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Giordani M, Meli MA, Roselli C, Betti M, Peruzzi F, Taussi M, Valentini L, Fagiolino I, Mattioli M. Could soluble minerals be hazardous to human health? Evidence from fibrous epsomite. ENVIRONMENTAL RESEARCH 2022; 206:112579. [PMID: 34968437 DOI: 10.1016/j.envres.2021.112579] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/03/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
From a toxicological point of view, particulates and fibres with high solubility in water and/or in biological environments have not been considered in detail and the knowledge to date in this area is very scarce. In this study, the water-soluble natural epsomite fibres from Perticara Mine (Italy) were investigated using SEM-EDS, XRPD, ICP-AES and alpha spectrometry measurements which were combined and integrated to characterise the fibres' morphology, crystal chemistry and mineralogy. The morphological and morphometric results showed that most of the fibres are of inhalable size (Dae 5.09 μm) and can be potentially adsorbed from all parts of the respiratory tract. Chemical analysis reveals significant amounts of toxic elements (As, Co, Fe, Mn, Ni, Sr, Ti, Zn) and surprisingly high contents of radioactive isotopes (210Po and 228Th) in epsomite crystals, making the inhalation of these fibres potentially hazardous to human health. Through this study, we want to focus on soluble minerals, such as epsomite, which can be present in both natural and anthropic environments and have never been considered from the point of view of their potential hazard.
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Affiliation(s)
- Matteo Giordani
- Department of Pure and Applied Sciences, University of Urbino Carlo Bo, Urbino, Italy.
| | - Maria Assunta Meli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Carla Roselli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Michele Betti
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Fabio Peruzzi
- Speleological Federation of the Emilia-Romagna Region, Bologna, Italy
| | - Marco Taussi
- Department of Pure and Applied Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Laura Valentini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | | | - Michele Mattioli
- Department of Pure and Applied Sciences, University of Urbino Carlo Bo, Urbino, Italy
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Berntsen HF, Moldes-Anaya A, Bjørklund CG, Ragazzi L, Haug TM, Strandabø RAU, Verhaegen S, Paulsen RE, Ropstad E, Tasker RA. Perfluoroalkyl acids potentiate glutamate excitotoxicity in rat cerebellar granule neurons. Toxicology 2020; 445:152610. [PMID: 33027616 DOI: 10.1016/j.tox.2020.152610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022]
Abstract
Perfluoroalkyl acids (PFAAs) are persistent man-made chemicals, ubiquitous in nature and present in human samples. Although restrictions are being introduced, they are still used in industrial processes as well as in consumer products. PFAAs cross the blood-brain-barrier and have been observed to induce adverse neurobehavioural effects in humans and animals as well as adverse effects in neuronal in vitro studies. The sulfonated PFAA perfluorooctane sulfonic acid (PFOS), has been shown to induce excitotoxicity via the N-methyl-D-aspartate receptor (NMDA-R) in cultures of rat cerebellar granule neurons (CGNs). In the present study the aim was to further characterise PFOS-induced toxicity (1-60 μM) in rat CGNs, by examining interactions between PFOS and elements of glutamatergic signalling and excitotoxicity. Effects of the carboxylated PFAA, perfluorooctanoic acid (PFOA, 300-500 μM) on the same endpoints were also examined. During experiments in immature cultures at days in vitro (DIV) 8, PFOS increased both the potency and efficacy of glutamate, whereas in mature cultures at DIV 14 only increased potency was observed. PFOA also increased potency at DIV 14. PFOS-enhanced glutamate toxicity was further antagonised by the competitive NMDA-R antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) at DIV 8. At DIV 8, PFOS also induced glutamate release (9-13 fold increase vs DMSO control) after 1-3 and 24 h exposure, whereas for PFOA a large (80 fold) increase was observed, but only after 24 h. PFOS and PFOA both also increased alanine and decreased serine levels after 24 h exposure. In conclusion, our results indicate that PFOS at concentrations relevant in an occupational setting, may be inducing excitotoxicity, and potentiation of glutamate signalling, via an allosteric action on the NMDA-R or by actions on other elements regulating glutamate release or NMDA-R function. Our results further support our previous findings that PFOS and PFOA at equipotent concentrations induce toxicity via different mechanisms of action.
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Affiliation(s)
- Hanne Friis Berntsen
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway; National Institute of Occupational Health, P.O. Box 8149 Dep N-0033, Oslo, Norway.
| | - Angel Moldes-Anaya
- Research and Development (R&D) Section, PET Imaging Center, University Hospital of North Norway (UNN), Tromsø, Norway; Nuclear Medicine and Radiation Biology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Cesilie Granum Bjørklund
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - Lorenzo Ragazzi
- Neurobiology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | | | | | - Steven Verhaegen
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - Ragnhild Elisabeth Paulsen
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Oslo, Norway
| | - Erik Ropstad
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - R Andrew Tasker
- Department of Biomedical Sciences, University of Prince Edward Island, Charlottetown, PEI, Canada; Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Delfino-Pereira P, Bertti-Dutra P, de Lima Umeoka EH, de Oliveira JAC, Santos VR, Fernandes A, Marroni SS, Del Vecchio F, Garcia-Cairasco N. Intense olfactory stimulation blocks seizures in an experimental model of epilepsy. Epilepsy Behav 2018; 79:213-224. [PMID: 29346088 DOI: 10.1016/j.yebeh.2017.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
There are reports of patients whose epileptic seizures are prevented by means of olfactory stimulation. Similar findings were described in animal models of epilepsy, such as the electrical kindling of amygdala, where olfactory stimulation with toluene (TOL) suppressed seizures in most rats, even when the stimuli were 20% above the threshold to evoke seizures in already kindled animals. The Wistar Audiogenic Rat (WAR) strain is a model of tonic-clonic seizures induced by acute acoustic stimulation, although it also expresses limbic seizures when repeated acoustic stimulation occurs - a process known as audiogenic kindling (AK). The aim of this study was to evaluate whether or not the olfactory stimulation with TOL would interfere on the behavioral expression of brainstem (acute) and limbic (chronic) seizures in the WAR strain. For this, animals were exposed to TOL or saline (SAL) and subsequently exposed to acoustic stimulation in two conditions that generated: I) acute audiogenic seizures (only one acoustic stimulus, without previous seizure experience before of the odor test) and II) after AK (20 acoustic stimuli [2 daily] before of the protocol test). We observed a decrease in the seizure severity index of animals exposed only to TOL in both conditions, with TOL presented 20s before the acoustic stimulation in both protocols. These findings were confirmed by behavioral sequential analysis (neuroethology), which clearly indicated an exacerbation of clusters of specific behaviors such as exploration and grooming (self-cleaning), as well as significant decrease in the expression of brainstem and limbic seizures in response to TOL. Thus, these data demonstrate that TOL, a strong olfactory stimulus, has anticonvulsant properties, detected by the decrease of acute and AK seizures in WARs.
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Affiliation(s)
- Polianna Delfino-Pereira
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil
| | - Poliana Bertti-Dutra
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Eduardo Henrique de Lima Umeoka
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - José Antônio Cortes de Oliveira
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Victor Rodrigues Santos
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Artur Fernandes
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil; Genetics Department, Ribeirão Preto School of Medicine, University of São Paulo, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Simone Saldanha Marroni
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Flávio Del Vecchio
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil
| | - Norberto Garcia-Cairasco
- Neurosciences and Behavioral Sciences Department, Ribeirão Preto School of Medicine, Universiy of São Paulo, Hospital das Clínicas, Campus Universitário S/N, 4° Andar, Ribeirão Preto, SP CEP: 14048-900, Brazil; Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Prédio Central, Avenida Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP: 14049-900, Brazil.
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Xia Y, Bo A, Liu Z, Chi B, Su Z, Hu Y, Luo R, Su X, Sun J. Effects of magnesium sulfate on apoptosis in cultured human gastric epithelial cells. FOOD AGR IMMUNOL 2015. [DOI: 10.1080/09540105.2015.1079596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Cruz SL, Rivera-García MT, Woodward JJ. Review of toluene action: clinical evidence, animal studies and molecular targets. ACTA ACUST UNITED AC 2014; 3. [PMID: 25360325 DOI: 10.4303/jdar/235840] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It has long been known that individuals will engage in voluntary inhalation of volatile solvents for their rewarding effects. However, research into the neurobiology of these agents has lagged behind that of more commonly used drugs of abuse such as psychostimulants, alcohol and nicotine. This imbalance has begun to shift in recent years as the serious effects of abused inhalants, especially among children and adolescents, on brain function and behavior have become appreciated and scientifically documented. In this review, we discuss the physicochemical and pharmacological properties of toluene, a representative member of a large class of organic solvents commonly used as inhalants. This is followed by a brief summary of the clinical and pre-clinical evidence showing that toluene and related solvents produce significant effects on brain structures and processes involved in the rewarding aspects of drugs. This is highlighted by tables highlighting toluene's effect on behaviors (reward, motor effects, learning, etc.) and cellular proteins (e.g. voltage and ligand-gated ion channels) closely associated the actions of abused substances. These sections demonstrate not only the significant progress that has been made in understanding the neurobiological basis for solvent abuse but also reveal the challenges that remain in developing a coherent understanding of this often overlooked class of drugs of abuse.
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Affiliation(s)
- Silvia L Cruz
- Departamento de Farmacobiología, Cinvestav, México, D.F., University of South Carolina, Charleston, SC
| | | | - John J Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
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6
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A review of potential neurotoxic mechanisms among three chlorinated organic solvents. Toxicol Appl Pharmacol 2011; 255:113-26. [DOI: 10.1016/j.taap.2011.05.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 05/06/2011] [Accepted: 05/08/2011] [Indexed: 12/17/2022]
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Chen HH, Lin YR, Chan MH. Toluene exposure during brain growth spurt and adolescence produces differential effects on N-methyl-D-aspartate receptor-mediated currents in rat hippocampus. Toxicol Lett 2011; 205:336-40. [PMID: 21726610 DOI: 10.1016/j.toxlet.2011.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/16/2011] [Accepted: 06/18/2011] [Indexed: 11/25/2022]
Abstract
Toluene, an industrial organic solvent, is voluntarily inhaled as drug of abuse. Because inhibition of N-methyl-d-aspartate (NMDA) receptors is one of the possible mechanisms underlying developmental neurotoxicity of toluene, the purpose of the present study was to examine the effects of toluene exposure during two major neurodevelopmental stages, brain growth spurt and adolescence, on NMDA receptor-mediated current. Rats were administered with toluene (500 mg/kg, i.p.) or corn oil daily over postnatal days (PN) 4-9 (brain growth spurt) or PN 21-26 (early adolescence). Intracellular electrophysiological recordings employing in CA1 pyramidal neurons in the hippocampal slices were performed during PN 30-38. Toluene exposure during brain growth spurt enhanced NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) by electrical stimulation, but impaired the paired-pulse facilitation and NMDA response by exogenous application of NMDA. Toluene exposure during adolescence resulted in an increase in NMDA receptor-mediated EPSCs and a decrease in exogenous NMDA-induced currents, while lack of any effect on paired-pulse facilitation. These findings suggest that toluene exposure during brain growth spurt and adolescence might result in an increase in synaptic NMDA receptor responsiveness and a decrease in extrasynaptic NMDA receptor responsiveness, while only toluene exposure during brain growth spurt can produce presynaptic modulation in CA1 pyramidal neurons. The functional changes in NMDA receptor-mediated transmission underlying developmental toluene exposure may lead to the neurobehavioral disturbances.
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Affiliation(s)
- Hwei-Hsien Chen
- Institute of Pharmacology and Toxicology, Tzu Chi University, 701, Sec. 3, Chung Yang Rd., Hualien 97004, Taiwan
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8
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Win-Shwe TT, Fujimaki H. Acute administration of toluene affects memory retention in novel object recognition test and memory function-related gene expression in mice. J Appl Toxicol 2011; 32:300-4. [DOI: 10.1002/jat.1693] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/20/2022]
Affiliation(s)
- Tin-Tin Win-Shwe
- Center for Environmental Risk Research; National Institute for Environmental Studies; 16-2 Onogawa; Tsukuba; Ibaraki; 305-8506; Japan
| | - Hidekazu Fujimaki
- Center for Environmental Risk Research; National Institute for Environmental Studies; 16-2 Onogawa; Tsukuba; Ibaraki; 305-8506; Japan
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Win-Shwe TT, Fujimaki H. Neurotoxicity of toluene. Toxicol Lett 2010; 198:93-9. [PMID: 20599484 DOI: 10.1016/j.toxlet.2010.06.022] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 11/17/2022]
Abstract
Chemical susceptibility is triggered by a large range of chemicals present both indoors and outdoors including pesticides, cleaning products, perfumes, scented products and cigarette smoke. Health risk after chemical exposure depends on age, sex, genetic factors, socioeconomic status, nutritional status, and environmental factors. Toluene is one of volatile organic chemicals that causes different sensitivity in individuals. Although neurotoxic and immunotoxic effects of toluene have been studied extensively, the underlying mechanism remains obscure. This review highlights the possible neuroimmune factors influencing toluene sensitivity and neurotoxicity in a mouse model.
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Affiliation(s)
- Tin-Tin Win-Shwe
- Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
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Abstract
Toluene is an organic solvent that is widely used by industry and is ubiquitous in our environment. As a result, exposure to solvents like toluene in work-related settings (i.e., relatively constant, low-level exposures) or through inhalant abuse (i.e., relatively intermittent, high-level exposures) is increasing for many women of reproductive age. Evidence suggests that the risk for pregnancy problems, as well as developmental delays and neurobehavioral difficulties, is higher for the children of women who have been exposed to high concentrations of organic solvents during pregnancy than for those who have not. These risks appear to be higher in cases of abuse exposure to solvents such as toluene, particularly in comparison to the risk for teratogenic outcomes with occupational solvent exposure. Despite this, the reproductive toxicology and teratology following abuse of toluene and other inhalants remains under-investigated. This brief review describes the current state of our understanding of the reproductive and teratogenic risk of gestational toluene abuse. The data to date suggest that the high levels of toluene exposure typical with inhalant abuse are more detrimental to fetal development than typical occupational exposure, and preclinical paradigms can be beneficial for investigating the processes and risks of prenatal solvent exposure. While substantial research has been done on the reproductive effects of occupational exposures to organic solvents, more research is needed on the outcomes and mechanisms of exposures typical of inhalant abuse.
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Affiliation(s)
- John H Hannigan
- Merrill Palmer Skillman Institute, Department of Obstetrics & Gynecology, C.S. Mott Center for Human Growth & Development, Wayne State University, Detroit, MI 48202, USA.
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Pascual R, Aedo L, Meneses JC, Vergara D, Reyes A, Bustamante C. Solvent inhalation (toluene and n-hexane) during the brain growth spurt impairs the maturation of frontal, parietal and occipital cerebrocortical neurons in rats. Int J Dev Neurosci 2010; 28:491-5. [PMID: 20600790 DOI: 10.1016/j.ijdevneu.2010.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 05/30/2010] [Accepted: 06/14/2010] [Indexed: 11/28/2022] Open
Abstract
Solvent abuse during pregnancy may cause "fetal solvent syndrome", which is characterized by mild brain atrophy and associated with behavioral, cognitive, and emotional abnormalities. The present study investigated whether solvent inhalation during the preweaning period (P2-P21) alters the morphological maturation of frontal, parietal, and occipital cortical neurons. Twelve hours after delivery (postnatal day 0, P0), litters were cross-fostered, culled to 8 pups/dam and housed together with a dam in standard laboratory cages. Litters were randomly assigned to the "air-only" group (n=64, 8 litters) and to the "solvent-sniffer" group (n=72, 9 litters). During P2-P21, each animal was exposed daily to either organic solvent vapors (75% toluene and 18% n-hexane, a solvent mixture commonly found in glues and adhesives) or clean air. To determine the impact of early solvent inhalation on cortical neuronal differentiation, brains were stained using the Golgi-Cox-Sholl procedure to quantitatively assess neocortical pyramidal cell dendrogenesis. Preweaning, solvent-exposed animals displayed dramatic impairments in dendritic growth as well as significant reductions in brain weight and size.
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Affiliation(s)
- Rodrigo Pascual
- Escuela de Kinesiología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
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Seo HS, Yang M, Song MS, Kim JS, Kim SH, Kim JC, Kim H, Shin T, Wang H, Moon C. Toluene inhibits hippocampal neurogenesis in adult mice. Pharmacol Biochem Behav 2009; 94:588-94. [PMID: 19969016 DOI: 10.1016/j.pbb.2009.11.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Revised: 11/02/2009] [Accepted: 11/30/2009] [Indexed: 10/20/2022]
Abstract
Toluene, a representative industrial solvent and abused inhalant, decreases neuronal activity in vitro and causes mental depression and cognitive impairment in humans. However, the effects of toluene on brain function and the sites of its action are poorly understood. This study investigated the temporal changes of neurogenesis in the hippocampus of adult C57BL/6 mice after acute administration of toluene using two immunohistochemical markers for neurogenesis, Ki-67 and doublecortin (DCX). In addition, after toluene treatment, depression-like behaviors and learning and memory tasks were examined to assess hippocampal neurogenesis-related behavioral dysfunction. The number of Ki-67- and DCX-positive cells in the dentate gyrus of adult hippocampi declined acutely between 0 h and 24 h after toluene treatment (500 mg/kg, i.p.) and increased gradually from 2 to 8 days post-administration. The level of Ki-67 and DCX immunoreactivity decreased in a dose-dependent manner within the range of toluene administered (0-1000 mg/kg). In tail suspension and forced-swim tests performed at 1 and 4 days after toluene treatment (500 mg/kg), mice showed significant depression-like behaviors compared to the vehicle-treated controls. In the contextual fear conditioning and object recognition memory test, the mice trained at 1 and 4 days after toluene treatment showed significant memory defects compared to the vehicle-treated controls. This study suggests that acute exposure to toluene reduces the rate of adult hippocampal neurogenesis and can cause hippocampal dysfunction such as depression and cognitive impairment.
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Affiliation(s)
- Heung-Sik Seo
- Department of Veterinary Anatomy, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
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Long C, Yang L, Faingold CL, Steven Evans M. Excitatory amino acid receptor-mediated responses in periaqueductal gray neurons are increased during ethanol withdrawal. Neuropharmacology 2006; 52:802-11. [PMID: 17123553 DOI: 10.1016/j.neuropharm.2006.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 06/09/2006] [Accepted: 09/27/2006] [Indexed: 10/23/2022]
Abstract
The ventrolateral periaqueductal gray (PAG) is critical for propagation in the neuronal network for ethanol withdrawal (ETX) seizures, and ethanol is known to alter glutamate effects. This study evaluated changes in glutamate antagonist effects on PAG neurophysiology in brain slices from rats treated with ethanol in vivo. Spontaneous action potentials were rare in control PAG neurons but common during ETX. Spontaneous excitatory postsynaptic potential (EPSP) frequency was increased during ETX, and an AMPA antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX) was more effective in suppressing this activity than an NMDA antagonist, 2-amino-7-phosphonoheptanoate (AP7). EPSPs evoked by stimulation of dorsolateral PAG were decreased by AP7 or DNQX in ETX and control neurons. EPSPs of ETX neurons were significantly less sensitive than controls to blockade by AP7 and DNQX. Paired-pulse facilitation of EPSPs was significantly increased during ETX, but paired-pulse inhibition occurred in controls. Thus, PAG hyperexcitability during ETX results from alterations of both NMDA and AMPA receptor-mediated neurotransmission, which may contribute importantly to ETX seizures. These results differ from previous findings in the seizure-initiating site for ETX seizures, inferior colliculus (IC), where NMDA receptor-mediated mechanisms dominate excitability increases during ETX. This dichotomy may be related to the different role played by IC and PAG in the ETX seizure network.
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Affiliation(s)
- Cheng Long
- Department of Pharmacology, Southern Illinois University School of Medicine, PO Box 19629, Springfield, IL 62794-9629, USA
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