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Biosca-Brull J, Basaure P, Guardia-Escote L, Cabré M, Blanco J, Morales-Navas M, Sánchez-Santed F, Colomina MT. Environmental exposure to chlorpyrifos during gestation, APOE polymorphism and the risk on autistic-like behaviors. ENVIRONMENTAL RESEARCH 2023; 237:116969. [PMID: 37659636 DOI: 10.1016/j.envres.2023.116969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/04/2023] [Accepted: 08/22/2023] [Indexed: 09/04/2023]
Abstract
Autism spectrum disorder (ASD) encompasses several neurodevelopmental conditions characterized by communication and social impairment, as well as repetitive patterns of behavior. However, it can co-occur with other mental conditions such as anxiety. The massive use of chlorpyrifos (CPF) has been linked to the increased prevalence of developmental disorders. Likewise, ASD has also been closely linked to a wide variety of genetic factors. The aims of the present investigation are to study how gestational CPF exposure and APOE polymorphism affects communication skills, early development and mid-term anxiety-like behaviors, as well as, changes in gene expression related to the cholinergic system. C57BL/6J and humanized apoE3 and apoE4 homozygous mice were exposed to 0 or 1 mg/kg/day of CPF through the diet, from gestational day (GD) 12-18. In addition, a group of C57BL/6J females were injected subcutaneously with 300 mg/kg/day of valproic acid (VPA) on GD 12 and 13. This group was used as a positive control for studying some core and associated autism-like behaviors. Communication skills by means of ultrasonic vocalizations and physical/motor development were assessed during the preweaning period, whereas locomotor activity, anxiety-like behaviors and the gene expression of cholinergic elements were evaluated during adolescence. Our results showed that C57BL/6J mice prenatally exposed to CPF or VPA showed a decrease in body weight and a delay in eye opening. Communication and anxiety behavior were affected differently depending on treatment, while gene expression was altered by sex and treatment. In addition, none of the parameters evaluated in apoE transgenic mice exposed to CPF were affected, but there were differences between genotypes. Therefore, we suggest that prenatal CPF exposure and VPA produce divergent effects on communication and anxiety.
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Affiliation(s)
- Judit Biosca-Brull
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain; Universitat Rovira i Virgili, Department of Psychology and Research Center for Behavior Assessment (CRAMC), Tarragona, Spain; Universitat Rovira i Virgili, Center of Environmental, Food and Toxicological Technology (TECNATOX), Reus, Spain.
| | - Pia Basaure
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain
| | - Laia Guardia-Escote
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain
| | - Maria Cabré
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain; Universitat Rovira i Virgili, Department of Biochemistry and Biotechnology, Tarragona, Spain
| | - Jordi Blanco
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain; Universitat Rovira i Virgili, Center of Environmental, Food and Toxicological Technology (TECNATOX), Reus, Spain; Universitat Rovira i Virgili, Department of Basic Medical Sciences, Reus, Spain
| | - Miguel Morales-Navas
- Department of Psychology, Health Research Center (CEINSA), Almeria University, 04120, Almeria, Spain
| | - Fernando Sánchez-Santed
- Department of Psychology, Health Research Center (CEINSA), Almeria University, 04120, Almeria, Spain
| | - Maria Teresa Colomina
- Universitat Rovira i Virgili, Research Group in Neurobehavior and Health (NEUROLAB), Tarragona, Spain; Universitat Rovira i Virgili, Department of Psychology and Research Center for Behavior Assessment (CRAMC), Tarragona, Spain; Universitat Rovira i Virgili, Center of Environmental, Food and Toxicological Technology (TECNATOX), Reus, Spain.
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Lin JW, Fu SC, Liu JM, Liu SH, Lee KI, Fang KM, Hsu RJ, Huang CF, Liu KM, Chang KC, Su CC, Chen YW. Chlorpyrifos induces neuronal cell death via both oxidative stress and Akt activation downstream-regulated CHOP-triggered apoptotic pathways. Toxicol In Vitro 2023; 86:105483. [DOI: 10.1016/j.tiv.2022.105483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/18/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022]
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APOE genetic background and sex confer different vulnerabilities to postnatal chlorpyrifos exposure and modulate the response to cholinergic drugs. Behav Brain Res 2019; 376:112195. [DOI: 10.1016/j.bbr.2019.112195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 08/20/2019] [Accepted: 08/28/2019] [Indexed: 01/30/2023]
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Abdelmalek MR, Beheiry EE, El-Shinety RM, Farag AT, Tayel SM. Scanning electron microscopic study of the effect of chlorpyrifos on the developing neural tube in comparison with Arsenic in mouse embryo. ALEXANDRIA JOURNAL OF MEDICINE 2019. [DOI: 10.1016/j.ajme.2015.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Miriam R.R.F. Abdelmalek
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
| | - Eman Elazab Beheiry
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
| | | | - Amina Tolba Farag
- Department of Pesticide Chemistry and toxicology, Faculty of Agriculture, University of Alexandria, Egypt
| | - Shawky Mahmoud Tayel
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
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Rohlman DS, Ismail A, Bonner MR, Abdel Rasoul G, Hendy O, Ortega Dickey L, Wang K, Olson JR. Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt. Neurotoxicology 2019; 74:1-6. [PMID: 31077682 DOI: 10.1016/j.neuro.2019.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Exposure to environmental chemicals, including organophosphorus pesticides, is associated with behavioral disorders such as attention deficit hyperactivity disorder (ADHD). However, the impact of occupational pesticide exposure on ADHD development in adolescents has not been examined. OBJECTIVE We examined the association between exposure to chlorpyrifos and ADHD symptoms among adolescents in Egypt. METHODS Adolescent pesticide applicators and non-applicators, 12-21 years old, participated in a 10-month longitudinal study examining health effects from pesticide exposure. Repeated urine and blood samples were collected at various time points during the 10-months to assess biomarkers of chlorpyrifos exposure (urinary trichloro-2-pyridinol or TCPy) and effect (blood acetyl cholinesterase activity and butyryl cholinesterase activity). Parents from a subset of the cohort (N = 64) completed the Short Form of Conners' Parent Rating Scale - Revised. Poisson regressions were used to examine the associations between the number of ADHD symptoms and occupation and biomarkers. RESULTS Pesticide applicators had significantly more symptoms of ADHD than participants in the non-applicator group. Urinary TCPy levels were associated with increased symptoms, demonstrating a dose-response effect. Applicators with ADHD reported applying pesticides for more hours during the application season and had greater cumulative TCPy levels than participants without ADHD. One fourth of all applicators met the criteria for an ADHD diagnosis (having 6 or more reported symptoms). CONCLUSIONS This study provides preliminary evidence of an association between occupational exposure to chlorpyrifos and ADHD symptoms among adolescent pesticide applicators in spite of its limited small sample size. There is a critical need to investigate the susceptibility of children and adolescents to repeated occupational and environmental exposures to pesticides because the developing brain may be uniquely sensitive to the neurotoxic effects of these agents.
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Affiliation(s)
- Diane S Rohlman
- Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA; Oregon Health and Science University, Portland, OR, USA.
| | - Ahmed Ismail
- Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA; Faculty of Medicine, Menoufia University, Shebin El-Kom, Egypt
| | - Matthew R Bonner
- Department of Epidemiology and Environmental Health, State University of New York Buffalo, NY, USA
| | | | - Olfat Hendy
- National Liver Institute, Menoufia University, Shebin El-Kom, Egypt
| | | | - Kai Wang
- Biostatistics, University of Iowa, Iowa City, IA, USA
| | - James R Olson
- Department of Epidemiology and Environmental Health, State University of New York Buffalo, NY, USA; Department of Pharmacology and Toxicology, State University of New York, Buffalo, NY, USA
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Guardia-Escote L, Basaure P, Blanco J, Cabré M, Pérez-Fernández C, Sánchez-Santed F, Domingo JL, Colomina MT. Postnatal exposure to chlorpyrifos produces long-term effects on spatial memory and the cholinergic system in mice in a sex- and APOE genotype-dependent manner. Food Chem Toxicol 2018; 122:1-10. [DOI: 10.1016/j.fct.2018.09.069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/22/2018] [Accepted: 09/28/2018] [Indexed: 12/13/2022]
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Pallotta MM, Ronca R, Carotenuto R, Porreca I, Turano M, Ambrosino C, Capriglione T. Specific Effects of Chronic Dietary Exposure to Chlorpyrifos on Brain Gene Expression-A Mouse Study. Int J Mol Sci 2017; 18:ijms18112467. [PMID: 29156651 PMCID: PMC5713433 DOI: 10.3390/ijms18112467] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/04/2017] [Accepted: 11/07/2017] [Indexed: 01/14/2023] Open
Abstract
Chlorpyrifos (CPF) is an organophosphate insecticide used to control pests on a variety of food and feed crops. In mammals, maternal exposure to CPF has been reported to induce cerebral cortex thinning, alteration of long-term brain cognitive function, and Parkinson-like symptoms, but the mechanisms of these processes are not fully understood. In this study, we aimed to gain a deeper understanding of the alterations induced in the brains of mice chronically exposed to CPF by dietary intake. For our purpose, we analysed F1 offspring (sacrificed at 3 and 8 months) of Mus musculus, treated in utero and postnatally with 3 different doses of CPF (0.1-1-10 mg/kg/day). Using RT2 Profiler PCR Arrays, we evaluated the alterations in the expression of 84 genes associated with neurodegenerative diseases. In the brains of exposed mice, we evidenced a clear dose–response relationship for AChE inhibition and alterations of gene expression. Some of the genes that were steadily down-regulated, such as Pink1, Park 2, Sv2b, Gabbr2, Sept5 and Atxn2, were directly related to Parkinson’s onset. Our experimental results shed light on the possibility that long-term CPF exposure may exert membrane signalling alterations which make brain cells more susceptible to develop neurodegenerative diseases.
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Affiliation(s)
- Maria Michela Pallotta
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Raffaele Ronca
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Rosa Carotenuto
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | | | - Mimmo Turano
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Concetta Ambrosino
- IRGS, Biogem, Via Camporeale, Ariano Irpino, 83031 Avellino, Italy.
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy.
| | - Teresa Capriglione
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
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Abreu-Villaça Y, Levin ED. Developmental neurotoxicity of succeeding generations of insecticides. ENVIRONMENT INTERNATIONAL 2017; 99:55-77. [PMID: 27908457 PMCID: PMC5285268 DOI: 10.1016/j.envint.2016.11.019] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 05/19/2023]
Abstract
Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids. The goal of new insecticide development is to more effectively kill target species with fewer toxic side effects on non-target species. From the experience with the developmental neurotoxicity caused by the generations of insecticides developed in the past advice is offered how to proceed with future insecticide development to decrease neurotoxic risk.
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Affiliation(s)
- Yael Abreu-Villaça
- Departamento de Ciências Fisiologicas, Universidade do Estado do Rio de Janeiro (UERJ), RJ, Brazil
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA.
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Eidels RR, Sparks DW, Whitaker JO, Sprague CA. Sub-lethal Effects of Chlorpyrifos on Big Brown Bats (Eptesicus fuscus). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 71:322-335. [PMID: 27491870 DOI: 10.1007/s00244-016-0307-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
We determined dose-response curves for sublethal effects of the organophosphorus (OP) insecticide, chlorpyrifos, on bats. Big brown bats (Eptesicus fuscus, n = 64) were given a single dose of chlorpyrifos (nominal concentrations) of 0, 5, 10, 15, 20, 25, 30, or 60 µg/g body weight and examined at 12 or 24 h after dosing. A second experiment dosed 32 bats with 0 or 60 µg/g body weight and examined 1, 3, 7, or 14 days after dosing. Skin temperature and behavioral changes were recorded, and brain and plasma cholinesterase (ChE) activity were measured. The benchmark dose (BMD10) of chlorpyrifos that altered brain and plasma ChE activity at 24 h was 3.7 and 10.1 µg/g, respectively. The 95 % lower confidence limit for the BMD10 (i.e., BMDL10) was 1.6 and 7.7 µg/g. The best of five models (as determined by AIC) for impaired flight, impaired movement, or presence of tremors provided a BMD10 of 6.2, 12.9, and 7.8 µg/g body weight of chlorpyrifos, respectively. BMDL10 for impaired flight, impaired movement, or presence of tremors was 3.5, 6.6, and 5.3 µg/g body weight, respectively. In the wild, impaired ability to fly or crawl could be life-threatening. Brain and plasma ChE activity remained low for 3 days after dosing. Gradual recovery of enzyme activity was observed by 7 days in survivors. Brain and plasma ChE activity were still significantly lower than that of the control group at 14 days after dosing.
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Affiliation(s)
- Ronny R Eidels
- Department of Biology, Indiana State University, Terre Haute, IN, USA
- University of Newcastle, Newcastle, NSW, Australia
| | - Daniel W Sparks
- U. S. Fish and Wildlife Service, 620 S. Walker St., Bloomington, IN, 47403, USA.
| | - John O Whitaker
- Department of Biology, Indiana State University, Terre Haute, IN, USA
| | - Charles A Sprague
- Department of Biology, Indiana State University, Terre Haute, IN, USA
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Amani N, Soodi M, Daraei B, Dashti A. Chlorpyrifos Toxicity in Mouse Cultured Cerebellar Granule Neurons at Different Stages of Development: Additive Effect on Glutamate-Induced Excitotoxicity. CELL JOURNAL 2016; 18:464-72. [PMID: 27602329 PMCID: PMC5011335 DOI: 10.22074/cellj.2016.4575] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/06/2016] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Chlorpyrifos (CPF) is a neurotoxic organophosphorus (OP) insecticide. Its mechanism of action includes oxidative stress, excitotoxicity, and inhibition of the acetylcholinesterase enzyme (AChE). The aim of the present study is to investigate CPF toxicity in mature and immature cerebellar granule neurons (CGNs), as well as its effect on glutamate induced excitotoxicity. MATERIALS AND METHODS This study was an in vitro experimental study performed on mice cultured CGNs. Immature and mature neurons were exposed to different concentrations of CPF (1-1000 µM) and glutamate (10-600 µM) for 48 hours after which we used the MTT assay to measure cytotoxicity. Immature neurons had exposure to CPF for 5 days in order to evaluate the cytotoxic effect on developing neurons. Mature neurons received sub-lethal concentrations of CPF (10, 100 µM) combined with different concentrations of glutamate. AChE activity and reactive oxygen species (ROS) generation were assessed after treatments. RESULTS Immature CGNs had increased sensitivity to CPF toxicity compared to mature neurons. We observed significantly greater ROS production in immature compared to mature neurons, however AChE activity was more inhibited in mature neurons. Although CPF toxicity was not well correlated with AChE inhibition, it correlated well with ROS production. Glutamate toxicity was potentiated by sub-lethal concentration of CPF, however glutamate induced ROS production was not affected. The results suggested that CPF potentiated glutamate toxicity by mechanisms other than oxidative stress. CONCLUSION CPF toxicity differed in mature and immature neurons. Potentiated glutamate toxicity by CPF implied that CPF exposure might be a risk factor for neurodegenerative disease.
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Affiliation(s)
- Nahid Amani
- Department of Toxicology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maliheh Soodi
- Department of Toxicology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Bahram Daraei
- Department of Toxicology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Abolfazl Dashti
- Department of Toxicology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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Abstract
Behavioral evaluations are emerging as a key component in neurotoxicity testing. A neurobehavioral screening battery that is most often used for hazard identification consists of a functional observational battery (FOB) and motor activity. The FOB was developed as an improvement over routine cageside observations: major differences include the specification of observations, operational definitions of the behaviors to be observed, grading the severity of effect, and location of observations (open arena vs. home cage). A typical FOB protocol consists of approximately 20 to 30 end points, allowing for the detection and description of a range of neurobehavioral changes. We have focused on assessing critical characteristics (i.e., sensitivity, specificity, validity, and reproducibility) of these tests. Concerns have been raised as to the validity and reliability of observational methods for neurotoxicity screening. These tests were therefore the focus of an international collaborative study, sponsored by the International Programme on Chemical Safety (IPCS). The purpose of the IPCS study was to assess the general utility and reliability of neurobehavioral screening procedures in a diversity of testing situations. The test protocol was essentially that described in current United States Environmental Protection Agency (US EPA) guidelines. The resultant data indicated that all participants could detect and characterize the effects of known neurotoxicants, and the divergent profiles of effect obtained for different chemicals demonstrated the specificity of the methods. One conclusion, therefore, was that behavior can be a useful tool for assessing neurotoxicity. In addition, the study also provided a wealth of control data, examination of which provides evidence for the consistency and baseline values of behavioral measures. Reliability estimates were statistically established, providing a measure of the usefulness of individual end points for detecting chemical-induced toxicity. Another conclusion of the IPCS collaborative study was that the application of these methods requires careful attention to details of experimental design, observer training, and experience; these capabilities should be adequately documented by the use of proficiency studies. Recently, modifications of the standard FOB have been introduced, including expanded clinical observations (ECO) for standard toxicity studies. Although there are end points common between the FOB and ECO, it is not known if the latter is sufficient for neurotoxicity screening. Appropriate validation studies have not been conducted on these expanded observations. With the increasing dependency on these methods for neurotoxicity testing, and the number of studies that will be incorporating these methods, issues of test validity as well as data interpretation are becoming more critical.
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Affiliation(s)
- Virginia C. Moser
- National Health and Environmental Effects Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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Rohlman DS, Ismail AA, Abdel-Rasoul G, Lasarev M, Hendy O, Olson JR. Characterizing exposures and neurobehavioral performance in Egyptian adolescent pesticide applicators. Metab Brain Dis 2014; 29:845-55. [PMID: 24833556 PMCID: PMC4465098 DOI: 10.1007/s11011-014-9565-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 05/01/2014] [Indexed: 10/25/2022]
Abstract
Children and adolescents may have occupational exposure to pesticides. Although previous studies examining prenatal pesticide exposure have identified neurobehavioral deficits in children, there are limited studies examining the impact of occupational exposure in children. The objectives of this study are to estimate exposures to the organophosphorus pesticide, chlorpyrifos (CPF), by measuring urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific CPF metabolite, and blood cholinesterase (ChE) activities and to characterize neurobehavioral performance in adolescents working as seasonal pesticide applicators and non-applicator controls. A neurobehavioral test battery, consisting of 14 tests, was used to assess a broad range of functions. Applicators performed worse than controls on the majority of tests. Principal component analysis was used to reduce the number of outcome variables and two components, focused on reasoning-short-term memory and attention-executive functioning, showed significant deficits in applicators compared to non-applicators. Elevated metabolite levels were found in the applicators compared to the non-applicators, confirming CPF exposure in the applicators. Although this study is limited by a small sample size, it provides preliminary evidence of moderate CPF exposures, decreased blood ChE in some applicators and decreased neurobehavioral performance in an adolescent working population.
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Affiliation(s)
- Diane Schertler Rohlman
- Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa CIty, IA, USA,
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Poet TS, Timchalk C, Hotchkiss JA, Bartels MJ. Chlorpyrifos PBPK/PD model for multiple routes of exposure. Xenobiotica 2014; 44:868-81. [DOI: 10.3109/00498254.2014.918295] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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14
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Lee JE, Lim MS, Park JH, Park CH, Koh HC. Nuclear NF-κB contributes to chlorpyrifos-induced apoptosis through p53 signaling in human neural precursor cells. Neurotoxicology 2014; 42:58-70. [DOI: 10.1016/j.neuro.2014.04.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 03/25/2014] [Accepted: 04/02/2014] [Indexed: 01/01/2023]
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Mitochondrial dysfunction in aging rat brain regions upon chlorpyrifos toxicity and cold stress: an interactive study. Cell Mol Neurobiol 2014; 34:737-56. [PMID: 24744124 DOI: 10.1007/s10571-014-0056-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/30/2014] [Indexed: 10/25/2022]
Abstract
Mitochondrial dysfunction and consequent energy depletion are the major causes of oxidative stress resulting to bring alterations in the ionic homeostasis causing loss of cellular integrity. Our previous studies have shown the age-associated interactive effects in rat central nervous system (CNS) upon co-exposure to chlorpyrifos (CPF) and cold stress leading to macromolecular oxidative damage. The present study elucidates a possible mechanism by which CPF and cold stress interaction cause(s) mitochondrial dysfunction in an age-related manner. In this study, the activity levels of Krebs cycle enzymes and electron transport chain (ETC) protein complexes were assessed in the isolated fraction of mitochondria. CPF and cold stress (15 and 20 °C) exposure either individually or in combination decreased the activity level of Krebs cycle enzymes and ETC protein complexes in discrete regions of rat CNS. The findings confirm that cold stress produces significant synergistic effect in CPF intoxicated aging rats. The synergism between CPF and cold stress at 15 °C caused a higher depletion of respiratory enzymes in comparison with CPF and cold stress alone and together at 20 °C indicating the extent of deleterious functional alterations in discrete regions of brain and spinal cord (SC) which may result in neurodegeneration and loss in neuronal metabolic control. Hence, co-exposure of CPF and cold stress is more dangerous than exposure of either alone. Among the discrete regions studied, the cerebellum and medulla oblongata appears to be the most susceptible regions when compared to cortex and SC. Furthermore, the study reveals a gradual decrease in sensitivity to CPF toxicity as the rat matures.
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Sagunski H, Roßkamp E. Richtwerte für die Innenraumluft: Tris(2-chlorethyl)phosphat. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2014; 45:300-6. [DOI: 10.1007/s00103-001-0365-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Pizzurro DM, Dao K, Costa LG. Diazinon and diazoxon impair the ability of astrocytes to foster neurite outgrowth in primary hippocampal neurons. Toxicol Appl Pharmacol 2014; 274:372-82. [PMID: 24342266 PMCID: PMC3916905 DOI: 10.1016/j.taap.2013.11.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/26/2013] [Accepted: 11/29/2013] [Indexed: 11/25/2022]
Abstract
Evidence from in vivo and epidemiological studies suggests that organophosphorus insecticides (OPs) are developmental neurotoxicants, but possible underlying mechanisms are still unclear. Astrocytes are increasingly recognized for their active role in normal neuronal development. This study sought to investigate whether the widely-used OP diazinon (DZ), and its oxygen metabolite diazoxon (DZO), would affect glial-neuronal interactions as a potential mechanism of developmental neurotoxicity. Specifically, we investigated the effects of DZ and DZO on the ability of astrocytes to foster neurite outgrowth in primary hippocampal neurons. The results show that both DZ and DZO adversely affect astrocyte function, resulting in inhibited neurite outgrowth in hippocampal neurons. This effect appears to be mediated by oxidative stress, as indicated by OP-induced increased reactive oxygen species production in astrocytes and prevention of neurite outgrowth inhibition by antioxidants. The concentrations of OPs were devoid of cytotoxicity, and cause limited acetylcholinesterase inhibition in astrocytes (18 and 25% for DZ and DZO, respectively). Among astrocytic neuritogenic factors, the most important one is the extracellular matrix protein fibronectin. DZ and DZO decreased levels of fibronectin in astrocytes, and this effect was also attenuated by antioxidants. Underscoring the importance of fibronectin in this context, adding exogenous fibronectin to the co-culture system successfully prevented inhibition of neurite outgrowth caused by DZ and DZO. These results indicate that DZ and DZO increase oxidative stress in astrocytes, and this in turn modulates astrocytic fibronectin, leading to impaired neurite outgrowth in hippocampal neurons.
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Affiliation(s)
- Daniella M. Pizzurro
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Khoi Dao
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Lucio G. Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
- Department of Neuroscience, University of Parma, Parma, Italy
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Mohammad F, Al-Baggou B, Naser A, Fadel M. In vitroinhibition of plasma and brain cholinesterases of growing chicks by chlorpyrifos and dichlorvos. JOURNAL OF APPLIED ANIMAL RESEARCH 2014. [DOI: 10.1080/09712119.2013.875912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bagri P, Kumar V, Sikka AK, Punia JS. Preliminary acute toxicity study on imidacloprid in Swiss albino mice. Vet World 2013. [DOI: 10.14202/vetworld.2013.955-959] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Badgujar PC, Jain SK, Singh A, Punia JS, Gupta RP, Chandratre GA. Immunotoxic effects of imidacloprid following 28 days of oral exposure in BALB/c mice. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 35:408-18. [PMID: 23467117 DOI: 10.1016/j.etap.2013.01.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 05/19/2023]
Abstract
Imidacloprid, a neonicotinoid insecticide has been in use worldwide for several years in agriculture and veterinary medicine. It is possible that residue of this compound may be recycled in the food chain and thus information regarding effects from potential exposure to it is warranted. The objective of the present study was to evaluate immunotoxic effects of imidacloprid in female BALB/c mice. Imidacloprid was administered orally daily at 10, 5, or 2.5mg/kg over 28 days. Specific parameters of humoral and cellular immune response including hemagglutinating antibody (HA) titer to sheep red blood cells (SRBC; T-dependent antigen), delayed type hypersensitivity (DTH) response to SRBC, and T-lymphocyte proliferation in response to phytohemagglutinin (PHA) were evaluated. The results showed that imidacloprid at high dose, specifically suppressed cell-mediated immune response as was evident from decreased DTH response and decreased stimulation index of T-lymphocytes to PHA. At this dose, there were also prominent histopathological alterations in spleen and liver. Histopathological analysis of footpad sections of mice revealed dose-related suppression of DTH response. Imidacloprid at low dose of 2.5mg/kg/day did not produce any significant alterations in cellular and humoral immune response and it seemed to be an appropriate dose for assessment of 'no observable adverse effects level' for immunotoxicity in BALB/c mice. The results also indicated that imidacloprid has immunosuppressive effects at doses >5mg/kg, which could potentially be attributed to direct cytotoxic effects of IMD against T cells (particularly TH cells) and that long-term exposure could be detrimental to the immune system.
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Affiliation(s)
- Prarabdh C Badgujar
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Sciences, CCS Haryana Agricultural University, Hisar, India.
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Foudoulakis M, Balaskas C, Csato A, Szentes C, Arapis G. Japanese quail acute exposure to methamidophos: experimental design, lethal, sub-lethal effects and cholinesterase biochemical and histochemical expression. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 450-451:334-347. [PMID: 23146311 DOI: 10.1016/j.scitotenv.2012.10.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 10/14/2012] [Accepted: 10/15/2012] [Indexed: 06/01/2023]
Abstract
We exposed the Japanese quail (Coturnix coturnix japonica) to the organophosphate methamidophos using acute oral test. Mortality and sub-lethal effects were recorded in accordance to internationally accepted protocols. In addition cholinesterases were biochemically estimated in tissues of the quail: brain, liver and plasma. Furthermore, brain, liver and duodenum cryostat sections were processed for cholinesterase histochemistry using various substrates and inhibitors. Mortalities occurred mainly in the first 1-2h following application. Sub-lethal effects, such as ataxia, ruffled feathers, tremor, salivation and reduced or no reaction to external stimuli were observed. Biochemical analysis in the brain, liver and plasma indicates a strong cholinesterase dependent inhibition with respect to mortality and sub-lethal effects of the quail. The histochemical staining also indicated a strong cholinesterase inhibition in the organs examined and the analysis of the stained sections allowed for an estimation and interpretation of the intoxication effects of methamidophos, in combination with tissue morphology visible by Haematoxylin and Eosin staining. We conclude that the use of biochemistry and histochemistry for the biomarker cholinesterase, may constitute a significantly novel approach for understanding the results obtained by the acute oral test employed in order to assess the effects of methamidophos and other chemicals known to inhibit this very important nervous system enzyme.
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Affiliation(s)
- Manousos Foudoulakis
- Laboratory of Ecology and Environmental Sciences, Agricultural University of Athens, Iera Odos 75, Athens 11854, Greece.
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Stamou M, Streifel KM, Goines PE, Lein PJ. Neuronal connectivity as a convergent target of gene × environment interactions that confer risk for Autism Spectrum Disorders. Neurotoxicol Teratol 2013; 36:3-16. [PMID: 23269408 PMCID: PMC3610799 DOI: 10.1016/j.ntt.2012.12.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 11/12/2012] [Accepted: 12/17/2012] [Indexed: 11/21/2022]
Abstract
Evidence implicates environmental factors in the pathogenesis of Autism Spectrum Disorders (ASD). However, the identity of specific environmental chemicals that influence ASD risk, severity or treatment outcome remains elusive. The impact of any given environmental exposure likely varies across a population according to individual genetic substrates, and this increases the difficulty of identifying clear associations between exposure and ASD diagnoses. Heritable genetic vulnerabilities may amplify adverse effects triggered by environmental exposures if genetic and environmental factors converge to dysregulate the same signaling systems at critical times of development. Thus, one strategy for identifying environmental risk factors for ASD is to screen for environmental factors that modulate the same signaling pathways as ASD susceptibility genes. Recent advances in defining the molecular and cellular pathology of ASD point to altered patterns of neuronal connectivity in the developing brain as the neurobiological basis of these disorders. Studies of syndromic ASD and rare highly penetrant mutations or CNVs in ASD suggest that ASD risk genes converge on several major signaling pathways linked to altered neuronal connectivity in the developing brain. This review briefly summarizes the evidence implicating dysfunctional signaling via Ca(2+)-dependent mechanisms, extracellular signal-regulated kinases (ERK)/phosphatidylinositol-3-kinases (PI3K) and neuroligin-neurexin-SHANK as convergent molecular mechanisms in ASD, and then discusses examples of environmental chemicals for which there is emerging evidence of their potential to interfere with normal neuronal connectivity via perturbation of these signaling pathways.
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Affiliation(s)
- Marianna Stamou
- Department of Molecular Biosciences, University of California at Davis School of Veterinary Medicine, Davis CA, 95616, United States
| | - Karin M. Streifel
- Department of Molecular Biosciences, University of California at Davis School of Veterinary Medicine, Davis CA, 95616, United States
| | - Paula E. Goines
- Department of Molecular Biosciences, University of California at Davis School of Veterinary Medicine, Davis CA, 95616, United States
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California at Davis School of Veterinary Medicine, Davis CA, 95616, United States
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Rezin GT, Scaini G, Ferreira GK, Cardoso MR, Gonçalves CL, Constantino LS, Deroza PF, Ghedim FV, Valvassori SS, Resende WR, Quevedo J, Zugno AI, Streck EL. Inhibition of acetylcholinesterase activity in brain and behavioral analysis in adult rats after chronic administration of fenproporex. Metab Brain Dis 2012; 27:453-8. [PMID: 22832793 DOI: 10.1007/s11011-012-9331-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 07/17/2012] [Indexed: 12/16/2022]
Abstract
Fenproporex is an amphetamine-based anorectic and it is rapidly converted in vivo into amphetamine. It elevates the levels of extracellular dopamine in the brain. Acetylcholinesterase is a regulatory enzyme which is involved in cholinergic synapses and may indirectly modulate the release of dopamine. Thus, we investigated whether the effects of chronic administration of fenproporex in adult rats alters acquisition and retention of avoidance memory and acetylcholinesterase activity. Adult male Wistar rats received repeated (14 days) intraperitoneal injection of vehicle or fenproporex (6.25, 12.5 or 25 mg/kg i.p.). For behavioral assessment, animals were submitted to inhibitory avoidance (IA) tasks and continuous multiple trials step-down inhibitory avoidance (CMIA). Acetylcholinesterase activity was measured in the prefrontal cortex, hippocampus, hypothalamus and striatum. The administration of fenproporex (6.25, 12.5 and 25 mg/kg) did not induce impairment in short and long-term IA or CMIA retention memory in rats. In addition, longer periods of exposure to fenproporex administration decreased acetylcholinesterase activity in prefrontal cortex and striatum of rats, but no alteration was verified in the hippocampus and hypothalamus. In conclusion, the present study showed that chronic fenproporex administration decreased acetylcholinesterase activity in the rat brain. However, longer periods of exposure to fenproporex did not produce impairment in short and long-term IA or CMIA retention memory in rats.
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Affiliation(s)
- Gislaine T Rezin
- Laboratório de Bioenergética, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, 88806-000, SC, Brazil
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Cholinesterase inhibition and toxicokinetics in immature and adult rats after acute or repeated exposures to chlorpyrifos or chlorpyrifos-oxon. Regul Toxicol Pharmacol 2012; 63:209-24. [PMID: 22504667 DOI: 10.1016/j.yrtph.2012.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/05/2012] [Accepted: 03/30/2012] [Indexed: 11/23/2022]
Abstract
The effect of age or dose regimen on cholinesterase inhibition (ChEI) from chlorpyrifos (CPF) or CPF-oxon (CPFO) was studied in Crl:CD(SD) rats. Rats were exposed to CPF by gavage in corn oil, rat milk (pups), or in the diet (adults) or to CPFO by gavage in corn oil. Blood CPF/CPFO levels were measured. With acute exposure, ChEI NOELs were 2 mg/kg CPF for brain and 0.5 mg/kg CPF for red blood cells (RBCs) in both age groups. In pups, ChEI and blood CPF levels were similar using either milk or corn oil vehicles. Compared to gavage, adults given dietary CPF (12 h exposure) had greater RBC ChEI, but lower brain ChEI at corresponding CPF doses, indicating an effect of dose rate. With repeated CPF exposures, ChEI NOELs were the same across ages (0.5 and 0.1 mg/kg/day for brain and RBCs, respectively). With CPFO dosing, the ChEI NOELs were 0.1 mg/kg (acute) and 0.01 mg/kg/day (repeated doses) for RBCs with no ChEI in brain at CPFO doses up to 0.5 (pup) or 10 mg/kg (adult) for acute dosing or 0.5 mg/kg/day for both ages with repeat dosing. Thus, there were no age-dependent differences in CPF ChEI via acute or repeated exposures. Pups had less ChEI than adults at comparable blood CPF levels. Oral CPFO resulted in substantial RBC ChEI, but no brain ChEI, indicating no CPFO systemic bioavailability to peripheral tissues.
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Nurulain SM, Shafiullah M. TERATOGENICITY AND EMBRYOTOXICITY OF ORGANOPHOSPHORUS COMPOUNDS IN ANIMAL MODELS - A SHORT REVIEW. ACTA ACUST UNITED AC 2012. [DOI: 10.31482/mmsl.2012.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Li AA, Lowe KA, McIntosh LJ, Mink PJ. Evaluation of epidemiology and animal data for risk assessment: chlorpyrifos developmental neurobehavioral outcomes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2012; 15:109-184. [PMID: 22401178 PMCID: PMC3386549 DOI: 10.1080/10937404.2012.645142] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Developmental neurobehavioral outcomes attributed to exposure to chlorpyrifos (CPF) obtained from epidemiologic and animal studies published before June 2010 were reviewed for risk assessment purposes. For epidemiological studies, this review considered (1) overall strength of study design, (2) specificity of CPF exposure biomarkers, (3) potential for bias, and (4) Hill guidelines for causal inference. In the case of animal studies, this review focused on evaluating the consistency of outcomes for developmental neurobehavioral endpoints from in vivo mammalian studies that exposed dams and/or offspring to CPF prior to weaning. Developmental neuropharmacologic and neuropathologic outcomes were also evaluated. Experimental design and methods were examined as part of the weight of evidence. There was insufficient evidence that human developmental exposures to CPF produce adverse neurobehavioral effects in infants and children across different cohort studies that may be relevant to CPF exposure. In animals, few behavioral parameters were affected following gestational exposures to 1 mg/kg-d but were not consistently reported by different laboratories. For postnatal exposures, behavioral effects found in more than one study at 1 mg/kg-d were decreased errors on a radial arm maze in female rats and increased errors in males dosed subcutaneously from postnatal day (PND) 1 to 4. A similar finding was seen in rats exposed orally from PND 1 to 21 with incremental dose levels of 1, 2, and 4 mg/kg-d, but not in rats dosed with constant dose level of 1 mg/kg-d. Neurodevelopmental behavioral, pharmacological, and morphologic effects occurred at doses that produced significant brain or red blood cell acetylcholinesterase inhibition in dams or offspring.
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Affiliation(s)
- Abby A Li
- Exponent Health Sciences Group, Menlo Park, California, USA.
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Moser VC. Age-related differences in acute neurotoxicity produced by mevinphos, monocrotophos, dicrotophos, and phosphamidon. Neurotoxicol Teratol 2011; 33:451-7. [DOI: 10.1016/j.ntt.2011.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/03/2011] [Accepted: 05/26/2011] [Indexed: 11/24/2022]
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Borkowski WJ, Riederer A, Prapamontol T. Neurological evaluation of newborn infants of mothers working in citrus groves in Northern Thailand. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2011; 17:135-43. [PMID: 21618945 DOI: 10.1179/107735211799030997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The purpose of this pilot study was to assess neurological function in newborn infants born to mothers working in citrus orchards in Northern Thailand for a period in excess of one year where pesticide applications average 35 times a year. Forty-one infants from uncomplicated term births at the community hospital in Fang, Thailand, were given neurological evaluations during the first four days of life. This was a cross-sectional study in which nine mothers worked in citrus orchards and 32 mothers did not. Examiners were not given the exposure history of the mothers. Twelve infants--five of them born to mothers from citrus orchards--had examinations demonstrating abnormal muscle tone. Using logistic regression, the final model showed that maternal citrus grove exposure and anesthesia use were significant predictors (p < 0.05) of abnormal muscle tone with adjusted odds ratios of 9.82 (CI = 1.42, 68.07) and 5.99 (CI = 1.003, 35.85) for exposure and anesthesia respectively.
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Affiliation(s)
- Winslow Joseph Borkowski
- Emory University, Environmental and Occupational Health Department, Rollins School of Public Health, Atlanta, GA, USA.
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Gu H, Pan Z, Xi B, Hainline BE, Shanaiah N, Asiago V, Nagana Gowda GA, Raftery D. 1H NMR metabolomics study of age profiling in children. NMR IN BIOMEDICINE 2009; 22:826-33. [PMID: 19441074 PMCID: PMC4009993 DOI: 10.1002/nbm.1395] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Metabolic profiling of urine provides a fingerprint of personalized endogenous metabolite markers that correlate to a number of factors such as gender, disease, diet, toxicity, medication, and age. It is important to study these factors individually, if possible to unravel their unique contributions. In this study, age-related metabolic changes in children of age 12 years and below were analyzed by (1)H NMR spectroscopy of urine. The effect of age on the urinary metabolite profile was observed as a distinct age-dependent clustering even from the unsupervised principal component analysis. Further analysis, using partial least squares with orthogonal signal correction regression with respect to age, resulted in the identification of an age-related metabolic profile. Metabolites that correlated with age included creatinine, creatine, glycine, betaine/TMAO, citrate, succinate, and acetone. Although creatinine increased with age, all the other metabolites decreased. These results may be potentially useful in assessing the biological age (as opposed to chronological) of young humans as well as in providing a deeper understanding of the confounding factors in the application of metabolomics.
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Affiliation(s)
- Haiwei Gu
- Department of Physics, Purdue University, West Lafayette, IN, USA
| | - Zhengzheng Pan
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Bowei Xi
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Bryan E. Hainline
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Vincent Asiago
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | | | - Daniel Raftery
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
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Comparative chlorpyrifos pharmacokinetics via multiple routes of exposure and vehicles of administration in the adult rat. Toxicology 2009; 261:47-58. [PMID: 19397948 DOI: 10.1016/j.tox.2009.04.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/14/2009] [Accepted: 04/19/2009] [Indexed: 11/20/2022]
Abstract
Chlorpyrifos (CPF) is a commonly used organophosphorus pesticide. A number of toxicity and mechanistic studies have been conducted in animals, where CPF has been administered via a variety of different exposure routes and dosing vehicles. This study compared chlorpyrifos (CPF) pharmacokinetics using oral, intravenous (IV), and subcutaneous (SC) exposure routes and corn oil, saline/Tween 20, and dimethyl sulfoxide (DMSO) as dosing vehicles. Two groups of rats were co-administered target doses (5 mg/kg) of CPF and isotopically labeled CPF (L-CPF). One group was exposed by both oral (CPF) and IV (L-CPF) routes using saline/Tween 20 vehicle; whereas, the second group was exposed by the SC route using two vehicles, corn oil (CPF) and DMSO (L-CPF). A third group was only administered CPF by the oral route in corn oil. For all treatments, blood and urine time course samples were collected and analyzed for 3,5,6-trichloro-2-pyridinol (TCPy), and isotopically labeled 3,5,6-trichloro-2-pyridinol (L-TCPy). Peak TCPy/L-TCPy concentrations in blood (20.2 micromol/l), TCPy/L-TCPy blood AUC (94.9 micromol/lh), and percent of dose excreted in urine (100%) were all highest in rats dosed orally with CPF in saline/Tween 20 and second highest in rats dosed orally with CPF in corn oil. Peak TCPy concentrations in blood were more rapidly obtained after oral administration of CPF in saline/Tween 20 compared to all other dosing scenarios (>1.5 h). These results indicate that orally administered CPF is more extensively metabolized than systemic exposures of CPF (SC and IV), and vehicle of administration also has an effect on absorption rates. Thus, equivalent doses via different routes and/or vehicles of administration could potentially lead to different body burdens of CPF, different rates of bioactivation to CPF-oxon, and different toxic responses. Simulations using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF are consistent with these possibilities. These results suggest that exposure route and dosing vehicle can substantially impact target tissue dosimetry. This is of particular importance when comparing studies that use varying exposure paradigms, which are then used for extrapolation of risk to humans.
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Gordon CJ, Ward WO. A multianalyte profile of serum proteins to screen for toxicological effects of anticholinesterase insecticides in the rat. Neurotoxicology 2009; 30:377-81. [DOI: 10.1016/j.neuro.2009.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 02/05/2009] [Accepted: 02/11/2009] [Indexed: 10/21/2022]
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Single fiber electromyographic jitter and detection of acute changes in neuromuscular function in young and adult rats. J Pharmacol Toxicol Methods 2009; 59:108-19. [PMID: 19367692 DOI: 10.1016/j.vascn.2009.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Exposure to irreversible cholinesterase (ChE)-inhibiting compounds, such as organophosphates may produce neuromuscular dysfunction. However, less is known about changes in neuromuscular transmission after treatment with reversible ChE-inhibitors. These studies adapted single fiber electromyography (SFEMG) techniques to quantify neuromuscular jitter in adult and juvenile rats after treatment with agents that alter cholinergic neurotransmission. METHODS Anesthetized adult and juvenile rats were tested using stimulation SFEMG, recorded in the gastrocnemius muscle, after stimulation in the sciatic notch region. The influence of electrode placement, treatment with decamethonium (to disrupt neuromuscular transmission) or physostigmine (reversible ChE inhibitor), and the impact of varied stimulation frequency were quantified. RESULTS No significant effects of needle placement or criterion amplitude were observed when calculating the mean consecutive difference (MCD). Treatment with decamethonium did not alter MCD values in adult or juvenile rats. However, decamethonium produced an increased blocking of muscle action potentials (MAP) in juveniles. Also, when stimulated at 9.09 Hz, both adult and juvenile animals had a greater decrease in MAP amplitude between the first and fourth responses (T(1)-T(4) decrement) after treatment with decamethonium. Prior to treatment with decamethonium, the T(1)-T(4) decrement averaged about 3 fold greater in juveniles than adults, and was larger at 3.03 and 9.09 Hz than with 0.91 Hz stimulation. Treatment with physostigmine resulted in at least 50% inhibition of muscle ChE activity, but produced minimal changes in the MCD values in adults or juveniles. Combined over treatments and stimulation frequencies, the median MCD for juveniles (11.6 micros) was less than that for of adults (18.8 micros). In juveniles, the median MCD increased from 9.3 micros to 13.9 micros as the stimulation rate was increased from 0.91 to 9.09 Hz. This stimulus-dependent change was more evident in juveniles than in adults. DISCUSSION A technique was developed to record stimulation SFEMG and neuromuscular jitter, in vivo, in adult and juvenile rats. The method was sufficiently sensitive to detect age-related differences, potentially allowing developmental processes to be examined. Based on the literature and the current data, the technique appears to be more sensitive to prolonged inhibition of ChE enzymes than the reversible inhibition produced by physostigmine.
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Eaton DL, Daroff RB, Autrup H, Bridges J, Buffler P, Costa LG, Coyle J, McKhann G, Mobley WC, Nadel L, Neubert D, Schulte-Hermann R, Spencer PS. Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment. Crit Rev Toxicol 2008; 38 Suppl 2:1-125. [PMID: 18726789 DOI: 10.1080/10408440802272158] [Citation(s) in RCA: 422] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abdel Rasoul GM, Abou Salem ME, Mechael AA, Hendy OM, Rohlman DS, Ismail AA. Effects of occupational pesticide exposure on children applying pesticides. Neurotoxicology 2008; 29:833-8. [DOI: 10.1016/j.neuro.2008.06.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2008] [Revised: 06/25/2008] [Accepted: 06/25/2008] [Indexed: 11/30/2022]
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Samarawickrema N, Pathmeswaran A, Wickremasinghe R, Peiris-John R, Karunaratna M, Buckley N, Dawson A, de Silva J. Fetal effects of environmental exposure of pregnant women to organophosphorus compounds in a rural farming community in Sri Lanka. Clin Toxicol (Phila) 2008; 46:489-95. [PMID: 18584359 DOI: 10.1080/15563650701837030] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND The possible deleterious effects of low-grade, chronic environmental and occupational exposure to organophosphorus compounds (OPCs) are not well documented. OBJECTIVE To investigate the possible effects of low-level, chronic exposure of pregnant mothers to OPCs on the fetus by measuring OPC levels, and using markers of OPC exposure, oxidative stress and oxidative tissue damage. METHODS Toxicity was assessed by measuring (i) OPC levels in breast milk and plasma from maternal and cord blood using gas chromatography, (ii) maternal and fetal butyrylcholinesterase (BChE) activity using inhibition assays, (iii) antioxidant status of the fetus using superoxide dismutase activity assays, (iv) oxidative stress in the fetus by determining malondialdehyde (MDA) concentrations, and (v) examining for fetal DNA fragmentation using electrophoresis. Samples were obtained from consenting mothers living in a farming community in southern Sri Lanka at the end of the pesticide spray season (study group) and just before the commencement of the spray season (in-between spray season; control group). RESULTS Organophosphate residues were detected in only two subjects (chlorpyrifos in maternal and cord blood of one during the spray season and dimethoate in breast milk of another during the in between spray season), but the test employed was capable of only detecting concentrations above 0.05 mg/l. However, cord blood obtained during the spray season showed significant inhibition of BChE activity, increased oxidative stress and more DNA fragmentation when compared with cord blood obtained during the in-between spray season. CONCLUSIONS Inhibition of cord blood BChE activity indicates fetal exposure to organophosphorus compounds during times when there is a high probability of environmental drift. This provides a plausible explanation for the increased oxidative stress and high DNA fragmentation in the fetus. Long-term outcomes of such exposures are unknown.
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Slotkin TA, Ryde IT, Levin ED, Seidler FJ. Developmental neurotoxicity of low dose diazinon exposure of neonatal rats: effects on serotonin systems in adolescence and adulthood. Brain Res Bull 2008; 75:640-7. [PMID: 18355640 PMCID: PMC2322865 DOI: 10.1016/j.brainresbull.2007.10.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 10/15/2007] [Accepted: 10/17/2007] [Indexed: 11/17/2022]
Abstract
The developmental neurotoxicity of organophosphate pesticides targets serotonin (5HT) systems, which are involved in emotional and appetitive behaviors. We exposed neonatal rats to daily doses of diazinon on postnatal days 1-4, using doses (0.5 or 2mg/kg) spanning the threshold for barely-detectable cholinesterase inhibition. We then evaluated the effects on 5HT(1A) and 5HT(2) receptors, and on the 5HT transporter in cerebral cortical regions and the brainstem in adolescence through adulthood. Diazinon evoked a lasting deficit in 5HT(1A) receptors in males only, whereas it caused a small but significant increase in 5HT transporters in females; neither effect showed a significant regional selectivity. This pattern differed substantially from that seen in earlier work with another organophosphate, chlorpyrifos, which at pharmacodynamically similar doses spanning the threshold for cholinesterase inhibition, evoked a much more substantial, global upregulation of 5HT receptor expression; with chlorpyrifos, effects on receptors were seen in females, albeit to a lesser extent than in males, and were also regionally distinct. The effects of diazinon were nonmonotonic, showing larger alterations at the lower dose, likely reflecting positive trophic effects of cholinergic stimulation once the threshold for cholinesterase inhibition is exceeded. Our results reinforce the idea that different organophosphates have fundamentally distinct effects on the developmental trajectories of specific neurotransmitter systems, unrelated to their shared action as cholinesterase inhibitors. The effects on 5HT circuits expand the scope of behavioral endpoints that need to be considered in evaluating the developmental neurotoxicity of organophosphates.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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Peiris-John RJ, Wickremasinghe R. Impact of low-level exposure to organophosphates on human reproduction and survival. Trans R Soc Trop Med Hyg 2008; 102:239-45. [PMID: 18242652 DOI: 10.1016/j.trstmh.2007.11.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Revised: 11/27/2007] [Accepted: 11/27/2007] [Indexed: 01/07/2023] Open
Abstract
Despite their widespread and longstanding use for the public good, organophosphate (OP) pesticides have led to many adverse effects on human health. Environmental exposure to OPs and adverse reproductive outcomes in men and women working on or living near farms are increasingly reported worldwide. The aim of the current review is to determine whether exposure to OPs, at levels lower than that which results in clinical manifestations of acute OP poisoning, leads to an adverse impact on fertility, growth and development, and to highlight possible effects for further investigation. There is evidence of impaired fertility due to a reduction in semen quality and possibly lower testosterone levels in exposed males. There is also evidence of impairment of fetal growth and development brought about by prenatal exposure to OPs. Paraoxonase gene (PON1) activity in the fetus and during early childhood makes the fetus and child more vulnerable to OP poisoning, suggesting that OP exposure has a greater impact on fetal and infant growth and development than on adults when exposed to the same concentrations of pesticides. This review raises concerns that exposure to OP pesticides at levels currently regarded as safe adversely affect human reproductive function and survival.
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Affiliation(s)
- Roshini J Peiris-John
- Department of Physiology, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka.
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Yang D, Howard A, Bruun D, Ajua-Alemanj M, Pickart C, Lein PJ. Chlorpyrifos and chlorpyrifos-oxon inhibit axonal growth by interfering with the morphogenic activity of acetylcholinesterase. Toxicol Appl Pharmacol 2007; 228:32-41. [PMID: 18076960 DOI: 10.1016/j.taap.2007.11.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 10/26/2007] [Accepted: 11/07/2007] [Indexed: 01/08/2023]
Abstract
A primary role of acetylcholinesterase (AChE) is regulation of cholinergic neurotransmission by hydrolysis of synaptic acetylcholine. In the developing nervous system, however, AChE also functions as a morphogenic factor to promote axonal growth. This raises the question of whether organophosphorus pesticides (OPs) that are known to selectively bind to and inactivate the enzymatic function of AChE also interfere with its morphogenic function to perturb axonogenesis. To test this hypothesis, we exposed primary cultures of sensory neurons derived from embryonic rat dorsal root ganglia (DRG) to chlorpyrifos (CPF) or its oxon metabolite (CPFO). Both OPs significantly decreased axonal length at concentrations that had no effect on cell viability, protein synthesis or the enzymatic activity of AChE. Comparative analyses of the effects of CPF and CPFO on axonal growth in DRG neurons cultured from AChE nullizygous (AChE -/-) versus wild type (AChE +/+) mice indicated that while these OPs inhibited axonal growth in AChE+/+ DRG neurons, they had no effect on axonal growth in AChE -/- DRG neurons. However, transfection of AChE -/- DRG neurons with cDNA encoding full-length AChE restored the wild type response to the axon inhibitory effects of OPs. These data indicate that inhibition of axonal growth by OPs requires AChE, but the mechanism involves inhibition of the morphogenic rather than enzymatic activity of AChE. These findings suggest a novel mechanism for explaining not only the functional deficits observed in children and animals following developmental exposure to OPs, but also the increased vulnerability of the developing nervous system to OPs.
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Affiliation(s)
- Dongren Yang
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, OR 97239, USA
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40
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Marty MS, Domoradzki JY, Hansen SC, Timchalk C, Bartels MJ, Mattsson JL. The Effect of Route, Vehicle, and Divided Doses on the Pharmacokinetics of Chlorpyrifos and Its Metabolite Trichloropyridinol in Neonatal Sprague-Dawley Rats. Toxicol Sci 2007; 100:360-73. [PMID: 17928393 DOI: 10.1093/toxsci/kfm239] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mary Sue Marty
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI 48674, USA.
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41
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Guo-Ross SX, Chambers JE, Meek EC, Carr RL. Altered Muscarinic Acetylcholine Receptor Subtype Binding in Neonatal Rat Brain following Exposure to Chlorpyrifos or Methyl Parathion. Toxicol Sci 2007; 100:118-27. [PMID: 17666426 DOI: 10.1093/toxsci/kfm195] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The neurodevelopmental effects of two organophosphorus (OP) insecticides, chlorpyrifos (CPS) and methyl parathion (MPS), on cholinesterase (ChE) activity and muscarinic acetylcholine receptor (mAChR) binding were investigated in neonatal rat brain. Animals were orally gavaged using an incremental dosing regimen from postnatal day 1 (PND1) until PND8 with a low, medium, and high dosage for both CPS and MPS. On PND4 and PND8, ChE activity was measured in whole brain while the total and subtype densities of mAChRs were measured in three brain sections: area anterior to optic chiasma (anterior forebrain), area from the optic chiasma to the medulla/pons (posterior forebrain); and the medulla/pons excluding the cerebellum. The ligands 3H-pirenzepine, 3H-AF-DX 384, 3H-4-DAMP, and 3H-QNB were used to measure the maximal binding of the M1, M2/M4, and M3 subtypes and total mAChR receptors, respectively. In the anterior and the posterior forebrain, the levels of all mAChRs nearly doubled from PND4 to PND8, while in the medulla/pons, M1- and M3-subtype mAChR densities were low and did not increase and M2/M4 subtype and total mAChR slightly increased from PND4 to PND8. Reduction of ChE activity and mAChR binding by CPS or MPS was more evident in rats at PND8 than at PND4. With respect to mAChR binding, the greatest effects were observed in the medulla/pons and the least effects were observed in the posterior region of the forebrain. These results demonstrate that OPs exert adverse effects on rat central nervous system development through the cholinergic system in an age- and region-dependent manner.
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Affiliation(s)
- Shirley X Guo-Ross
- Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762, USA
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42
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Timchalk C, Kousba AA, Poet TS. An age-dependent physiologically based pharmacokinetic/pharmacodynamic model for the organophosphorus insecticide chlorpyrifos in the preweanling rat. Toxicol Sci 2007; 98:348-65. [PMID: 17504771 DOI: 10.1093/toxsci/kfm119] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Juvenile rats are more susceptible than adults to the acute toxicity of organophosphorus insecticides like chlorpyrifos (CPF). Age- and dose-dependent differences in metabolism may be responsible. Of importance are CYP450 activation and detoxification of CPF to chlorpyrifos-oxon (CPF-oxon) and trichloropyridinol (TCP), as well as B-esterase (B-est) and PON-1 (A-esterase) detoxification of CPF-oxon to TCP. In the current study, a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model incorporating age-dependent changes in CYP450, PON-1, and tissue B-est levels for rats was developed. In this model, age was used as a dependent function to estimate body weight which was then used to allometrically scale both metabolism and tissue cholinesterase (ChE) levels. In addition, age-dependent changes in brain, liver, and fat volumes and brain blood flow were obtained from the literature and used in the simulations. Model simulations suggest that preweanling rats are particularly sensitive to CPF toxicity, with levels of CPF-oxon in blood and brain disproportionately increasing, relative to the response in adult rats. This age-dependent nonlinear increase in CPF-oxon concentration may potentially result from both the depletion of nontarget B-est and a lower PON-1 metabolic capacity in younger animals. The PBPK/PD model behaves consistently with the general understanding of CPF toxicity, pharmacokinetics, and tissue ChE inhibition in neonatal and adult rats. Hence, this model represents an important starting point for developing a computational model to assess the neurotoxic potential of environmentally relevant organophosphate exposures in infants and children.
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Affiliation(s)
- Charles Timchalk
- Battelle Pacific Northwest Division, Center for Biological Monitoring and Modeling, Richland, Washington 99352, USA.
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Hasegawa R, Hirata-Koizumi M, Dourson M, Parker A, Hirose A, Nakai S, Kamata E, Ema M. Pediatric susceptibility to 18 industrial chemicals: A comparative analysis of newborn with young animals. Regul Toxicol Pharmacol 2007; 47:296-307. [PMID: 17157422 DOI: 10.1016/j.yrtph.2006.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Indexed: 11/26/2022]
Abstract
We comprehensively re-analyzed the toxicity data for 18 industrial chemicals from repeated oral exposures in newborn and young rats, which were previously published. Two new toxicity endpoints specific to this comparative analysis were identified, the first, the presumed no observed adverse effect level (pNOAEL) was estimated based on results of both main and dose-finding studies, and the second, the presumed unequivocally toxic level (pUETL) was defined as a clear toxic dose giving similar severity in both newborn and young rats. Based on the analyses of both pNOAEL and pUETL ratios between the different ages, newborn rats demonstrated greater susceptibility (at most 8-fold) to nearly two thirds of these 18 chemicals (mostly phenolic substances), and less or nearly equal sensitivity to the other chemicals. Exceptionally one chemical only showed toxicity in newborn rats. In addition, Benchmark Dose Lower Bound (BMDL) estimates were calculated as an alternative endpoint. Most BMDLs were comparable to their corresponding pNOAELs and the overall correlation coefficient was 0.904. We discussed how our results can be incorporated into chemical risk assessment approaches to protect pediatric health from direct oral exposure to chemicals.
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Affiliation(s)
- R Hasegawa
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
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Mack CM, Gordon CJ. Differential sensitivity to anticholinesterase insecticides in the juvenile rat: effects on thermoregulation. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2007; 70:439-44. [PMID: 17454568 DOI: 10.1080/15287390600755299] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Organophosphate (OP) and carbamate (CB) insecticides inhibit cholinesterase (ChE) activity and induce acute hypothermia in adult rats. Studies showed that juveniles are generally more susceptible to neurotoxic insult than adults. However, little is known concerning the effects of OP and CB pesticides on thermoregulation in developing animals. Thus, alterations in core body temperature (Tc) in juvenile animals exposed to an OP and CB insecticide were investigated. Male rat pups were anesthetized on postnatal day (PND) 15 with metofane and a radio transmitter (Data Sciences) was implanted in the abdominal cavity to monitor Tc and motor activity (MA). Two days were allowed for recovery. The PND 17 pups were then dosed by oral gavage with the OP chlorpyrifos (CHP) (1, 5, 10, or 15 mg/kg) or the CB carbaryl (CAR) (10, 20, 80, 120, or 160 mg/kg) or the corn oil vehicle. Pups were returned to their dams and littermates immediately after dosing and monitored for the next several days. CHP doses of 10 and 15 mg/kg resulted in 1.0 degrees C and 2.4 degrees C reductions in Tc, respectively. Tc recovered to control levels by approximately 16 h after dosing. There was significant mortality in rats dosed with 15 mg/kg CHP (6 of 11). CAR doses of 10 to 80 mg/kg had little effect on Tc. The highest dose of CAR (160 mg/kg) resulted in a 1.3 degrees C reduction in Tc that recovered in 9 h. In contrast, past studies found that adult male rats become hypothermic at CHP doses of >25 mg/kg, whereas a CAR dose of 50 mg/kg is effective at inducing hypothermia. Overall, it appears that during the development from preweanling to adult rat, there is a progressive attenuation in CHP-induced hypothermia. Conversely, CAR-induced hypothermia increases as a function of development.
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Affiliation(s)
- Cina M Mack
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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45
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Rauh VA, Garfinkel R, Perera FP, Andrews HF, Hoepner L, Barr DB, Whitehead R, Tang D, Whyatt RW. Impact of prenatal chlorpyrifos exposure on neurodevelopment in the first 3 years of life among inner-city children. Pediatrics 2006; 118:e1845-59. [PMID: 17116700 PMCID: PMC3390915 DOI: 10.1542/peds.2006-0338] [Citation(s) in RCA: 481] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The purpose of this study was to investigate the impact of prenatal exposure to chlorpyrifos on 3-year neurodevelopment and behavior in a sample of inner-city minority children. METHODS As part of an ongoing prospective cohort study in an inner-city minority population, neurotoxicant effects of prenatal exposure to chlorpyrifos were evaluated in 254 children through the first 3 years of life. This report examined cognitive and motor development at 12, 24, and 36 months (measured with the Bayley Scales of Infant Development II) and child behavior at 36 months (measured with the Child Behavior Checklist) as a function of chlorpyrifos levels in umbilical cord plasma. RESULTS Highly exposed children (chlorpyrifos levels of >6.17 pg/g plasma) scored, on average, 6.5 points lower on the Bayley Psychomotor Development Index and 3.3 points lower on the Bayley Mental Development Index at 3 years of age compared with those with lower levels of exposure. Children exposed to higher, compared with lower, chlorpyrifos levels were also significantly more likely to experience Psychomotor Development Index and Mental Development Index delays, attention problems, attention-deficit/hyperactivity disorder problems, and pervasive developmental disorder problems at 3 years of age. CONCLUSIONS The adjusted mean 36-month Psychomotor Development Index and Mental Development Index scores of the highly and lower exposed groups differed by only 7.1 and 3.0 points, respectively, but the proportion of delayed children in the high-exposure group, compared with the low-exposure group, was 5 times greater for the Psychomotor Development Index and 2.4 times greater for the Mental Development Index, increasing the number of children possibly needing early intervention services.
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Affiliation(s)
- Virginia A Rauh
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 60 Haven Ave, B-109, New York, NY 10032, USA.
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Kousba AA, Poet TS, Timchalk C. Age-Related Brain Cholinesterase Inhibition Kinetics following In Vitro Incubation with Chlorpyrifos-Oxon and Diazinon-Oxon. Toxicol Sci 2006; 95:147-55. [PMID: 17018647 DOI: 10.1093/toxsci/kfl123] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chlorpyrifos and diazinon are two commonly used organophosphorus insecticides (OPs), and their primary mechanism of action involves the inhibition of acetylcholinesterase by their metabolites chlorpyrifos-oxon (CPO) and diazinon-oxon (DZO), respectively. The study objectives were to assess the in vitro age-related inhibition kinetics of neonatal rat brain cholinesterase (ChE) for CPO and DZO by estimating the bimolecular inhibitory rate constant (k(i)) values. Brain ChE inhibition and k(i) values following CPO and DZO incubation with neonatal Sprague-Dawley rat brain homogenates were determined at postnatal day (PND) 5, 12, and 17 and compared with the corresponding inhibition and k(i) values obtained in the adult rat. A modified Ellman method was utilized for measuring the ChE activity. CPO caused a greater ChE inhibition than DZO as evidenced from the estimated k(i) values of both compounds. Neonatal brain ChE inhibition kinetics exhibited a marked age-related sensitivity to CPO, with the order of ChE inhibition being PND 5 > PND 7 > PND 17 with k(i) values of 0.95, 0.50, and 0.22 nM(-1)hr(-1), respectively. In contrast, DZO ChE inhibition was not age related in the neonatal brain, and the estimated k(i) value at all PND ages was 0.02 nM(-1)hr(-1). These results demonstrated an age- and OP-selective inhibition of rat brain ChE, which may be critically important in understanding the potential sensitivity of juveniles to specific OPs exposures.
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Affiliation(s)
- Ahmed A Kousba
- Department of Pharmaceutical Property Assessments, TargeGen Inc., San Diego, California 92121, USA.
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47
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Furlong CE, Holland N, Richter RJ, Bradman A, Ho A, Eskenazi B. PON1 status of farmworker mothers and children as a predictor of organophosphate sensitivity. Pharmacogenet Genomics 2006; 16:183-90. [PMID: 16495777 DOI: 10.1097/01.fpc.0000189796.21770.d3] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The objective was to determine PON1 status as a predictor for organophosphorus insecticide sensitivity in a cohort of Latina mothers and newborns from the Salinas Valley, California, an area with high levels of organophosphorus insecticide use. PON1 status was established for 130 pregnant Latina women and their newborns using a high-throughput two substrate activity/analysis method which plots rates of diazoxon (DZO) hydrolysis against rates of paraoxon (PO) hydrolysis. Arylesterase activity (AREase) was determined using phenylacetate as a substrate, allowing comparison of PON1 levels across PON1192 genotypes in mothers and children. Phenylacetate hydrolysis is not affected by the Q192R polymorphism. Among newborns, levels of PON1 (AREase) varied by 26-fold (4.3-110.7 U/ml) and among mothers by 14-fold (19.8-281.4 U/ml). On average, children's PON1 levels were four-fold lower than the mothers' PON1 levels (P<0.001). Average PON1 levels in newborns were comparable with reported hPON1 levels in transgenic mice expressing human PON1Q192 or PON1R192, allowing for prediction of relative sensitivity to chlorpyrifos oxon (CPO) and DZO. The predicted range of variability in sensitivity of mothers and children in the same Latino cohort was 65-fold for DZO and 131 to 164-fold for CPO. Overall, these findings indicate that many of the newborns and some of the mothers in this cohort would be more susceptible to the adverse effects of specific organophosphorus pesticide exposure due to their PON1 status. Of particular concern are exposures of pregnant mothers and newborns with low PON1 status.
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Affiliation(s)
- Clement E Furlong
- Department of Genome Sciences, Division of Medical Genetics, University of Washington, Seattle, Washington 98195-7720, USA.
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Kofman O, Sher T. Postnatal exposure to diisopropylfluorophosphate enhances discrimination learning in adult mice. Prog Neuropsychopharmacol Biol Psychiatry 2006; 30:914-8. [PMID: 16616984 DOI: 10.1016/j.pnpbp.2006.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Visual discrimination and reversal learning were tested in adult C57Bl/6 mice that had been treated on postnatal days (PND) 4-10 with diisopropylfluorophosphate (DFP), an acetylcholinesterase inhibitor. DFP-treated mice attained the learning criterion in the Y maze significantly earlier than saline-treated mice. Female mice treated with DFP showed a more rapid decline in errors in the initial discrimination task, compared to female mice treated with saline. There was no effect of DFP treatment on learning the reverse discrimination. The data suggest that long-lasting effects of treatment with an acetylcholinesterase inhibitor can improve discrimination learning, similarly to the improvement reported by acute administration in adults.
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Affiliation(s)
- Ora Kofman
- Department of Behavioral Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beersheva, Israel.
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Watson A, Opresko D, Young R, Hauschild V. Development and application of acute exposure guideline levels (AEGLs) for chemical warfare nerve and sulfur mustard agents. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2006; 9:173-263. [PMID: 16621779 DOI: 10.1080/15287390500194441] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Acute exposure guideline levels (AEGLs) have been developed for the chemical warfare agents GB, GA, GD, GF, VX, and sulfur mustard. These AEGLs were approved by the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances after Federal Register publication and comment, and judged as scientifically valid by the National Research Council Committee on Toxicology Subcommittee on AEGLs. AEGLs represent general public exposure limits for durations ranging from 10 min to 8 h, and for three levels of severity (AEGL-1, AEGL-2, AEGL-3). Mild effects are possible at concentrations greater than AEGL-1, while life-threatening effects are expected at concentrations greater than AEGL-3. AEGLs can be applied to various civilian and national defense purposes, including evacuation and shelter-in-place protocols, reentry levels, protective clothing specifications, and analytical monitoring requirements. This report documents development and derivation of AEGL values for six key chemical warfare agents, and makes recommendations for their application to various potential exposure scenarios.
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Affiliation(s)
- Annetta Watson
- Toxicology and Hazard Assessment Group, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830-6480, USA.
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50
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Moser VC, Simmons JE, Gennings C. Neurotoxicological interactions of a five-pesticide mixture in preweanling rats. Toxicol Sci 2006; 92:235-45. [PMID: 16611628 DOI: 10.1093/toxsci/kfj189] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The estimation of risk following exposure to mixtures is an important feature of pesticide risk assessment. Also of concern is the potential for increased sensitivity of the young to pesticide toxicity. We have conducted interaction studies using a mixture of five organophosphorus (OP) pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) in both adult (published previously) and preweanling rats using a fixed-ratio ray design. In the present study, cholinesterase inhibition and behavioral changes (motor activity, gait, and tail-pinch response) were measured in 17-day-old Long-Evans male rats following acute exposure to the OPs. The ratio of pesticides in the mixture reflected the relative dietary exposure estimates projected by the U.S. Environmental Protection Agency Dietary Exposure Evaluation Model. Dose-response data were collected for each OP alone, which were used (alone or in conjunction with the mixture data) to build an additivity model to predict the effects of the pesticide mixture along a ray of increasing total doses, using the same fixed ratio of components. The mixture data (full ray) were similarly modeled and statistically compared to the additivity model along the ray. Since malathion has been shown to produce synergistic interactions with certain OPs, it was of interest to evaluate the influence of malathion in this study. A second pesticide mixture, without malathion (reduced ray), was tested using the same dose levels of the remaining four OPs. Analysis of the full ray revealed significant greater-than-additive responses for all endpoints. The magnitude of this shift ranged from two- to threefold for estimates of the ED(20) and ED(50). The deviation from additivity was also detected in the reduced ray for all but two endpoints (motor activity and tail-pinch response); however, for all endpoints, the reduced ray was significantly different from the full ray. Thus, greater-than-additive responses were detected in preweanling rats with this OP mixture, and this effect can only partially be attributed to the malathion in the mixture.
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Affiliation(s)
- Virginia C Moser
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory/Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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