Faculty of Health Sciences, University of State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Antonio Pereira
- Department of Electrical and Biomedical Engineering, Institute of Technology, Federal University of Pará (UFPA), Belém, PA, Brazil.
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Costa IM, Lima FOV, Fernandes LCB, Norrara B, Neta FI, Alves RD, Cavalcanti JRLP, Lucena EES, Cavalcante JS, Rego ACM, Filho IA, Queiroz DB, Freire MAM, Guzen FP. Astragaloside IV Supplementation Promotes A Neuroprotective Effect in Experimental Models of Neurological Disorders: A Systematic Review. Curr Neuropharmacol 2020; 17:648-665. [PMID: 30207235 PMCID: PMC6712289 DOI: 10.2174/1570159x16666180911123341] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 01/22/2023] Open
Abstract
Background: Neurological disorders constitute a growing worldwide concern due to the progressive aging of the population and the risky behavior they represent. Herbal medicines have scientific relevance in the treatment of these pathol-ogies. One of these substances, Astragaloside IV (AS-IV), is the main active compound present in the root of Astragalus membranaceus (Fisch.) Bge, a Chinese medicinal herb with neuroprotective properties. Objective: In the present study we performed a systematic review that sought to comprehend the neuroprotective effect pre-sented by AS-IV in experimental models of neurological disorders. Method: This study is a systematic review, where an electronic search in United States National Library of Medicine (Pub-Med), Science Direct, Cochrane Library, Scientific Electronic Library Online (SciELO), Scopus, Web of Science, Medline via Proquest and Periodicos Capes databases covering the years between 2007 and 2017, using “Astragaloside IV” and “Neurodegenerative diseases”; “Astragaloside IV” and “ Neurological disorders” as reference terms was made. Results: A total of 16 articles were identified, in which the efficacy of AS-IV was described in experimental models of Par-kinson’s disease, Alzheimer’s disease, cerebral ischemia and autoimmune encephalomyelitis, by improving motor deficits and/or neurochemical activity, especially antioxidant systems, reducing inflammation and oxidative stress. Conclusion: The findings of the present study indicate that the administration of AS-IV can improve behavioral and neuro-chemical deficits largely due to its antioxidant, antiapoptotic and anti-inflammatory properties, emerging as an alternative therapeutic approach for the treatment of neurological disorders.
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Affiliation(s)
- Ianara M Costa
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Francisca O V Lima
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Luciana C B Fernandes
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Bianca Norrara
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Francisca I Neta
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Rodrigo D Alves
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - José R L P Cavalcanti
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Eudes E S Lucena
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Jeferson S Cavalcante
- Laboratory of Neurochemical Studies, Center of Biological Sciences, Federal University of Rio Grande do Norte (UFRN), Natal/RN, Brazil
| | - Amalia C M Rego
- Post Graduation Program in Biotechnology, Health School, Potiguar University (UnP), Natal/RN, Brazil
| | - Irami A Filho
- Post Graduation Program in Biotechnology, Health School, Potiguar University (UnP), Natal/RN, Brazil
| | - Dinalva B Queiroz
- Post Graduation Program in Biotechnology, Health School, Potiguar University (UnP), Natal/RN, Brazil
| | - Marco A M Freire
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil
| | - Fausto P Guzen
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte (UERN), Mossoro/RN, Brazil.,Post Graduation Program in Biotechnology, Health School, Potiguar University (UnP), Natal/RN, Brazil
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Freire MAM, Santana LNS, Bittencourt LO, Nascimento PC, Fernandes RM, Leão LKR, Fernandes LMP, Silva MCF, Amado LL, Gomes-Leal W, Crespo-Lopez ME, Maia CDSF, Lima RR. Methylmercury intoxication and cortical ischemia: Pre-clinical study of their comorbidity. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 174:557-565. [PMID: 30865911 DOI: 10.1016/j.ecoenv.2019.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/01/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Stroke is one of the main causes of human disability worldwide. Ischemic stroke is mostly characterized by metabolic collapse and fast tissue damage, followed by secondary damage in adjacent regions not previously affected. Heavy metals intoxication can be associated with stroke incidence, because of their damaging action in the vascular system. Mercury, in particular, possesses a high tropism by metabolically active regions, such as the brain. In the present study we sought to evaluate whether methylmercury (MeHg) intoxication can aggravate the tissue damage caused by an ischemic stroke induced by microinjections of endothelin-1 (ET-1) into the motor cortex of adult rats. Following MeHg intoxication by gavage (0.04 mg/kg/day) during 60 days, the animals were injected with ET-1 (1 μl, 40 pmol/μl) or vehicle (1 μl). After 7 days, all animals were submitted to behavioral tests and then their brains were processed to biochemical and immunohistochemical analyses. We observed that long-term MeHg intoxication promoted a significant Hg deposits in the motor cortex, with concomitant increase of microglial response, followed by reduction of the neuronal population following ischemia and MeHg intoxication, as well as disturbance in the antioxidant defense mechanisms by misbalance of oxidative biochemistry with increase of both lipid peroxidation and nitrite levels, associated to behavioral deficits. MeHg exposure and cortical ischemia demonstrated that both injuries are able of causing significant neurobehavioural impairments in motor coordination and learning accompanied of an exacerbated microglial activation, oxidative stress and neuronal loss in the motor cortex, indicating that MeHg as a source of metabolic disturbance can act as an important increasing factor of ischemic events in the brain.
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Affiliation(s)
| | - Luana Nazaré S Santana
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Monteiro Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Luana Ketlen R Leão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Luanna Melo P Fernandes
- Laboratory of Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Marcia Cristina F Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Lílian Lund Amado
- Laboratory of Ecotoxicology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Cristiane do Socorro F Maia
- Laboratory of Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil.
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Pereira CM, Freire MAM, Santos JR, Guimarães JS, Dias-Florencio G, Santos S, Pereira A, Ribeiro S. Non-visual exploration of novel objects increases the levels of plasticity factors in the rat primary visual cortex. PeerJ 2018; 6:e5678. [PMID: 30370183 PMCID: PMC6202959 DOI: 10.7717/peerj.5678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/29/2018] [Indexed: 12/23/2022] Open
Abstract
Background Historically, the primary sensory areas of the cerebral cortex have been exclusively associated with the processing of a single sensory modality. Yet the presence of tactile responses in the primary visual (V1) cortex has challenged this view, leading to the notion that primary sensory areas engage in cross-modal processing, and that the associated circuitry is modifiable by such activity. To explore this notion, here we assessed whether the exploration of novel objects in the dark induces the activation of plasticity markers in the V1 cortex of rats. Methods Adult rats were allowed to freely explore for 20 min a completely dark box with four novel objects of different shapes and textures. Animals were euthanized either 1 (n = 5) or 3 h (n = 5) after exploration. A control group (n = 5) was placed for 20 min in the same environment, but without the objects. Frontal sections of the brains were submitted to immunohistochemistry to measure protein levels of egr-1 and c-fos, and phosphorylated calcium-dependent kinase (pCaKMII) in V1 cortex. Results The amount of neurons labeled with monoclonal antibodies against c-fos, egr-1 or pCaKMII increased significantly in V1 cortex after one hour of exploration in the dark. Three hours after exploration, the number of labeled neurons decreased to basal levels. Conclusions Our results suggest that non-visual exploration induces the activation of immediate-early genes in V1 cortex, which is suggestive of cross-modal processing in this area. Besides, the increase in the number of neurons labeled with pCaKMII may signal a condition promoting synaptic plasticity.
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Affiliation(s)
- Catia M Pereira
- Instituto Internacional de Neurociências de Natal Edmond e Lily Safra, Macaiba, RN, Brasil
| | - Marco Aurelio M Freire
- Programa de Pós-graduação em Saúde e Sociedade, Universidade do Estado do Rio Grande do Norte, Mossoró, RN, Brasil
| | - José R Santos
- Departamento de Biociências, Universidade Federal de Sergipe, Itabaiana, SE, Brasil
| | | | | | - Sharlene Santos
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil
| | - Antonio Pereira
- Faculdade de Engenharia Elétrica, Universidade Federal do Pará, Belém, PA, Brasil
| | - Sidarta Ribeiro
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil
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7
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Colón-Rodríguez A, Hannon HE, Atchison WD. Effects of methylmercury on spinal cord afferents and efferents-A review. Neurotoxicology 2017; 60:308-320. [PMID: 28041893 PMCID: PMC5447474 DOI: 10.1016/j.neuro.2016.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 12/21/2016] [Accepted: 12/21/2016] [Indexed: 10/20/2022]
Abstract
Methylmercury (MeHg) is an environmental neurotoxicant of public health concern. It readily accumulates in exposed humans, primarily in neuronal tissue. Exposure to MeHg, either acutely or chronically, causes severe neuronal dysfunction in the central nervous system and spinal neurons; dysfunction of susceptible neuronal populations results in neurodegeneration, at least in part through Ca2+-mediated pathways. Biochemical and morphologic changes in peripheral neurons precede those in central brain regions, despite the fact that MeHg readily crosses the blood-brain barrier. Consequently, it is suggested that unique characteristics of spinal cord afferents and efferents could heighten their susceptibility to MeHg toxicity. Transient receptor potential (TRP) ion channels are a class of Ca2+-permeable cation channels that are highly expressed in spinal afferents, among other sensory and visceral organs. These channels can be activated in numerous ways, including directly via chemical irritants or indirectly via Ca2+ release from intracellular storage organelles. Early studies demonstrated that MeHg interacts with heterologous TRP channels, though definitive mechanisms of MeHg toxicity on sensory neurons may involve more complex interaction with, and among, differentially-expressed TRP populations. In spinal efferents, glutamate receptors of the N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and possibly kainic acid (KA) classes are thought to play a major role in MeHg-induced neurotoxicity. Specifically, the Ca2+-permeable AMPA receptors, which are abundant in motor neurons, have been identified as being involved in MeHg-induced neurotoxicity. In this review, we will describe the mechanisms that could contribute to MeHg-induced spinal cord afferent and efferent neuronal degeneration, including the possible mediators, such as uniquely expressed Ca2+-permeable ion channels.
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Affiliation(s)
- Alexandra Colón-Rodríguez
- Department of Pharmacology and Toxicology, 1355 Bogue Street, Life Sciences Building Rm. B440, Michigan State University, East Lansing, MI, United States; Institute for Integrative Toxicology, 1129 Farm Lane, Food Safety and Toxicology Rm. 165, Michigan State University, East Lansing, MI, United States; Comparative Medicine and Integrative Biology Program, 784 Wilson Road, Veterinary Medical Center Rm. G-100, Michigan State University, East Lansing, MI, United States.
| | - Heidi E Hannon
- Department of Pharmacology and Toxicology, 1355 Bogue Street, Life Sciences Building Rm. B440, Michigan State University, East Lansing, MI, United States; Institute for Integrative Toxicology, 1129 Farm Lane, Food Safety and Toxicology Rm. 165, Michigan State University, East Lansing, MI, United States; Comparative Medicine and Integrative Biology Program, 784 Wilson Road, Veterinary Medical Center Rm. G-100, Michigan State University, East Lansing, MI, United States.
| | - William D Atchison
- Department of Pharmacology and Toxicology, 1355 Bogue Street, Life Sciences Building Rm. B440, Michigan State University, East Lansing, MI, United States; Institute for Integrative Toxicology, 1129 Farm Lane, Food Safety and Toxicology Rm. 165, Michigan State University, East Lansing, MI, United States; Comparative Medicine and Integrative Biology Program, 784 Wilson Road, Veterinary Medical Center Rm. G-100, Michigan State University, East Lansing, MI, United States.
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Freire MAM, Guimaraes JS, Santos JR, Simplício H, Gomes-Leal W. Morphometric analysis of NADPH diaphorase reactive neurons in a rat model of focal excitotoxic striatal injury. Neuropathology 2016; 36:527-534. [DOI: 10.1111/neup.12311] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/23/2016] [Accepted: 04/30/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Marco Aurelio M. Freire
- Postgraduate Program in Health and Society; Faculty of Health Sciences, State University of Rio Grande do Norte (UERN); Mossoró RN Brazil
- Laboratory of Experimental Neuroprotection and Neuroregeneration; Institute of Biological Sciences, Federal University of Pará (UFPA); Belém PA Brazil
| | - Joanilson S. Guimaraes
- Laboratory of Experimental Neuroprotection and Neuroregeneration; Institute of Biological Sciences, Federal University of Pará (UFPA); Belém PA Brazil
| | - Jose Ronaldo Santos
- Laboratory of Behavioral and Evolutionary Neurobiology; Department of Biosciences, Federal University of Sergipe (UFS); Itabaiana SE Brazil
| | - Hougelle Simplício
- Postgraduate Program in Health and Society; Faculty of Health Sciences, State University of Rio Grande do Norte (UERN); Mossoró RN Brazil
- Anita Garibaldi Center for Education and Research in Health; Santos Dumont Institute (ISD); Macaíba RN Brazil
- Edmond and Lily Safra International Institute of Neuroscience; Santos Dumont Institute (ISD); Macaíba RN Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration; Institute of Biological Sciences, Federal University of Pará (UFPA); Belém PA Brazil
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Freire MAM, Faber J, Lemos NAM, Santos JR, Cavalcanti PF, Lima RH, Morya E. Distribution and Morphology of Calcium-Binding Proteins Immunoreactive Neurons following Chronic Tungsten Multielectrode Implants. PLoS One 2015; 10:e0130354. [PMID: 26098896 PMCID: PMC4476592 DOI: 10.1371/journal.pone.0130354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 05/19/2015] [Indexed: 12/25/2022] Open
Abstract
The development of therapeutic approaches to improve the life quality of people suffering from different types of body paralysis is a current major medical challenge. Brain-machine interface (BMI) can potentially help reestablishing lost sensory and motor functions, allowing patients to use their own brain activity to restore sensorimotor control of paralyzed body parts. Chronic implants of multielectrodes, employed to record neural activity directly from the brain parenchyma, constitute the fundamental component of a BMI. However, before this technique may be effectively available to human clinical trials, it is essential to characterize its long-term impact on the nervous tissue in animal models. In the present study we evaluated how chronic implanted tungsten microelectrode arrays impact the distribution and morphology of interneurons reactive to calcium-binding proteins calbindin (CB), calretinin (CR) and parvalbumin (PV) across the rat’s motor cortex. Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation. Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted. Moreover, restricted microglial activation was observed on the implanted sites. On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.
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Affiliation(s)
- Marco Aurelio M. Freire
- Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil
| | - Jean Faber
- Laboratory of Neuroengineering, Department of Science and Technology, Federal University of São Paulo (UNIFESP), Sao Jose dos Campos, SP, Brazil
| | - Nelson Alessandretti M. Lemos
- Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil
| | - Jose Ronaldo Santos
- Laboratory of Neuroscience, Department of Biosciences, Federal University of Sergipe (UFS), Itabaiana, SE, Brazil
| | - Pedro França Cavalcanti
- Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil
| | - Ramon Hypolito Lima
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil
| | - Edgard Morya
- Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil
- Associação Alberto Santos Dumont para Apoio a Pesquisa, Sirio-Libanes Hospital, São Paulo, SP, Brazil
- * E-mail:
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Permanently compromised NADPH-diaphorase activity within the osmotically activated supraoptic nucleus after in utero but not adult exposure to Aroclor 1254. Neurotoxicology 2015; 47:37-46. [DOI: 10.1016/j.neuro.2014.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/29/2014] [Accepted: 12/19/2014] [Indexed: 12/30/2022]
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Olmesartan decreased levels of IL-1β and TNF-α, down-regulated MMP-2, MMP-9, COX-2, RANK/RANKL and up-regulated SOCs-1 in an intestinal mucositis model. PLoS One 2014; 9:e114923. [PMID: 25531650 PMCID: PMC4273993 DOI: 10.1371/journal.pone.0114923] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/15/2014] [Indexed: 11/22/2022] Open
Abstract
Methotrexate (MTX) is a pro-oxidant compound that depletes dihydrofolate pools and is widely used in the treatment of leukaemia and other malignancies. The efficacy of methotrexate is often limited by mucositis and intestinal injury, which are major causes of morbidity in children and adults. The aim of this study was to evaluate the effect of olmesartan (OLM), an angiotensin II receptor antagonist, on an Intestinal Mucositis Model (IMM) induced by MTX in Wistar rats. IMM was induced via intraperitoneal (i.p.) administration of MTX (7 mg/kg) for three consecutive days. The animals were pre-treated with oral OLM at 0.5, 1 or 5 mg/kg or with vehicle 30 min prior to exposure to MTX. Small intestinal homogenates were assayed for levels of the IL-1β, IL-10 and TNF-α cytokines, malondialdehyde and myeloperoxidase activity. Additionally, immunohistochemical analyses of MMP-2, MMP-9, COX-2, RANK/RANKL and SOCS-1 and confocal microscopy analysis of SOCS-1 expression were performed. Treatment with MTX + OLM (5 mg/kg) resulted in a reduction of mucosal inflammatory infiltration, ulcerations, vasodilatation and haemorrhagic areas (p<0.05) as well as reduced concentrations of MPO (p<0.001) and the pro-inflammatory cytokines IL-1β (p<0.001) and TNF-a (p<0.01), and increase anti-inflammatory cytocine IL-10 (p<0.05). Additionally, the combined treatment reduced expression of MMP-2, MMP-9, COX-2, RANK and RANKL(p<0.05) and increased cytoplasmic expression of SOCS-1 (p<0.05). Our findings confirm the involvement of OLM in reducing the inflammatory response through increased immunosuppressive signalling in an IMM. We also suggest that the beneficial effect of olmesartan treatment is specifically exerted during the damage through blocking inflammatory cytocines.
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Hinova-Palova DV, Edelstein L, Landzhov B, Minkov M, Malinova L, Hristov S, Denaro FJ, Alexandrov A, Kiriakova T, Brainova I, Paloff A, Ovtscharoff W. Topographical distribution and morphology of NADPH-diaphorase-stained neurons in the human claustrum. Front Syst Neurosci 2014; 8:96. [PMID: 24904317 PMCID: PMC4034338 DOI: 10.3389/fnsys.2014.00096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/06/2014] [Indexed: 12/21/2022] Open
Abstract
We studied the topographical distribution and morphological characteristics of NADPH-diaphorase-positive neurons and fibers in the human claustrum. These neurons were seen to be heterogeneously distributed throughout the claustrum. Taking into account the size and shape of stained perikarya as well as dendritic and axonal characteristics, Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd)-positive neurons were categorized by diameter into three types: large, medium and small. Large neurons ranged from 25 to 35 μm in diameter and typically displayed elliptical or multipolar cell bodies. Medium neurons ranged from 20 to 25 μm in diameter and displayed multipolar, bipolar and irregular cell bodies. Small neurons ranged from 14 to 20 μm in diameter and most often displayed oval or elliptical cell bodies. Based on dendritic characteristics, these neurons were divided into spiny and aspiny subtypes. Our findings reveal two populations of NADPHd-positive neurons in the human claustrum-one comprised of large and medium cells consistent with a projection neuron phenotype, the other represented by small cells resembling the interneuron phenotype as defined by previous Golgi impregnation studies.
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Affiliation(s)
- Dimka V Hinova-Palova
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | | | - Boycho Landzhov
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Minko Minkov
- Department of Anatomy and Histology, Medical University Varna, Bulgaria
| | - Lina Malinova
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Stanislav Hristov
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Frank J Denaro
- Department of Biology, Morgan State University Baltimore, MD, USA
| | - Alexandar Alexandrov
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Teodora Kiriakova
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Ilina Brainova
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Adrian Paloff
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Wladimir Ovtscharoff
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
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13
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Spinal neuronal NOS activation mediates intrathecal fentanyl preconditioning induced remote cardioprotection in rats. Int Immunopharmacol 2014; 19:127-31. [PMID: 24462544 DOI: 10.1016/j.intimp.2014.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/02/2014] [Accepted: 01/13/2014] [Indexed: 11/22/2022]
Abstract
Fentanyl has been widely used in anesthesia and analgesia, especially for cardiovascular surgeries. The aim of the study was to evaluate whether remote intrathecal fentanyl preconditioning (RFPC) provides cardioprotection and the role of spinal nitric oxide synthase (NOS) system in this effect. Fentanyl (0.3μg/kg) was administered intrathecally during RFPC by 3 cycles of 5-minute infusions interspersed with 5-minute infusion free periods. A non-specific nitric oxide synthase (NOS) inhibitor NG-nitro l-arginine methyl ester (l-NAME, 30nmol) and a selective nNOS inhibitor 7-nitroindazole (7-NI, 100nmol) were administered intrathecally 10min before RFPC, and were used to evaluate the involvement of the NOS system of the spinal cord. RFPC group markedly reduced the infarct size compared with control. However, the cardioprotection of RFPC could be abolished by pretreatment with l-NAME and 7-NI. RFPC merely increased the expression of nNOS and did not affect iNOS and eNOS expression. l-NAME reversed nNOS expression up-regulation induced by RFPC treatment. The present study demonstrated that RFPC effectively induced cardioprotection through activating the nNOS in the spinal cord.
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14
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Yadav AP, Fuentes R, Zhang H, Vinholo T, Wang CH, Freire MAM, Nicolelis MAL. Chronic spinal cord electrical stimulation protects against 6-hydroxydopamine lesions. Sci Rep 2014; 4:3839. [PMID: 24452435 PMCID: PMC3899601 DOI: 10.1038/srep03839] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 01/06/2014] [Indexed: 11/09/2022] Open
Abstract
Although L-dopa continues to be the gold standard for treating motor symptoms of Parkinson's disease (PD), it presents long-term complications. Deep brain stimulation is effective, but only a small percentage of idiopathic PD patients are eligible. Based on results in animal models and a handful of patients, dorsal column stimulation (DCS) has been proposed as a potential therapy for PD. To date, the long-term effects of DCS in animal models have not been quantified. Here, we report that DCS applied twice a week in rats treated with bilateral 6-OHDA striatal infusions led to a significant improvement in symptoms. DCS-treated rats exhibited a higher density of dopaminergic innervation in the striatum and higher neuronal cell count in the substantia nigra pars compacta compared to a control group. These results suggest that DCS has a chronic therapeutical and neuroprotective effect, increasing its potential as a new clinical option for treating PD patients.
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Affiliation(s)
- Amol P Yadav
- Department of Biomedical Engineering, Duke University, Durham, NC, 27780
| | - Romulo Fuentes
- Edmond and Lily Safra Institute of Neuroscience of Natal, Natal, Brazil, 59066-060
| | - Hao Zhang
- Department of Neurobiology, Duke University, Durham, NC, 27710
| | - Thais Vinholo
- Department of Neurobiology, Duke University, Durham, NC, 27710
| | - Chi-Han Wang
- Department of Neurobiology, Duke University, Durham, NC, 27710
| | | | - Miguel A L Nicolelis
- 1] Department of Biomedical Engineering, Duke University, Durham, NC, 27780 [2] Edmond and Lily Safra Institute of Neuroscience of Natal, Natal, Brazil, 59066-060 [3] Department of Neurobiology, Duke University, Durham, NC, 27710 [4] Duke Center for Neuroengineering, Duke University, Durham, NC, 27710 [5] Department of Psychology and Neuroscience, Duke University, Durham, NC, 27708
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15
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Freire MAM, Santos JR. Distinct morphological features of NADPH diaphorase neurons across rodent's primary cortices. Front Neural Circuits 2013; 7:83. [PMID: 23637654 PMCID: PMC3636462 DOI: 10.3389/fncir.2013.00083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/12/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marco A M Freire
- Laboratory of Cellular Neurobiology, Edmond and Lily Safra International Institute for Neuroscience of Natal Natal, Brazil
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16
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Schmidt L, Bizzi CA, Duarte FA, Dressler VL, Flores EM. Evaluation of drying conditions of fish tissues for inorganic mercury and methylmercury speciation analysis. Microchem J 2013. [DOI: 10.1016/j.microc.2012.12.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Hassauer M, Kaiser E, Schneider K, Schuhmacher‐Wolz U. Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury). ACTA ACUST UNITED AC 2012. [DOI: 10.2903/sp.efsa.2012.en-297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin Hassauer
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Eva Kaiser
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Klaus Schneider
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
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18
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Freire MAM, Faber J, Picanço-Diniz CW, Franca JG, Pereira A. Morphometric variability of nicotinamide adenine dinucleotide phosphate diaphorase neurons in the primary sensory areas of the rat. Neuroscience 2011; 205:140-53. [PMID: 22226695 DOI: 10.1016/j.neuroscience.2011.12.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 12/21/2022]
Abstract
Even though there is great regional variation in the distribution of inhibitory neurons in the mammalian isocortex, relatively little is known about their morphological differences across areal borders. To obtain a better understanding of particularities of inhibitory circuits in cortical areas that correspond to different sensory modalities, we investigated the morphometric differences of a subset of inhibitory neurons reactive to the enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) within the primary auditory (A1), somatosensory (S1), and visual (V1) areas of the rat. One hundred and twenty NADPH-d-reactive neurons from cortical layer IV (40 cells in each cortical area) were reconstructed using the Neurolucida system. We collected morphometric data on cell body area, dendritic field area, number of dendrites per branching order, total dendritic length, dendritic complexity (Sholl analysis), and fractal dimension. To characterize different cell groups based on morphology, we performed a cluster analysis based on the previously mentioned parameters and searched for correlations among these variables. Morphometric analysis of NADPH-d neurons allowed us to distinguish three groups of cells, corresponding to the three analyzed areas. S1 neurons have a higher morphological complexity than those found in both A1 and V1. The difference among these groups, based on cluster analysis, was mainly related to the size and complexity of dendritic branching. A principal component analysis (PCA) applied to the data showed that area of dendritic field and fractal dimension are the parameters mostly responsible for dataset variance among the three areas. Our results suggest that the nitrergic cortical circuitry of primary sensory areas of the rat is differentially specialized, probably reflecting peculiarities of both habit and behavior of the species.
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Affiliation(s)
- M A M Freire
- Laboratory of Neurodegeneration and Infection, João de Barros Barreto Universitary Hospital, Federal University of Pará, 66073-000 Belém, PA, Brazil
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19
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Freire MAM, Morya E, Faber J, Santos JR, Guimaraes JS, Lemos NAM, Sameshima K, Pereira A, Ribeiro S, Nicolelis MAL. Comprehensive analysis of tissue preservation and recording quality from chronic multielectrode implants. PLoS One 2011; 6:e27554. [PMID: 22096594 PMCID: PMC3212580 DOI: 10.1371/journal.pone.0027554] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 10/19/2011] [Indexed: 11/18/2022] Open
Abstract
Multielectrodes have been used with great success to simultaneously record the activity of neuronal populations in awake, behaving animals. In particular, there is great promise in the use of this technique to allow the control of neuroprosthetic devices by human patients. However, it is crucial to fully characterize the tissue response to the chronic implants in animal models ahead of the initiation of human clinical trials. Here we evaluated the effects of unilateral multielectrode implants on the motor cortex of rats weekly recorded for 1-6 months using several histological methods to assess metabolic markers, inflammatory response, immediate-early gene (IEG) expression, cytoskeletal integrity and apoptotic profiles. We also investigated the correlations between each of these features and firing rates, to estimate the impact of post-implant time on neuronal recordings. Overall, limited neuronal loss and glial activation were observed on the implanted sites. Reactivity to enzymatic metabolic markers and IEG expression were not significantly different between implanted and non-implanted hemispheres. Multielectrode recordings remained viable for up to 6 months after implantation, and firing rates correlated well to the histochemical and immunohistochemical markers. Altogether, our results indicate that chronic tungsten multielectrode implants do not substantially alter the histological and functional integrity of target sites in the cerebral cortex.
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Affiliation(s)
| | - Edgard Morya
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
| | - Jean Faber
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
- Foundation Nanosciences and Clinatec/LETI/CEA, Grenoble, France
| | - Jose Ronaldo Santos
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Joanilson S. Guimaraes
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Nelson A. M. Lemos
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Koichi Sameshima
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
- Department of Radiology, School of Medicine, University of São Paulo, São Paulo/SP, Brazil
| | - Antonio Pereira
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Miguel A. L. Nicolelis
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
- Center for Neuroengineering, Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- Department of Psychological and Brain Sciences, Duke University, Durham, North Carolina, United States of America
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20
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Maia CDSF, Ferreira VMM, Kahwage RL, do Amaral MN, Serra RB, Noro dos Santos S, do Nascimento JLM, Rodrigues LG, Trévia N, Diniz CWP. Adult brain nitrergic activity after concomitant prenatal exposure to ethanol and methyl mercury. Acta Histochem 2010; 112:583-91. [PMID: 19748654 DOI: 10.1016/j.acthis.2009.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 06/08/2009] [Accepted: 06/11/2009] [Indexed: 01/13/2023]
Abstract
Pregnant rats were exposed to ethanol (EtOH) and/or methyl mercury (MeHg) during fetal brain development. Nitrergic activity was quantified by densitometric measurement of formazan deposits in the hippocampus, cerebellum and striatum of two-month-old offspring following histochemical assay for NADPH-diaphorase (NADPH-d) activity. Compared to control subjects, an increase in nitrergic activity was found in the molecular layer of dentate gyrus and in the lacunosum molecular and stratum radiatum of CA1 (cornus amoni 1) in the EtOH+MeHg group, whereas a single administration of EtOH increased the activity in all striatal segments. The cerebellum seems to be less sensitive at this time-point to intoxication, and presented an increase only at the molecular layer of EtOH-exposed animals when compared to the MeHg and EtOH+MeHg groups (ANOVA, one-way followed by Tukey's test, p<0.05 or p<0.01). Taken together, results suggest that developmental exposure to EtOH and MeHg, singularly or in combination, alters nitrergic activity in adult rat in different ways depending on the region and layer of the central nervous system (CNS), and that these alterations might be related to different local metabolic properties.
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21
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Freire MAM, Rocha EG, Oliveira JLF, Guimarães JS, Silveira LCL, Elston GN, Pereira A, Picanço-Diniz CW. Morphological variability of NADPH diaphorase neurons across areas V1, V2, and V3 of the common agouti. Brain Res 2009; 1318:52-63. [PMID: 20036219 DOI: 10.1016/j.brainres.2009.12.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/11/2009] [Accepted: 12/14/2009] [Indexed: 01/24/2023]
Abstract
Previous studies have shown a noticeable phenotypic diversity for pyramidal cells among cortical areas in the cerebral cortex. Both the extent and systematic nature of this variation suggests a correlation with particular aspects of cortical processing. Nevertheless, regional variations in the morphology of inhibitory cells have not been evaluated with the same detail. In the present study we performed a 3D morphometric analysis of 120 NADPH diaphorase (NADPH-d) type I neurons in the visual cortex of a South American Hystricomorph rodent, the diurnal agouti (Dasyprocta sp.). We found significant differences in morphology of NADPH-d type I neurons among visual cortical areas: cells became progressively larger and more branched from V1 to V2 and V3. Presumably, the specialized morphology of these cells is correlated with different sampling geometry and function. The data suggest that area-specific specializations of cortical inhibitory circuitry are also present in rodents.
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Affiliation(s)
- Marco Aurélio M Freire
- Lab. Neurodegeneração e Infecção, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, 66073-000 Belém, PA, Brazil
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22
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Freire MAM, Guimarães JS, Leal WG, Pereira A. Pain modulation by nitric oxide in the spinal cord. Front Neurosci 2009; 3:175-81. [PMID: 20011139 PMCID: PMC2751623 DOI: 10.3389/neuro.01.024.2009] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 07/08/2009] [Indexed: 01/24/2023] Open
Abstract
Nitric oxide (NO) is a versatile messenger molecule first associated with endothelial relaxing effects. In the central nervous system (CNS), NO synthesis is primarily triggered by activation of N-methyl-D-aspartate (NMDA) receptors and has a Janus face, with both beneficial and harmful properties. There are three isoforms of the NO synthesizing enzyme nitric oxide synthase (NOS): neuronal (nNOS), endothelial (eNOS), and inducible nitric oxide synthase (iNOS), each one involved with specific events in the brain. In the CNS, nNOS is involved with modulation of synaptic transmission through long-term potentiation in several regions, including nociceptive circuits in the spinal cord. Here, we review the role played by NO on central pain sensitization.
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Affiliation(s)
- Marco Aurélio M Freire
- Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN) Natal, RN, Brazil
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23
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Freire MAM, Tourinho SC, Guimarães JS, Oliveira JLF, Picanço-Diniz CW, Gomes-Leal W, Pereira A. Histochemical characterization, distribution and morphometric analysis of NADPH diaphorase neurons in the spinal cord of the agouti. Front Neuroanat 2008; 2:2. [PMID: 18958200 PMCID: PMC2525924 DOI: 10.3389/neuro.05.002.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 05/08/2008] [Indexed: 01/12/2023] Open
Abstract
We evaluated the neuropil distribution of the enzymes NADPH diaphorase (NADPH-d) and cytochrome oxidase (CO) in the spinal cord of the agouti, a medium-sized diurnal rodent, together with the distribution pattern and morphometrical characteristics of NADPH-d reactive neurons across different spinal segments. Neuropil labeling pattern was remarkably similar for both enzymes in coronal sections: reactivity was higher in regions involved with pain processing. We found two distinct types of NADPH-d reactive neurons in the agouti's spinal cord: type I neurons had large, heavily stained cell bodies while type II neurons displayed relatively small and poorly stained somata. We concentrated our analysis on type I neurons. These were found mainly in the dorsal horn and around the central canal of every spinal segment, with a few scattered neurons located in the ventral horn of both cervical and lumbar regions. Overall, type I neurons were more numerous in the cervical region. Type I neurons were also found in the white matter, particularly in the ventral funiculum. Morphometrical analysis revealed that type I neurons located in the cervical region have dendritic trees that are more complex than those located in both lumbar and thoracic regions. In addition, NADPH-d cells located in the ventral horn had a larger cell body, especially in lumbar segments. The resulting pattern of cell body and neuropil distribution is in accordance with proposed schemes of segregation of function in the mammalian spinal cord.
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Affiliation(s)
- Marco Aurélio M Freire
- Laboratory of Functional Neuroanatomy, Institute of Biological Sciences, Federal University of Pará Belém, Brazil
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