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Moghe M, Kim SS, Guan M, Rait A, Pirollo KF, Harford JB, Chang EH. scL-2PAM: A Novel Countermeasure That Ameliorates Neuroinflammation and Neuronal Losses in Mice Exposed to an Anticholinesterase Organophosphate. Int J Mol Sci 2024; 25:7539. [PMID: 39062781 PMCID: PMC11276659 DOI: 10.3390/ijms25147539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 07/28/2024] Open
Abstract
Due to their inhibition of acetylcholinesterase, organophosphates are among the most toxic of chemicals. Pralidoxime (a.k.a 2-PAM) is the only acetylcholinesterase reactivator approved in the U.S., but 2-PAM only poorly traverses the blood-brain barrier. Previously, we have demonstrated that scL-2PAM, a nanoformulation designed to enter the brain via receptor-mediated transcytosis, is superior to unencapsulated 2-PAM for reactivating brain acetylcholinesterase, ameliorating cholinergic crisis, and improving survival rates for paraoxon-exposed mice. Here, we employ histology and transcriptome analyses to assess the ability of scL-2PAM to prevent neurological sequelae including microglial activation, expression of inflammatory cytokines, and ultimately loss of neurons in mice surviving paraoxon exposures. Levels of the mRNA encoding chemokine ligand 2 (CCL2) were significantly upregulated after paraoxon exposures, with CCL2 mRNA levels in the brain correlating well with the intensity and duration of cholinergic symptoms. Our nanoformulation of 2-PAM was found to be superior to unencapsulated 2-PAM in reducing the levels of the CCL2 transcript. Moreover, brain histology revealed that scL-2PAM was more effective than unencapsulated 2-PAM in preventing microglial activation and the subsequent loss of neurons. Thus, scL-2PAM appears to be a new and improved countermeasure for reducing neuroinflammation and mitigating brain damage in survivors of organophosphate exposures.
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Affiliation(s)
- Manish Moghe
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
| | - Sang-Soo Kim
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
- SynerGene Therapeutics, Inc., Potomac, MD 20854, USA;
| | - Miaoyin Guan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
| | - Antonina Rait
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
| | - Kathleen F. Pirollo
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
| | | | - Esther H. Chang
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA; (M.M.); (A.R.); (K.F.P.)
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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De Araujo Furtado M, Aroniadou-Anderjaska V, Figueiredo TH, Pidoplichko VI, Apland JP, Rossetti K, Braga MFM. Preventing Long-Term Brain Damage by Nerve Agent-Induced Status Epilepticus in Rat Models Applicable to Infants: Significant Neuroprotection by Tezampanel Combined with Caramiphen but Not by Midazolam Treatment. J Pharmacol Exp Ther 2024; 388:432-450. [PMID: 37739807 PMCID: PMC10801760 DOI: 10.1124/jpet.123.001710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 09/24/2023] Open
Abstract
Acute exposure to nerve agents induces a peripheral cholinergic crisis and prolonged status epilepticus (SE), causing death or long-term brain damage. To provide preclinical data pertinent to the protection of infants and newborns, we compared the antiseizure and neuroprotective effects of treating soman-induced SE with midazolam (MDZ) versus tezampanel (LY293558) in combination with caramiphen (CRM) in 12- and 7-day-old rats. The anticonvulsants were administered 1 hour after soman exposure; neuropathology data were collected up to 6 months postexposure. In both ages, the total duration of SE within 24 hours after soman exposure was significantly shorter in the LY293558 plus CRM groups compared with the MDZ groups. Neuronal degeneration was substantial in the MDZ-treated groups but absent or minimal in the groups treated with LY293558 plus CRM. Loss of neurons and interneurons in the basolateral amygdala and CA1 hippocampal area was significant in the MDZ-treated groups but virtually absent in the LY293558 plus CRM groups. Atrophy of the amygdala and hippocampus occurred only in MDZ-treated groups. Neuronal/interneuronal loss and atrophy of the amygdala and hippocampus deteriorated over time. Reduction of inhibitory activity in the basolateral amygdala and increased anxiety were found only in MDZ groups. Spontaneous recurrent seizures developed in the MDZ groups, deteriorating over time; a small percentage of rats from the LY293558 plus CRM groups also developed seizures. These results suggest that brain damage can be long lasting or permanent if nerve agent-induced SE in infant victims is treated with midazolam at a delayed timepoint after SE onset, whereas antiglutamatergic treatment with tezampanel and caramiphen provides significant neuroprotection. SIGNIFICANCE STATEMENT: To protect the brain and the lives of infants in a mass exposure to nerve agents, an anticonvulsant treatment must be administered that will effectively stop seizures and prevent neuropathology, even if offered with a relative delay after seizure onset. The present study shows that midazolam, which was recently approved by the Food and Drug Administration for the treatment of nerve agent-induced status epilepticus, is not an effective neuroprotectant, whereas brain damage can be prevented by targeting glutamate receptors.
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Affiliation(s)
- Marcio De Araujo Furtado
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - Vassiliki Aroniadou-Anderjaska
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - Taiza H Figueiredo
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - Volodymyr I Pidoplichko
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - James P Apland
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - Katia Rossetti
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
| | - Maria F M Braga
- Departments of Anatomy, Physiology, and Genetics (M.D.A.F., V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neuroscience Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Gunpowder, Maryland (J.P.A.)
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Blair RE, Hawkins E, Pinchbeck LR, DeLorenzo RJ, Deshpande LS. Chronic Epilepsy and Mossy Fiber Sprouting Following Organophosphate-Induced Status Epilepticus in Rats. J Pharmacol Exp Ther 2024; 388:325-332. [PMID: 37643794 PMCID: PMC10801751 DOI: 10.1124/jpet.123.001739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/31/2023] Open
Abstract
Organophosphate (OP) compounds are highly toxic and include pesticides and chemical warfare nerve agents. OP exposure inhibits the acetylcholinesterase enzyme, causing cholinergic overstimulation that can evolve into status epilepticus (SE) and produce lethality. Furthermore, OP-induced SE survival is associated with mood and memory dysfunction and spontaneous recurrent seizures (SRS). In male Sprague-Dawley rats, we assessed hippocampal pathology and chronic SRS following SE induced by administration of OP agents paraoxon (2 mg/kg, s.c.), diisopropyl fluorophosphate (4 mg/kg, s.c.), or O-isopropyl methylphosphonofluoridate (GB; sarin) (2 mg/kg, s.c.), immediately followed by atropine and 2-PAM. At 1-hour post-OP-induced SE onset, midazolam was administered to control SE. Approximately 6 months after OP-induced SE, SRS were evaluated using video and electroencephalography monitoring. Histopathology was conducted using hematoxylin and eosin (H&E), while silver sulfide (Timm) staining was used to assess mossy fiber sprouting (MFS). Across all the OP agents, over 60% of rats that survived OP-induced SE developed chronic SRS. H&E staining revealed a significant hippocampal neuronal loss, while Timm staining revealed extensive MFS within the inner molecular region of the dentate gyrus. This study demonstrates that OP-induced SE is associated with hippocampal neuronal loss, extensive MFS, and the development of SRS, all hallmarks of chronic epilepsy. SIGNIFICANCE STATEMENT: Models of organophosphate (OP)-induced SE offer a unique resource to identify molecular mechanisms contributing to neuropathology and the development of chronic OP morbidities. These models could allow the screening of targeted therapeutics for efficacious treatment strategies for OP toxicities.
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Affiliation(s)
- Robert E Blair
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Elisa Hawkins
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Lauren R Pinchbeck
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Robert J DeLorenzo
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Laxmikant S Deshpande
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
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Puthillathu N, Moffett JR, Korotcov A, Bosomtwi A, Vengilote R, Krishnan JKS, Johnson EA, Arun P, Namboodiri AM. Brief isoflurane administration as an adjunct treatment to control organophosphate-induced convulsions and neuropathology. Front Pharmacol 2023; 14:1293280. [PMID: 38230376 PMCID: PMC10790757 DOI: 10.3389/fphar.2023.1293280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/21/2023] [Indexed: 01/18/2024] Open
Abstract
Organophosphate-based chemical agents (OP), including nerve agents and certain pesticides such as paraoxon, are potent acetylcholinesterase inhibitors that cause severe convulsions and seizures, leading to permanent central nervous system (CNS) damage if not treated promptly. The current treatment regimen for OP poisoning is intramuscular injection of atropine sulfate with an oxime such as pralidoxime (2-PAM) to mitigate cholinergic over-activation of the somatic musculature and autonomic nervous system. This treatment does not provide protection against CNS cholinergic overactivation and therefore convulsions require additional medication. Benzodiazepines are the currently accepted treatment for OP-induced convulsions, but the convulsions become refractory to these GABAA agonists and repeated dosing has diminishing effectiveness. As such, adjunct anticonvulsant treatments are needed to provide improved protection against recurrent and prolonged convulsions and the associated excitotoxic CNS damage that results from them. Previously we have shown that brief, 4-min administration of 3%-5% isoflurane in 100% oxygen has profound anticonvulsant and CNS protective effects when administered 30 min after a lethal dose of paraoxon. In this report we provide an extended time course of the effectiveness of 5% isoflurane delivered for 5 min, ranging from 60 to 180 min after a lethal dose of paraoxon in rats. We observed substantial effectiveness in preventing neuronal loss as shown by Fluoro-Jade B staining when isoflurane was administered 1 h after paraoxon, with diminishing effectiveness at 90, 120 and 180 min. In vivo magnetic resonance imaging (MRI) derived T2 and mean diffusivity (MD) values showed that 5-min isoflurane administration at a concentration of 5% prevents brain edema and tissue damage when administered 1 h after a lethal dose of paraoxon. We also observed reduced astrogliosis as shown by GFAP immunohistochemistry. Studies with continuous EEG monitoring are ongoing to demonstrate effectiveness in animal models of soman poisoning.
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Affiliation(s)
- Narayanan Puthillathu
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - John R. Moffett
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Alexandru Korotcov
- Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, United States
| | - Asamoah Bosomtwi
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, United States
| | - Ranjini Vengilote
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Jishnu K. S. Krishnan
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Erik A. Johnson
- Department of Neuroscience, United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Peethambaran Arun
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Aryan M. Namboodiri
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Figueiredo TH, Aroniadou-Anderjaska V, Apland JP, Rossetti K, Braga MFM. Delayed tezampanel and caramiphen treatment but not midazolam protects against long-term neuropathology after soman exposure. Exp Biol Med (Maywood) 2023; 248:612-623. [PMID: 37300407 PMCID: PMC10350803 DOI: 10.1177/15353702231171911] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 03/09/2023] [Indexed: 06/12/2023] Open
Abstract
Prolonged status epilepticus (SE) can cause brain damage; therefore, treatment must be administered promptly after seizure onset to limit SE duration and prevent neuropathology. Timely treatment of SE is not always feasible; this would be particularly true in a mass exposure to an SE-inducing agent such as a nerve agent. Therefore, the availability of anticonvulsant treatments that have neuroprotective efficacy even if administered with a delay after SE onset is an imperative. Here, we compared the long-term neuropathology resulting from acutely exposing 21-day-old male and female rats to the nerve agent soman, and treating them with midazolam (3 mg/kg) or co-administration of tezampanel (10 mg/kg) and caramiphen (50 mg/kg), at 1 h postexposure (~50 min after SE onset). Midazolam-treated rats had significant neuronal degeneration in limbic structures, mainly at one month postexposure, followed by neuronal loss in the basolateral amygdala and the CA1 hippocampal area. Neuronal loss resulted in significant amygdala and hippocampal atrophy, deteriorating from one to six months postexposure. Rats treated with tezampanel-caramiphen had no evidence of neuropathology, except for neuronal loss in the basolateral amygdala at the six-month timepoint. Anxiety was increased only in the midazolam-treated rats, at one, three, and six months postexposure. Spontaneous recurrent seizures appeared only in midazolam-treated rats, at three and six months postexposure in males and only at six months in females. These findings suggest that delayed treatment of nerve agent-induced SE with midazolam may result in long-lasting or permanent brain damage, while antiglutamatergic anticonvulsant treatment consisting of tezampanel and caramiphen may provide full neuroprotection.
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Affiliation(s)
- Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - James P Apland
- Neuroscience Program, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Katia Rossetti
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Maria FM Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Figueiredo TH, Aroniadou-Anderjaska V, Pidoplichko VI, Apland JP, Braga MFM. Antiseizure and Neuroprotective Efficacy of Midazolam in Comparison with Tezampanel (LY293558) against Soman-Induced Status Epilepticus. TOXICS 2022; 10:409. [PMID: 35893842 PMCID: PMC9330837 DOI: 10.3390/toxics10080409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 12/12/2022]
Abstract
Acute exposure to nerve agents induces status epilepticus (SE), which can cause death or long-term brain damage. Diazepam is approved by the FDA for the treatment of nerve agent-induced SE, and midazolam (MDZ) is currently under consideration to replace diazepam. However, animal studies have raised questions about the neuroprotective efficacy of benzodiazepines. Here, we compared the antiseizure and neuroprotective efficacy of MDZ (5 mg/kg) with that of tezampanel (LY293558; 10 mg/kg), an AMPA/GluK1 receptor antagonist, administered 1 h after injection of the nerve agent, soman (1.2 × LD50), in adult male rats. Both of the anticonvulsants promptly stopped SE, with MDZ having a more rapid effect. However, SE reoccurred to a greater extent in the MDZ-treated group, resulting in a significantly longer total duration of SE within 24 h post-exposure compared with the LY293558-treated group. The neuroprotective efficacy of the two drugs was studied in the basolateral amygdala, 30 days post-exposure. Significant neuronal and inter-neuronal loss, reduced ratio of interneurons to the total number of neurons, and reduction in spontaneous inhibitory postsynaptic currents accompanied by increased anxiety were found in the MDZ-treated group. The rats treated with LY293558 did not differ from the control rats (not exposed to soman) in any of these measurements. Thus, LY293558 has significantly greater efficacy than midazolam in protecting against prolonged seizures and brain damage caused by acute nerve agent exposure.
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Affiliation(s)
- Taiza H. Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Volodymyr I. Pidoplichko
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
| | - James P. Apland
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, MD 21010, USA;
| | - Maria F. M. Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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7
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Countermeasures in organophosphorus intoxication: pitfalls and prospects. Trends Pharmacol Sci 2022; 43:593-606. [DOI: 10.1016/j.tips.2022.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/14/2022] [Accepted: 04/17/2022] [Indexed: 11/24/2022]
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8
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Aroniadou-Anderjaska V, Apland JP, Figueiredo TH, De Araujo Furtado M, Braga MF. Acetylcholinesterase inhibitors (nerve agents) as weapons of mass destruction: History, mechanisms of action, and medical countermeasures. Neuropharmacology 2020; 181:108298. [DOI: 10.1016/j.neuropharm.2020.108298] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/21/2020] [Accepted: 09/02/2020] [Indexed: 02/07/2023]
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Deshpande LS, Blair RE, Halquist M, Kosmider L, DeLorenzo RJ. Intramuscular atenolol and levetiracetam reduce mortality in a rat model of paraoxon-induced status epilepticus. Ann N Y Acad Sci 2020; 1480:219-232. [PMID: 32961584 DOI: 10.1111/nyas.14500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/21/2020] [Accepted: 09/01/2020] [Indexed: 12/01/2022]
Abstract
Organophosphorus (OP) compounds are chemical threat agents and are irreversible inhibitors of the enzyme acetylcholinesterase that lead to a hypercholinergic response that could include status epilepticus (SE). SE particularly targets the heart and brain and despite existing therapies, it is still associated with significant mortality and morbidity. Here, we investigated the effect of intramuscular (i.m.) adjunct therapy consisting of atenolol (AT) and levetiracetam (LV) when administered after paraoxon (POX)-induced SE. The combination therapy was administered twice daily for 2, 7, or 14 days. POX exposure in rats produced rapid SE onset that was treated with atropine, pralidoxime chloride, and midazolam. Here, AT + LV therapy produced significant reductions in POX SE mortality assessed at 30 days post-SE. AT + LV therapy exhibited muscle pathology inflammation scores that were not significantly different from saline-treated controls. Pharmacokinetic analyses revealed that the i.m. route achieved faster and stabler plasma therapeutic levels for both AT and LV under OP SE conditions compared with oral administrations. Our data provide evidence of the safety and efficacy of i.m. AT + LV therapy for reducing mortality following POX SE.
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Affiliation(s)
- Laxmikant S Deshpande
- Department of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Robert E Blair
- Department of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Matthew Halquist
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Leon Kosmider
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Robert J DeLorenzo
- Department of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
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Zare Z, Zarbakhsh S, Tehrani M, Mohammadi M. Paraoxon-induced damage in rat hippocampus is associated with alterations in the expression of apoptosis-related proteins. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 166:104580. [PMID: 32448426 DOI: 10.1016/j.pestbp.2020.104580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/02/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
To determine the possible role of apoptosis in the development of paraoxon-induced brain damage, we evaluated expression of apoptosis-related proteins, the extent of neuronal damage, and activation of astrocytes in rat hippocampus. Adult male Wistar rats were intraperitoneally injected with one of three doses of paraoxon (0.3, 0.7, or 1 mg/kg) or corn oil (vehicle). After 14 or 28 days, expression of apoptosis-related proteins, including B-cell leukemia/lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), and caspase-3, as well as the number of neurons and glial fibrillary acidic protein (GFAP) positive cells in hippocampus were examined by western blot, cresyl blue staining, and immunohistochemistry, respectively. After 14 and 28 days, Bax and caspase-3 proteins were significantly increased in rats receiving 0.7 and 1 mg/kg of paraoxon. A significant decrease in Bcl-2 protein levels was also observed in 0.7 and 1 mg/kg groups after 14 days and in 1 mg/kg group after 28 days. Animals treated with 1 mg/kg of paraoxon showed a significant decrease in the number of neurons in the CA1 area. Also, those treated with 0.7 and 1 mg/kg of paraoxon showed an increase in the number of GFAP positive cells in both CA1 and CA3 areas as well as a significant decrease in survived neurons in the CA3 area. Our results indicated that neuronal damage induced by convulsive doses of paraoxon in rat hippocampus is mediated in part through apoptosis mechanism. Activation of astrocytes might lead to reduced extent of damage and damage and consequently increased neuronal survival.
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Affiliation(s)
- Zohreh Zare
- Department of Anatomical Sciences, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sam Zarbakhsh
- Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Mohsen Tehrani
- Department of Immunology, Gastrointestinal Cancer Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Moslem Mohammadi
- Department of Physiology, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
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11
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Dail MB, Leach CA, Meek EC, Olivier AK, Pringle RB, Green CE, Chambers JE. Novel Brain-Penetrating Oxime Acetylcholinesterase Reactivators Attenuate Organophosphate-Induced Neuropathology in the Rat Hippocampus. Toxicol Sci 2020; 169:465-474. [PMID: 30835286 DOI: 10.1093/toxsci/kfz060] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Organophosphate (OP) anticholinesterases cause excess acetylcholine leading to seizures which, if prolonged, result in neuronal damage in the rodent brain. Novel substituted phenoxyalkyl pyridinium oximes have previously shown evidence of penetrating the rat blood-brain barrier (BBB) in in vivo tests with a sarin surrogate (nitrophenyl isopropyl methylphosphonate, NIMP) or the active metabolite of the insecticide parathion, paraoxon (PXN), by reducing the time to cessation of seizure-like behaviors and accumulation of glial fibrillary acidic protein, whereas 2-PAM did not. The neuroprotective ability of our lead oximes (15, 20, and 55) was tested using NeuN, Nissl, and Fluoro-Jade B staining in the rat hippocampus. Following lethal-level subcutaneous challenge with NIMP or PXN, rats were intramuscularly administered a novel oxime or 2-PAM plus atropine and euthanized at 4 days. There were statistically significant increases in the median damage scores of the NeuN-stained NIMP, NIMP/2-PAM, and NIMP/Oxime 15 groups compared with the control whereas the scores of the NIMP/Oxime 20 and NIMP/Oxime 55 were not significantly different from the control. The same pattern of statistical significance was observed with PXN. Nissl staining provided a similar pattern, but without statistical differences. Fluoro-Jade B indicated neuroprotection from PXN with novel oximes but not with 2-PAM. The longer blood residence times of Oximes 20 and 55 compared with Oxime 15 might have contributed to their greater efficacy. These results suggest that novel oximes 20 and 55 were able to penetrate the BBB and attenuate neuronal damage after NIMP and PXN exposure, indicating potential broad-spectrum usefulness.
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Affiliation(s)
- Mary B Dail
- *Department of Basic Sciences, Center for Environmental Health Sciences
| | - Charles A Leach
- *Department of Basic Sciences, Center for Environmental Health Sciences
| | - Edward C Meek
- *Department of Basic Sciences, Center for Environmental Health Sciences
| | - Alicia K Olivier
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762
| | - Ronald B Pringle
- *Department of Basic Sciences, Center for Environmental Health Sciences
| | - Carol E Green
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Janice E Chambers
- *Department of Basic Sciences, Center for Environmental Health Sciences
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12
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De Araujo Furtado M, Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Braga MFM. Electroencephalographic analysis in soman-exposed 21-day-old rats and the effects of midazolam or LY293558 with caramiphen. Ann N Y Acad Sci 2020; 1479:122-133. [PMID: 32237259 DOI: 10.1111/nyas.14331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 12/19/2022]
Abstract
Acute nerve agent exposure induces status epilepticus (SE), which can cause brain damage or death. Research aiming at developing effective therapies for controlling nerve agent-induced SE is commonly performed in adult rats. The characteristics of nerve agent-induced SE in young rats are less clear; relevant knowledge is necessary for developing effective pediatric therapies. Here, we have used electroencephalographic (EEG) recordings and analysis to study seizures in postnatal day 21 rats exposed to 1.2 × LD50 of soman, and compared the antiseizure efficacy of midazolam (MDZ)-currently considered by the Food and Drug Administration to replace diazepam for treating SE in victims of nerve agent exposure-with that of LY293558, an AMPA/GluK1 receptor antagonist, administered in combination with caramiphen, an antimuscarinic with N-methyl-d-aspartate receptor antagonistic properties. Prolonged SE developed in 80% of the rats and was reflected in behavioral seizures/convulsions. Both MDZ and LY293558 + caramiphen stopped the SE induced by soman, but there was a significant recurrence of seizures within 24 h postexposure only in the MDZ-treated group, as revealed in the raw EEG data and their representation in the frequency domain using a fast Fourier transform and in spectral analysis over 24 hours. In contrast to the high efficacy of LY293558 + caramiphen, MDZ is not an effective treatment for SE induced by soman in young animals.
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Affiliation(s)
- Marcio De Araujo Furtado
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - James P Apland
- Neurotoxicology Branch, the United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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13
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Midazolam and isoflurane combination reduces late brain damage in the paraoxon-induced status epilepticus rat model. Neurotoxicology 2020; 78:99-105. [PMID: 32084435 DOI: 10.1016/j.neuro.2020.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 11/20/2022]
Abstract
Organophosphates (OPs) are widely used as pesticides and have been employed as warfare agents. OPs inhibit acetylcholinesterase, leading to over-stimulation of cholinergic synapses and can cause status epilepticus (SE). OPs poisoning can result in irreversible brain damage and death. Despite termination of SE, recurrent seizures and abnormal brain activity remain common sequelae often associated with long-term neural damage and cognitive dysfunction. Therefore, early treatment for prevention of seizures is of high interest. Using a rat model of paraoxon poisoning, we tested the efficacy of different neuroprotective and anti-epileptic drugs (AEDs) in suppressing early seizures and preventing brain damage. Electrocorticographic recordings were performed prior, during and after injection of 4.5 LD50 paraoxon, followed by injections of atropine and toxogonin (obidoxime) to prevent death. Thirty minutes later, rats were injected with midazolam alone or in combination with different AEDs (lorazepam, valproic acid, phenytoin) or neuroprotective drugs (losartan, isoflurane). Outcome measures included SE duration, early seizures frequency and epileptiform activity duration in the first 24 -hs after poisoning. To assess delayed brain damage, we performed T2-weighted magnetic resonance imaging one month after poisoning. SE duration and the number of recurrent seizures were not affected by the addition of any of the drugs tested. Delayed brain injury was most prominent in the septum, striatum, amygdala and piriform network. Only isoflurane anesthesia significantly reduced brain damage. We show that acute treatment with isoflurane, but not AEDs, reduces brain damage following SE. This may offer a new therapeutic approach for exposed individuals.
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14
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Czajka M, Matysiak-Kucharek M, Jodłowska-Jędrych B, Sawicki K, Fal B, Drop B, Kruszewski M, Kapka-Skrzypczak L. Organophosphorus pesticides can influence the development of obesity and type 2 diabetes with concomitant metabolic changes. ENVIRONMENTAL RESEARCH 2019; 178:108685. [PMID: 31479978 DOI: 10.1016/j.envres.2019.108685] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 08/09/2019] [Accepted: 08/21/2019] [Indexed: 06/10/2023]
Abstract
Widespread use and the bioaccumulation of pesticides in the environment lead to the contamination of air, water, soil and agricultural resources. A huge body of evidence points to the association between the pesticide exposure and increase in the incidence of chronic diseases, e.g. cancer, birth defects, reproductive disorders, neurodegenerative, cardiovascular and respiratory diseases, developmental disorders, metabolic disorders, chronic renal disorders or autoimmune diseases. Organophosphorus compounds are among the most widely used pesticides. A growing body of evidence is suggesting the potential interdependence between the organophosphorus pesticides (OPs) exposure and risk of obesity and type 2 diabetes mellitus (T2DM). This article reviews the current literature to highlight the latest in vitro and in vivo evidences on the possible influence of OPs on obesity and T2DM development, as well as epidemiological evidence for the metabolic toxicity of OPs in humans. The article also draws attention to the influence of maternal OPs exposure on offspring. Summarized studies suggest that OPs exposure is associated with metabolic changes linked with obesity and T2DM indicated that such exposures may increase risk or vulnerability to other contributory components.
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Affiliation(s)
- Magdalena Czajka
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland.
| | - Magdalena Matysiak-Kucharek
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland
| | - Barbara Jodłowska-Jędrych
- Department of Histology and Embryology with Experimental Cytology Unit, Medical University of Lublin, 20-080, Lublin, Poland
| | - Krzysztof Sawicki
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland
| | - Berta Fal
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland
| | - Bartłomiej Drop
- Department of Medical Informatics and Statistics with E-learning Lab, Medical University of Lublin, 20-090, Lublin, Poland
| | - Marcin Kruszewski
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland; Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195, Warsaw, Poland
| | - Lucyna Kapka-Skrzypczak
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20-090, Lublin, Poland.
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15
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Robidillo CJT, Wandelt S, Dalangin R, Zhang L, Yu H, Meldrum A, Campbell RE, Veinot JGC. Ratiometric Detection of Nerve Agents by Coupling Complementary Properties of Silicon-Based Quantum Dots and Green Fluorescent Protein. ACS APPLIED MATERIALS & INTERFACES 2019; 11:33478-33488. [PMID: 31414591 DOI: 10.1021/acsami.9b10996] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ratiometric photoluminescent detection of the toxicologically potent organophosphate ester nerve agents paraoxon (PX) and parathion (PT) using the complementary optical and chemical properties of the long Stokes shift green fluorescent protein variant, mAmetrine1.2 (mAm), and red-emitting silicon-based quantum dots (SiQDs) is reported. PX and PT selectively quench SiQD photoluminescence (PL) through a dynamic quenching mechanism, thereby, facilitating the development of a ratiometric sensor platform that shows micromolar limits of detection for PX and PT and that is unaffected by the presence of common inorganic and organic interferents. As a part of the present study, we also demonstrate that the paper-based sensors derived from mAm and SiQDs detect PX and PT at concentrations as low as 5 μM using a readily available commercial color analysis smartphone "app". The ratiometric sensor reported herein can potentially be used for the convenient and rapid on-site detection and quantification of PX and PT in real-world samples.
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Affiliation(s)
- Christopher Jay T Robidillo
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
- Department of Physical Sciences and Mathematics , University of the Philippines Manila , P. Faura Street , Ermita, Manila 1000 , Philippines
| | - Sophia Wandelt
- Faculty of Chemistry and Pharmacy , Ludwig-Maximilians-Universität München , Munich 81377 , Germany
| | - Rochelin Dalangin
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
| | - Lijuan Zhang
- Department of Physics , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - Haoyang Yu
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
| | - Alkiviathes Meldrum
- Department of Physics , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - Robert E Campbell
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
- Department of Chemistry , The University of Tokyo , Tokyo 113-0033 , Japan
| | - Jonathan G C Veinot
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
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16
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Pearson-Smith JN, Patel M. Antioxidant drug therapy as a neuroprotective countermeasure of nerve agent toxicity. Neurobiol Dis 2019; 133:104457. [PMID: 31028872 PMCID: PMC7721294 DOI: 10.1016/j.nbd.2019.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
The use of chemical warfare agents is an ongoing, significant threat to both civilians and military personnel worldwide. Nerve agents are by far the most formidable toxicants in terms of their lethality and toxicity. Nerve agents initiate neurotoxicity by the irreversible inhibition of acetylcholinesterase and resultant accumulation of acetylcholine in excitable tissues. The cholinergic toxidrome presents as miosis, lacrimation, diarrhea, fasciculations, seizures, respiratory arrest and coma. Current medical countermeasures can attenuate acute mortality and confer limited protection against secondary neuronal injury when given rapidly after exposure. However, there is an urgent need for the development of novel, add-on neuroprotective therapies to prevent mortality and long-term toxicity of nerve agents. Increasing evidence suggests that pathways other than direct acetylcholinesterase inhibition contribute to neurotoxicity and secondary neuronal injury. Among these, oxidative stress is emerging as a key therapeutic target for nerve agent toxicity. In this review, we discuss the rationale for targeting oxidative stress in nerve agent toxicity and highlight research investigating antioxidant therapy as a neuroprotective medical countermeasure to attenuate oxidative stress, neuroinflammation and neurodegeneration.
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Affiliation(s)
- Jennifer N Pearson-Smith
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America.
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17
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Putra M, Sharma S, Gage M, Gasser G, Hinojo-Perez A, Olson A, Gregory-Flores A, Puttachary S, Wang C, Anantharam V, Thippeswamy T. Inducible nitric oxide synthase inhibitor, 1400W, mitigates DFP-induced long-term neurotoxicity in the rat model. Neurobiol Dis 2019; 133:104443. [PMID: 30940499 DOI: 10.1016/j.nbd.2019.03.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/22/2019] [Accepted: 03/28/2019] [Indexed: 11/26/2022] Open
Abstract
Chemical nerve agents (CNA) are increasingly becoming a threat to both civilians and military personnel. CNA-induced acute effects on the nervous system have been known for some time and the long-term consequences are beginning to emerge. In this study, we used diisopropylfluorophosphate (DFP), a seizurogenic CNA to investigate the long-term impact of its acute exposure on the brain and its mitigation by an inducible nitric oxide synthase (iNOS) inhibitor, 1400W as a neuroprotectant in the rat model. Several experimental studies have demonstrated that DFP-induced seizures and/or status epilepticus (SE) causes permanent brain injury, even after the countermeasure medication (atropine, oxime, and diazepam). In the present study, DFP-induced SE caused a significant increase in iNOS and 3-nitrotyrosine (3-NT) at 24 h, 48 h, 7d, and persisted for a long-term (12 weeks post-exposure), which led to the hypothesis that iNOS is a potential therapeutic target in DFP-induced brain injury. To test the hypothesis, we administered 1400W (20 mg/kg, i.m.) or the vehicle twice daily for the first three days of post-exposure. 1400W significantly reduced DFP-induced iNOS and 3-NT upregulation in the hippocampus and piriform cortex, and the serum nitrite levels at 24 h post-exposure. 1400W also prevented DFP-induced mortality in <24 h. The brain immunohistochemistry (IHC) at 7d post-exposure revealed a significant reduction in gliosis and neurodegeneration (NeuN+ FJB positive cells) in the 1400W-treated group. 1400W, in contrast to the vehicle, caused a significant reduction in the epileptiform spiking and spontaneous recurrent seizures (SRS) during 12 weeks of continuous video-EEG study. IHC of brain sections from the same animals revealed a significant reduction in reactive gliosis (both microgliosis and astrogliosis) and neurodegeneration across various brain regions in the 1400W-treated group when compared to the vehicle-treated group. A multiplex assay from hippocampal lysates at 6 weeks post-exposure showed a significant increase in several key pro-inflammatory cytokines/chemokines such as IL-1α, TNFα, IL-1β, IL-2, IL-6, IL-12, IL-17a, MCP-1, LIX, and Eotaxin, and a growth factor, VEGF in the vehicle-treated animals. 1400W significantly suppressed IL-1α, TNFα, IL-2, IL-12, and MCP-1 levels. It also suppressed DFP-induced serum nitrite levels at 6 weeks post-exposure. In the Morris water maze, the vehicle-treated animals spent significantly less time in the target quadrant in a probe trial at 9d post-exposure compared to their time spent in the same quadrant 11 days previously (i.e., 2 days prior to DFP exposure). Such a difference was not observed in the 1400W and control groups. However, learning and short-term memory were unaffected when tested at 10-16d and 28-34d post-exposure. Accelerated rotarod, horizontal bar test, and the forced swim test revealed no significant changes between groups. Overall, the findings from this study suggest that 1400W may be considered as a potential therapeutic agent as a follow-on therapy for CNA exposure, after controlling the acute symptoms, to prevent mortality and some of the long-term neurotoxicity parameters such as epileptiform spiking, SRS, neurodegeneration, reactive gliosis in some brain regions, and certain key proinflammatory cytokines and chemokine.
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Affiliation(s)
- Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Shaunik Sharma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Andy Hinojo-Perez
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Ashley Olson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Adriana Gregory-Flores
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, United States
| | - Chong Wang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States.
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18
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Deshpande LS, DeLorenzo RJ. Novel therapeutics for treating organophosphate-induced status epilepticus co-morbidities, based on changes in calcium homeostasis. Neurobiol Dis 2019; 133:104418. [PMID: 30872159 DOI: 10.1016/j.nbd.2019.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/26/2019] [Accepted: 03/09/2019] [Indexed: 11/24/2022] Open
Abstract
Organophosphate (OP) chemicals include pesticides such as parathion, and nerve gases such as sarin and soman and are considered major chemical threat agents. Acute OP exposure is associated with a cholinergic crisis and status epilepticus (SE). It is also known that the survivors of OP toxicity exhibit neurobehavioral deficits such as mood changes, depression, and memory impairment, and acquired epilepsy. Our research has focused on addressing the need to develop effective therapeutic agents that could be administered even after prolonged seizures and would prevent or lessen the chronic morbidity associated with OP-SE survival. We have developed rat survival models of OP pesticide metabolite paraoxon (POX) and nerve agent sarin surrogate diisopropyl fluorophosphate (DFP) induced SE that are being used to screen for medical countermeasures against an OP attack. Our research has focused on studying neuronal calcium (Ca2+) homeostatic mechanisms for identifying mechanisms and therapeutics for the expression of neurological morbidities associated with OP-SE survival. We have observed development of a "Ca2+ plateau" characterized by sustained elevations in neuronal Ca2+ levels in OP-SE surviving rats that coincided with the appearance of OP-SE chronic morbidities. These Ca2+ elevations had their origin in Ca2+ release from the intracellular stores such that blockade with antagonists like dantrolene, carisbamate, and levetiracetam lowered OP-SE mediated Ca2+ plateau and afforded significant neuroprotection. Since the Ca2+ plateau lasts for a prolonged period, our studies suggest that blocking it after the control of SE may represent a unique target for development of novel countermeasures to prevent long term Ca2+ mediated OP-SE neuropsychiatric comorbidities such as depression, anxiety, and acquired epilepsy (AE).
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Affiliation(s)
- Laxmikant S Deshpande
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Robert J DeLorenzo
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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19
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Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Braga MF. Targeting the glutamatergic system to counteract organophosphate poisoning: A novel therapeutic strategy. Neurobiol Dis 2019; 133:104406. [PMID: 30798006 DOI: 10.1016/j.nbd.2019.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/23/2019] [Accepted: 02/20/2019] [Indexed: 12/15/2022] Open
Abstract
One of the devastating effects of acute exposure to organophosphates, like nerve agents, is the induction of severe and prolonged status epilepticus (SE), which can cause death, or brain damage if death is prevented. Seizures after exposure are initiated by muscarinic receptor hyperstimulation-after inhibition of acetylcholinesterase by the organophosphorus agent and subsequent elevation of acetylcholine-but they are reinforced and sustained by glutamatergic hyperexcitation, which is the primary cause of brain damage. Diazepam is the FDA-approved anticonvulsant for the treatment of nerve agent-induced SE, and its replacement by midazolam is currently under consideration. However, clinical data derived from the treatment of SE of any etiology, as well as studies on the control of nerve agent-induced SE in animal models, have indicated that diazepam and midazolam control seizures only temporarily, their antiseizure efficacy is reduced as the latency of treatment from the onset of SE increases, and their neuroprotective efficacy is limited or absent. Here, we review data on the discovery of a novel anticonvulsant and neuroprotectant, LY293558, an AMPA/GluK1 receptor antagonist. Treatment of soman-exposed immature, young-adult, and aged rats with LY293558, terminates SE with limited recurrence of seizures, significantly protects from brain damage, and prevents long-term behavioral deficits, even when LY293558 is administered 1 h post-exposure. More beneficial effects and complete neuroprotection is obtained when LY293558 administration is combined with caramiphen, which antagonizes NMDA receptors. Further efficacy studies may bring the LY293558 + caramiphen combination therapy on the pathway to approval for human use.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States of America; Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States of America.
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States of America.
| | - James P Apland
- Neuroscience Program, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, United States of America.
| | - Maria F Braga
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States of America; Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States of America.
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20
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Anxiolytic activity of paraoxon is associated with alterations in rat brain glutamatergic system. Neurotoxicol Teratol 2018; 71:32-40. [PMID: 30576762 DOI: 10.1016/j.ntt.2018.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 01/18/2023]
Abstract
Exposure to organophosphate (OP) compounds leads to behavioral alterations. To determine whether paraoxon has effects on anxiety, anxiety-like behaviors were assessed in paraoxon-exposed rats. Protein expression of glutamate transporters has also been measured in hippocampus and prefrontal cortex. Three doses of paraoxon (0.3, 0.7, or 1 mg/kg) or corn oil (vehicle) were intraperitoneally injected to adult male rats. At 14 or 28 days after exposure, behavioral tests were done using elevated plus-maze (EPM) or open field tests. Thereafter, animals were sacrificed and both hippocampi and prefrontal cortices were extracted for cholinesterase assay and western blotting. Animals treated with convulsive doses of paraoxon (0.7 and 1 mg/kg) showed an increase in percentage of time spent in open arms and percentage of open arm entries in the EPM. In the open field test, an increase in the time spent in central area was observed in rats treated with the same doses of paraoxon. These effects of paraoxon were independent of any changes in locomotor activity. There was an increase in both astrocytic glutamate transporter proteins (GLAST and GLT-1) in the hippocampus of animals treated with 0.7 and 1 mg/kg of paraoxon. In the prefrontal cortex, protein levels of the GLAST and GLT-1 increased in 0.7 and decreased in 1 mg/kg groups. Only a significant decrease in EAAC1 protein was observed in the prefrontal cortex at 14 days following exposure to 1 mg/kg of paraoxon. Collectively, this study showed that exposure to convulsive doses of paraoxon induced anxiolytic-like behaviors in both behavioral tests. This effect may be attributed to alterations of glutamate transporter proteins in the rat hippocampus and prefrontal cortex.
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Chao CK, Balasubramanian N, Gerdes JM, Thompson CM. The inhibition, reactivation and mechanism of VX-, sarin-, fluoro-VX and fluoro-sarin surrogates following their interaction with HuAChE and HuBuChE. Chem Biol Interact 2018; 291:220-227. [PMID: 29920286 PMCID: PMC6061941 DOI: 10.1016/j.cbi.2018.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/20/2018] [Accepted: 06/15/2018] [Indexed: 10/14/2022]
Abstract
In this study, the mechanisms of HuAChE and HuBChE inhibition by Me-P(O) (OPNP) (OR) [PNP = p-nitrophenyl; R = CH2CH3, CH2CH2F, OCH(CH3)2, OCH(CH3) (CH2F)] representing surrogates and fluoro-surrogates of VX and sarin were studied by in vitro kinetics and mass spectrometry. The in vitro measures showed that the VX- and fluoro-VX surrogates were relatively strong inhibitors of HuAChE and HuBChE (ki ∼ 105-106 M-1min-1) and underwent spontaneous and 2-PAM-mediated reactivation within 30 min. The sarin surrogates were weaker inhibitors of HuAChE and HuBChE (ki ∼ 104-105 M-1min-1), and in general did not undergo spontaneous reactivation, although HuAChE adducts were partially reactivatable at 18 h using 2-PAM. The mechanism of HuAChE and HuBChE inhibition by the surrogates was determined by Q-TOF and MALDI-TOF mass spectral analyses. The surrogate-adducted proteins were trypsin digested and the active site-containing peptide bearing the OP-modified serine identified by Q-TOF as triply- and quadruply-charged ions representing the respective increase in mass of the attached OP moiety. Correspondingly, monoisotopic ions of the tryptic peptides representing the mass increase of the OP-adducted peptide was identified by MALDI-TOF. The mass spectrometry analyses validated the identity of the OP moiety attached to HuAChE or HuBChE as MeP(O) (OR)-O-serine peptides (loss of the PNP leaving group) via mechanisms consistent with those found with chemical warfare agents. MALDI-TOF MS analyses of the VX-modified peptides versus time showed a steady reduction in adduct versus parent peptide (reactivation), whereas the sarin-surrogate-modified peptides remained largely intact over the course of the experiment (24 h). Overall, the presence of a fluorine atom on the surrogate modestly altered the rate constants of inhibition and reactivation, however, the mechanism of inhibition (ejection of PNP group) did not change.
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Affiliation(s)
- Chih-Kai Chao
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, United States
| | | | - John M Gerdes
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, United States
| | - Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, United States.
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Selvolini G, Băjan I, Hosu O, Cristea C, Săndulescu R, Marrazza G. DNA-Based Sensor for the Detection of an Organophosphorus Pesticide: Profenofos. SENSORS 2018; 18:s18072035. [PMID: 29941847 PMCID: PMC6068880 DOI: 10.3390/s18072035] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/10/2018] [Accepted: 06/19/2018] [Indexed: 11/16/2022]
Abstract
In this work, we propose an electrochemical DNA aptasensor for the detection of profenofos, an organophosphorus pesticide, based on a competitive format and disposable graphite screen-printed electrodes (GSPEs). A thiol-tethered DNA capture probe, which results to be complementary to the chosen aptamer sequence, was immobilised on gold nanoparticles/polyaniline composite film-modified electrodes (AuNPs/PANI/GSPE). Different profenofos solutions containing a fixed amount of the biotinylated DNA aptamer were dropped onto the realized aptasensors. The hybridisation reaction was measured using a streptavidin-alkaline phosphatase enzyme conjugate, which catalyses the hydrolysis of 1-naphthyl -phosphate. The 1-naphtol enzymatic product was detected by means of differential pulse voltammetry (DPV). The aptasensor showed itself to work as a signal off sensor, according to the competitive format used. A dose response curve was obtained between 0.10 μM and 10 μM with a detection limit of 0.27 μM.
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Affiliation(s)
- Giulia Selvolini
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
| | - Ioana Băjan
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
- Department of Analytical Chemistry, University of Medicine and Pharmacy "Iuliu Haţieganu", 4 Pasteur Street, 400349 Cluj-Napoca, Romania.
| | - Oana Hosu
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
- Department of Analytical Chemistry, University of Medicine and Pharmacy "Iuliu Haţieganu", 4 Pasteur Street, 400349 Cluj-Napoca, Romania.
| | - Cecilia Cristea
- Department of Analytical Chemistry, University of Medicine and Pharmacy "Iuliu Haţieganu", 4 Pasteur Street, 400349 Cluj-Napoca, Romania.
| | - Robert Săndulescu
- Department of Analytical Chemistry, University of Medicine and Pharmacy "Iuliu Haţieganu", 4 Pasteur Street, 400349 Cluj-Napoca, Romania.
| | - Giovanna Marrazza
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
- Istituto Nazionale Biostrutture e Biosistemi (INBB), Unit of Florence, Viale delle Medaglie d'Oro 305, 00136 Roma, Italy.
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Phillips KF, Deshpande LS, DeLorenzo RJ. Hypothermia Reduces Mortality, Prevents the Calcium Plateau, and Is Neuroprotective Following Status Epilepticus in Rats. Front Neurol 2018; 9:438. [PMID: 29942282 PMCID: PMC6005175 DOI: 10.3389/fneur.2018.00438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/24/2018] [Indexed: 12/13/2022] Open
Abstract
Status Epilepticus (SE) is a major neurological emergency and is considered a leading cause of Acquired Epilepsy (AE). We have shown that SE produces neuronal injury and prolonged alterations in hippocampal calcium levels ([Ca2+]i) that may underlie the development of AE. Interventions preventing the SE-induced Ca2+ plateau could therefore prove to be beneficial in lowering the development of AE after SE. Hypothermia is used clinically to prevent neurological complications associated with Traumatic Brain Injury, cardiac arrest, and stroke. Here, we investigated whether hypothermia prevented the development of Ca2+ plateau following SE. SE was induced in hippocampal neuronal cultures (HNC) by exposing them to no added MgCl2 solution for 3 h. To terminate SE, low Mg2+ solution was washed off with 31°C (hypothermic) or 37°C (normothermic) physiological recording solution. [Ca2+]i was estimated with ratiometric Fura-2 imaging. HNCs washed with hypothermic solution exhibited [Ca2+]i ratios, which were significantly lower than ratios obtained from HNCs washed with normothermic solution. For in vivo SE, the rat pilocarpine (PILO) model was used. Moderate hypothermia (30–33°C) in rats was induced at 30-min post-SE using chilled ethanol spray in a cold room. Hypothermia following PILO-SE significantly reduced mortality. Hippocampal neurons isolated from hypothermia-treated PILO SE rats exhibited [Ca2+]i ratios which were significantly lower than ratios obtained from PILO SE rats. Hypothermia also provided significant neuroprotection against SE-induced delayed hippocampal injury as characterized by decreased FluoroJade C labeling in hypothermia-treated PILO SE rats. We previously demonstrated that hypothermia reduced Ca2+ entry via N-methyl-D-aspartate and ryanodine receptors in HNC. Together, our studies indicate that by targeting these two receptor systems hypothermia could interfere with epileptogenesis and prove to be an effective therapeutic intervention for reducing SE-induced AE.
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Affiliation(s)
- Kristin F Phillips
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
| | - Laxmikant S Deshpande
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States.,Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Robert J DeLorenzo
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States.,Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
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Apland JP, Aroniadou-Anderjaska V, Figueiredo TH, Pidoplichko VI, Rossetti K, Braga MFM. Comparing the Antiseizure and Neuroprotective Efficacy of LY293558, Diazepam, Caramiphen, and LY293558-Caramiphen Combination against Soman in a Rat Model Relevant to the Pediatric Population. J Pharmacol Exp Ther 2018; 365:314-326. [PMID: 29467308 PMCID: PMC5878669 DOI: 10.1124/jpet.117.245969] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/08/2018] [Indexed: 12/13/2022] Open
Abstract
The currently Food and Drug Administration-approved anticonvulsant for the treatment of status epilepticus (SE) induced by nerve agents is the benzodiazepine diazepam; however, diazepam does not appear to offer neuroprotective benefits. This is of particular concern with respect to the protection of children because, in the developing brain, synaptic transmission mediated via GABAA receptors, the target of diazepam, is weak. In the present study, we exposed 21-day-old male rats to 1.2 × LD50 soman and compared the antiseizure, antilethality, and neuroprotective efficacy of diazepam (10 mg/kg), LY293558 (an AMPA/GluK1 receptor antagonist; 15 mg/kg), caramiphen (CRM, an antimuscarinic with NMDA receptor-antagonistic properties; 50 mg/kg), and LY293558 (15 mg/kg) + CRM (50 mg/kg), administered 1 hour after exposure. Diazepam, LY293558, and LY293558 + CRM, but not CRM alone, terminated SE; LY293558 + CRM treatment acted significantly faster and produced a survival rate greater than 85%. Thirty days after soman exposure, neurodegeneration in limbic regions was most severe in the CRM-treated group, minimal to severe-depending on the region-in the diazepam group, absent to moderate in the LY293558-treated group, and totally absent in the LY293558 + CRM group. Amygdala and hippocampal atrophy, a severe reduction in spontaneous inhibitory activity in the basolateral amygdala, and increased anxiety-like behavior in the open-field and acoustic startle response tests were present in the diazepam and CRM groups, whereas the LY293558 and LY293558 + CRM groups did not differ from controls. The combined administration of LY293558 and CRM, by blocking mainly AMPA, GluK1, and NMDA receptors, is a very effective anticonvulsant and neuroprotective therapy against soman in young rats.
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Affiliation(s)
- James P Apland
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Vassiliki Aroniadou-Anderjaska
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Taiza H Figueiredo
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Volodymyr I Pidoplichko
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Katia Rossetti
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.); and Departments of Anatomy, Physiology, and Genetics (V.A.-A., T.H.F., V.I.P., K.R., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Zenki KC, Kalinine E, Zimmer ER, dos Santos TG, Mussulini BHM, Portela LVC, de Oliveira DL. Memantine decreases neuronal degeneration in young rats submitted to LiCl-pilocarpine-induced status epilepticus. Neurotoxicology 2018; 66:45-52. [DOI: 10.1016/j.neuro.2018.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 12/25/2022]
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Full Protection Against Soman-Induced Seizures and Brain Damage by LY293558 and Caramiphen Combination Treatment in Adult Rats. Neurotox Res 2018; 34:511-524. [PMID: 29713995 DOI: 10.1007/s12640-018-9907-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 04/14/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
Acute exposure to nerve agents induces status epilepticus (SE), which causes brain damage or death. LY293558, an antagonist of AMPA and GluK1 kainate receptors is a very effective anticonvulsant and neuroprotectant against soman; however, some neuronal damage is still present after treatment of soman-exposed rats with LY293558. Here, we have tested whether combining LY293558 with an NMDA receptor antagonist can eliminate the residual damage. For this purpose, we chose caramiphen (CRM), an antimuscarinic compound with NMDA receptor antagonistic properties. Adult male rats were exposed to 1.2 × LD50 soman, and at 20 min after soman exposure, were injected with atropine + HI-6, or atropine + HI-6 + LY293558 (15 mg/kg), or atropine + HI-6 + LY293558 + CRM (50 mg/kg). We found that (1) the LY293558 + CRM treatment terminated SE significantly faster than LY293558 alone; (2) after cessation of the initial SE, seizures did not return in the LY293558 + CRM-treated group, during 72 h of monitoring; (3) power spectrum analysis of continuous EEG recordings for 7 days post-exposure showed increased delta and decreased gamma power that lasted beyond 24 h post-exposure only in the rats who did not receive anticonvulsant treatment; (4) spontaneous recurrent seizures appeared on day 7 only in the group that did not receive anticonvulsant treatment; (5) significant neuroprotection was achieved by LY293558 administration, while the rats who received LY293558 + CRM displayed no neurodegeneration; (6) body weight loss and recovery in the LY293558 + CRM-treated rats did not differ from those in control rats who were not exposed to soman. The data show that treatment with LY293558 + CRM provides full antiseizure and neuroprotective efficacy against soman.
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Phillips KF, Deshpande LS. Chronic Neurological Morbidities and Elevated Hippocampal Calcium Levels in a DFP-Based Rat Model of Gulf War Illness. Mil Med 2018; 183:552-555. [DOI: 10.1093/milmed/usx148] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 12/22/2017] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kristin F Phillips
- Department of Neurology, Virginia Commonwealth University, PO Box 980599, 1217 East Marshall Street, Richmond, VA 23284
| | - Laxmikant S Deshpande
- Department of Neurology, Virginia Commonwealth University, PO Box 980599, 1217 East Marshall Street, Richmond, VA 23284
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1217 East Marshall Street, Richmond, VA 23284
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Nirwan N, Vyas P, Vohora D. Animal models of status epilepticus and temporal lobe epilepsy: a narrative review. Rev Neurosci 2018; 29:757-770. [DOI: 10.1515/revneuro-2017-0086] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/26/2018] [Indexed: 11/15/2022]
Abstract
Abstract
Temporal lobe epilepsy (TLE) is the chronic and pharmacoresistant form of epilepsy observed in humans. The current literature is insufficient in explicating the comprehensive mechanisms underlying its pathogenesis and advancement. Consequently, the development of a suitable animal model mimicking the clinical characteristics is required. Further, the relevance of status epilepticus (SE) to animal models is dubious. SE occurs rarely in people; most epilepsy patients never experience it. The present review summarizes the established animal models of SE and TLE, along with a brief discussion of the animal models that have the distinctiveness and carries the possibility to be developed as effective models for TLE. The review not only covers the basic requirements, mechanisms, and methods of induction of each model but also focuses upon their major limitations and possible modifications for their future use. A detailed discussion on chemical, electrical, and hypoxic/ischemic models as well as a brief explanation on the genetic models, most of which are characterized by development of SE followed by neurodegeneration, is presented.
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Affiliation(s)
- Nikita Nirwan
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
| | - Preeti Vyas
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
| | - Divya Vohora
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
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Krishnan JK, Figueiredo TH, Moffett JR, Arun P, Appu AP, Puthillathu N, Braga MF, Flagg T, Namboodiri AM. Brief isoflurane administration as a post-exposure treatment for organophosphate poisoning. Neurotoxicology 2017; 63:84-89. [DOI: 10.1016/j.neuro.2017.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 07/19/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
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Miller SL, Aroniadou-Anderjaska V, Pidoplichko VI, Figueiredo TH, Apland JP, Krishnan JKS, Braga MFM. The M1 Muscarinic Receptor Antagonist VU0255035 Delays the Development of Status Epilepticus after Organophosphate Exposure and Prevents Hyperexcitability in the Basolateral Amygdala. J Pharmacol Exp Ther 2016; 360:23-32. [PMID: 27799295 DOI: 10.1124/jpet.116.236125] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/27/2016] [Indexed: 12/31/2022] Open
Abstract
Exposure to organophosphorus toxins induces seizures that progress to status epilepticus (SE), which can cause brain damage or death. Seizures are generated by hyperstimulation of muscarinic receptors, subsequent to inhibition of acetylcholinesterase; this is followed by glutamatergic hyperactivity, which sustains and reinforces seizure activity. It has been unclear which muscarinic receptor subtypes are involved in seizure initiation and the development of SE in the early phases after exposure. Here, we show that pretreatment of rats with the selective M1 receptor antagonist, VU0255035 [N-(3-oxo-3-(4-(pyridine-4-yl)piperazin-1-yl)propyl)-benzo[c][1,2,5]thiadiazole-4 sulfonamide], significantly suppressed seizure severity and prevented the development of SE for about 40 minutes after exposure to paraoxon or soman, suggesting an important role of the M1 receptor in the early phases of seizure generation. In addition, in in vitro brain slices of the basolateral amygdala (a brain region that plays a key role in seizure initiation after nerve agent exposure), VU0255035 blocked the effects produced by bath application of paraoxon-namely, a brief barrage of spontaneous inhibitory postsynaptic currents, followed by a significant increase in the ratio of the total charge transferred by spontaneous excitatory postsynaptic currents over that of the inhibitory postsynaptic currents. Furthermore, paraoxon enhanced the hyperpolarization-activated cation current Ih in basolateral amygdala principal cells, which could be one of the mechanisms underlying the increased glutamatergic activity, an effect that was also blocked in the presence of VU0255035. Thus, selective M1 antagonists may be an efficacious pretreatment in contexts in which there is risk for exposure to organophosphates, as these antagonists will delay the development of SE long enough for medical assistance to arrive.
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Affiliation(s)
- Steven L Miller
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - Vassiliki Aroniadou-Anderjaska
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - Volodymyr I Pidoplichko
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - Taiza H Figueiredo
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - James P Apland
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - Jishnu K S Krishnan
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
| | - Maria F M Braga
- Departments of Anatomy, Physiology, and Genetics (S.L.M., V.A.-A., V.I.P., T.H.F., J.K.S.K., M.F.M.B.) and Psychiatry (V.A.-A., M.F.M.B.), and Program in Neuroscience (S.L.M., V.A.-A., M.F.M.B.), F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland; and Neurotoxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (J.P.A.)
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Chronic Treatment with Naltrexone Prevents Memory Retention Deficits in Rats Poisoned with the Sarin Analog Diisopropylfluorophosphate (DFP) and Treated with Atropine and Pralidoxime. J Med Toxicol 2016; 11:433-8. [PMID: 25925946 DOI: 10.1007/s13181-015-0480-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Humans and rats poisoned with sarin develop chronic neurological disabilities that are not prevented with standardized antidotal therapy. We hypothesized that rats poisoned with the sarin analogue diisopropylfluorophosphate (DFP) and resuscitated with atropine and pralidoxime would have long-term memory deficits that were preventable with naltrexone treatment. Long Evans rats (250-275 g) were randomized to: DFP (N = 8): single subcutaneous (SC) injection of DFP (5 mg/kg). Treatment (N = 9): DFP (5 mg/kg) followed by chronic naltrexone (5 mg/kg/day × 12 weeks). Control (N = 12): single SC injection of isopropyl alcohol, (DFP vehicle) followed by chronic naltrexone (5 mg/kg/day). If toxicity developed after injection, antidotal therapy was initiated with atropine (2 mg/kg) and pralidoxime (25 mg/kg) and repeated as needed. After 12 weeks, rats underwent testing for place learning (acquisition) across 5 days of training using the Morris Water Maze. On day 6 a memory retention test was performed. Statistical analysis was performed using IBM SPSS Statistics. Rats receiving DFP rapidly developed toxicity requiring antidotal rescue. No differences in acquisition were seen between the DFP vs. DFP + naltrexone rats. During memory testing, DFP-poisoned rats spent significantly less time (29.4 ± 2.11 versus 38.5 ± 2.5 s, p < 0.05) and traveled less distance (267 ± 24.6 versus 370 ± 27.5 cm, p < 0.05) in the target quadrant compared to the treatment group. Treatment rats performed as well as control rats (p > 0.05) on the test for memory retention. Poisoning with DFP induced impaired memory retention. Deficits were not prevented by acute rescue with atropine and pralidoxime. Chronic naltrexone treatment led to preserved memory after DFP poisoning.
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Pouliot W, Bealer SL, Roach B, Dudek FE. A rodent model of human organophosphate exposure producing status epilepticus and neuropathology. Neurotoxicology 2016; 56:196-203. [PMID: 27527991 DOI: 10.1016/j.neuro.2016.08.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/10/2016] [Accepted: 08/03/2016] [Indexed: 01/13/2023]
Abstract
Exposure to organophosphates (OPs) often results in seizures and/or status epilepticus (SE) that produce neural damage within the central nervous system (CNS). Early control of SE is imperative for minimizing seizure-related CNS neuropathology. Although standard therapies exist, more effective agents are needed to reduce OP-induced SE and neuronal loss, particularly therapies with efficacy when administered 10's of minutes after the onset of SE. To evaluate novel antiseizure compounds, animal models should simulate the CNS effects of OP exposure observed in humans. We characterized in rats the effects of the OP, diisopropyl flourophosphate (DFP) as a function of dose and route of administration of supporting agents (pyridostigmine, 2-PAM, atropine); outcome measures were mortality, electrographic seizure activity during SE, and subsequent CNS neuropathology. Doses of DFP between 3 and 7mg/kg consistently caused SE, and the latency to behavioral tremors and to subsequent initiation of SE were dose related. In distinction, all doses of DFP that resulted in electrographic SE (3-7mg/kg) produced seizures of similar intensity and duration, and similar CNS neuropathology (i.e., the effects were all-or-none). Although SE was similar across doses, mortality progressively increased with higher doses of DFP. Mortality was significantly lower when the route of administration of therapeutic agents was intramuscular compared to intraperitoneal. This rodent model of OP poisoning demonstrates pathological characteristics similar to those observed in humans, and thus begins to validate this model for investigating potential new therapeutic approaches.
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Affiliation(s)
- W Pouliot
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108-9999, United States
| | - S L Bealer
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108-9999, United States; Department of Pharmacology and Toxicology, University of Utah School of Medicine and College of Pharmacy, United States.
| | - B Roach
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108-9999, United States
| | - F E Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108-9999, United States
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33
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Pearson JN, Patel M. The role of oxidative stress in organophosphate and nerve agent toxicity. Ann N Y Acad Sci 2016; 1378:17-24. [PMID: 27371936 DOI: 10.1111/nyas.13115] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/03/2016] [Accepted: 05/05/2016] [Indexed: 01/06/2023]
Abstract
Organophosphate (OP) nerve agents exert their toxicity through inhibition of acetylcholinesterase. The excessive stimulation of cholinergic receptors rapidly causes neuronal damage, seizures, death, and long-term neurological impairment in those that survive. Owing to the lethality of organophosphorus agents and the growing risk they pose, medical interventions that prevent OP toxicity and the delayed injury response are much needed. Studies have shown that oxidative stress occurs in models of subacute, acute, and chronic exposure to OP agents. Key findings of these studies include alterations in mitochondrial function and increased free radical-mediated injury, such as lipid peroxidation. This review focuses on the role of reactive oxygen species in OP neurotoxicity and its dependence on seizure activity. Understanding the sources, mechanisms, and pathological consequences of OP-induced oxidative stress can lead to the development of rational therapies for treating toxic exposures.
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Affiliation(s)
| | - Manisha Patel
- Neuroscience Program. .,Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado.
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34
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Deshpande LS, Blair RE, Phillips KF, DeLorenzo RJ. Role of the calcium plateau in neuronal injury and behavioral morbidities following organophosphate intoxication. Ann N Y Acad Sci 2016; 1374:176-83. [PMID: 27327161 DOI: 10.1111/nyas.13122] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/04/2016] [Accepted: 05/10/2016] [Indexed: 12/28/2022]
Abstract
Organophosphate (OP) chemicals include nerve agents and pesticides, and there is a growing concern of OP-based chemical attacks against civilians. Current antidotes are essential in limiting immediate mortality associated with OP exposure. However, further research is needed to identify the molecular mechanisms underlying long-term neurological deficits following survival of OP toxicity in order to develop effective therapeutics. We have developed rat survival models of OP-induced status epilepticus (SE) that mimic chronic mortality and morbidity following OP intoxication. We have observed significant elevations in hippocampal calcium levels after OP SE that persisted for weeks following initial survival. Drugs inhibiting intracellular calcium-induced calcium release, such as dantrolene, levetiracetam, and carisbamate, lowered OP SE-mediated protracted calcium elevations. Given the critical role of calcium signaling in modulating behavior and cell death mechanisms, drugs targeted at preventing the development of the calcium plateau could enhance neuroprotection, help reduce morbidity, and improve outcomes following survival of OP SE.
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Affiliation(s)
- Laxmikant S Deshpande
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia.,Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Robert E Blair
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia
| | - Kristin F Phillips
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia
| | - Robert J DeLorenzo
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia.,Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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35
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McCarren HS, McDonough JH. Anticonvulsant discovery through animal models of status epilepticus induced by organophosphorus nerve agents and pesticides. Ann N Y Acad Sci 2016; 1374:144-50. [DOI: 10.1111/nyas.13092] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hilary S. McCarren
- Pharmacology Department U.S. Army Medical Research Institute of Chemical Defense Aberdeen Proving Ground Maryland
| | - John H. McDonough
- Pharmacology Department U.S. Army Medical Research Institute of Chemical Defense Aberdeen Proving Ground Maryland
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36
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Pharmacological blockade of the calcium plateau provides neuroprotection following organophosphate paraoxon induced status epilepticus in rats. Neurotoxicol Teratol 2016; 56:81-86. [PMID: 27224207 DOI: 10.1016/j.ntt.2016.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/05/2016] [Accepted: 05/16/2016] [Indexed: 12/25/2022]
Abstract
Organophosphate (OP) compounds which include nerve agents and pesticides are considered chemical threat agents. Currently approved antidotes are crucial in limiting OP mediated acute mortality. However, survivors of lethal OP exposure exhibit delayed neuronal injury and chronic behavioral morbidities. In this study, we investigated neuroprotective capabilities of dantrolene and carisbamate in a rat survival model of paraoxon (POX) induced status epilepticus (SE). Significant elevations in hippocampal calcium levels were observed 48-h post POX SE survival, and treatment with dantrolene (10mg/kg, i.m.) and carisbamate (90mg/kg, i.m.) lowered these protracted calcium elevations. POX SE induced delayed neuronal injury as characterized by Fluoro Jade C labeling was observed in critical brain areas including the dentate gyrus, parietal cortex, amygdala, and thalamus. Dantrolene and carisbamate treatment provided significant neuroprotection against delayed neuronal damage in these brain regions when administered one-hour after POX-SE. These results indicate that dantrolene or carisbamate could be effective adjuvant therapies to the existing countermeasures to reduce neuronal injury and behavioral morbidities post OP SE survival.
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37
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Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Prager EM, Pidoplichko VI, Miller SL, Braga MFM. Long-term neuropathological and behavioral impairments after exposure to nerve agents. Ann N Y Acad Sci 2016; 1374:17-28. [PMID: 27002925 DOI: 10.1111/nyas.13028] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/15/2016] [Accepted: 01/25/2016] [Indexed: 01/11/2023]
Abstract
One of the deleterious effects of acute nerve agent exposure is the induction of status epilepticus (SE). If SE is not controlled effectively, it causes extensive brain damage. Here, we review the neuropathology observed after nerve agent-induced SE, as well as the ensuing pathophysiological, neurological, and behavioral alterations, with an emphasis on their time course and longevity. Limbic structures are particularly vulnerable to damage by nerve agent exposure. The basolateral amygdala (BLA), which appears to be a key site for seizure initiation upon exposure, suffers severe neuronal loss; however, GABAergic BLA interneurons display a delayed death, perhaps providing a window of opportunity for rescuing intervention. The end result is a long-term reduction of GABAergic activity in the BLA, with a concomitant increase in spontaneous excitatory activity; such pathophysiological alterations are not observed in the CA1 hippocampal area, despite the extensive neuronal loss. Hyperexcitability in the BLA may be at least in part responsible for the development of recurrent seizures and increased anxiety, while hippocampal damage may underlie the long-term memory impairments. Effective control of SE after nerve agent exposure, such that brain damage is also minimized, is paramount for preventing lasting neurological and behavioral deficits.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - James P Apland
- Neurotoxicology Branch, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Eric M Prager
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Volodymyr I Pidoplichko
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Steven L Miller
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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38
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Krishnan JKS, Arun P, Appu AP, Vijayakumar N, Figueiredo TH, Braga MFM, Baskota S, Olsen CH, Farkas N, Dagata J, Frey WH, Moffett JR, Namboodiri AMA. Intranasal delivery of obidoxime to the brain prevents mortality and CNS damage from organophosphate poisoning. Neurotoxicology 2016; 53:64-73. [PMID: 26751814 DOI: 10.1016/j.neuro.2015.12.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 01/08/2023]
Abstract
Intranasal delivery is an emerging method for bypassing the blood brain barrier (BBB) and targeting therapeutics to the CNS. Oximes are used to counteract the effects of organophosphate poisoning, but they do not readily cross the BBB. Therefore, they cannot effectively counteract the central neuropathologies caused by cholinergic over-activation when administered peripherally. For these reasons we examined intranasal administration of oximes in an animal model of severe organophosphate poisoning to determine their effectiveness in reducing mortality and seizure-induced neuronal degeneration. Using the paraoxon model of organophosphate poisoning, we administered the standard treatment (intramuscular pralidoxime plus atropine sulphate) to all animals and then compared the effectiveness of intranasal application of obidoxime (OBD) to saline in the control groups. Intranasally administered OBD was effective in partially reducing paraoxon-induced acetylcholinesterase inhibition in the brain and substantially reduced seizure severity and duration. Further, intranasal OBD completely prevented mortality, which was 41% in the animals given standard treatment plus intranasal saline. Fluoro-Jade-B staining revealed extensive neuronal degeneration in the surviving saline-treated animals 24h after paraoxon administration, whereas no detectable degenerating neurons were observed in any of the animals given intranasal OBD 30min before or 5min after paraoxon administration. These findings demonstrate that intranasally administered oximes bypass the BBB more effectively than those administered peripherally and provide an effective method for protecting the brain from organophosphates. The addition of intranasally administered oximes to the current treatment regimen for organophosphate poisoning would improve efficacy, reducing both brain damage and mortality.
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Affiliation(s)
- Jishnu K S Krishnan
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Peethambaran Arun
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Abhilash P Appu
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Nivetha Vijayakumar
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Taíza H Figueiredo
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Maria F M Braga
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Sudikshya Baskota
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Cara H Olsen
- Biostatistics Consulting Center, USUHS Bethesda, MD, United States
| | - Natalia Farkas
- Section on Metrology, NIST, Gaithersburg, MD, United States
| | - John Dagata
- Section on Metrology, NIST, Gaithersburg, MD, United States
| | - William H Frey
- Center for Memory & Aging, Regions Hospital, Health Partners Institute for Education and Research, St. Paul, MN, United States
| | - John R Moffett
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States
| | - Aryan M A Namboodiri
- Department of Anatomy, Physiology and Genetics, and Neurosciences Program, USUHS, Bethesda, 20814 MD, United States.
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39
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Phillips KF, Deshpande LS. Repeated low-dose organophosphate DFP exposure leads to the development of depression and cognitive impairment in a rat model of Gulf War Illness. Neurotoxicology 2015; 52:127-33. [PMID: 26619911 DOI: 10.1016/j.neuro.2015.11.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/20/2015] [Accepted: 11/22/2015] [Indexed: 02/02/2023]
Abstract
Approximately 175,000-250,000 of the returning veterans from the 1991 Persian Gulf War exhibit chronic multi-symptom illnesses that includes neurologic co-morbidities such as depression, anxiety and cognitive impairments. Amongst a host of causative factors, exposure to low levels of the nerve agent Sarin has been strongly implicated for expression of Gulf War Illness (GWI). Nerve agents similar to pesticides are organophosphate (OP) compounds. There is evidence from civilian population that exposure to OPs such as in agricultural workers and nerve agents such as the survivors and first-responders of the Tokyo subway Sarin gas attack suffer from chronic neurological problems similar to GWI symptoms. Given this unique chemical profile, OPs are ideal to study the effects of nerve agents and develop models of GWI in civilian laboratories. In this study, we used repeated low-dose exposure to OP agent diisopropyl fluorophosphate (DFP) over a 5-day period to approximate the duration and level of Sarin exposure during the Persian Gulf War. We tested the rats at 3-months post DFP exposure. Using a battery of behavioral assays, we observed the presence of symptoms of chronic depression, anxiety and memory problems as characterized by increased immobility time in the Forced Swim Test, anhedonia in the Sucrose Preference Test, anxiety in the Elevated Plus Maze, and spatial memory impairments in the Object Location Test, respectively. Chronic low dose DFP exposure was also associated with hippocampal neuronal damage as characterized by the presence of Fluoro-Jade staining. Given that OP exposure is considered a leading cause of GWI related morbidities, this animal model will be ideally suited to study underlying molecular mechanisms for the expression of GWI neurological symptoms and identify drugs for the effective treatment of GWIs.
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Affiliation(s)
- Kristin F Phillips
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
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40
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Cao Z, Zou X, Cui Y, Hulsizer S, Lein PJ, Wulff H, Pessah IN. Rapid throughput analysis demonstrates that chemicals with distinct seizurogenic mechanisms differentially alter Ca2+ dynamics in networks formed by hippocampal neurons in culture. Mol Pharmacol 2015; 87:595-605. [PMID: 25583085 DOI: 10.1124/mol.114.096701] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Primary cultured hippocampal neurons (HN) form functional networks displaying synchronous Ca(2+) oscillations (SCOs) whose patterns influence plasticity. Whether chemicals with distinct seizurogenic mechanisms differentially alter SCO patterns was investigated using mouse HN loaded with the Ca(2+) indicator fluo-4-AM. Intracellular Ca(2+) dynamics were recorded from 96 wells simultaneously in real-time using fluorescent imaging plate reader. Although quiescent at 4 days in vitro (DIV), HN acquired distinctive SCO patterns as they matured to form extensive dendritic networks by 16 DIV. Challenge with kainate, a kainate receptor (KAR) agonist, 4-aminopyridine (4-AP), a K(+) channel blocker, or pilocarpine, a muscarinic acetylcholine receptor agonist, caused distinct changes in SCO dynamics. Kainate at <1 µM produced a rapid rise in baseline Ca(2+) (Phase I response) associated with high-frequency and low-amplitude SCOs (Phase II response), whereas SCOs were completely repressed with >1 µM kainate. KAR competitive antagonist CNQX [6-cyano-7-nitroquinoxaline-2,3-dione] (1-10 µM) normalized Ca(2+) dynamics to the prekainate pattern. Pilocarpine lacked Phase I activity but caused a sevenfold prolongation of Phase II SCOs without altering either their frequency or amplitude, an effect normalized by atropine (0.3-1 µM). 4-AP (1-30 µM) elicited a delayed Phase I response associated with persistent high-frequency, low-amplitude SCOs, and these disturbances were mitigated by pretreatment with the KCa activator SKA-31 [naphtho[1,2-d]thiazol-2-ylamine]. Consistent with its antiepileptic and neuroprotective activities, nonselective voltage-gated Na(+) and Ca(2+) channel blocker lamotrigine partially resolved kainate- and pilocarpine-induced Ca(2+) dysregulation. This rapid throughput approach can discriminate among distinct seizurogenic mechanisms that alter Ca(2+) dynamics in neuronal networks and may be useful in screening antiepileptic drug candidates.
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Affiliation(s)
- Zhengyu Cao
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Xiaohan Zou
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Yanjun Cui
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Susan Hulsizer
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Pamela J Lein
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Heike Wulff
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
| | - Isaac N Pessah
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, P.R. China (Z.C., X.Z., Y.C.); Department of Molecular Biosciences, School of Veterinary Medicine (Z.C., Y.C., S.H., P.J.L., I.N.P.) and Department of Pharmacology, School of Medicine (H.W.),University of California, Davis, California
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41
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Kaur S, Singh S, Chahal KS, Prakash A. Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity. Can J Physiol Pharmacol 2014; 92:893-911. [DOI: 10.1139/cjpp-2014-0113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.
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Affiliation(s)
- Shamsherjit Kaur
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
- Punjab Technical University, Kapurthala 144601, Punjab, India
| | - Satinderpal Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Karan Singh Chahal
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Atish Prakash
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
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42
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Deshpande LS, Phillips K, Huang B, DeLorenzo RJ. Chronic behavioral and cognitive deficits in a rat survival model of paraoxon toxicity. Neurotoxicology 2014; 44:352-7. [PMID: 25172410 DOI: 10.1016/j.neuro.2014.08.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/07/2014] [Accepted: 08/08/2014] [Indexed: 01/15/2023]
Abstract
Organophosphate (OP) compounds, including paraoxon (POX), are similar to nerve agents such as sarin. There is a growing concern that OP agents could be weaponized to cause mass civilian causalities. We have developed a rodent survival model of POX toxicity that is being used to evaluate chronic morbidity and to screen for medical countermeasures against severe OP exposure. It is well known that the survivors of nerve gas and chronic OP exposure exhibit neurobehavioral deficits such as mood changes, depression, and memory impairments. In this study we investigated whether animals surviving severe POX exposure exhibited long-term neurological impairments. POX exposure produced overt signs of cholinergic toxicity. Rats were rescued using an optimized atropine, 2-PAM and diazepam therapy. Surviving rats were studied using established behavioral assays for identifying symptoms of depression and memory impairment 3-months after POX exposure. In the forced swim test, POX rats exhibited increased immobility time indicative of a despair-like state. In the sucrose preference test, POX rats consumed significantly less sucrose water indicating anhedonia-like condition. POX rats also displayed increased anxiety as characterized by significantly lower performance in the open arm of the elevated plus maze. Further, when tested with a novel object recognition paradigm, POX rats exhibited a negative discrimination ratio indicative of impaired recognition memory. The results indicate that this model of survival from severe POX exposure can be employed to study some of the molecular bases for OP-induced chronic behavioral and cognitive comorbidities and develop therapies for their treatment.
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Affiliation(s)
| | - Kristin Phillips
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Beverly Huang
- Department of Neuroscience, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Robert J DeLorenzo
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Department of Molecular Biophysics and Biochemistry, Virginia Commonwealth University, Richmond, VA 23298, USA.
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