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Méndez-López M, Gómez-Armesto A, Alonso-Vega F, Pontevedra-Pombal X, Fonseca F, de Figueiredo T, Arias-Estévez M, Nóvoa-Muñoz JC. The role of afforestation species as a driver of Hg accumulation in organic horizons of forest soils from a Mediterranean mountain area in SW Europe. Sci Total Environ 2022; 827:154345. [PMID: 35257764 DOI: 10.1016/j.scitotenv.2022.154345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/10/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Forest areas are a primary sink of atmospheric mercury (Hg) within terrestrial ecosystems, whereas forest vegetation plays a key role in atmospheric Hg transfer to soil horizons. This study assessed variations in total Hg contents (HgT) and accumulation (HgRes) in the soil organic horizons of a forest area in NE Portugal, where post-wildfire afforestation led to the substitution of the native deciduous species (Quercus pyrenaica) by fast-growing coniferous species (Pseudotsuga menziesii and Pinus nigra). The study also evaluated, for each species, the links between Hg contents and other biophilic elements of soil organic matter (C, N, S) present in organic subhorizons (OL, OF, OH). Mean HgT in the organic horizons of the different tree species follow the sequence: P. nigra (88 μg kg-1) < Q.pyrenaica (101 μg kg-1) <P. menziesii (141 μg kg-1). The highest HgRes for the entire organic horizon was found under P. menziesii (471 μg m-2), followed by P. nigra (253 μg m-2) and Q. pyrenaica (189 μg m-2). Among the organic subhorizons, values of HgT and HgRes follow the sequence OL < OF < OH, which is consistent with the degree of organic matter humification. Indeed, HgT and HgRes correlated significantly with the C/N and C/S ratios for all species and organic subhorizons, suggesting that the quality of organic matter may influence strongly the Hg fate in these forest soils. Soils from P. menziesii plots have shown an HgRes 2.5 times higher than in plots dominated by the native Q. pyrenaica. Hg accumulation in the organic horizons, promoted in the coniferous species, may increase the risk of Hg mobilization due to wildfires and forest management practices. Therefore, forest management plans should select cautiously the tree species for afforestation in order to minimize adverse environmental effects caused by changes in the biogeochemical cycle of contaminants such as Hg.
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Affiliation(s)
- M Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain.
| | - A Gómez-Armesto
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - F Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - X Pontevedra-Pombal
- Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, 15786 Santiago de Compostela, Spain
| | - F Fonseca
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta Apolónia, 5300-253 Bragança, Portugal
| | - T de Figueiredo
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta Apolónia, 5300-253 Bragança, Portugal
| | - M Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - J C Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
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Gómez-Armesto A, Méndez-López M, Pérez-Rodríguez P, Fernández-Calviño D, Arias-Estévez M, Nóvoa-Muñoz JC. Litterfall Hg deposition to an oak forest soil from southwestern Europe. J Environ Manage 2020; 269:110858. [PMID: 32561026 DOI: 10.1016/j.jenvman.2020.110858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
Litterfall constitutes one of the main vectors for mercury (Hg) transfer to forested ecosystems, so we studied the deposition of Hg through senescent vegetation (oak leaves, twigs and miscellaneous) in a deciduous forest plot of Southwest Europe dominated by Quercus robur in 2015 and 2016. Total Hg concentrations increased in the following order: bole wood (1.4 μg kg-1) < bark (8.3 μg kg-1) < twigs (12.2 μg kg-1) < miscellaneous (36.0 μg kg-1) < oak leaves (39.3 μg kg-1) < mineral soil (42.4 μg kg-1) < Oi horizons (48.7 μg kg-1) < Oe + Oa horizons (71.6 μg kg-1). Mercury accumulation rates in oak leaves during the growing season were 0.15-0.18 μg kg-1 day-1. Mercury deposition fluxes were 26 and 21 μg m-2 yr-1 for 2015 and 2016, respectively, with oak leaves being the fraction that contributed the most. Mercury determination in litterfall sorted biomass fractions lead to a more accurate estimation of the total annual Hg deposition fluxes through litterfall. Higher Hg content was obtained for organic horizons (average of 60.2 μg kg-1) than for mineral soil (mean of 42.4 μg kg-1), but the soil Hg pool was higher in the latter. The results confirmed the necessity of taking into account the Hg pool in the deeper mineral soil layers as they accumulate substantial quantities of Hg associated to organic C and Al compounds, preventing its mobilization to other compartments of the terrestrial ecosystems.
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Affiliation(s)
- A Gómez-Armesto
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain.
| | - M Méndez-López
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain
| | - P Pérez-Rodríguez
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain
| | - D Fernández-Calviño
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain
| | - M Arias-Estévez
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain
| | - J C Nóvoa-Muñoz
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Facultade de Ciencias, Universidade de Vigo, 32004, Ourense, Spain; Environmental Technology and Assessment Laboratory, Campus da Auga, Campus of Ourense, University of Vigo, 32004, Ourense, Spain
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Zorzo C, Méndez-López M, Méndez M, Arias JL. Adult social isolation leads to anxiety and spatial memory impairment: Brain activity pattern of COx and c-Fos. Behav Brain Res 2019; 365:170-177. [PMID: 30851318 DOI: 10.1016/j.bbr.2019.03.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/19/2019] [Accepted: 03/05/2019] [Indexed: 12/22/2022]
Abstract
Social isolation during adulthood is a frequent problem that leads to a large variety of adverse emotional and cognitive effects. However, most of the social isolation rodent procedures begin the separation early post-weaning. This work explores locomotor activity, anxiety-like behaviour, and spatial working memory after twelve weeks of adult social isolation. In order to study the functional contribution of selected brain areas following a working memory task, we assessed neuronal metabolic activity through quantitative cytochrome oxidase histochemistry and c-Fos immunohistochemistry. Behaviourally, we found that isolated animals (IS) showed anxiety-like behaviour and worse working memory than controls, whereas motor functions were preserved. Moreover, IS rats showed lower levels of learning-related c-Fos immunoreactivity, compared to controls, in the medial prefrontal cortex (mPFC), ventral tegmental area (VTA), and nucleus accumbens shell. In addition, the IS group showed lower neuronal metabolic activity in the mPFC, VTA, and CA1 subfield of the hippocampus. These results indicate that twelve weeks of social isolation in adult rats leads to different behavioural and brain alterations, and they highlight the importance of social support, not only in development, but also in adulthood.
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Affiliation(s)
- Candela Zorzo
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
| | - Magdalena Méndez-López
- IIS Aragón, Departamento de Psicología y Sociología, Universidad de Zaragoza, Zaragoza, Spain.
| | - Marta Méndez
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
| | - Jorge L Arias
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
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Méndez-López M, Moreno-Serna V, Inostroza-Rivera R, Ramos A, Molero L, Bonardd S, Diaz Diaz D, Leiva A, Saldías C. Optical and electronic activities of biobased films of chitosan/POTE containing gold nanoparticles: Experimental and theoretical analyses. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.08.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Rodríguez-Andrés D, Juan MC, Méndez-López M, Pérez-Hernández E, Lluch J. MnemoCity Task: Assessment of Childrens Spatial Memory Using Stereoscopy and Virtual Environments. PLoS One 2016; 11:e0161858. [PMID: 27579715 PMCID: PMC5007040 DOI: 10.1371/journal.pone.0161858] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/13/2016] [Indexed: 11/19/2022] Open
Abstract
This paper presents the MnemoCity task, which is a 3D application that introduces the user into a totally 3D virtual environment to evaluate spatial short-term memory. A study has been carried out to validate the MnemoCity task for the assessment of spatial short-term memory in children, by comparing the children’s performance in the developed task with current approaches. A total of 160 children participated in the study. The task incorporates two types of interaction: one based on standard interaction and another one based on natural interaction involving physical movement by the user. There were no statistically significant differences in the results of the task using the two types of interaction. Furthermore, statistically significant differences were not found in relation to gender. The correlations between scores were obtained using the MnemoCity task and a traditional procedure for assessing spatial short-term memory. Those results revealed that the type of interaction used did not affect the performance of children in the MnemoCity task.
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Affiliation(s)
- David Rodríguez-Andrés
- Instituto Universitario de Automática e Informática Industrial, Universitat Politècnica de València, Camino de Vera, s/n. 46022, València, Spain
| | - M.-Carmen Juan
- Instituto Universitario de Automática e Informática Industrial, Universitat Politècnica de València, Camino de Vera, s/n. 46022, València, Spain
- * E-mail:
| | | | - Elena Pérez-Hernández
- Departamento de Psicología Evolutiva y de la Educación, Universidad Autónoma de Madrid, Madrid, Spain
| | - Javier Lluch
- Instituto Universitario de Automática e Informática Industrial, Universitat Politècnica de València, Camino de Vera, s/n. 46022, València, Spain
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Méndez-López M, Méndez M, Arias J, Arias JL. Effects of a high protein diet on cognition and brain metabolism in cirrhotic rats. Physiol Behav 2015; 149:220-8. [PMID: 26048304 DOI: 10.1016/j.physbeh.2015.05.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a neurological complication observed in patients with liver disease. Patients who suffer from HE present neuropsychiatric, neuromuscular and behavioral symptoms. Animal models proposed to study HE resulting from cirrhosis mimic the clinical characteristics of cirrhosis and portal hypertension, and require the administration of hepatotoxins such as thioacetamide (TAA). The aim of this study was to assess the effects of a high protein diet on motor function, anxiety and memory processes in a model of cirrhosis induced by TAA administration. In addition, we used cytochrome c-oxidase (COx) histochemistry to assess the metabolic activity of the limbic system regions. Male rats were distributed into groups: control, animals with cirrhosis, Control rats receiving a high protein diet, and animals with cirrhosis receiving a high protein diet. Results showed preserved motor function and normal anxiety levels in all the groups. The animals with cirrhosis showed an impairment in active avoidance behavior and spatial memory, regardless of the diet they received. However, the animals with cirrhosis and a high protein diet showed longer escape latencies on the spatial memory task. The model of cirrhosis presented an under-activation of the dentate gyrus and CA3 hippocampal subfields and the medial part of the medial mammillary nucleus. The results suggest that a high protein intake worsens spatial memory deficits shown by the TAA-induced model of cirrhosis. However, high protein ingestion has no influence on the COx hypoactivity associated with the model.
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Affiliation(s)
- M Méndez-López
- Department of Psychology, University of Zaragoza, Campus Ciudad Escolar s/n., 44003 Teruel, Spain.
| | - M Méndez
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n., 33003 Oviedo, Spain.
| | - J Arias
- Faculty of Medicine, Complutense University of Madrid, Ciudad Universitaria s/n., 28040 Madrid, Spain.
| | - J L Arias
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n., 33003 Oviedo, Spain.
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Méndez-López M, Méndez M, Sampedro-Piquero P, Arias JL. Spatial learning-related changes in metabolic activity of limbic structures at different posttask delays. J Neurosci Res 2012; 91:151-9. [PMID: 23073928 DOI: 10.1002/jnr.23134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 07/29/2012] [Accepted: 07/30/2012] [Indexed: 11/07/2022]
Abstract
The aim of this study was to assess the functional contribution of brain limbic system regions at different moments after the acquisition of a short-term spatial memory task performed in the Morris water maze. Adult male Wistar rats were submitted to a matching-to-sample procedure with a hidden platform. The trials were made up of two daily identical visits to the platform, sample (swim-1) and retention (swim-2). To study oxidative metabolic activity, we applied cytochrome oxidase (COx) histochemistry. Densitometric measurements were taken at 1.5, 6, 24, and 48 hr posttask. An untrained group was added to explore the COx changes not specific to the learning process. The brain regions studied showed a different pattern of metabolic activity at different time points after the spatial memory task. Specifically, a significant increase of COx was found in the septal dentate gyrus, anteromedial thalamus, medial mammillary nucleus, and entorhinal cortex at early moments after learning. The entorhinal cortex maintained an increase of COx at later stages of the posttask period. In addition, an increase of COx activity was found in the supramammillary nucleus and the retrosplenial, perirhinal, and parietal cortices a long time after learning. These findings suggest that diencephalic and cortical regions are involved in this spatial learning and contribute at different moments to process this information.
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Affiliation(s)
- M Méndez-López
- Departamento de Psicología y Sociología, Universidad de Zaragoza, Facultad de Ciencias Sociales y Humanas, Teruel, Spain.
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López-Crespo G, Daza MT, Méndez-López M. Visual working memory in deaf children with diverse communication modes: improvement by differential outcomes. Res Dev Disabil 2012; 33:362-368. [PMID: 22119682 DOI: 10.1016/j.ridd.2011.10.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 10/26/2011] [Indexed: 05/31/2023]
Abstract
Although visual functions have been proposed to be enhanced in deaf individuals, empirical studies have not yet established clear evidence on this issue. The present study aimed to determine whether deaf children with diverse communication modes had superior visual memory and whether their performance was improved by the use of differential outcomes. Severely or profoundly deaf children who employed spoken Spanish, Spanish Sign Language (SSL), and both spoken Spanish and SSL modes of communication were tested in a delayed matching-to-sample task for visual working memory assessment. Hearing controls were used to compare performance. Participants were tested in two conditions, differential outcome and non-differential outcome conditions. Deaf groups with either oral or SSL modes of communication completed the task with less accuracy than bilingual and control hearing children. In addition, the performances of all groups improved through the use of differential outcomes.
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Affiliation(s)
- Ginesa López-Crespo
- Departamento de Psicología y Sociología, Facultad de Ciencias Sociales y Humanas, Universidad de Zaragoza, 44003 Teruel, Spain.
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Méndez-López M, Méndez M, López L, Arias JL. Memory performance and scopolamine: hypoactivity of the thalamus revealed by cytochrome oxidase histochemistry. Acta Histochem 2011; 113:465-71. [PMID: 20546863 DOI: 10.1016/j.acthis.2010.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/11/2010] [Accepted: 04/12/2010] [Indexed: 11/28/2022]
Abstract
Spatial memory learning is related to the functioning of a neuronal circuit composed of cortical, hippocampal and diencephalic brain regions. The Morris water maze (MWM) is frequently used to assess spatial memory in rats. In this study, the neuronal functional activity of some brain limbic system regions after a memory task in adult male Wistar rats injected with scopolamine (1.0mg/kg, i.p.) was assessed using cytochrome oxidase (COx) histochemistry. The rats were trained following a working memory schedule in the MWM. A trained group injected with saline and an untreated control group were examined to compare changes in COx activity in the dorsal hippocampus, anterior thalamus, mammillary nuclei, prefrontal cortex and ventral tegmental area. The scopolamine-treated group showed an impairment of spatial learning. Also, a decrease in COx activity was found in this group as compared to the saline group in the anteroventral and anteromedial thalamic nuclei. Overall, these findings suggest that memory deficits induced by scopolamine may be due to impairment of the cholinergic function in the anterior thalamic nuclei.
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Affiliation(s)
- Magdalena Méndez-López
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain.
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Méndez M, Méndez-López M, López L, Aller MA, Arias J, Arias JL. Acetylcholinesterase activity in an experimental rat model of Type C hepatic encephalopathy. Acta Histochem 2011; 113:358-62. [PMID: 20138653 DOI: 10.1016/j.acthis.2010.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 01/15/2010] [Accepted: 01/18/2010] [Indexed: 01/15/2023]
Abstract
Patients with liver malfunction often suffer from hepatic encephalopathy, a neurological complication which can affect attention and cognition. Diverse experimental models have been used to study brain alterations that may be responsible for hepatic encephalopathy symptoms. The aim of the study was to determine whether cognitive impairment found in cirrhosis could be due to disturbance of acetylcholinesterase activity. Acetylcholinesterase activity was assessed in the brains of Wistar rats with thioacetamide-induced cirrhosis. The cirrhotic group displayed up-regulation of acetylcholinesterase levels in the entorrhinal cortex, anterodorsal and anteroventral thalamus and accumbens, whereas down-regulation was found in the CA1, CA3 and dentate gyrus of the hippocampus. Our results indicate that the experimental model of hepatic encephalopathy by chronic administration of thioacetamide presents alterations of acetylcholinesterase activity in brain limbic system regions, which play a role in attention and memory.
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Affiliation(s)
- Marta Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, Oviedo, Spain.
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Méndez M, Méndez-López M, López L, Aller MA, Arias J, Arias JL. Portosystemic hepatic encephalopathy model shows reversal learning impairment and dysfunction of neural activity in the prefrontal cortex and regions involved in motivated behavior. J Clin Neurosci 2011; 18:690-4. [PMID: 21371891 DOI: 10.1016/j.jocn.2010.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 09/15/2010] [Accepted: 09/22/2010] [Indexed: 11/16/2022]
Abstract
Hepatic encephalopathy (HE) is a neurological complication that affects attention and memory. Experimental animal models have been used to study HE, the most frequent being the portacaval shunt (PCS). In order to investigate learning impairment and brain functional alterations in this model, we assessed reversal learning and neural metabolic activity in a PCS rat model. PCS and sham-operated rats were tested for reversal learning in the Morris water maze. Brains were then processed for cytochrome oxidase (CO) histochemistry. The PCS group had reversal learning impairment and a reduction in CO activity in the prefrontal cortex, ventral tegmental area and accumbens shell nucleus. These results suggest that this model of portosystemic HE shows learning impairments that could be linked to dysfunction in neural activity in the prefrontal cortex and regions involved in motivated behavior.
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Affiliation(s)
- M Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n. 33003, Oviedo, Spain.
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Cimadevilla J, Méndez-López M, Méndez M, Arias J. Interhippocampal transfer in passive avoidance task modifies metabolic activity in limbic structures. Hippocampus 2010; 21:48-55. [DOI: 10.1002/hipo.20720] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Méndez-López M, Méndez M, López L, Arias JL. Changes in cytochrome oxidase activity following spatial working memory learning in rats treated with tacrine. Psicothema 2010; 22:893-897. [PMID: 21044529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We evaluated change in cytochrome oxidase (COx) activity of the hippocampus and related structures of the limbic system following spatial working memory learning in rats after treatment with tacrine (8.0mg/kg). Control groups treated with saline and tacrine and an untreated group were added. Acetylcholinesterase optical density levels were also measured. The tacrine and saline groups showed similar behavioral results, but a decrease in COx activity was found in the tacrine group in the prefrontal cortex, nucleus accumbens, anterior thalamus, hippocampus and nucleus basalis of Meynert. Similarly, acetylcholinesterase levels of the tacrine group were lower in most of the regions. Learning-related increase in COx activity was found in the prefrontal cortex and dentate gyrus in the saline group. The tacrine group presented the same increase in the anterodorsal thalamus, dentate gyrus, CA3 and mammillary nuclei. These results suggest that inhibition of the acetylcholinesterase produces a different pattern of learning-related neuronal activity in the limbic system of the rat.
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Méndez-López M, Méndez M, Begega A, Arias JL. Spatial short-term memory in rats: Effects of learning trials on metabolic activity of limbic structures. Neurosci Lett 2010; 483:32-5. [DOI: 10.1016/j.neulet.2010.07.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/21/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
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Méndez M, Méndez-López M, López L, Begega A, Aller MA, Arias J, Arias JL. Reversal learning impairment and alterations in the prefrontal cortex and the hippocampus in a model of portosystemic hepatic encephalopathy. Acta Neurol Belg 2010; 110:246-254. [PMID: 21114133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Patients with liver dysfunction often suffer from hepatic encephalopathy (HE), a neurological complication that affects attention and memory. Various experimental animal models have been used to study HE, the most frequently used being the portocaval shunt (PCS). In order to determine brain substrates of cognitive impairment in this model, we assessed reversal learning and c-Fos expression in a rat model of portosystemic derivation. PCS and sham-operated rats (SHAM) were tested for reversal learning. Brains were processed for c-Fos immunocytochemistry. The total number of c-Fos positive nuclei was quantified in the prefrontal cortex and hippocampus. The spatial reference memory task showed no differences between groups in escape latencies. The no-platform probe test showed that both the PCS and the SHAM learned the location of platform. However, the PCS group perseverated in the old target during reversal. The PCS group presented less c-Fos- positive cells in prelimbic cortex, CA1 and dentate gyrus of the dorsal hippocampus than SHAM. Overall, these results suggest that this specific model of portosystemic hepatic encephalopathy produces reversal learning impairment that could be linked to dysfunction in neuronal activity in the prefrontal cortex and hippocampus.
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Affiliation(s)
- Marta Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Spain.
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Méndez-López M, Méndez M, López L, Arias JL. Spatial working memory in Wistar rats: Brain sex differences in metabolic activity. Brain Res Bull 2009; 79:187-92. [DOI: 10.1016/j.brainresbull.2009.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/16/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
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Méndez-López M, Méndez M, López L, Cimadevilla JM, Arias JL. Hippocampal heterogeneity in spatial memory revealed by cytochrome oxidase. Neurosci Lett 2009; 452:162-6. [DOI: 10.1016/j.neulet.2009.01.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 01/16/2009] [Accepted: 01/23/2009] [Indexed: 11/30/2022]
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Aller M, Vara E, García C, Méndez M, Méndez-López M, Mejía I, López L, Arias J, Arias J. Prehepatic portal hypertension worsens the enterohepatic redox balance in thioacetamide-cirrhotic rats. Pathophysiology 2008; 15:233-42. [DOI: 10.1016/j.pathophys.2008.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 09/19/2008] [Indexed: 02/07/2023] Open
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Méndez M, Méndez-López M, López L, Aller MA, Arias J, Arias JL. Associative learning deficit in two experimental models of hepatic encephalopathy. Behav Brain Res 2008; 198:346-51. [PMID: 19056427 DOI: 10.1016/j.bbr.2008.11.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 11/04/2008] [Accepted: 11/09/2008] [Indexed: 01/26/2023]
Abstract
People with hepatic insufficiency can develop hepatic encephalopathy (HE), a complex neuropsychological syndrome covering a wide range of neurological and cognitive and motor alterations. The cognitive deficits include disturbances in intellectual functions such as memory and learning. In spite of its high prevalence in western societies, the causes of HE have not yet been clearly established. For this reason, experimental models of HE are used to study this condition. In this work, two experimental models were used, one Type B HE (portacaval shunt) and the other Type C HE (cirrhosis by intoxication with thioacetamide), to evaluate its effect on two tasks of associative learning: two-way active avoidance and step-through passive avoidance. The results show an impediment both in acquisition and retention of active avoidance in both models of HE. However, in passive avoidance, only the rats with portacaval shunt presented a memory deficit for the aversive event. In our opinion, these results can be explained by alterations in the neurotransmission system presented by animals with hepatic insufficiency, which are mainly caused by a rise in cerebral histamine and a dysfunction of the glutamatergic system.
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Affiliation(s)
- Marta Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain
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Méndez M, Méndez-López M, López L, Aller MA, Arias J, Arias JL. Working memory impairment and reduced hippocampal and prefrontal cortex c-Fos expression in a rat model of cirrhosis. Physiol Behav 2008; 95:302-7. [PMID: 18634813 DOI: 10.1016/j.physbeh.2008.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 06/05/2008] [Accepted: 06/23/2008] [Indexed: 10/21/2022]
Abstract
Hepatic encephalopathy (HE) is a frequent neurological complication observed in patients with liver malfunction. Previous studies have shown memory impairment in these patients. In order to investigate brain substrates of spatial working memory impairment in chronic HE, neuronal expression of c-Fos protein was studied in an experimental model of cirrhosis. Control and cirrhotic rats were trained on a spatial working memory task in the Morris water maze (MWM). Differences between groups were found in the working memory task. Cirrhotic rats were unable to locate the platform in the retention trial. Neuronal activation, measured by c-Fos protein, was compared between groups. No differences were found in c-Fos expression of control and cirrhotic rats that were not tested in the MWM. Working memory task produced increase in c-Fos positive cells in dorsal hippocampus, CA1 and CA3, and prefrontal cortex in control group compared to thioacetamide group or naïve, which only swam in the maze during a similar time. These findings suggest that cirrhotic rats show spatial working memory impairment that could be linked to dysfunction in neuronal activity in prefrontal cortex and hippocampus.
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Affiliation(s)
- Marta Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain
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Méndez M, Méndez-López M, López L, Aller MA, Arias J, Cimadevilla JM, Arias JL. Spatial memory alterations in three models of hepatic encephalopathy. Behav Brain Res 2007; 188:32-40. [PMID: 18063138 DOI: 10.1016/j.bbr.2007.10.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 10/18/2007] [Accepted: 10/21/2007] [Indexed: 01/01/2023]
Abstract
A behavioural evaluation was carried out on three chronic models of hepatic encephalopathy: two models of type B HE, portacaval shunt (PCS) and portal hypertension (PH) and one of type C HE with cirrhosis and portal hypertension from thioacetamide intoxication (TAA). The tasks selected cover a wide range of behaviours related to: locomotion (rotarod-accelerod test), anxiety (open field and elevated plus maze) and memory (Morris water maze). The results indicate that neither locomotor activity nor anxiety was affected in our models, in comparison with their respective controls. However, this is not the case for the mnesic tasks. Hence, the PCS and TAA groups displayed a severe alteration in spatial reference memory and cannot correctly perform the Morris maze task, while this alteration is less severe in the PH group. On the contrary, the PH group revealed a deficit in spatial working memory, like the TAA group, but this does not occur in subjects with PCS. These results reveal a double dissociation in spatial reference memory and spatial working memory between the PCS and PH groups, which would be of great interest to study about cerebral causes and substrates of the alterations accompanying HE.
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Affiliation(s)
- Marta Méndez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain
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Méndez-López M, Méndez M, López L, Aller MA, González-Pardo H, Nava MP, Sánchez-Patán F, Arias J, Arias JL. Increased cytochrome oxidase activity in adrenal glands of thioacetamide-cirrhotic rats. Neuro Endocrinol Lett 2005; 26:719-23. [PMID: 16380689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 10/26/2005] [Indexed: 05/05/2023]
Abstract
OBJECTIVES Cytochrome oxidase activity has been determined in the adrenal glands of thioacetamide (TAA)-cirrhotic rats. MATERIAL AND METHODS Two groups of animals (Control group; n=10 and TAA group; n=11) of three months evolution were used to study the cytochrome oxidase activity in the suprarenal cortex (glomerular, fascicular and reticular layers) and medulla. TAA was administered orally and cytochrome oxidase (COX) activity was assayed by an immunohistochemical technique. RESULTS In TAA-cirrhotic rats, COX activity increases in the cortex fascicular layer (221 +/- 1.79 vs 181.9 +/- 2.75; p<0.001) as well as in the medulla (146.6 +/- 1.72 vs 129 +/- 3.09; p<0.001). CONCLUSION These results make it possible to consider the existence of hypothalamic-pituitary-adrenal-axis and adrenomedullary sympathetic system hyperactivity, both peripheral limbs of the stress system, in this experimental model of cirrhosis.
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