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Xuereb N, Ólafsdóttir K, Samarra F, Svavarsson J, Magnúsdóttir EE. POPs in long-finned pilot whales mass stranded in Iceland as a proxy for their physiological condition. MARINE POLLUTION BULLETIN 2023; 197:115758. [PMID: 37979533 DOI: 10.1016/j.marpolbul.2023.115758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 09/13/2023] [Accepted: 11/03/2023] [Indexed: 11/20/2023]
Abstract
Long-finned pilot whales (Globicephala melas) are the most frequently stranded cetaceans in the world; however, the predominant drivers of these events are poorly understood. In this study the levels of persistent organic pollutants from pilot whales stranded in North-east Iceland were quantified and compared to historical data and physical parameters to investigate whether contaminant load may have influenced the physiological state of stranded individuals, how these loads fluctuate with sex and age group, and if this is consistent with the literature. Historical comparison was also carried out to discern how pollutant contamination has changed throughout the past few decades. DDE, transnonachlor and PCB-153 were the top three pollutants respectively. The accumulation of POPs was greater on average in immature individuals than adults, whilst among adults, males had higher concentration than females. Moreover, despite an indication of decreasing POP loads throughout the years, knowledge of harmful thresholds remains exceedingly limited.
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Affiliation(s)
- Nicholai Xuereb
- Faculty of Life and Environmental Sciences, University of Iceland, Askja, Sturlugata 7, 102 Reykjavík, Iceland.
| | - Kristín Ólafsdóttir
- Department of Pharmacology and Toxicology, University of Iceland, Hofsvallagata 53, 107 Reykjavík, Iceland
| | - Filipa Samarra
- University of Iceland's Institute of Research Centers, Ægisgata 2, 900 Vestmannaeyjar, Iceland
| | - Jörundur Svavarsson
- Faculty of Life and Environmental Sciences, University of Iceland, Askja, Sturlugata 7, 102 Reykjavík, Iceland
| | - Edda Elísabet Magnúsdóttir
- Faculty of Life and Environmental Sciences, University of Iceland, Askja, Sturlugata 7, 102 Reykjavík, Iceland; Faculty of Subject Teacher Education, University of Iceland, Askja, Sturlugata 7, 102 Reykjavík, Iceland
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Sasaki N, Morse G, Jones L, Carpenter DO. Effects of mixtures of polychlorinated biphenyls (PCBs) and three organochlorine pesticides on cognitive function differ between older Mohawks at Akwesasne and older adults in NHANES. ENVIRONMENTAL RESEARCH 2023; 236:116861. [PMID: 37562737 DOI: 10.1016/j.envres.2023.116861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/14/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Akwesasne Mohawks has been exposed to high concentrations of polychlorinated biphenyls (PCBs) and background levels of organochlorine pesticides, hexachlorobenzene (HCB), dichlorodiphenyl dichloroethylene (DDE), and mirex. We have previously reported relative contributions to the mixture of low- and high-chlorinated PCBs, HCB, and DDE on cognitive decrements in Mohawks of various ages. OBJECTIVE This study examines differences in the mixture effects of PCB congener groups, HCB, DDE, and mirex on cognitive function in older Mohawks and less PCB-exposed older adults from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 cycles. METHODS We used Bayesian kernel machine regression (BKMR) to evaluate the mixture effects of different PCB congener groups, HCB, DDE, and mirex on cognitive function in both populations. Models were adjusted for age, sex, education levels, and race/ethnicity focusing on individuals 60 years and older. RESULTS Older Mohawks had 3-fold higher mean total PCB concentrations and 1.8-fold higher mirex, but slightly lower mean DDE and HCB levels than NHANES older adults. Higher mixture concentrations were significantly associated with greater cognitive decline. In older Mohawks, low- and high-chlorinated PCBs, HCB, and DDE contributed to the cognitive score decline. In contrast, score decline in older NHANES adults were primarily from high-chlorinated PCBs and DDE with a threshold dose of approximately 2.08-2.27 ng/g and 2.02-2.40 ng/g, respectively. CONCLUSION Mixtures of PCBs and organochlorine pesticides increase the risk of cognitive decline in both older Mohawks and NHANES older adults. However, contributions to these mixture effects show significant differences. In older Mohawks, high- and low-chlorinated PCBs, DDE, and HCB are the primary contributors, while high-chlorinated PCBs and DDE are important contributors in NHANES older adults. Due to chronic heavy exposures to PCBs, older Mohawks had a significantly increased risk of cognitive decline compared to general older adults from NHANES.
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Affiliation(s)
- Nozomi Sasaki
- Institute for Health and the Environment, University at Albany, Rensselaer, NY, 12144, USA.
| | - Gayle Morse
- Institute for Health and the Environment, University at Albany, Rensselaer, NY, 12144, USA; Department of Psychology, School of Health Sciences, Russell Sage College, Troy, NY, 12180, USA
| | - Laura Jones
- Center for Biostatistics, Bassett Research Institute, Bassett Health, Cooperstown, NY, 13326, USA; Epidemiology and Biostatistics, SUNY Albany School of Public Health, Rensselaer, NY 12144, USA
| | - David O Carpenter
- Institute for Health and the Environment, University at Albany, Rensselaer, NY, 12144, USA
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Bandara SB, Sadowski RN, Schantz SL, Gilbert ME. Developmental exposure to an environmental PCB mixture delays the propagation of electrical kindling from the amygdala. Neurotoxicology 2016; 58:42-49. [PMID: 27816614 DOI: 10.1016/j.neuro.2016.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 10/01/2016] [Accepted: 10/28/2016] [Indexed: 11/28/2022]
Abstract
Developmental PCB exposure impairs hearing and induces brainstem audiogenic seizures in adult offspring. The degree to which this enhanced susceptibility to seizure is manifest in other brain regions has not been examined. Thus, electrical kindling of the amygdala was used to evaluate the effect of developmental exposure to an environmentally relevant PCB mixture on seizure susceptibility in the rat. Female Long-Evans rats were dosed orally with 0 or 6mg/kg/day of the PCB mixture dissolved in corn oil vehicle 4 weeks prior to mating and continued through gestation and up until postnatal day (PND) 21. On PND 21, pups were weaned, and two males from each litter were randomly selected for the kindling study. As adults, the male rats were implanted bilaterally with electrodes in the basolateral amygdala. For each animal, afterdischarge (AD) thresholds in the amygdala were determined on the first day of testing followed by once daily stimulation at a standard 200μA stimulus intensity until three stage 5 generalized seizures (GS) ensued. Developmental PCB exposure did not affect the AD threshold or total cumulative AD duration, but PCB exposure did increase the latency to behavioral manifestations of seizure propagation. PCB exposed animals required significantly more stimulations to reach stage 2 seizures compared to control animals, indicating attenuated focal (amygdala) excitability. A delay in kindling progression in the amygdala stands in contrast to our previous finding of increased susceptibility to brainstem-mediated audiogenic seizures in PCB-exposed animals in response to a an intense auditory stimulus. These seemingly divergent results are not unexpected given the distinct source, type, and mechanistic underpinnings of these different seizure models. A delay in epileptogenesis following focal amygdala stimulation may reflect a decrease in neuroplasticity following developmental PCB exposure consistent with reductions in use-dependent synaptic plasticity that have been reported in the hippocampus of developmentally PCB exposed animals.
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Affiliation(s)
- Suren B Bandara
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States.
| | - Renee N Sadowski
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 60801, United States
| | - Susan L Schantz
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 60801, United States; Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States
| | - Mary E Gilbert
- U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
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Choi SY, Lee K, Park Y, Lee SH, Jo SH, Chung S, Kim KT. Non-Dioxin-Like Polychlorinated Biphenyls Inhibit G-Protein Coupled Receptor-Mediated Ca2+ Signaling by Blocking Store-Operated Ca2+ Entry. PLoS One 2016; 11:e0150921. [PMID: 26963511 PMCID: PMC4786281 DOI: 10.1371/journal.pone.0150921] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/22/2016] [Indexed: 12/12/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitous pollutants which accumulate in the food chain. Recently, several molecular mechanisms by which non-dioxin-like (NDL) PCBs mediate neurodevelopmental and neurobehavioral toxicity have been elucidated. However, although the G-protein coupled receptor (GPCR) is a significant target for neurobehavioral disturbance, our understanding of the effects of PCBs on GPCR signaling remains unclear. In this study, we investigated the effects of NDL-PCBs on GPCR-mediated Ca2+ signaling in PC12 cells. We found that ortho-substituted 2,2’,6-trichlorinated biphenyl (PCB19) caused a rapid decline in the Ca2+ signaling of bradykinin, a typical Gq- and phospholipase Cβ-coupled GPCR, without any effect on its inositol 1,4,5-trisphosphate production. PCB19 reduced thapsigargin-induced sustained cytosolic Ca2+ levels, suggesting that PCB19 inhibits SOCE. The abilities of other NDL-PCBs to inhibit store-operated Ca2+ entry (SOCE) were also examined and found to be of similar potencies to that of PCB19. PCB19 also showed a manner equivalent to that of known SOCE inhibitors. PCB19-mediated SOCE inhibition was confirmed by demonstrating the ability of PCB19 to inhibit the SOCE current and thapsigargin-induced Mn2+ influx. These results imply that one of the molecular mechanism by which NDL-PCBs cause neurobehavioral disturbances involves NDL-PCB-mediated inhibition of SOCE, thereby interfering with GPCR-mediated Ca2+ signaling.
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Affiliation(s)
- Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
- Department of Life Sciences, Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Keimin Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Yurim Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Seung-Hyun Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Su-Hyun Jo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Sungkwon Chung
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Kyong-Tai Kim
- Department of Life Sciences, Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- * E-mail:
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Zhang Q, Liu W, Niu Q, Wang Y, Zhao H, Zhang H, Song J, Tsuda S, Saito N. Effects of perfluorooctane sulfonate and its alternatives on long-term potentiation in the hippocampus CA1 region of adult rats in vivo. Toxicol Res (Camb) 2016; 5:539-546. [PMID: 30090368 DOI: 10.1039/c5tx00184f] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022] Open
Abstract
With the limited but ongoing usage of perfluorooctane sulfonate (PFOS), the health effects of both PFOS and its alternatives are far from being understood. Long-term potentiation (LTP) was evaluated in rats after exposure to PFOS and its alternatives, aiming to provide some evidence about their potential to affect cognitive ability. Different dosages of PFOS and alternative chemicals, including perfluorohexane sulfonate (PFHxS), perfluorobutane sulfonate (PFBS) and chlorinated polyfluorinated ether sulfonate (Cl-PFAES), were given to rats via acute intracerebroventricular injection. The field excitatory postsynaptic potential (fEPSP) amplitude of the input/output functions, paired-pulse facilitations, and LTP in vivo were recorded. PFOS and its alternatives inhibited LTP in varying degrees, without significant effects on the normal synaptic transmission. In addition, PFHxS and Cl-PFAES exhibited comparable potential to PFOS in disturbing LTP. The results suggested that acute exposure to PFOS and its alternatives impaired the synaptic plasticity by a postsynaptic rather than a presynaptic mechanism. Besides, the fEPSP amplitude of the baseline was reduced by Cl-PFAES but not by other compounds, indicating that Cl-PFAES might act in a different mode. Providing some electrophysiological evidence and the potential mechanism of the neurotoxicity induced by PFOS and its alternatives, the present study addresses further evaluation of their safety and health risks.
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Affiliation(s)
- Qian Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Wei Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Qiao Niu
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Yu Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Huimin Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Huifang Zhang
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Jing Song
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Shuji Tsuda
- Research Institute for Environmental Sciences and Public Health of Iwate Prefecture , Morioka , Iwate , Japan
| | - Norimitsu Saito
- Research Institute for Environmental Sciences and Public Health of Iwate Prefecture , Morioka , Iwate , Japan
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Lombardo JP, Berger DF, Hunt A, Carpenter DO. Inhalation of Polychlorinated Biphenyls (PCB) Produces Hyperactivity in Rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:1142-1153. [PMID: 26398098 DOI: 10.1080/15287394.2015.1060913] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a serious behavioral syndrome seen in children, and more common in males than females. There is increasing evidence that prenatal and/or early life exposure to persistent organic pollutants (POP) such as polychlorinated biphenyls (PCB) is associated with increased risk of ADHD occurrence. While PCB exposure is usually attributed to ingestion of contaminated food, recent reports of elevated PCB concentrations in indoor air, especially in schools, raised concern regarding inhalation as an important route of exposure to PCB with consequent effects on neurobehavior. The effects of exposure to air contaminated with Aroclor 1248 or contaminated sediment (SED) from the St. Lawrence River were examined on operant behavior of male and female Sprague-Dawley rats. Data showed that relative to controls, vapor-phase inhalation of PCB, whether from blowing air over Aroclor 1248 or from blowing air over sediment contaminated with PCB, resulted in hyperactivity and impatience in rats, more pronounced in males than females. These results are consistent with the hypothesis that inhalation of PCB may contribute to behavioral abnormalities in children.
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Affiliation(s)
- John P Lombardo
- a Department of Psychology , SUNY College at Cortland , Cortland , New York , USA
| | - David F Berger
- a Department of Psychology , SUNY College at Cortland , Cortland , New York , USA
| | | | - David O Carpenter
- c Institute for Health and the Environment, University at Albany , Rensselaer , New York , USA
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Johansen EB, Fonnum F, Lausund PL, Walaas SI, Bærland NE, Wøien G, Sagvolden T. Behavioral changes following PCB 153 exposure in the spontaneously hypertensive rat - an animal model of Attention-Deficit/Hyperactivity Disorder. Behav Brain Funct 2014; 10:1. [PMID: 24405777 PMCID: PMC3896790 DOI: 10.1186/1744-9081-10-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 12/11/2013] [Indexed: 11/17/2022] Open
Abstract
Background Attention-Deficit/Hyperactivity Disorder (ADHD) is a behavioral disorder affecting 3-5% of children. Although ADHD is highly heritable, environmental factors like exposure during early development to various toxic substances like polychlorinated biphenyls (PCBs) may contribute to the prevalence. PCBs are a group of chemical industrial compounds with adverse effects on neurobiological and cognitive functioning, and may produce behavioral impairments that share significant similarities with ADHD. The present study examined the relation between exposure to PCB 153 and changes in ADHD-like behavior in an animal model of ADHD, the spontaneously hypertensive rats (SHR/NCrl), and in Wistar Kyoto (WKY/NHsd) controls. Methods SHR/NCrl and WKY/NHsd, males and females, were orally given PCB 153 dissolved in corn oil at around postnatal day (PND) 8, 14, and 20 at a dosage of 1, 3 or 6 mg/kg bodyweight at each exposure. The control groups were orally administered corn oil only. The animals were behaviorally tested for exposure effects from PND 37 to 64 using an operant procedure. Results Exposure to PCB 153 was associated with pronounced and long-lasting behavioral changes in SHR/NCrl. Exposure effects in the SHR/NCrl depended on dose, where 1 mg/kg tended to reduce ADHD-like behaviors and produce opposite behavioral effects compared to 3 mg/kg and 6 mg/kg, especially in the females. In the WKY/NHsd controls and for the three doses tested, PCB 153 exposure produced a few specific behavioral changes only in males. The data suggest that PCB 153 exposure interacts with strain and sex, and also indicate a non-linear dose–response relation for the behaviors observed. Conclusions Exposure to PCB 153 seems to interact with several variables including strain, sex, dose, and time of testing. To the extent that the present findings can be generalized to humans, exposure effects of PCB 153 on ADHD behavior depends on amount of exposure, where high doses may aggravate ADHD symptoms in genetically vulnerable individuals. In normal controls, exposure may not constitute an environmental risk factor for developing the full range of ADHD symptoms, but can produce specific behavioral changes.
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Affiliation(s)
- Espen Borgå Johansen
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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Detection of tris-(2, 3-dibromopropyl) isocyanurate as a neuronal toxicant in environmental samples using neuronal toxicity-directed analysis. Sci China Chem 2011. [DOI: 10.1007/s11426-011-4371-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Developmental exposure to methylmercury and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) affects cerebral dopamine D1-like and D2-like receptors of weanling and pubertal rats. Arch Toxicol 2011; 85:1281-94. [DOI: 10.1007/s00204-011-0660-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/25/2011] [Indexed: 11/25/2022]
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10
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Carpenter DO. Health effects of persistent organic pollutants: the challenge for the Pacific Basin and for the world. REVIEWS ON ENVIRONMENTAL HEALTH 2011; 26:61-69. [PMID: 21714383 DOI: 10.1515/reveh.2011.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Persistent organic pollutants include some organo-metals, such as methylmercury; lipophilic halogenated organics, such as dioxins, polychlorinated biphenyls, chlorinated pesticides, and polybrominated flame retardants; and perfluorinated compounds used as repellants. These compounds are resistant to degradation both in the environment and in the human body and tend to bioaccumulate within the food chain. Persistent organic pollutants cause a variety of adverse health effects, including cancer, immune system suppression, decrements in cognitive and neurobehavioral function, disruption of sex steroid and thyroid function, and at least some of them increase the risk of chronic diseases, such as hypertension, cardiovascular disease, and diabetes. Some compounds are byproducts of industry and combustion. Although the manufacture and use of most man-made chemicals has been reduced in recent years, the levels currently present in the population are still associated with an elevated risk of human disease. Others are still manufactured and used. These are dangerous chemicals that have contaminated even areas remote from the industrialized world, such as the polar regions.
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Affiliation(s)
- David O Carpenter
- Institute for Health and the Environment, University of Albany, Rensselaer, NY 12144, USA.
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Currás-Collazo MC. Nitric oxide signaling as a common target of organohalogens and other neuroendocrine disruptors. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:495-536. [PMID: 21790323 DOI: 10.1080/10937404.2011.578564] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Organohalogen compounds such as polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) are global environmental pollutants and highly persistent, bioaccumulative chemicals that produce adverse effects in humans and wildlife. Because of the widespread use of these organohalogens in household items and consumer products, indoor contamination is a significant source of human exposure, especially for children. One significant concern with regard to health effects associated with exposure to organohalogens is endocrine disruption. Toxicological studies on organohalogen pollutants primarily focused on sex steroid and thyroid hormone actions, and findings have largely shaped the way one envisions their disruptive effects occurring. Organohalogens exert additional effects on other systems including other complex endocrine systems that may be disregulated at various levels of organization. Over the last 20 years evidence has mounted in favor of a critical role of nitric oxide (NO) in numerous functions ranging from neuroendocrine functions to learning and memory. With its participation in multiple systems and action at several levels of integration, NO signaling has a pervasive influence on nervous and endocrine functions. Like blockers of NO synthesis, PCBs and PBDEs produce multifaceted effects on physiological systems. Based on this unique set of converging information it is proposed that organohalogen actions occur, in part, by hijacking processes associated with this ubiquitous bioactive molecule. The current review examines the emerging evidence for NO involvement in selected organohalogen actions and includes recent progress from our laboratory that adds to our current understanding of the actions of organohalogens within hypothalamic neuroendocrine circuits. The thyroid, vasopressin, and reproductive systems as well as processes associated with long-term potentiation were selected as sample targets of organohalogens that rely on regulation by NO. Information is provided about other toxicants with demonstrated interference of NO signaling. Our focus on the convergence between NO system and organohalogen toxicity offers a novel approach to understanding endocrine and neuroendocrine disruption that is particularly problematic for developing organisms. This new working model is proposed as a way to encourage future study in elucidating common mechanisms of action that are selected with a better operational understanding of the systems affected.
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Affiliation(s)
- Margarita C Currás-Collazo
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California 92521, USA.
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Rhind SM, Kyle CE, Mackie C, McDonald L, Zhang Z, Duff EI, Bellingham M, Amezaga MR, Mandon-Pepin B, Loup B, Cotinot C, Evans NP, Sharpe RM, Fowler PA. Maternal and fetal tissue accumulation of selected endocrine disrupting compounds (EDCs) following exposure to sewage sludge-treated pastures before or after conception. JOURNAL OF ENVIRONMENTAL MONITORING : JEM 2010; 12:1582-93. [PMID: 20676422 PMCID: PMC3175732 DOI: 10.1039/c0em00009d] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 06/14/2010] [Indexed: 11/23/2022]
Abstract
Liver concentrations of selected pollutant classes were determined in groups of sheep fetuses and their dams, at 55 (Experiment 1) and 110 (Experiment 2) days of gestation (term = 145 d) following exposure, throughout their breeding lives and after mating, to pasture treated with either inorganic fertiliser (control, CC) or with sewage sludge (treated, TT). In a unique study designed to separate the respective contributions of environmental sources and mobilised tissue to the available EDC burden, in additional groups of animals, pollutant burdens at 110 days gestation were assessed following exposure to the respective treatments, either throughout their breeding lives until mating, but not thereafter (TC), or only between mating and slaughter (CT) (Experiment 3). With very few exceptions, maternal and fetal liver concentrations of diethylhexyl phthalate (DEHP) and selected polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDE) and polycyclic aromatic hydrocarbons (PAHs) were not significantly affected by sludge exposure in any group. In some cases, maternal and fetal tissue EDC concentrations were different but the differences were not consistent, and maternal and fetal concentrations of none of the classes of chemical were significantly correlated. It was not possible to identify a single chemical, or class of chemical, that may be responsible for previously observed physiological effects of exposure to sludge-treated pastures. It is concluded that exposure of sheep to pastures fertilised with sewage sludge was not associated with increased liver concentrations of EDCs, irrespective of the stage of development at which they were measured and of maternal tissue mobilisation and EDC release during gestation. Thus, retrospective measurements of EDC tissue burdens could not be used to accurately assess earlier fetal EDC insults.
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Affiliation(s)
- S. M. Rhind
- Macaulay Land Use Research Institute , Craigiebuckler , Aberdeen , AB15 8QH , UK . ; Fax: +44 (0) 1224 395010 ; Tel: +44 (0) 1224 395228
| | - C. E. Kyle
- Macaulay Land Use Research Institute , Craigiebuckler , Aberdeen , AB15 8QH , UK . ; Fax: +44 (0) 1224 395010 ; Tel: +44 (0) 1224 395228
| | - C. Mackie
- Macaulay Land Use Research Institute , Craigiebuckler , Aberdeen , AB15 8QH , UK . ; Fax: +44 (0) 1224 395010 ; Tel: +44 (0) 1224 395228
| | - L. McDonald
- Macaulay Land Use Research Institute , Craigiebuckler , Aberdeen , AB15 8QH , UK . ; Fax: +44 (0) 1224 395010 ; Tel: +44 (0) 1224 395228
| | - Z. Zhang
- Macaulay Land Use Research Institute , Craigiebuckler , Aberdeen , AB15 8QH , UK . ; Fax: +44 (0) 1224 395010 ; Tel: +44 (0) 1224 395228
| | - E. I. Duff
- Biomathematics and Statistics , Scotland , Craigiebuckler , Aberdeen , AB15 8QH , Scotland, UK
| | - M. Bellingham
- Division of Cell Sciences , Institute of Comparative Medicine , University of Glasgow Veterinary School , Glasgow , G61 1QH , UK
| | - M. R. Amezaga
- Department of Obstetrics and Gynaecology , Institute of Medical Sciences , CLSM , University of Aberdeen , Foresterhill , Aberdeen , AB25 2ZD , UK
| | - B. Mandon-Pepin
- INRA , UMR 1198 , Biologie du Developpement et de la Reproduction , 78350 , Jouy-en-Josas , France
| | - B. Loup
- INRA , UMR 1198 , Biologie du Developpement et de la Reproduction , 78350 , Jouy-en-Josas , France
| | - C. Cotinot
- INRA , UMR 1198 , Biologie du Developpement et de la Reproduction , 78350 , Jouy-en-Josas , France
| | - N. P. Evans
- Division of Cell Sciences , Institute of Comparative Medicine , University of Glasgow Veterinary School , Glasgow , G61 1QH , UK
| | - R. M. Sharpe
- MRC Human Reproductive Sciences Unit , Queen's Medical Research Institute , University of Edinburgh , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK
| | - P. A. Fowler
- Department of Obstetrics and Gynaecology , Institute of Medical Sciences , CLSM , University of Aberdeen , Foresterhill , Aberdeen , AB25 2ZD , UK
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Yang JM, Salmon AG, Marty MA. Development of TEFs for PCB congeners by using an alternative biomarker--thyroid hormone levels. Regul Toxicol Pharmacol 2010; 56:225-36. [PMID: 20043972 DOI: 10.1016/j.yrtph.2009.12.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 12/08/2009] [Accepted: 12/22/2009] [Indexed: 01/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitous toxic contaminants. Health risk assessment for this class of chemicals is complex: the current toxic equivalency factor (TEF) method covers dioxin-like (DL-) PCBs, dibenzofurans, and dioxins, but excludes non-DL-PCBs. To address this deficiency, we evaluated published data for several PCB congeners to determine common biomarkers of effect. We found that the most sensitive biomarkers for DL-non-ortho-PCB 77 and PCB 126 are liver enzyme (e.g., ethoxyresorufin-O-deethylase, EROD) induction, circulating thyroxine (T4) decrease, and brain dopamine (DA) elevation. For DL-ortho-PCB 118 and non-DL-ortho-PCB 28 and PCB 153, the most sensitive biomarkers are brain DA decrease and circulating T4 decrease. The only consistent biomarker for both DL- and non-DL-PCBs is circulating T4 decrease. The calculated TEF-(TH), based on the effective dose to decrease T4 by 30% (ED(30)) with reference to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is identical to both TEF-(WHO98) and TEF-(WHO05) for TCDD and DL-PCBs (correlation coefficients are r=1.00, P<0.001; and r=0.99, P<0.001, respectively). We conclude that T4 decrease is a prospective biomarker for generating a new TEF scheme which includes some non-DL-congeners. The new TEF-(TH) parallels the TEF-(WHO) for DL-PCBs and, most importantly, is useful for non-DL-PCBs in risk assessment to address thyroid endocrine disruption and potentially the neurotoxic effects of PCBs.
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Affiliation(s)
- Jian-Ming Yang
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, CA 94612, USA.
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Londoño M, Shimokawa N, Miyazaki W, Iwasaki T, Koibuchi N. Hydroxylated PCB induces Ca2+oscillations and alterations of membrane potential in cultured cortical cells. J Appl Toxicol 2009; 30:334-42. [DOI: 10.1002/jat.1501] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Montie EW, Reddy CM, Gebbink WA, Touhey KE, Hahn ME, Letcher RJ. Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2009; 157:2345-2358. [PMID: 19375836 DOI: 10.1016/j.envpol.2009.03.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 03/13/2009] [Accepted: 03/19/2009] [Indexed: 05/27/2023]
Abstract
Concentrations of several congeners and classes of organohalogen contaminants (OHCs) and/or their metabolites, namely organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), hydroxylated-PCBs (OH-PCBs), methylsulfonyl-PCBs (MeSO(2)-PCBs), polybrominated diphenyl ether (PBDE) flame retardants, and OH-PBDEs, were measured in cerebrospinal fluid (CSF) of short-beaked common dolphins (n = 2), Atlantic white-sided dolphins (n = 8), and gray seal (n = 1) from the western North Atlantic. In three Atlantic white-sided dolphins, cerebellum gray matter (GM) was also analyzed. The levels of OCs, PCBs, MeSO(2)-PCBs, PBDEs, and OH-PBDEs in cerebellum GM were higher than the concentrations in CSF. 4-OH-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) was the only detectable OH-PCB congener present in CSF. The sum (Sigma) OH-PCBs/Sigma PCB concentration ratio in CSF was approximately two to three orders of magnitude greater than the ratio in cerebellum GM for dolphins.
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Affiliation(s)
- Eric W Montie
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
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Neurobehavioural functions in adult progeny of rat mothers exposed to methylmercury or 2,2', 4,4', 5,5'-hexachlorobiphenyl (PCB 153) alone or their combination during gestation and lactation. Int J Occup Med Environ Health 2009; 22:277-91. [DOI: 10.2478/v10001-009-0020-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Todaka T, Hori T, Hirakawa H, Kajiwara J, Yasutake D, Onozuka D, Iida T, Furue M. Congener-specific analysis of non-dioxin-like polychlorinated biphenyls in blood collected from 127 elderly residents in Nakagawa Town, Fukuoka Prefecture, Japan. CHEMOSPHERE 2008; 73:865-72. [PMID: 18768207 DOI: 10.1016/j.chemosphere.2008.07.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2008] [Revised: 07/19/2008] [Accepted: 07/21/2008] [Indexed: 05/16/2023]
Abstract
We conducted congener-specific analysis of non-dioxin-like polychlorinated biphenyls (non-dioxin-like PCBs) in blood collected in February 2004 from 127 elderly residents living in Nakagawa Town, Fukuoka Prefecture, Japan. The present study is one of the few studies in which 56 non-dioxin-like PCBs congeners were measured in human blood. Of the 127 elderly residents, 51 were men (mean: 68.1 years) and 76 were women (mean: 68.1 years). Among 197 non-dioxin-like PCB congeners, 56 were identified in the blood of elderly residents. The arithmetic mean total concentrations of 56 non-dioxin-like PCBs congeners in the blood of elderly men and women in Nakagawa Town were 419 (median: 378) and 363 (median: 323)ngg(-1)lipid, respectively, and the concentrations were in the range of 172-1102 and 119-1226ngg(-1)lipid, respectively, indicating that the total concentrations in elderly men are significantly higher than those in elderly women. The contamination of non-dioxin-like PCBs in the blood of elderly men and women in Fukuoka Prefecture was found to have decreased compared to past levels. The ratios of hexachlorinated biphenyls (hexaCBs) to the total concentrations of 56 non-dioxin-like PCBs congeners in the blood of elderly men and women were 44.6% and 45.6%, respectively, which was particularly high compared with those of other congeners. 2,2',4,4',5,5'-HexaCB (#153) among hexaCBs congeners, the most abundant congener in the blood of elderly men and women, contributed approximately 23.0% and 23.5% to the total concentrations of 56 non-dioxin-like PCBs congeners, respectively. Furthermore, 2,2',3,4,4',5'-hexaCB (#138), 2,3,3',4',5,6-hexaCB (#163)/2,3,3',4',5',6-hexaCB (#164), 2,2',3,4,4',5,5'-heptaCB (#180), and 2,2',3,4,4',5,6'-heptaCB (#182)/2,2',3,4',5,5',6-heptaCB (#187) also showed high ratios to the total concentrations of 56 non-dioxin-like PCBs congeners detected in the blood of elderly men and women. A statistical examination of the relationship between the total concentrations of 56 non-dioxin-like PCBs congeners in blood and the age of elderly residents who were over 60 years indicated statistically significant correlations between the total concentrations of these PCBs congeners and the age of elderly women. However, similar correlations were not observed in elderly men. The results of the present study have indicated the current levels of non-dioxin-like PCBs in the blood of elderly men and women in Fukuoka Prefecture, Japan and can be used as baseline data for those over age 60.
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Affiliation(s)
- Takashi Todaka
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
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Coccini T, Roda E, Castoldi AF, Goldoni M, Poli D, Bernocchi G, Manzo L. Perinatal co-exposure to methylmercury and PCB153 or PCB126 in rats alters the cerebral cholinergic muscarinic receptors at weaning and puberty. Toxicology 2007; 238:34-48. [PMID: 17618726 DOI: 10.1016/j.tox.2007.05.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 05/10/2007] [Accepted: 05/14/2007] [Indexed: 10/23/2022]
Abstract
In the last few decades, combined exposure to methylmercury (MeHg) and polychlorinated biphenyls (PCBs) from fish and seafood, and their potentially interactive effects on neurodevelopment, have been giving increasing cause for concern. We examined the combined effects of MeHg and either a non-dioxin PCB (PCB153) or a dioxin-like PCB (PCB126) congener on the developing brain cholinergic muscarinic receptors (MRs). These receptors are known to play a major role in many central functions including higher cognitive processes and the modulation of extrapyramidal motor activity. MRs in pup rat brains diminished following prenatal and lactational exposure, from gestational day [GD]7 to postnatal day [PND]21, to MeHg (0.5mg/kgbodyweight[bw]/day), PCB153 (5mg/kgbw/day), and PCB126 (100ng/kg/day), alone or in combination. Total MR density, as well as M1, M2, and M3 receptor subtypes of the weanling and pubertal rats, were affected in a brain-area-, gender-, time- and compound-dependent fashion. MeHg decreased (by 15-20%) the total MR density in a delayed (PND36) manner in the cerebral cortex of both genders, and early (at weaning) in the cerebellum of both genders, with the effect lasting until puberty (in males only). MeHg decreased the ACh M1- and M3-immunopositive neurons in the cerebral cortex and also increased the M2-immunopositive Bergmann glia in the cerebellum. PCB153 also induced a delayed (PND36) decrease (of 20%) in total MR number in the cerebellum of the male offspring and in the cerebral cortex of both genders. The latter effect was coupled with a decrease in ACh M1- and ACh M3-immunopositive neuron populations. PCB126 decreased (by 30-40%) total MR density in a gender-dependent manner, males being more sensitive than females. The effect was evident early (at PND21) and lasted until puberty in the cerebellum, while it was observed later (at PND36) in the cerebral cortex. The M1 and M3 receptors were similarly affected by PCB126. Co-exposure to MeHg and either PCB153 or PCB126 had the same effect on the cerebral MRs as exposure to each compound alone. The results rule out additive or synergistic interactions between MeHg and PCB153 or PCB126 on MRs in the brain areas examined. Some early-onset changes persisted until puberty, while other modifications became manifest only at the advanced time point (PND36), when the brain levels of total Hg, PCB153, and PCB126 had declined. These data support the ability of MeHg and PCBs to induce delayed neurotoxicity after developmental exposure.
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Affiliation(s)
- Teresa Coccini
- IRCCS Salvatore Maugeri Foundation, Toxicology Division, Institute of Pavia, Italy.
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Mariussen E, Fonnum F. Neurochemical targets and behavioral effects of organohalogen compounds: an update. Crit Rev Toxicol 2006; 36:253-89. [PMID: 16686424 DOI: 10.1080/10408440500534164] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Organohalogen compounds (OHCs) have been used and still are used extensively as pesticides, flame retardants, hydraulic fluids, and in other industrial applications. These compounds are stable, most often lipophilic, and may therefore easily biomagnify. Today these compounds are found distributed both in human tissue, including breast milk, and in wildlife animals. In the late 1960s and early 1970s, high levels of the polychlorinated biphenyls (PCBs) and the pesticide dichlorodiphenyl trichloroethane (DDT) were detected in the environment. In the 1970s it was discovered that PCBs and some chlorinated pesticides, such as lindane, have neurotoxic potentials after both acute and chronic exposure. Although the use of PCBs, DDT, and other halogenated pesticides has been reduced, and environmental levels of these compounds are slowly diminishing, other halogenated compounds with potential of toxic effects are being found in the environment. These include the brominated flame retardants, chlorinated paraffins (PCAs), and perfluorinated compounds, whose levels are increasing. It is now established that several OHCs have neurobehavioral effects, indicating adverse effects on the central nervous system (CNS). For instance, several reports have shown that OHCs alter neurotransmitter functions in CNS and Ca2+ homeostatic processes, induce protein kinase C (PKC) and phospholipase A2 (PLA2) mobilization, and induce oxidative stress. In this review we summarize the findings of the neurobehavioral and neurochemical effects of some of the major OHCs with our main focus on the PCBs. Further, we try to elucidate, on the basis of available literature, the possible implications of these findings on human health.
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Affiliation(s)
- E Mariussen
- Norwegian Institute for Air Research, Kjeller, Norway.
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20
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Castoldi AF, Blandini F, Randine G, Samuele A, Manzo L, Coccini T. Brain monoaminergic neurotransmission parameters in weanling rats after perinatal exposure to methylmercury and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153). Brain Res 2006; 1112:91-8. [PMID: 16904659 DOI: 10.1016/j.brainres.2006.07.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/30/2006] [Accepted: 07/08/2006] [Indexed: 11/15/2022]
Abstract
The individual and joint effects of methylmercury (MeHg; 1 mg/kg body weight/day, GD7-PND7) and PCB153 (20 mg/kg body weight/day, GD10-GD16), administered orally to rat dams, were explored in 21-day-old rat offspring brain in terms of monoamine oxidase B (MAO-B) activity and regional content of dopamine (DA), serotonin (5-HT), 5-hydroxy-indole-3-acetic acid (5-HIAA) and homovanillic acid (HVA). Neither treatment altered MAO-B in striatum, hippocampus, cerebellum and cerebral cortex of female pups. In males the cerebellum displayed a significantly reduced enzyme activity (25-45%) following all treatments. Concerning biogenic amines, 5-HT levels were decreased by 30-50% in the cerebral cortex of males and females by PCB153 alone and combined with MeHg, without changes in 5-HIAA and dopaminergic endpoints. In cerebellum of all pups, MeHg enhanced 5-HIAA levels, whereas PCB153, either alone or combined with MeHg, did not affect this endpoint. In striatum, PCB153 reduced the content of DA, HVA and 5-HIAA (respective control values: 2-3; 60-80; 8-10 ng/mg protein) to a similar extent when administered alone or together with MeHg (20-40%). Perinatal exposure to MeHg and/or PCB153 results in regionally and/or gender-specific alterations in the central dopaminergic and serotonergic systems at weaning. The combined treatment with MeHg and PCB153 does not exacerbate the neurochemical effects of the individual compounds.
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Affiliation(s)
- Anna F Castoldi
- IRCCS Maugeri Foundation, Toxicology Division, Research Centre, Via Palestro 26, 27100 Pavia, Italy.
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21
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Hussain RJ, Carpenter DO. A comparison of the roles of protein kinase C in long-term potentiation in rat hippocampal areas CA1 and CA3. Cell Mol Neurobiol 2005; 25:649-61. [PMID: 16075383 DOI: 10.1007/s10571-005-4045-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Accepted: 12/10/2003] [Indexed: 10/25/2022]
Abstract
1. Using agonists and antagonists with specificity toward various isozymes, we have examined the role of protein kinase C (PKC) in long-term potentiation (LTP) in rat hippocampal areas CA1 and CA3. 2. Agonists (indolactum V but not phorbol ester) and antagonists (sphingosine, staurosporine, chelerytherene) acting at all PKC isozymes reduce or block LTP induction at both sites. 3. However ingenol, a relatively specific agonist at the delta and epsilon isozymes, blocks LTP in the MF-CA3 pathway, but not in the SC-CA1 pathway. 4. Go6976, a relatively specific antagonist of the alpha and beta isozymes, blocks LTP in the SC-CA1 pathway at both ages tested (30- and 60-day-old animals), but blocks LTP in the MF-CA3 in 60 but not 30-day-old animals. 5. Our studies indicate that different PKC isozymes are crucial to LTP induction in these two areas of hippocampus, and that there are development changes in the profile of isozymes.
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Affiliation(s)
- Rifat J Hussain
- Department of Environmental Health & Toxicology, School of Public Health, University at Albany, One University Place A217, Rensselaer, New York 12144-3456, USA
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22
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Ozcan M, Yilmaz B, King WM, Carpenter DO. Hippocampal long-term potentiation (LTP) is reduced by a coplanar PCB congener. Neurotoxicology 2005; 25:981-8. [PMID: 15474616 DOI: 10.1016/j.neuro.2004.03.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2003] [Accepted: 03/31/2004] [Indexed: 11/18/2022]
Abstract
Neurotoxicity of polychlorinated biphenyls (PCBs) is usually ascribed to the ortho-substituted congeners. We have examined the effects of acute perfusion of 3,3',4,4'-tetrachlorobiphenyl (PCB 77), a coplanar, dioxin-like congener, on long-term potentiation (LTP) in the Schaffer collateral-CA1 and the mossy fiber-CA3 pathways in mouse hippocampus. LTP in both pathways was blocked by PCB 77, with a threshold effect at a concentration of 1 microM. LTP is a useful model of learning and memory function in which a patterned stimulation of an afferent pathway produces a persistent increase in the efficacy of synaptic transmission. LTP is reduced by PCB mixtures and ortho-substituted congeners at concentrations comparable to those studied here. These observations provide evidence in support of the hypothesis that dioxin-like and non-dioxin-like PCB congeners are equally potent in causing the cognitive decrements seen in children exposed prenatally to PCBs.
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Affiliation(s)
- Mete Ozcan
- School of Public Health, University at Albany, One University Place, Rensselaer, NY 12144-3456, USA
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23
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Gilbert ME. Perinatal exposure to polychlorinated biphenyls alters excitatory synaptic transmission and short-term plasticity in the hippocampus of the adult rat. Neurotoxicology 2004; 24:851-60. [PMID: 14637380 DOI: 10.1016/s0161-813x(03)00073-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Developmental exposure to polychlorinated biphenyls (PCBs) has been associated with cognitive deficits in humans and laboratory animals. Previous work has demonstrated a reduced capacity to support long-term potentiation (LTP) in animals exposed to a PCB mixture, Aroclor 1254 (A1254) via the dam in utero and throughout the preweaning period [Brain Res. 850;1999:87-95; Toxicol. Sci. 57;2000:102-11]. Assessment of normalized input/output (I/O) functions collected prior to LTP induction failed to reveal consistent differences in baseline synaptic transmission between control and PCB-exposed groups. The present study was designed to systematically evaluate excitatory and inhibitory synaptic transmission using a more extensive I/O analysis and paired pulse functions to assess short-term plasticity. Pregnant Long-Evans rats were administered either corn oil (control) or 6 mg/kg per day of A1254 by gavage from gestational day (GD) 6 until pups were weaned on postnatal day (PND) 21. In adult male offspring (5-11 months of age), field potentials evoked by perforant path stimulation were recorded in the dentate gyrus under urethane anesthesia. Detailed I/O functions were assessed by averaging the responses evoked in the dentate gyrus to stimulus pulses delivered to the perforant path in an extensive ascending intensity series. Population spike (PS) and postsynaptic potential (PSP) amplitudes recorded in the dentate gyrus were significantly enhanced in PCB-exposed animals relative to controls at midrange intensities. No group differences were observed in EPSP slope amplitudes. Short-term plasticity was assessed by delivering pairs of stimulus pulses at interpulse intervals (IPIs) ranging from 10 to 70 ms. In the dentate gyrus this range of intervals activates both inhibitory and excitatory mechanisms leading to a pattern of depression at brief intervals (<30 ms) followed by facilitation as the interval between pulses is extended. Paired pulse depression was decreased at an intermediate IPI (30 ms) with submaximal stimulus intensities. These data augment previous work demonstrating persistent changes in hippocampal plasticity as a result of exposure to PCBs during development. Furthermore, as increases in field potential amplitudes were observed, these findings support previous conclusions that A1254-induced LTP deficits are not readily attributable to reductions in synaptic excitability. Thus, in addition to impairment in use-dependent synaptic plasticity reported previously, the present report reveals that basic components of information processing within the hippocampus are permanently altered as a result of perinatal exposure to PCBs.
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Affiliation(s)
- M E Gilbert
- Neurotoxicology Division (B105-05), National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Gilbert ME, Lasley SM. Long-term consequences of developmental exposure to lead or polychlorinated biphenyls: Synaptic transmission and plasticity in the rodent CNS. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2002; 12:105-117. [PMID: 21782630 DOI: 10.1016/s1382-6689(02)00029-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Exposure to lead (Pb) or polychlorinated biphenyls (PCBs) during early development has been associated with deficits in cognitive function in children (Pediatrics 87 (1991) 219; N. Engl. J. Med. 335 (1996) 783). These effects persist in the child long after exposure has ceased and body burdens have diminished. Despite intensive research, no consensus on the mechanisms of neurotoxicity of these chemicals has resulted. As the primary neurotoxic action of these agents is to impair cognitive ability, a number of laboratories have examined and reported on the detrimental the effects of Pb or PCBs on hippocampal synaptic transmission and long-term potentiation (LTP) in animals exposed during the perinatal period. Use-dependent synaptic plasticity, of which hippocampal LTP is the primary model system, is a fundamental property of neuronal function. In forebrain structures such as amygdala and hippocampus, LTP and related processes are purported to represent a physiological substrate for memory. During brain ontogeny, this type of plasticity guides the establishment and maintenance of synaptic connections in cortical structures based on sensory input. We postulate that the actions of PCBs and Pb in the developing nervous system perturb activity-dependent plasticity and promote organizational changes in brain. Aberrant connectivity derived from perturbations in activity-dependent plasticity during development may manifest as impaired LTP and cognitive ability in the adult organism.
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Affiliation(s)
- M E Gilbert
- Neurotoxicology Division (MD 74B), National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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25
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Carpenter DO, Hussain RJ, Berger DF, Lombardo JP, Park HY. Electrophysiologic and behavioral effects of perinatal and acute exposure of rats to lead and polychlorinated biphenyls. ENVIRONMENTAL HEALTH PERSPECTIVES 2002; 110 Suppl 3:377-86. [PMID: 12060832 PMCID: PMC1241186 DOI: 10.1289/ehp.02110s3377] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Lead and polychlorinated biphenyls (PCBs) both cause a reduction of intelligence quotient and behavioral abnormalities in exposed children that have features in common with attention deficit hyperactivity disorder. We have used rats as a model to study the effects of both perinatal and acute exposure to lead or PCBs in an effort to compare and understand the mechanisms of these nervous system decrements. Long-term potentiation (LTP) is an electrophysiologic measurement that correlates well with cognitive ability. We have determined the effects of chronic perinatal exposure to lead or PCB 153 as well as acute application of these substances to isolated brain slices, with recordings in two areas of the hippocampus, CA1 and CA3. Both substances, whether chronically or acutely applied, significantly reduced LTP in CA1 in animals at age 30 and 60 days. In CA3, they reduced LTP in 30-day animals but potentiated it in 60-day animals. Although neither lead nor PCB 153 alters baseline synaptic transmission at low stimulus strengths, at higher levels they induce changes in the same direction as those of LTP. These results show surprisingly similar actions of these quite different chemicals, and the similarity of effects on chronic and acute application indicates that effects are both pharmacologic and developmental. Behavioral studies of rats exposed to PCBs from contaminated fish show hyperactivity, impulsiveness, and increased frustration relative to unexposed controls. These results demonstrate that lead and PCBs have similar effects on synaptic plasticity and behavior and suggest that the compounds may act through a common mechanism.
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Affiliation(s)
- David O Carpenter
- School of Public Health, University at Albany, One University Place B242, Rensselaer, NY 12144-3456, USA.
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26
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Carpenter DO, Arcaro K, Spink DC. Understanding the human health effects of chemical mixtures. ENVIRONMENTAL HEALTH PERSPECTIVES 2002; 110 Suppl 1:25-42. [PMID: 11834461 PMCID: PMC1241145 DOI: 10.1289/ehp.02110s125] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Most research on the effects of chemicals on biologic systems is conducted on one chemical at a time. However, in the real world people are exposed to mixtures, not single chemicals. Although various substances may have totally independent actions, in many cases two substances may act at the same site in ways that can be either additive or nonadditive. Many even more complex interactions may occur if two chemicals act at different but related targets. In the extreme case there may be synergistic effects, in which case the effects of two substances together are greater than the sum of either effect alone. In reality, most persons are exposed to many chemicals, not just one or two, and therefore the effects of a chemical mixture are extremely complex and may differ for each mixture depending on the chemical composition. This complexity is a major reason why mixtures have not been well studied. In this review we attempt to illustrate some of the principles and approaches that can be used to study effects of mixtures. By the nature of the state of the science, this discussion is more a presentation of what we do not know than of what we do know about mixtures. We approach the study of mixtures at three levels, using specific examples. First, we discuss several human diseases in relation to a variety of environmental agents believed to influence the development and progression of the disease. We present results of selected cellular and animal studies in which simple mixtures have been investigated. Finally, we discuss some of the effects of mixtures at a molecular level.
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Affiliation(s)
- David O Carpenter
- School of Public Health, Department of Environmental Health and Toxiciology, University at Albany, State University of New York, Rensselaer 12144, USA.
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Costa LG, Guizzetti M, Lu H, Bordi F, Vitalone A, Tita B, Palmery M, Valeri P, Silvestrini B. Intracellular signal transduction pathways as targets for neurotoxicants. Toxicology 2001; 160:19-26. [PMID: 11246120 DOI: 10.1016/s0300-483x(00)00435-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The multiple cascades of signal transduction pathways that lead from receptors on the cell membrane to the nucleus, thus translating extracellular signals into changes in gene expression, may represent important targets for neurotoxic compounds. Among the biochemical steps and pathways that have been investigated are the metabolism of cyclic nucleotides, the formation of nitric oxide, the metabolism of membrane phospholipids, the activation of a multitude of protein kinases and the induction of transcription factors. This brief review will focus on the interactions of three known neurotoxicants, lead, ethanol and polychlorinated biphenyls, with signal transduction pathways, particularly the family of protein kinase C isozymes, and discusses how such effects may be involved in their neurotoxicity.
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Affiliation(s)
- L G Costa
- Department of Environmental Health, University of Washington, 4225 Roosevelt #100, Seattle, WA 98105, USA.
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