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Burzynski HE, Ayala KE, Frick MA, Dufala HA, Woodruff JL, Macht VA, Eberl BR, Hollis F, McQuail JA, Grillo CA, Fadel JR, Reagan LP. Delayed cognitive impairments in a rat model of Gulf War Illness are stimulus-dependent. Brain Behav Immun 2023; 113:248-258. [PMID: 37437820 PMCID: PMC10530066 DOI: 10.1016/j.bbi.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/07/2023] [Accepted: 07/05/2023] [Indexed: 07/14/2023] Open
Abstract
Gulf War Illness (GWI) collectively describes the multitude of central and peripheral disturbances affecting soldiers who served in the 1990-1991 Gulf War. While the mechanisms responsible for GWI remain elusive, the prophylactic use of the reversible acetylcholinesterase inhibitor, pyridostigmine bromide (PB), and war-related stress have been identified as chief factors in GWI pathology. Post-deployment stress is a common challenge faced by veterans, and aberrant cholinergic and/or immune responses to these psychological stressors may play an important role in GWI pathology, especially the cognitive impairments experienced by many GWI patients. Therefore, the current study investigated if an immobilization stress challenge would produce abnormal responses in PB-treated rats three months later. Results indicate that hippocampal cholinergic responses to an immobilization stress challenge are impaired three months after PB administration. We also assessed if an immune or stress challenge reveals deficits in PB-treated animals during hippocampal-dependent learning and memory tasks at this delayed timepoint. Novel object recognition (NOR) testing paired with either acute saline or lipopolysaccharide (LPS, 30 µg/kg, i.p.), as well as Morris water maze (MWM) testing was conducted approximately three months after PB administration and/or repeated restraint stress. Rats with a history of PB treatment exhibited 24-hour hippocampal-dependent memory deficits when challenged with LPS, but not saline, in the NOR task. Similarly, in the same cohort, PB-treated rats showed 24-hour memory deficits in the MWM task. Ultimately, these studies highlight the long-term effects of PB treatment on hippocampal function and provide insight into the progressive cognitive deficits observed in veterans with GWI.
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Affiliation(s)
- H E Burzynski
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States.
| | - K E Ayala
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - M A Frick
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - H A Dufala
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - J L Woodruff
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - V A Macht
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - B R Eberl
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - F Hollis
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC 29208, United States
| | - J A McQuail
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC 29208, United States
| | - C A Grillo
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC 29208, United States
| | - J R Fadel
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC 29208, United States
| | - L P Reagan
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC 29208, United States
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Kodali M, Jankay T, Shetty AK, Reddy DS. Pathophysiological basis and promise of experimental therapies for Gulf War Illness, a chronic neuropsychiatric syndrome in veterans. Psychopharmacology (Berl) 2023; 240:673-697. [PMID: 36790443 DOI: 10.1007/s00213-023-06319-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/17/2023] [Indexed: 02/16/2023]
Abstract
This article describes the pathophysiology and potential treatments for Gulf War Illness (GWI), which is a chronic neuropsychiatric illness linked to a combination of chemical exposures experienced by service personnel during the first Gulf War in 1991. However, there is currently no effective treatment for veterans with GWI. The article focuses on the current status and efficacy of existing therapeutic interventions in preclinical models of GWI, as well as potential perspectives of promising therapies. GWI stems from changes in brain and peripheral systems in veterans, leading to neurocognitive deficits, as well as physiological and psychological effects resulting from multifaceted changes such as neuroinflammation, oxidative stress, and neuronal damage. Aging not only renders veterans more susceptible to GWI symptoms, but also attenuates their immune capabilities and response to therapies. A variety of experimental models are being used to investigate the pathophysiology and develop therapies that have the ability to alleviate devastating symptoms. Over two dozen therapeutic interventions targeting neuroinflammation, mitochondrial dysfunction, neuronal injury, and neurogenesis are being tested, including agents such as curcumin, curcumin nanoparticles, monosodium luminol, melatonin, resveratrol, fluoxetine, rolipram, oleoylethanolamide, ketamine, levetiracetam, nicotinamide riboside, minocycline, pyridazine derivatives, and neurosteroids. Preclinical outcomes show that some agents have promise, including curcumin, resveratrol, and ketamine, which are being tested in clinical trials in GWI veterans. Neuroprotectants and other compounds such as monosodium luminol, melatonin, levetiracetam, oleoylethanolamide, and nicotinamide riboside appear promising for future clinical trials. Neurosteroids have been shown to have neuroprotective and disease-modifying properties, which makes them a promising medicine for GWI. Therefore, accelerated clinical studies are urgently needed to evaluate and launch an effective therapy for veterans displaying GWI.
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Affiliation(s)
- Maheedhar Kodali
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University School of Medicine, College Station, TX, USA
| | - Tanvi Jankay
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University School of Medicine, College Station, TX, USA.,Texas A&M Health Institute of Pharmacology and Neurotherapeutics, Texas A&M University Health Science Center, 8447 Riverside Pkwy, Bryan, TX, 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, TX, USA. .,Texas A&M Health Institute of Pharmacology and Neurotherapeutics, Texas A&M University Health Science Center, 8447 Riverside Pkwy, Bryan, TX, 77807, USA.
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Abstract
Gulf War Illness (GWI) is a chronic multisymptomatic disorder that afflicts over 1/3rd of the 1991 GW veterans. It spans multiple bodily systems and presents itself as a syndrome exhibiting diverse symptoms including fatigue, depression, mood, and memory and concentration deficits, musculoskeletal pain and gastrointestinal distress in GW veterans. The etiology of GWI is complex and many factors, including chemical, physiological, and environmental stressors present in the GW arena, have been implicated for its development. It has been over 30 years since the end of the GW but, GWI has been persistent in suffering veterans who are also dealing with paucity of effective treatments. The multifactorial aspect of GWI along with genetic heterogeneity and lack of available data surrounding war-time exposures have proved to be challenging in developing pre-clinical models of GWI. Despite this, over a dozen GWI animal models exist in the literature. In this article, following a brief discussion of GW history, GWI definitions, and probable causes for its pathogenesis, we will expand upon various experimental models used in GWI laboratory research. These animal models will be discussed in the context of their attempts at mimicking GW-related exposures with regards to the variations in chemical combinations, doses, and frequency of exposures. We will discuss their advantages and limitations in modeling GWI followed by a discussion of behavioral and molecular findings in these models. The mechanistic data obtained from these preclinical studies have offered multiple molecular pathways including chronic inflammation, mitochondrial dysfunction, oxidative stress, lipid disturbances, calcium homeostatic alterations, changes in gut microbiota, and epigenetic modifications, amongst others for explaining GWI development and its persistence. Finally, these findings have also informed us on novel druggable targets in GWI. While, it has been difficult to conceive a single pre-clinical model that could express all the GWI signs and exhibit biological complexity reflective of the clinical presentation in GWI, animal models have been critical for identifying molecular underpinnings of GWI and evaluating treatment strategies for GWI.
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Affiliation(s)
- Ana C R Ribeiro
- Departments of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Laxmikant S Deshpande
- Departments of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA; Departments of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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Bricher Choque PN, Vieira RP, Ulloa L, Grabulosa C, Irigoyen MC, De Angelis K, Ligeiro De Oliveira AP, Tracey KJ, Pavlov VA, Consolim-Colombo FM. The Cholinergic Drug Pyridostigmine Alleviates Inflammation During LPS-Induced Acute Respiratory Distress Syndrome. Front Pharmacol 2021; 12:624895. [PMID: 34017249 PMCID: PMC8129580 DOI: 10.3389/fphar.2021.624895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/13/2021] [Indexed: 01/12/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a critical illness complication that is associated with high mortality. ARDS is documented in severe cases of COVID-19. No effective pharmacological treatments for ARDS are currently available. Dysfunctional immune responses and pulmonary and systemic inflammation are characteristic features of ARDS pathogenesis. Recent advances in our understanding of the regulation of inflammation point to an important role of the vagus-nerve-mediated inflammatory reflex and neural cholinergic signaling. We examined whether pharmacological cholinergic activation using a clinically approved (for myasthenia gravis) cholinergic drug, the acetylcholinesterase inhibitor pyridostigmine alters pulmonary and systemic inflammation in mice with lipopolysaccharide (LPS)-induced ARDS. Male C57Bl/6 mice received one intratracheal instillation of LPS or were sham manipulated (control). Both groups were treated with either vehicle or pyridostigmine (1.5 mg/kg twice daily, 3 mg/day) administered by oral gavage starting at 1 h post-LPS and euthanized 24 h after LPS administration. Other groups were either sham manipulated or received LPS for 3 days and were treated with vehicle or pyridostigmine and euthanized at 72 h. Pyridostigmine treatment reduced the increased total number of cells and neutrophils in the bronchoalveolar lavage fluid (BALF) in mice with ARDS at 24 and 72 h. Pyridostigmine also reduced the number of macrophages and lymphocytes at 72 h. In addition, pyridostigmine suppressed the levels of TNF, IL-1β, IL-6, and IFN-γ in BALF and plasma at 24 and 72 h. However, this cholinergic agent did not significantly altered BALF and plasma levels of the anti-inflammatory cytokine IL-10. Neither LPS nor pyridostigmine affected BALF IFN-γ and IL-10 levels at 24 h post-LPS. In conclusion, treatments with the cholinergic agent pyridostigmine ameliorate pulmonary and systemic inflammatory responses in mice with endotoxin-induced ARDS. Considering that pyridostigmine is a clinically approved drug, these findings are of substantial interest for implementing pyridostigmine in therapeutic strategies for ARDS.
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Affiliation(s)
- Pamela Nithzi Bricher Choque
- Laboratory of Pulmonary Immunology, Postgraduate Program in Medicine, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
| | - Rodolfo P. Vieira
- Post-graduation Program in Bioengineering and in Biomedical Engineering, Universidade Brasil, São Paulo, Brazil
- Brazilian Institute of Teaching and Research in Pulmonary and Exercise Immunology (IBEPIPE), São Paulo, Brazil
- Federal University of São Paulo (UNIFESP), Post-graduation Program in Sciences of Human Movement and Rehabilitation, São Paulo, Brazil
- Departament of Physiology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Luis Ulloa
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Caren Grabulosa
- Laboratory of Pulmonary Immunology, Postgraduate Program in Medicine, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
| | - Maria Claudia Irigoyen
- Hypertension Unit, Heart Institute (INCOR), Medical School of University of São Paulo, São Paulo, Brazil
| | - Katia De Angelis
- Departament of Physiology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Ana Paula Ligeiro De Oliveira
- Laboratory of Pulmonary Immunology, Postgraduate Program in Medicine, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
| | - Kevin J. Tracey
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, United States
| | - Valentin A. Pavlov
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, United States
| | - Fernanda Marciano Consolim-Colombo
- Laboratory of Pulmonary Immunology, Postgraduate Program in Medicine, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
- Hypertension Unit, Heart Institute (INCOR), Medical School of University of São Paulo, São Paulo, Brazil
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Gargas NM, Ethridge VT, Miklasevich MK, Rohan JG. Altered hippocampal function and cytokine levels in a rat model of Gulf War illness. Life Sci 2021; 274:119333. [PMID: 33705732 DOI: 10.1016/j.lfs.2021.119333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 01/09/2023]
Abstract
AIMS Gulf War illness (GWI) is a disorder affecting military personnel deployed in the Gulf War (GW) from 1990 to 1991. Here, we will use a rat model of GWI to evaluate hippocampal function and cytokine levels. MATERIALS AND METHODS Rats were exposed to diethyltoluamide and permethrin via dermal absorption and pyridostigmine bromide via gavage with or without a 5-min restraint for 28 days. Immediate and delayed effects of GW chemical exposure were evaluated using electrophysiology to quantitate hippocampal function, behavioral tests to assess cognitive effects and biochemical assays to measure neurotransmitter and cytokine levels. KEY FINDINGS Behavioral data revealed a statistically significant increase in motor activity at 3 months following completion of exposures, potentially indicating increased excitability, and/or restlessness. Electrophysiology data revealed statistically significant changes in paired pulse facilitation and input-output function of CA1 hippocampal neurons within 24 h and 3 months following completion of exposures. There was also a statistically significant reduction in the frequency of spontaneous firing activity of hippocampal neurons within 24 h following exposures. Naïve hippocampal slices directly incubated in GW chemicals also resulted in similar changes in electrophysiological parameters. Biochemical measurements revealed reduced hippocampal glutamate level at 3 months post-exposure. Furthermore, there was a statistically significant increase in plasma and hippocampal levels of IL-13, as well as decrease in plasma level of IL-1β. SIGNIFICANCE Our data support an effect on glutamate signaling within the hippocampus as indicated by changes in PPF and hippocampal level of glutamate, with some activation of T helper type 2 immune response.
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Affiliation(s)
- Nathan M Gargas
- Naval Medical Research Unit Dayton, 2728 Q Street, Area B, Building 837, WPAFB, OH 45433, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817, USA; Odyssey Systems Consulting Group, Ltd, 201 Edgewater Drive Suite 270, Wakefield, MA 01880, USA
| | - Victoria T Ethridge
- Naval Medical Research Unit Dayton, 2728 Q Street, Area B, Building 837, WPAFB, OH 45433, USA; Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd, Oak Ridge, TN 37830, USA
| | - Molly K Miklasevich
- Naval Medical Research Unit Dayton, 2728 Q Street, Area B, Building 837, WPAFB, OH 45433, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817, USA
| | - Joyce G Rohan
- Naval Medical Research Unit Dayton, 2728 Q Street, Area B, Building 837, WPAFB, OH 45433, USA.
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Giacomini AC, Bueno BW, Marcon L, Scolari N, Genario R, Demin KA, Kolesnikova TO, Kalueff AV, de Abreu MS. An acetylcholinesterase inhibitor, donepezil, increases anxiety and cortisol levels in adult zebrafish. J Psychopharmacol 2020; 34:1449-1456. [PMID: 32854587 DOI: 10.1177/0269881120944155] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A potent acetylcholinesterase inhibitor, donepezil is a cognitive enhancer clinically used to treat neurodegenerative diseases. However, its complete pharmacological profile beyond cognition remains unclear. The zebrafish (Danio rerio) is rapidly becoming a powerful novel model organism in neuroscience and central nervous system drug screening. AIM Here, we characterize the effects of 24-h donepezil administration on anxiety-like behavioral and endocrine responses in adult zebrafish. METHODS We evaluated zebrafish anxiety-like behaviors in the novel tank, the light-dark and the shoaling tests, paralleled by assessing brain acetylcholinesterase activity and whole-body cortisol levels. RESULTS Overall, donepezil dose-dependently decreased zebrafish locomotor activity in the novel tank test and reduced time in light in the light-dark test, likely representing hypolocomotion and anxiety-like behaviors. Donepezil predictably decreased brain acetylcholinesterase activity, also increasing whole-body cortisol levels, thus further linking acetylcholinesterase inhibition to anxiety-like behavioral and endocrine responses. CONCLUSION Collectively, these findings suggest negative modulation of zebrafish affective behavior by donepezil, support the key role of cholinergic mechanisms in behavioral regulation in zebrafish, and reinforce the growing utility of zebrafish models for studying complex behavioral processess and their neuroendocrine and neurochemical regulation.
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Affiliation(s)
- Ana Cvv Giacomini
- Postgraduate Program in Environmental Sciences, University of Passo Fundo, Passo Fundo, Brazil.,Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil
| | - Barbara W Bueno
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil
| | - Leticia Marcon
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil
| | - Naiara Scolari
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil
| | - Rafael Genario
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil
| | - Konstantin A Demin
- Institute of Experimental Medicine, Almazov Medical Research Centre, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia.,Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Tatyana O Kolesnikova
- Granov Scientific Research Center for Radiology and Surgical Technologies, St Petersburg, Russia
| | - Allan V Kalueff
- School of Pharmacy, Southwest University, Chongqing, China.,Ural Federal University, Ekaterinburg, Russia
| | - Murilo S de Abreu
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil.,The International Zebrafish Neuroscience Research Consortium, Slidell, USA
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Keledjian K, Tsymbalyuk O, Semick S, Moyer M, Negoita S, Kim K, Ivanova S, Gerzanich V, Simard JM. The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone, ameliorates neurofunctional and neuroinflammatory abnormalities in a rat model of Gulf War Illness. PLoS One 2020; 15:e0242427. [PMID: 33186383 DOI: 10.1371/journal.pone.0242427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
Background Gulf War (GW) Illness (GWI) is a debilitating condition with a complex constellation of immune, endocrine and neurological symptoms, including cognitive impairment, anxiety and depression. We studied a novel model of GWI based on 3 known common GW exposures (GWE): (i) intranasal lipopolysaccharide, to which personnel were exposed during desert sand storms; (ii) pyridostigmine bromide, used as prophylaxis against chemical warfare; and (iii) chronic unpredictable stress, an inescapable element of war. We used this model to evaluate prophylactic treatment with the PPARγ agonist, rosiglitazone (ROSI). Methods Rats were subjected to the three GWE for 33 days. In series 1 and 2, male and female GWE-rats were compared to naïve rats. In series 3, male rats with GWE were randomly assigned to prophylactic treatment with ROSI (GWE-ROSI) or vehicle. After the 33-day exposures, three neurofunctional domains were evaluated: cognition (novel object recognition), anxiety-like behaviors (elevated plus maze, open field) and depression-like behaviors (coat state, sucrose preference, splash test, tail suspension and forced swim). Brains were analyzed for astrocytic and microglial activation and neuroinflammation (GFAP, Iba1, tumor necrosis factor and translocator protein). Neurofunctional data from rats with similar exposures were pooled into 3 groups: naïve, GWE and GWE-ROSI. Results Compared to naïve rats, GWE-rats showed significant abnormalities in the three neurofunctional domains, along with significant neuroinflammation in amygdala and hippocampus. There were no differences between males and females with GWE. GWE-ROSI rats showed significant attenuation of neuroinflammation and of some of the neurofunctional abnormalities. Conclusion This novel GWI model recapitulates critical neurofunctional abnormalities reported by Veterans with GWI. Concurrent prophylactic treatment with ROSI was beneficial in this model.
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Hoffman JF, Kalinich JF. Effects of Incubation of Human Brain Microvascular Endothelial Cells and Astrocytes with Pyridostigmine Bromide, DEET, or Permethrin in the Absence or Presence of Metal Salts. Int J Environ Res Public Health 2020; 17:ijerph17228336. [PMID: 33187257 PMCID: PMC7696739 DOI: 10.3390/ijerph17228336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/19/2022]
Abstract
Gulf War Illness (GWI) is a chronic, multi-symptom illness suffered by over one-third of American military veterans who served in the Persian Gulf War between 1990 and 1991. No current single-exposure scenario accounts for all the symptoms observed in GWI, and instead may be due to a multi-exposure scenario. As a larger effort to understand how one category of multi-exposure scenarios of organic compounds such as nerve gas prophylactic pyridostigmine bromide, or insecticides/pesticides such as N,N-diethyl-m-toluamide (DEET) and permethrin, plus heavy metals found in inhaled dust particles (Al, Fe, Ni, Sr, DU, Co, Cu, Mn, and Zn) might play a role in neural aspects of GWI, we begin this initial study to examine the toxicity and oxidative damage markers of human brain endothelial cell and human astrocyte cell cultures in response to these compounds. A battery of cytotoxicity assessments, including the MTT assay, Neutral Red uptake, and direct microscopic observation, was used to determine a non-toxic dose of the test compounds. After testing a wide range of doses of each compound, we chose a sub-toxic dose of 10 µM for the three organic compounds and 1 µM for the nine metals of interest for co-exposure experiments on cell cultures and examined an array of oxidative stress-response markers including nitric oxide production, formation of protein carbonyls, production of thiobarbituric acid-reactive substances, and expression of proteins involved in oxidative stress and cell damage. Many markers were not significantly altered, but we report a significant increase in nitric oxide after exposure to any of the three compounds in conjunction with depleted uranium.
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Macht VA, Woodruff JL, Maissy ES, Grillo CA, Wilson MA, Fadel JR, Reagan LP. Pyridostigmine bromide and stress interact to impact immune function, cholinergic neurochemistry and behavior in a rat model of Gulf War Illness. Brain Behav Immun 2019; 80:384-93. [PMID: 30953774 DOI: 10.1016/j.bbi.2019.04.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 02/06/2023] Open
Abstract
Gulf War Illness (GWI) is characterized by a constellation of symptoms that includes cognitive dysfunction. While the causes for GWI remain unknown, prophylactic use of the acetylcholinesterase inhibitor pyridostigmine bromide (PB) in combination with the stress of deployment has been proposed to be among the causes of the cognitive dysfunction in GWI. Mechanistically, clinical studies suggest that altered immune function may be an underlying factor in the neurochemical and neurobehavioral complications of GWI. Accordingly, the goal of this study was to determine how responses to an immune challenge (lipopolysaccharide; LPS) or stress impacts inflammation, acetylcholine (ACh) neurochemistry and behavior in an experimental model of GWI. Rats with a history of PB treatment exhibited potentiated increases in C-reactive protein levels in response to a submaximal LPS challenge compared to control rats, indicating that prior treatment with this cholinesterase inhibitor leads to exacerbated inflammatory responses to a subsequent immune challenge. ACh responses to LPS administration were decreased in the hippocampus, but not prefrontal cortex (PFC), in rats with a prior history of PB treatment or stress exposure. Additionally, ACh release in response to acute immobilization stress was attenuated in the PFC and hippocampus in these groups. These attenuated cholinergic responses were accompanied by impairments in contextual and cue-based fear learning. The results of this study suggest that stress and LPS challenges adversely affect central ACh neurochemistry in a rodent model of GWI and support the hypothesis that dysregulated immune responses are mechanistically linked to the neurological complications of GWI.
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Lataro RM, Silva MAB, Mestriner FL, Cau SBA, Tostes RCA, Salgado HC. Chronic Treatment With Acetylcholinesterase Inhibitors Attenuates Vascular Dysfunction in Spontaneously Hypertensive Rats. Am J Hypertens 2019; 32:579-587. [PMID: 30875426 DOI: 10.1093/ajh/hpz036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/18/2019] [Accepted: 03/06/2019] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Acetylcholinesterase inhibition prevents autonomic imbalance, reduces inflammation, and attenuates the development of hypertension. Considering that vascular dysfunction is a crucial feature of arterial hypertension, we investigated the effects of chronic administration of acetylcholinesterase inhibitors-pyridostigmine or donepezil-on vascular reactivity of spontaneously hypertensive rats (SHR). METHODS Endothelium-dependent relaxant responses to acetylcholine (ACh) and contractile responses induced by electric field stimulation (EFS) and alpha-adrenergic agonist were studied in mesenteric resistance arteries from SHR and Wistar Kyoto rats. SHR were treated for 16 weeks with vehicle, pyridostigmine (1.5 mg/kg/day) or donepezil (1.4 mg/kg/day). RESULTS Pyridostigmine and donepezil decreased the vasoconstrictor responses to EFS, which were increased in vehicle-treated SHR. Acetylcholinesterase inhibition increased the modulatory effects of nitric oxide (NO) on SHR vascular reactivity, that is, N(ω)-nitro-(L)-arginine methyl ester (L-NAME) increased EFS-induced contractions and reduced ACh-induced relaxation, with more significant effects in pyridostigmine- and donepezil-treated SHR. The acetylcholinesterase inhibitors also decreased vascular reactive oxygen species levels. CONCLUSIONS This study demonstrates for the first time that long-term administration of acetylcholinesterase inhibitors, pyridostigmine or donepezil, attenuates vascular reactivity dysfunction in SHR by decreasing reactive oxygen species generation and increasing NO bioavailability; possibly via increased endothelial NO synthase activity, and inhibition of NADPH oxidase activity.
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Affiliation(s)
- Renata M Lataro
- Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Marcondes A B Silva
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Fabiola L Mestriner
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Stefany B A Cau
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Rita C A Tostes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Helio C Salgado
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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Pung T, Zimmerman K, Klein B, Ehrich M. Corticosterone in drinking water: altered kinetics of a single oral dose of corticosterone and concentrations of plasma sodium, albumin, globulin, and total protein. Toxicol Ind Health 2016; 19:171-82. [PMID: 15747778 DOI: 10.1191/0748233703th182oa] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Effects of chronic exposure to corticosterone in drinking water on corticosterone kinetics, blood chemistry, and concentrations of catecholamines in parts of brain were studied in Long-Evans rats. Rats were randomly grouped into 3-2 treatments (n-4), with three treatments of drinking water (tap water, or 2.5% ethanol, or 400 mg/mL of corticosterone in 2.5% ethanol) for 28 days and two treatments of gavage with a single dose of either corn oil or corticosterone 20 mg/kg on day 28. Blood samples were collected at 0, 15, 30, 60, 120, 240, 480, and 720 min after dosing to determine plasma corticosterone concentrations. Blood samples were collected for clinical pathology on day 42. Hippocampus, cerebral cortex, caudate-putamen, and pons were examined to determine concentrations of catecholamines and activities of esterases. Concentrations of plasma corticosterone before gavage of the corticosterone-drinking rats (47.619 ± 1.13 ng/mL) were lower than the water (418.479 ± 1.13 ng/mL) or the ethanol rats (383.719 ± 1.13 ng/mL, P <0.0001). Plasma corticosterone rose to peak concentrations by 15 min after gavage in all three groups of drinking rats. Corticosterone- drinking rats had concentrations of plasma corticosterone that returned to basal levels slower than water- and ethanol-drinking rats. Plasma sodium and chloride concentrations were lower in the corticosterone-drinking rats than the water-drinking rats P <0.01). Plasma albumin, globulin, and total protein were highest in the corticosterone-drinking rats when compared to the other groups of drinking rats P <0.001, P <0.05, and P <0.001, respectively). Corticosterone in drinking water did not affect activities of brain neurotoxic esterase, carboxylesterase, acetylcholinesterase, or concentrations of monoamines and their metabolites. A single oral dose of corticosterone reduced neurotoxic esterase activity in the cerebral cortex P <0.05) and increased norepinephrine concentrations in the hippocampus P <0.05).
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Affiliation(s)
- Thitiya Pung
- Department of Biomedical Sciences and Pathology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061-0442, USA
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Lataro RM, Silva CAA, Tefé-Silva C, Prado CM, Salgado HC. Acetylcholinesterase Inhibition Attenuates the Development of Hypertension and Inflammation in Spontaneously Hypertensive Rats. Am J Hypertens 2015; 28:1201-8. [PMID: 25758777 DOI: 10.1093/ajh/hpv017] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/22/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND It is hypothesized that chronic increase of availability of acetylcholine, resulting from the effect of antiacetylcholinesterases, may prevent autonomic imbalance and reduce inflammation yielding benefic effects for cardiovascular disorders in hypertension. The effect of long-term administration of antiacetylcholinesterase agents with central and/or peripheral action, i.e., donepezil and pyridostigmine, were investigated on arterial pressure (AP), sympathovagal balance, plasma cytokine levels, and cardiac remodeling in spontaneously hypertensive rats (SHR). METHODS Chronic treatment with donepezil or pyridostigmine started before the onset of hypertension. AP was measured by plethysmography every 4 weeks. At the end of 16 weeks of treatment, methylatropine was used to evaluate the cardiac vagal tone; AP and pulse interval (PI) variability were also evaluated followed by plasma and heart collection for analysis. RESULTS Pyridostigmine, which does not cross the blood-brain barrier, increased cardiac vagal tone, and reduced cardiomyocyte diameter and collagen density, but did not affect the AP and plasma cytokine levels. Donepezil, which crosses the blood-brain barrier, attenuated the development of hypertension, increased cardiac vagal tone, and improved AP and PI variability. Likewise, donepezil reduced the plasma levels of tumor necrosis factor-α, interleukin 6, and interferon γ, besides reducing cardiomyocyte diameter and collagen density. CONCLUSIONS Donepezil attenuated the development of hypertension in SHR probably involving antiinflammatory effects, indicating that acetylcholinesterase inhibition yields benefic effects for antihypertensive therapy.
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Affiliation(s)
- Renata M Lataro
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carlos A A Silva
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Cristiane Tefé-Silva
- Department of Pathology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Cibele M Prado
- Department of Pathology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Helio C Salgado
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil;
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Sayin H, Scridon A, Oréa V, Chapuis B, Chevalier P, Barrès C, Julien C. Pyridostigmine enhances atrial tachyarrhythmias in aging spontaneously hypertensive rats. Clin Exp Pharmacol Physiol 2015; 42:1084-91. [DOI: 10.1111/1440-1681.12458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Halil Sayin
- Neurocardiology Unit; Medical School Lyon East; University Claude Bernard Lyon 1; Lyon France
| | - Alina Scridon
- Physiology Department; University of Medicine and Pharmacy of Tîrgu Mureș; Tîrgu Mureș Romania
| | - Valérie Oréa
- Laboratory of Tissue Biology and Therapeutic Engineering; National Center for Scientific Research UMR 5305 and Technical Platform ANIPHY; University Claude Bernard Lyon 1; Lyon France
| | - Bruno Chapuis
- Neurocardiology Unit; Medical School Lyon East; University Claude Bernard Lyon 1; Lyon France
| | - Philippe Chevalier
- Neurocardiology Unit; Medical School Lyon East; University Claude Bernard Lyon 1; Lyon France
- Rhythmology Department; Louis Pradel Cardiology Hospital; Hospices Civils de Lyon; Bron France
| | - Christian Barrès
- Neurocardiology Unit; Medical School Lyon East; University Claude Bernard Lyon 1; Lyon France
| | - Claude Julien
- Neurocardiology Unit; Medical School Lyon East; University Claude Bernard Lyon 1; Lyon France
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Fischer A, Wolman M, Granato M, Parsons M, McCallion AS, Proescher J, English E. Carbamate nerve agent prophylatics exhibit distinct toxicological effects in the zebrafish embryo model. Neurotoxicol Teratol 2015; 50:1-10. [PMID: 25968237 DOI: 10.1016/j.ntt.2015.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 03/25/2015] [Accepted: 05/01/2015] [Indexed: 12/14/2022]
Abstract
Pyridostigmine bromide (PB) is an FDA-approved drug for the treatment of myasthenia gravis and a prophylactic pre-treatment for organophosphate nerve agent poisoning. Current methods for evaluating nerve agent treatments include enzymatic studies and mammalian models. Rapid whole animal screening tools for assessing the effects of nerve agent pre-treatment and post-exposure drugs represent an underdeveloped area of research. We used zebrafish as a model for acute and chronic developmental exposure to PB and two related carbamate acetylcholinesterase (AChE) inhibitors, neostigmine bromide (NB) and physostigmine (PS). Lethal doses and gross morphological phenotypes resulting from exposure to sub-lethal doses of these compounds were determined. Quantitative analyses of motility impairment and AChE enzyme inhibition were used to determine optimal dosing conditions for evaluation of the effects of carbamate exposures on neuronal development; ~50% impairment of response to startle stimuli and >50% inhibition of AChE activity were observed at 80 mMPB, 20 mM NB and 0.1 mM PS. PB induced stunted somite length, but no other phenotypic effects were observed. In contrast, NB and PS induced more severe phenotypic morphological defects than PB as well as neurite outgrowth mislocalization. Additionally, NB induced mislocalization of nicotinic acetylcholine receptors, resulting in impaired synapse formation. Taken together, these data suggest that altered patterns of neuronal connectivity contribute to the developmental neurotoxicity of carbamates and demonstrate the utility of the zebrafish model for distinguishing subtle structure-based differential effects of AChE inhibitors, which include nerve agents, pesticides and drugs.
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Affiliation(s)
- Audrey Fischer
- Asymmetric Operations Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, United States; McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Marc Wolman
- Department of Cell & Developmental Biology, University of Pennsylvania, School of Medicine, Philadelphia, PA 19104, United States
| | - Michael Granato
- Department of Cell & Developmental Biology, University of Pennsylvania, School of Medicine, Philadelphia, PA 19104, United States
| | - Michael Parsons
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Andrew S McCallion
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States; Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Jody Proescher
- Asymmetric Operations Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, United States
| | - Emily English
- Research and Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, United States.
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Corrêa WG, Durand MT, Becari C, Tezini GC, do Carmo JM, de Oliveira M, Prado CM, Fazan R, Salgado HC. Pyridostigmine prevents haemodynamic alterations but does not affect their nycthemeral oscillations in infarcted mice. Auton Neurosci 2015; 187:50-5. [DOI: 10.1016/j.autneu.2014.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/10/2014] [Accepted: 11/09/2014] [Indexed: 12/20/2022]
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Morasch KC, Aaron CL, Moon JE, Gordon RK. Physiological and neurobehavioral effects of cholinesterase inhibition in healthy adults. Physiol Behav 2014; 138:165-72. [PMID: 25455867 DOI: 10.1016/j.physbeh.2014.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/26/2014] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Based on common pharmacodynamic mechanisms, recent efforts to develop second generation alternatives for organophosphate (OP) prophylaxis have expanded to include cholinesterase (ChE) inhibiting compounds traditionally approved for use in the treatment of Alzheimer's disease (AD). The primary purpose of this study was to determine the extent to which low-dose huperzine A, galantamine, or donepezil selectively inhibited acetylcholinesterase (AChE) versus butyrylcholinesterase (BChE) activity in healthy adults and whether such inhibition impacted neurobehavioral performance. METHODS In addition to hourly red blood cell cholinesterase sampling, neurobehavioral function was assessed before and after a single oral dose of huperzine A (100 or 200 μg), galantamine (4 or 8 mg), donepezil (2.5 or 5mg), or placebo (n=12 subjects per drug/dose). RESULTS Compared to placebo, both dosages of huperzine A and galantamine inhibited circulating AChE but not BChE. With the exception of huperzine A (200 μg), which maintained declarative recall performance across sessions, compounds did not improve neurobehavioral performance. Some aspects of neurobehavioral performance correlated with AChE activity, although associations may have reflected time of day effects. DISCUSSION Although huperzine A and galantamine significantly inhibited AChE (and likely increased central acetylcholine levels), neither compound improved neurobehavioral performance. The latter was likely due to ceiling effects in this young, healthy test population. Under conditions of reduced cholinergic activity (e.g., Alzheimer's disease), AChE inhibition (and corresponding maintenance of cholinergic tone) could potentially maintain/augment some aspects of neurobehavioral function.
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Affiliation(s)
| | | | - James E Moon
- Walter Reed Army Institute of Research, United States
| | - Richard K Gordon
- United States Army Medical Research and Materiel Command, United States
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Komloova M, Horova A, Hrabinova M, Jun D, Dolezal M, Vinsova J, Kuca K, Musilek K. Preparation, in vitro evaluation and molecular modelling of pyridinium–quinolinium/isoquinolinium non-symmetrical bisquaternary cholinesterase inhibitors. Bioorg Med Chem Lett 2013; 23:6663-6. [DOI: 10.1016/j.bmcl.2013.10.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 10/19/2013] [Accepted: 10/22/2013] [Indexed: 10/26/2022]
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Ozturk G, Feller KH, Dornbusch K, Timur S, Alp S, Ergun Y. Development of fluorescent array based on sol-gel/chitosan encapsulated acetylcholinesterase and pH sensitive oxazol-5-one derivative. J Fluoresc 2010; 21:161-7. [PMID: 20617372 DOI: 10.1007/s10895-010-0700-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 06/22/2010] [Indexed: 11/28/2022]
Abstract
A highly sensitive fluorescent enzyme array for quantitative acetylcholine detection is developed. The enzyme array has been constructed by spotting of pH sensitive fluorophore 2-phenyl-4-[4-(1,4,7,10-tetraoxa-13-azacycloopentadecyl)benzylidene]oxazol-5-one and acetylcholinesterase doped in tetraethoxysilane/chitosan matrix via a microarrayer. The constructed tetraethoxysilane/chitosan network provided a microenvironment in which the enzyme molecule was active biologically. The optimal operational conditions for the array developed were investigated. The response of the developed biosensor array to acetylcholine was highly reproducible (RSD = 3.27%, n = 6). A good linearity was observed for acetylcholine in the concentrations up to 1 × 10(-8) M, with a detection limit of 0.27 × 10(-8) M.
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Affiliation(s)
- Gulsiye Ozturk
- Faculty of Arts and Sciences, Department of Chemistry, University of Dokuz Eylul, Izmir, Turkey.
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Demar JC, Clarkson ED, Ratcliffe RH, Campbell AJ, Thangavelu SG, Herdman CA, Leader H, Schulz SM, Marek E, Medynets MA, Ku TC, Evans SA, Khan FA, Owens RR, Nambiar MP, Gordon RK. Pro-2-PAM therapy for central and peripheral cholinesterases. Chem Biol Interact 2010; 187:191-8. [PMID: 20156430 DOI: 10.1016/j.cbi.2010.02.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/04/2010] [Accepted: 02/09/2010] [Indexed: 11/29/2022]
Abstract
Novel therapeutics to overcome the toxic effects of organophosphorus (OP) chemical agents are needed due to the documented use of OPs in warfare (e.g. 1980-1988 Iran/Iraq war) and terrorism (e.g. 1995 Tokyo subway attacks). Standard OP exposure therapy in the United States consists of atropine sulfate (to block muscarinic receptors), the acetylcholinesterase (AChE) reactivator (oxime) pralidoxime chloride (2-PAM), and a benzodiazepine anticonvulsant to ameliorate seizures. A major disadvantage is that quaternary nitrogen charged oximes, including 2-PAM, do not cross the blood brain barrier (BBB) to treat brain AChE. Therefore, we have synthesized and evaluated pro-2-PAM (a lipid permeable 2-PAM derivative) that can enter the brain and reactivate CNS AChE, preventing seizures in guinea pigs after exposure to OPs. The protective effects of the pro-2-PAM after OP exposure were shown using (a) surgically implanted radiotelemetry probes for electroencephalogram (EEG), (b) neurohistopathology of brain, (c) cholinesterase activities in the PNS and CNS, and (d) survivability. The PNS oxime 2-PAM was ineffective at reducing seizures/status epilepticus (SE) in diisopropylfluorophosphate (DFP)-exposed animals. In contrast, pro-2-PAM significantly suppressed and then eliminated seizure activity. In OP-exposed guinea pigs, there was a significant reduction in neurological damage with pro-2-PAM but not 2-PAM. Distinct regional areas of the brains showed significantly higher AChE activity 1.5h after OP exposure in pro-2-PAM treated animals compared to the 2-PAM treated ones. However, blood and diaphragm showed similar AChE activities in animals treated with either oxime, as both 2-PAM and pro-2-PAM are PNS active oximes. In conclusion, pro-2-PAM can cross the BBB, is rapidly metabolized inside the brain to 2-PAM, and protects against OP-induced SE through restoration of brain AChE activity. Pro-2-PAM represents the first non-invasive means of administering a CNS therapeutic for the deleterious effects of OP poisoning by reactivating CNS AChE.
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Affiliation(s)
- James C Demar
- Walter Reed Army Institute of Research, Division of Regulated Activities, Department of Regulated Laboratories, Silver Spring, MD 20910-7500, United States
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Amourette C, Lamproglou I, Barbier L, Fauquette W, Zoppe A, Viret R, Diserbo M. Gulf War illness: Effects of repeated stress and pyridostigmine treatment on blood–brain barrier permeability and cholinesterase activity in rat brain. Behav Brain Res 2009; 203:207-14. [DOI: 10.1016/j.bbr.2009.05.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 04/30/2009] [Accepted: 05/03/2009] [Indexed: 11/25/2022]
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Lamproglou I, Barbier L, Diserbo M, Fauvelle F, Fauquette W, Amourette C. Repeated stress in combination with pyridostigmine Part I: long-term behavioural consequences. Behav Brain Res 2009; 197:301-10. [PMID: 18793677 DOI: 10.1016/j.bbr.2008.08.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/21/2008] [Accepted: 08/24/2008] [Indexed: 11/21/2022]
Abstract
Since their return from the first Persian Gulf War, some veterans have complained of a variety of symptoms that were designated as "Gulf War Illness" (GWI). Among other factors, pyridostigmine, used as a prophylaxis treatment against intoxication by nerve agents, has been proposed by many authors as a cause of late social and/or cognitive dysfunction related to GWI. One of the hypotheses placed to explain these behavioural disorders is that operational stress has modified the side effects of pyridostigmine given to soldiers. In an attempt to establish an experimental model of GWI to evaluate the long-term behavioural effects of pyridostigmine administered in stressful conditions, we have developed a new model of repeated stress based on the pole-climbing avoidance technique. We used it to evaluate the effects of pyridostigmine treatment combined to repeated stress over the months following the end of the treatment. We observed that this stress induces impulsiveness and aggressiveness in adult male rat. Moreover, pyridostigmine treatment administered daily 30 min before each stressful session amplifies these behavioural disorders and induces long-term learning dysfunction and slight but significant decrease in phosphocholine level in hippocampus. This suggests that repeated administration of pyridostigmine combined to pole-climbing avoidance (PCA) stress conditions can induce adverse effects in rat central nervous system.
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Barbier L, Diserbo M, Lamproglou I, Amourette C, Peinnequin A, Fauquette W. Repeated stress in combination with pyridostigmine Part II: changes in cerebral gene expression. Behav Brain Res 2008; 197:292-300. [PMID: 18796314 DOI: 10.1016/j.bbr.2008.08.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/21/2008] [Accepted: 08/24/2008] [Indexed: 12/29/2022]
Abstract
Organophosphates (OP) represent a potential threat in terrorism or during military conflicts. Due to its faculty to protect cholinesterase (ChE) activity against irreversible inactivation by OP, pyridostigmine bromide (PB) was used as a prophylaxis treatment during the first Persian Gulf War. To explain dysfunctions reported by Gulf War Veterans (GWV), it was suggested a potentiation of the operational stress effects by PB given to soldiers. Our companion paper (see part 1 in the same journal issue) describes that PB treatment administered in repeated stress conditions results in long-term perturbations of learning and social behaviour. The present paper examines, in adult male Wistar rats, consequences of the association of repeated stress and PB treatment on gene expression in hypothalamus and hippocampus. PB treatment (1.5 mg/kg/day) was orally administered 30 min before each stress session to inhibit 40% of blood ChE as recommended by NATO. 10 days of stress alone induce a decrease in hypothalamic Il-1alpha expression. Treatment with PB alone increases mineralocorticoid receptor expression in hypothalamus which means that PB may thus modify stress perception by animals. Stressed-PB animals showed increase in hippocampal expression of BDNF, TrkB and CamKIIalpha, three genes implicated in memory development. As a supplement to previous studies showing behavioural and biochemical effects of the association of stress with PB, our data reveal that behavioural effects of this association may be linked with genomic changes in hippocampus. Mechanisms underlying these modifications and their link with memory disturbances reported by GWV remain to be further determined.
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Affiliation(s)
- Laure Barbier
- Department of Radiobiology and Radiopathology, Centre de Recherches Emile Pardé, 24, Avenue des Maquis du Grésivaudan, BP87-38700 La Tronche Cedex, France. laure
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Park D, Jeon JH, Shin S, Jang JY, Choi BI, Nahm SS, Kang JK, Hwang SY, Kim JC, Kim YB. Debilitating stresses do not increase blood-brain barrier permeability: Lack of the involvement of corticosteroids. Environ Toxicol Pharmacol 2008; 26:30-37. [PMID: 21783884 DOI: 10.1016/j.etap.2008.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 12/24/2007] [Accepted: 01/03/2008] [Indexed: 05/31/2023]
Abstract
The involvement of corticosteroids in stress-induced change in blood-brain barrier (BBB) permeability was investigated. Mice were adrenalectomized and administered with pyridostigmine bromide (PB) or Evan's blue, markers of BBB penetration, followed by 18-h cold-restraint stress (CRS). Rats were administered with mifepristone, a corticosteroid receptor blocker, and the markers, followed by 4-h water immersion-restraint stress (WIRS). Separately, soman was administered to induce seizures-mediated BBB opening. CRS did not induce PB and Evan's blue penetration, which were not affected by adrenalectomy. Also, the markers were not detected in the brain of rats subjected to WIRS, regardless of the treatment of mifepristone. In comparison, 1-h epileptic seizures increased the penetration of Evan's blue by 875%. The results suggest that in contrast to seizure-related BBB opening, profound stresses do not practically increase the BBB permeability, and that corticosteroids are not involved in the stress-induced BBB penetration of charged chemicals and albumin-dye complex.
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Affiliation(s)
- Dongsun Park
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University, 410 Seongbongro (Gaeshin-dong), Cheongju, Chungbuk 361-763, Republic of Korea
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Mach M, Grubbs RD, Price WA, Nagaoka M, Dubovický M, Lucot JB. Delayed behavioral and endocrine effects of sarin and stress exposure in mice. J Appl Toxicol 2008; 28:132-9. [PMID: 17503400 DOI: 10.1002/jat.1258] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The organophosphorus agent sarin is a potent inhibitor of acetylcholinesterase. Experiments tested the influence of exposure to low doses of sarin along with psychological stress on delayed behavioral and endocrine changes in mice. Motor activity, acoustic startle response (ASR), pre-pulse inhibition (PPI) of ASR, activity of cholinesterase in blood and catecholamine levels in adrenals were evaluated after low dose sarin exposure (3 x 0.4 LD50 subcutaneously) combined with chronic intermittent stress in C57BL/6J mice. While sarin alone produced depression of motor activity, no interaction of the stress with sarin exposure was observed. Cholinesterase activity was significantly reduced 24 h after exposure to sarin; however, the basal activity was re-established 3 weeks later. The combination of low dose sarin exposure and stress produced delayed behavioral change manifested as excessive grooming together with endocrine alterations in adrenals 7 weeks after exposure. The size of the adrenals in the combined exposure group was increased and the concentration of catecholamines was significantly decreased. In conclusion, these findings indicate that sarin in low doses is more dangerous when combined with shaker stress inducing delayed behavioral and endocrine changes.
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Affiliation(s)
- Mojmir Mach
- Wright State University, Boohnshoft School of Medicine, Dayton, OH 45435, USA.
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Hancock S, Ehrich M, Hinckley J, Pung T, Jortner BS. The effect of stress on the acute neurotoxicity of the organophosphate insecticide chlorpyrifos. Toxicol Appl Pharmacol 2007; 219:136-41. [PMID: 17196233 DOI: 10.1016/j.taap.2006.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 11/06/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
A study was conducted to determine if multiple exposures to several stress paradigms might affect the anticholinesterase effect of subsequently administered organophosphate insecticide chlorpyrifos. Male Sprague-Dawley rats were subject to daily periods of restraint, swimming, a combination of the two, or neither of the two (controls) (n=8/group) for 5 days per week over a six-week period. The most profound stress, as measured by reduced body weight gain and elevated levels of plasma corticosterone, was swimming. On day 39 of the study, shortly after the daily stress episode, one half of the rats in each group was dosed with 60 mg/kg chlorpyrifos subcutaneously. This had no effect on subsequent levels of plasma corticosterone. There were no stress-related differences in the degree of chlorpyrifos-induced inhibition of brain acetylcholinesterase in animals sacrificed on day 43.
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Affiliation(s)
- Sandra Hancock
- Laboratory for Neurotoxicity Studies Virginia-Maryland Regional College of Veterinary Medicine Virginia Tech Blacksburg, VA 24061-0442, USA
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Servatius RJ, Beck KD. Mild interoceptive stressors affect learning and reactivity to contextual cues: toward understanding the development of unexplained illnesses. Neuropsychopharmacology 2005; 30:1483-91. [PMID: 15714226 DOI: 10.1038/sj.npp.1300691] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Contextual learning is evident with repeated experiences with agents and treatments that induce frank illness and interoceptive stress. Here, we examined whether acute treatment with mild interoceptive stressors (low doses of pyridostigmine bromide (PB), neostigmine bromide (NB), and interleukin (IL)-1beta) may serve as unconditional stimuli supporting contextual learning. Rats were exposed to interoceptive and exteroceptive stressors in contexts distinguished by visual or olfactory cues. Acoustic startle responses (ASRs) were measured the day following exposure and 2 weeks thereafter, without delivery of the unconditional stimuli. The appearance, form, and duration of startle potentiation depended on the distinguishing features of the context and the nature of the interoceptive stressor. Rats given cholinesterase inhibitors (PB and NB), but not IL-1beta or exposed to an exteroceptive stressor, exhibited exaggerated ASRs in a novel context distinguished by visual cues. Treatment with either PB or IL-1beta led to potentiated ASRs in the presence of odors congruent with those experiences during exposure to the stressor. Startle potentiation by odor was still apparent 2 weeks after treatment. For contexts differentiated by visual stimuli, cholinomimetics transiently alter reactivity within novel contexts. In the case of contexts differentiated by odors, learning is apparent at least 2 weeks after acute treatment of cholinomimetics and IL-1beta. Contextual learning and changes in reactivity consequent to mild interoceptive stressors such as PB may play a role in the development of nonspecific symptoms typical of unexplained illnesses, such as Gulf War Illness.
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Affiliation(s)
- Richard J Servatius
- Neurobehavioral Research Laboratory, Department of Veterans Affairs, New Jersey Health Care System, East Orange, NJ 07019, USA.
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Wang D, Perides G, Liu YF. Vaccination alone or in combination with pyridostigmine promotes and prolongs activation of stress-activated kinases induced by stress in the mouse brain. J Neurochem 2005; 93:1010-20. [PMID: 15857404 DOI: 10.1111/j.1471-4159.2005.03093.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Gulf war illnesses (GWI) are currently affecting thousands of veterans. To date, the molecular mechanisms underlying the pathogenesis of these illnesses remain unknown. During Gulf war I, military personnel were exposed to multiple stressors, one or more vaccines, pyridostigmine (PY), and other chemicals. In our previous studies, we found that stress induces activation of mitogen activated protein-kinase kinase 4 (MKK4) and c-Jun-N-terminal kinase (JNK) in the mouse brain (Liu et al. 2004). Our working hypothesis is that stress, vaccination, and PY may synergistically induce activation of MKK4 and JNK in the brain, leading to over-activation of these kinases and neurological injuries. To test our hypothesis, we examined the effect of keyhole limpet hemocyanin (KLH) immunization alone or in combination with PY on activation of MKK4 and JNK induced by stress. We found that KLH immunization alone had a small effect on MKK4 or JNK activity but it significantly enhanced and prolonged activation of these kinases induced by stress, from a few hours to several days. Additionally, KLH immunization caused activation of p38MAPK. PY treatment further enhanced and prolonged activation of these kinases induced by stress in combination with KLH immunization and triggered activation of caspase-3. Our current studies suggest that stress, vaccination, and PY may synergistically act on multiple stress-activated kinases in the brain to cause neurological impairments in GWI.
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Affiliation(s)
- Dechun Wang
- Department of Pharmacology, Boston University School of Medicine, Massachusetts 02118, USA
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Taysse L, Christin D, Delamanche S, Bellier B, Breton P. Peripheral ChE Inhibition Modulates Brain Monoamines Levels and c-fos Oncogene in Mice Subjected to a Stress Situation. Neurochem Res 2005; 30:391-402. [PMID: 16018584 DOI: 10.1007/s11064-005-2614-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The present study examined, in mice, whether regional patterns of brain monoamines concentrations (DA, 5-HT and their metabolites) and expression of c-Fos protein, that may represent a prolonged functional change in neurons, could be changed after a combined exposure to stress and the peripheral cholinesterase reversible inhibitor pyridostigmine (PYR). Animals were subjected every day to a random combination of mild unescapable electric footshocks and immobilization over a 12-day period, resulting in a significant increase of glucocorticoids levels and an activation of c-fos in hippocampus, thalamus and piriform cortex. This stress protocol induced a significant increase of 5-HT levels in striatum, hippocampus and ponto mesencephalic area (PMA) but failed to induce any DA activation. When PYR (0.2 mg/kg s.c. inducing 19-35% inhibition of the plasmatic ChE activity) was administered twice a day during the last 5 days of the stress session, 5-HIAA levels and expression of c-fos oncogene were significantly increased in the most of the brain areas studied. DA levels were also enhanced in striatum/hippocampus as a result of a possible activation of mesolimbic and nigrostriatal dopamine systems. Taken together, these results suggest that a combined exposure to certain stress conditions and PYR leads, in mice, to functional changes in neurons and may affect centrally controlled functions. The mechanisms underlying these modifications and their behavioral implications remain to be further investigated.
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Affiliation(s)
- L Taysse
- Centre études du Bouchet (Defence Research Center), 91710, Vert le Petit, France.
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Barber DS, Ehrich MF, Jortner BS. The effect of stress on the temporal and regional distribution of uranium in rat brain after acute uranyl acetate exposure. J Toxicol Environ Health A 2005; 68:99-111. [PMID: 15762549 DOI: 10.1080/15287390590885910] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Long-term exposure to depleted uranium (DU) has been shown to increase brain uranium and alter hippocampal function; however, little is known about the short-term kinetics of DU in the brain. To address this issue, temporal and regional distribution of brain uranium was investigated in male Sprague-Dawley rats treated with a single intraperitoneal injection of 1 mg uranium/kg as uranyl acetate. Due to the inherent stress of combat and the potential for stress to alter blood-brain barrier permeability, the impact of forced swim stress on brain uranium distribution was also examined in this model. Uranium in serum, hippocampus, striatum, cerebellum, and frontal cortex was quantified by inductively coupled plasma-mass spectrometry (ICP-MS) at 8 h, 24 h, 7 d, and 30 d after exposure. Uranium entered the brain rapidly and was initially concentrated in hippocampus and striatum. While multiple phases of uranium clearance were observed, overall clearance was relatively slow and the uranium content of hippocampus, cerebellum, and cortex remained elevated for more than 7 d after a single exposure. Prior exposure to stress significantly reduced hippocampal and cerebellar uranium 24 h post-exposure and tended to reduce uranium in all brain regions 7 d after exposure. The application of stress appeared to increase brain uranium clearance, as initial tissue levels were similar in stressed and unstressed rats.
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Affiliation(s)
- David S Barber
- Department of Physiological Sciences, Center for Human and Environmental Toxicology, University of Florida, Gainesville, Florida 32611, USA.
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Soreq H, Yirmiya R, Cohen O, Glick D. Acetylcholinesterase as a window onto stress responses. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0921-0709(05)80032-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Staines D. Do vasoactive neuropeptide autoimmune disorders explain pyridostigmine’s association with Gulf War syndrome? Med Hypotheses 2005; 65:591-4. [PMID: 16004938 DOI: 10.1016/j.mehy.2005.02.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 02/28/2005] [Indexed: 01/03/2023]
Abstract
Gulf War syndrome (GWS) is a perplexing multi-symptom condition comprising a constellation of signs and symptoms consistently described in the literature. These include muscle fatigue and tiredness, malaise, myalgia, impaired cognition, ataxia, diarrhoea, bladder dysfunction, sweating disturbances, headaches, fever, arthralgia, skin rashes, and gastrointestinal and sleep disturbances. Excessive chemical sensitivity and odour intolerance is reported. Epidemiological analysis suggests association with pyridostigmine bromide (PB) use as nerve gas prophylaxis, insect repellent, certain vaccination regimes, a variety of possible chemical exposures and physical and psychological stress. Pituitary adenylate cyclase-activating polypeptide (PACAP), calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP) are potent vasoactive (vasodilatory) neuropeptides (VNs) having pleiotropic functions as immunomodulators, neuroregulators and hormones. VNs also have neurotrophic and anti-apoptotic roles. VNs act on G protein-coupled receptors (GPCRs) to activate adenylate cyclase, an important step in cyclic AMP metabolism. Autoimmune dysfunction of these VNs or their receptors is postulated to give rise to fatigue-related conditions such as chronic fatigue syndrome (CFS). Complex mechanisms involving heat shock proteins (hsps) and cytosine-guanine dinucleotide (CpG) DNA fragments may also be associated with autoimmunity to VNs or their GPCRs in contributing to fatigue-related conditions. Dysfunction of certain VNs may be the missing link in explaining the nebulous nexus between PB and GWS. This paper explores a possible link between exposures to PB and other chemical, physical and psychological stressors in producing a fatigue-related illness possibly related to autoimmune dysfunction of certain VNs. Treatment options involving restoration of VN function are considered in the context of analogues with other neurotransmitter fatigue-related conditions such as myasthenia gravis (MG). While evidence associating these conditions is thin, vasoactive neuropeptide neurotransmitters of the VIP/PACAP family have acetylcholine co-transmission functions via specific GPCRs. Autoimmune reactions to these receptors may have parallels with muscarinic (e.g., Sjogren's syndrome) and nicotinic (e.g., MG) acetylcholine neurotransmission. Hence theoretically, treatment options such as thymectomy, corticosteroids, plasma exchange, anti-idiotype antibodies and receptor genomic expression reactivation/suppression may be considered. Paradoxically pyridostigmine may prove to have a role in therapy although VN treatment/replacement may be associated with tachyphylaxis.
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Affiliation(s)
- Donald Staines
- Gold Coast Public Health Unit, 10-12 Young Street, Southport 4215, Queensland, Australia.
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Joaquim LF, Farah VM, Bernatova I, Fazan R, Grubbs R, Morris M. Enhanced heart rate variability and baroreflex index after stress and cholinesterase inhibition in mice. Am J Physiol Heart Circ Physiol 2004; 287:H251-7. [PMID: 14988080 DOI: 10.1152/ajpheart.01136.2003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments tested the effect of stress coupled with cholinesterase inhibition on blood pressure, heart rate, baroreflex index, and variability in time and frequency domain in conscious mice. The objective was to determine whether cholinergic systems interact with stress to alter cardiovascular responses. Male C57BL/6J mice with arterial catheters were exposed to 3-day treatments: 1) intermittent shaker stress, 2) pyridostigmine (10 mg.kg(-1).day(-1)); or 3) combined pyridostigmine and stress. Pyridostigmine reduced blood cholinesterase (-33%) with no added effects of stress. Twenty-four-hour blood pressure recordings showed that there were no differences in blood pressure and heart rate with the treatments. Pulse interval standard deviation was greatly increased in the pyridostigmine/stress group compared with stress or pyridostigmine groups (11.0 +/- 1.4, 5.0 +/- 0.9, and 7.5 +/- 0.9 ms, respectively). Spectral analysis showed two distinct components for pulse interval variability (low and high frequency). Variability in the low-frequency range was greatly enhanced in the pyridostigmine/stress group, seen as a doubling of the power (9.5 +/- 1.7, 3.3 +/- 0.9, and 5.0 +/- 0.6 ms for pyridostigmine/stress, stress and pyridostigmine groups, respectively). Baroreflex sensitivity was also increased in the pyridostigmine/stress group (3.6 +/- 0.5 compared with 1.8 +/- 0.3 and 1.7 +/- 0.5 ms/mmHg in the stress and pyridostigmine groups, respectively). There was no difference in blood pressure variability or its spectral components. Results demonstrate that there are potent interactions between a mild stressor and cholinesterase inhibition seen as an accentuation of low-frequency variability in pulse interval time series, probably associated with baroreflex input and autonomic drive.
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Affiliation(s)
- Luis F Joaquim
- Department of Pharmacology and Toxicology, Wright State University School of Medicine, 3640 Colonel Glenn Hwy., Dayton, OH 45435, USA
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Gutiérrez R, Rodriguez-Ortiz CJ, De La Cruz V, Núñez-Jaramillo L, Bermudez-Rattoni F. Cholinergic dependence of taste memory formation: Evidence of two distinct processes. Neurobiol Learn Mem 2003; 80:323-31. [PMID: 14521874 DOI: 10.1016/s1074-7427(03)00066-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Learning the aversive or positive consequences associated with novel taste solutions has a strong significance for an animal's survival. A lack of recognition of a taste's consequences could prevent ingestion of potential edibles or encounter death. We used conditioned taste aversion (CTA) and attenuation of neophobia (AN) to study aversive and safe taste memory formation. To determine if muscarinic receptors in the insular cortex participate differentially in both tasks, we infused the muscarinic antagonists scopolamine at distinct times before or after the presentation of a strong concentration of saccharin, followed by either an i.p. injection of a malaise-inducing agent or no injection. Our results showed that blockade of muscarinic receptors before taste presentation disrupts both learning tasks. However, the same treatment after the taste prevents AN but not CTA. These results clearly demonstrate that cortical cholinergic activity participates in the acquisition of both safe and aversive memory formation, and that cortical muscarinic receptors seem to be necessary for safe but not for aversive taste memory consolidation. These results suggest that the taste memory trace is processed in the insular cortex simultaneously by at least two independent mechanisms, and that their interaction would determine the degree of aversion or preference learned to a novel taste.
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Affiliation(s)
- Ranier Gutiérrez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, 04510 Cd., México, DF, México
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Abstract
Pyridostigmine is a short-acting inhibitor of cholinesterase (ChE) used as a pretreatment against potential nerve agent exposure during the Persian Gulf War. As pyridostigmine contains a quaternary ammonium group, it is generally believed to elicit changes in the peripheral nervous system function only. It has been hypothesized, however, that the neurotoxicity of pyridostigmine may be altered by either stress or combined exposures to other toxicants. We evaluated the effects of forced running stress, exposure to the organophosphate anticholinesterase paraoxon, or a combination of both on the acute neurotoxicity of pyridostigmine. ChE (blood, diaphragm, and selected brain regions) and carboxylesterase (CE; liver, plasma) inhibition was also evaluated. Young adult male Sprague-Dawley rats were either given vehicle or paraoxon (0.1 mg/kg, i.m.) and subsets placed in their home cage or forced to run on a treadmill for 60 min. Pyridostigmine (0, 10 or 30 mg/kg, p.o.) was given 60 min after paraoxon dosing and rats were evaluated for cholinergic toxicity just prior to sacrifice 60 min later. No signs of toxicity were noted following paraoxon exposure while both dosages of pyridostigmine (10 and 30 mg/kg, p.o.) elicited signs of functional toxicity. Toxicity was not different with combined paraoxon-pyridostigmine exposures and forced running did not influence toxicity under any conditions. Paraoxon (0.1 mg/kg, i.m.) caused moderate (23-46%) ChE inhibition in blood, diaphragm and brain 2 h after exposure. Pyridostigmine (10 or 30 mg/kg, p.o.) caused extensive inhibition of blood (88-94%) and diaphragm (75-85%) ChE activity but no significant effect on brain regional ChE activity. Forced running stress did not influence the degree of tissue ChE inhibition following either paraoxon, pyridostigmine or paraoxon-pyridostigmine combined exposures. CE activities were inhibited (26-43%) in plasma and liver by paraoxon but inhibition was not influenced by either stress or combined paraoxon-pyridostigmine exposures. These results suggest that subclinical paraoxon exposure and forced running stress, by themselves or in combination, have little effect on acute pyridostigmine toxicity in rats.
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Affiliation(s)
- Jamaluddin Shaikh
- College of Veterinary Medicine, Oklahoma State University, 264 McElroy Hall, Stillwater, OK 74078, USA
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Beck KD, Brennan FX, Moldow RL, Ottenweller JE, Zhu G, Servatius RJ. Stress interacts with peripheral cholinesterase inhibitors to cause central nervous system effects. Life Sci 2003; 73:41-51. [PMID: 12726885 DOI: 10.1016/s0024-3205(03)00255-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pyridostigmine bromide (PB), a peripheral cholinesterase inhibitor, has been shown to have central cholinesterase inhibition properties under certain conditions (such as when ingested with other chemical compounds or following a high level of stress). Here we tested if stressing rats, using an intermittent 1 hr tailshock protocol, affected the degree of brain acetylcholinesterase (AChE) inhibition caused by a subsequent single injection of PB (2.0 mg/kg) or neostigmine bromide (NB, 0.32 mg/kg), another peripheral carbamate cholinesterase inhibitor. Stressed rats treated with PB had lower levels of AChE activity in the basal forebrain/striatum, but not in other brain areas. Stressed rats treated with NB did not show basal forebrain/striatum AChE activity changes but did show minor reductions of AChE activity in the cortex and cerebellum. These results confirm that prior stress can change the characteristic actions of certain peripherally acting drugs, thus possibly leading to unexpected central nervous system effects. Possible causes for these effects are discussed.
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Affiliation(s)
- Kevin D Beck
- Neurobehavioral Research Laboratory (129), Department of Veterans Affairs New Jersey Health Care System, East Orange, NJ 07018, USA
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Abstract
Sarin (O-isopropylmethylphosphonofluoridate) is a highly toxic nerve agent produced for chemical warfare. Sarin is an extremely potent acetylcholinesterase (AchE) inhibitor with high specificity and affinity for the enzyme. Death by sarin is due to anoxia resulting from airway obstruction, weakness of the muscles of respiration, convulsions and respiratory failure. The main clinical symptoms of acute toxicity of sarin are seizures, tremors and hypothermia. Exposure to sarin during incidents in Japan in 1994, 1995 and 1998, and possible exposure to low levels of sarin during the Gulf War, resulted in the deaths and injury of many people in Japan and caused possible long-term health effects on Gulf War veterans. Symptoms related to sarin poisoning in Japan still exist 1-3 years after the incident and include fatigue, asthenia, shoulder stiffness and blurred vision. Sarin produced seizures in rats and pigs. Recent studies showed that long-term exposure to low levels of sarin caused neurophysiological and behavioral alterations. Toxicity from sarin significantly increased following concurrent exposure to other chemicals such as pyridostigmine bromide. Further research to examine effects of sarin on the cellular and the molecular levels, gene transcription, endocrine system as well as its long-term impact is needed.
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Affiliation(s)
- A W Abu-Qare
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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