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Wang Y, Wang C, Tian Q, Li Y. Recent Research Progress in Oxime Insecticides and Perspectives for the Future. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:15077-15091. [PMID: 38920088 DOI: 10.1021/acs.jafc.4c02096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
In recent decades, the unique structural attributes and purported insecticidal properties of oximes have garnered increasing attention. A variety of insecticides, encompassing fluxametamide, fluhexafon, and lepimectin, have been synthesized, all of which incorporate oximes. This review endeavors to encapsulate the insecticidal efficacy, structure-activity correlations, and operative mechanisms of oxime-containing compounds. Furthermore, it delves into the conceptual frameworks underpinning the design of innovative oxime-based insecticides, thereby shedding light on prospective advancements in this field.
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Affiliation(s)
- Yu Wang
- Key Laboratory of Agri-Food Safety of Anhui Province, Anhui Agricultural University, Hefei 230036, China
| | - Chuxia Wang
- Key Laboratory of Agri-Food Safety of Anhui Province, Anhui Agricultural University, Hefei 230036, China
| | - Qingqiang Tian
- Key Laboratory of Agri-Food Safety of Anhui Province, Anhui Agricultural University, Hefei 230036, China
| | - Yahui Li
- Key Laboratory of Agri-Food Safety of Anhui Province, Anhui Agricultural University, Hefei 230036, China
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2
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Zheng X, Liu G, Ozoe Y, Ju XL. Mechanistic insights into the selectivity of bicyclophosphorothionate antagonists for housefly versus rat GABA receptors. PEST MANAGEMENT SCIENCE 2024; 80:1382-1399. [PMID: 37926485 DOI: 10.1002/ps.7869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/18/2023] [Accepted: 11/06/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND γ-Aminobutyric acid (GABA) receptors (GABARs) are validated targets of insecticides. Bicyclophosphorothionates are a group of insecticidal compounds that act as noncompetitive antagonists of GABARs. We previously reported that the analogs exhibit various degrees of selectivity for housefly versus rat GABARs, depending on substitutions at the 3- and 4-positions. We here sought to elucidate the unsolved mechanisms of the receptor selectivity using quantitative structure-activity relationship (QSAR), molecular docking, and molecular dynamics approaches. RESULTS Three-dimensional (3D)-QSAR studies using Topomer comparative molecular field analysis quantitatively demonstrated how the introduction of a small alkyl group at the 3-position of bicyclophosphorothionates contributes to the housefly versus rat GABAR selectivity. To investigate the molecular mechanisms of the selective action, bicyclophosphorothionates were docked into housefly Resistance to dieldrin (RDL) GABAR and rat α1β2γ2 GABAR homology models built using the published 3D-structures of human GABARs as templates. The results of molecular docking and molecular dynamics simulations revealed that the 2'Ala and 6'Thr residues of the RDL subunit within the channel are the key amino acids for binding to the housefly GABARs, whereas the 2'Ser residue of γ2 subunit plays a crucial role in binding to rat GABARs. CONCLUSION We revealed the molecular mechanisms underlying the selective antagonistic action of bicyclophosphorothionates on housefly versus rat GABARs. The information presented should help design and develop novel, safe GABAR-targeting insecticides. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Xiaojiao Zheng
- Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Genyan Liu
- Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Yoshihisa Ozoe
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Sciences, Shimane University, Matsue, Japan
| | - Xiu-Lian Ju
- Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
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El Mahmoudi A, Fegrouche R, Tachallait H, Lumaret JP, Arshad S, Karrouchi K, Bougrin K. Green synthesis, characterization, and biochemical impacts of new bioactive isoxazoline-sulfonamides as potential insecticidal agents against the Sphodroxia maroccana Ley. PEST MANAGEMENT SCIENCE 2023; 79:4847-4857. [PMID: 37500586 DOI: 10.1002/ps.7686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/22/2023] [Accepted: 07/28/2023] [Indexed: 07/29/2023]
Abstract
BACKGROUND Sphodroxia maroccana Ley is a pest of cork oak crops that damages the roots of seedlings and can severely impair cork oak regeneration. Since the banning of carbosulfan and chlorpyriphos, which were widely used against the larvae of Sphodroxia maroccana because of their harmful impact on the environment, until now there has been no pesticide against these pests. Therefore, it is particularly urgent to develop highly effective insecticidal molecules with novel scaffolds. Isoxazolines are a class of insecticides that act on γ-aminobutyric acid (GABA)-gated chloride channel allosteric modulators. In this work, a green synthesis of novel 3,5-disubstituted isoxazoline-sulfonamide derivatives was achieved in water via ultrasound-assisted four-component reactions, and their insecticidal activities against fourth-instar larvae of S. maroccana were evaluated. RESULTS Most of the tested compounds showed insecticidal activity compared to fluralaner as positive control and commercially available insecticide. Especially, the isoxazoline-secondary sulfonamides containing halogens (Br and Cl) on the phenyl group attached to the isoxazoline, 6g (LC50 = 0.31 mg/mL), 6j (LC50 = 0.38 mg/mL), 6k (LC50 = 0.18 mg/mL), 6L (LC50 = 0.49 mg/mL), 6m (LC50 = 0.24 mg/mL), 6q (LC50 = 0.46 mg/mL), exhibited much higher larvicidal activity than fluralaner (LC50 = 0.99 mg/mL). CONCLUSION Novel isoxazolines containing sulfonamide moieties were designed, synthesized and confirmed by two single-crystal structures of 4e and 6q. Their bioassay results showed significant larvicidal activity with significant morphological changes in vivo. These results will lay the foundation for the further discovery and development of isoxazoline-sulfonamide derivatives as novel crop protection larvicides of cork oak. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Ayoub El Mahmoudi
- Equipe de Chimie des Plantes et de Synthèse Organique et Bioorganique, URAC23, Faculty of Science, B.P. 1014, Geophysics, Natural Patrimony and Green Chemistry (GEOPAC) Research Center, Mohammed V University in Rabat, Agdal, Morocco
| | - Rachida Fegrouche
- Laboratory of Biodiversity, Ecology, and Genome (BioEcoGen), Faculty of Sciences, B.P. 1014, Biotechnologies Végétale et Microbienne, Biodiversité et Environnement (Biobio) Research Center, Mohammed V University in Rabat, Agdal, Morocco
| | - Hamza Tachallait
- Chemical & Biochemical Sciences Green-Process Engineering (CBS) Mohammed VI Polytechnic University, Benguerir, Morocco
| | - Jean-Pierre Lumaret
- Zoogeography Laboratory, University Paul-Valéry Montpellier 3, Montpellier, France
| | - Suhana Arshad
- X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, Penang, Malaysia
| | - Khalid Karrouchi
- Laboratory of Analytical Chemistry and Bromatology, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Agdal, Morocco
| | - Khalid Bougrin
- Equipe de Chimie des Plantes et de Synthèse Organique et Bioorganique, URAC23, Faculty of Science, B.P. 1014, Geophysics, Natural Patrimony and Green Chemistry (GEOPAC) Research Center, Mohammed V University in Rabat, Agdal, Morocco
- Chemical & Biochemical Sciences Green-Process Engineering (CBS) Mohammed VI Polytechnic University, Benguerir, Morocco
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Zhang Y, Huang Q, Sheng C, Liu G, Zhang K, Jia Z, Tang T, Mao X, Jones AK, Han Z, Zhao C. G3'MTMD3 in the insect GABA receptor subunit, RDL, confers resistance to broflanilide and fluralaner. PLoS Genet 2023; 19:e1010814. [PMID: 37384781 DOI: 10.1371/journal.pgen.1010814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Meta-diamides (e.g. broflanilide) and isoxazolines (e.g. fluralaner) are novel insecticides that target the resistant to dieldrin (RDL) subunit of insect γ-aminobutyric acid receptors (GABARs). In this study, we used in silico analysis to identify residues that are critical for the interaction between RDL and these insecticides. Substitution of glycine at the third position (G3') in the third transmembrane domain (TMD3) with methionine (G3'M TMD3), which is present in vertebrate GABARs, had the strongest effect on fluralaner binding. This was confirmed by expression of RDL from the rice stem borer, Chilo suppressalis (CsRDL) in oocytes of the African clawed frog, Xenopus laevis, where the G3'MTMD3 mutation almost abolished the antagonistic action of fluralaner. Subsequently, G3'MTMD3 was introduced into the Rdl gene of the fruit fly, Drosophila melanogaster, using the CRISPR/Cas9 system. Larvae of heterozygous lines bearing G3'MTMD3 did not show significant resistance to avermectin, fipronil, broflanilide, and fluralaner. However, larvae homozygous for G3'MTMD3 were highly resistant to broflanilide and fluralaner whilst still being sensitive to fipronil and avermectin. Also, homozygous lines showed severely impaired locomotivity and did not survive to the pupal stage, indicating a significant fitness cost associated with the G3'MTMD3. Moreover, the M3'GTMD3 in the mouse Mus musculus α1β2 GABAR increased sensitivity to fluralaner. Taken together, these results provide convincing in vitro and in vivo evidence for both broflanilide and fluralaner acting on the same amino acid site, as well as insights into potential mechanisms leading to target-site resistance to these insecticides. In addition, our findings could guide further modification of isoxazolines to achieve higher selectivity for the control of insect pests with minimal effects on mammals.
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Affiliation(s)
- Yichi Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Qiutang Huang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Chengwang Sheng
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Genyan Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Kexin Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Zhongqiang Jia
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, People's Republic of China
| | - Xin Mao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Zhaojun Han
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Chunqing Zhao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
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Liu Y, Li X, Lin L. Transcriptome of the pygmy grasshopper Formosatettix qinlingensis (Orthoptera: Tetrigidae). PeerJ 2023; 11:e15123. [PMID: 37016680 PMCID: PMC10066883 DOI: 10.7717/peerj.15123] [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: 07/27/2022] [Accepted: 03/03/2023] [Indexed: 04/03/2023] Open
Abstract
Formosatettix qinlingensis (Zheng, 1982) is a tiny grasshopper endemic to Qinling in China. For further study of its transcriptomic features, we obtained RNA-Seq data by Illumina HiSeq X Ten sequencing platform. Firstly, transcriptomic analysis showed that transcriptome read numbers of two female and one male samples were 25,043,314, 24,429,905, and 25,034,457, respectively. We assembled 65,977 unigenes, their average length was 1,072.09 bp, and the length of N50 was 2,031 bp. The average lengths of F. qinlingensis female and male unigenes were 911.30 bp, and 941.82 bp, and the N50 lengths were 1,745 bp and 1,735 bp, respectively. Eight databases were used to annotate the functions of unigenes, and 23,268 functional unigenes were obtained. Besides, we also studied the body color, immunity and insecticide resistance of F. qinlingensis. Thirty-nine pigment-related genes were annotated. Some immunity genes and signaling pathways were found, such as JAK-STAT and Toll-LIKE receptor signaling pathways. There are also some insecticide resistance genes and signal pathways, like nAChR, GST and DDT. Further, some of these genes were differentially expressed in female and male samples, including pigment, immunity and insecticide resistance. The transcriptomic study of F. qinlingensis will provide data reference for gene prediction and molecular expression study of other Tetrigidae species in the future. Differential genetic screening of males and females provides a basis for studying sex and immune balance in insects.
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Affiliation(s)
- Yuxin Liu
- Shaanxi Normal University, Xi’an, China
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Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) causes seizure activity in larval zebrafish via antagonism of γ-aminobutyric acid type A receptor α1β2γ2. Arch Toxicol 2023; 97:1355-1365. [PMID: 36912926 PMCID: PMC10110628 DOI: 10.1007/s00204-023-03475-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/02/2023] [Indexed: 03/14/2023]
Abstract
Hexahydro-1,3,5-trinitro-1,3,5-triazine, or Royal Demolition Explosive (RDX), is a major component of plastic explosives such as C-4. Acute exposures from intentional or accidental ingestion are a documented clinical concern, especially among young male U.S. service members in the armed forces. When ingested in large enough quantity, RDX causes tonic-clonic seizures. Previous in silico and in vitro experiments predict that RDX causes seizures by inhibiting α1β2γ2 γ-aminobutyric acid type A (GABAA) receptor-mediated chloride currents. To determine whether this mechanism translates in vivo, we established a larval zebrafish model of RDX-induced seizures. After a 3 h of exposure to 300 µM RDX, larval zebrafish exhibited a significant increase in motility in comparison to vehicle controls. Researchers blinded to experimental group manually scored a 20-min segment of video starting at 3.5 h post-exposure and found significant seizure behavior that correlated with automated seizure scores. Midazolam (MDZ), an nonselective GABAAR positive allosteric modulator (PAM), and a combination of Zolpidem (α1 selective PAM) and compound 2-261 (β2/3-selective PAM) were effective in mitigating RDX-triggered behavioral and electrographic seizures. These findings confirm that RDX induces seizure activity via inhibition of the α1β2γ2 GABAAR and support the use of GABAAR-targeted anti-seizure drugs for the treatment of RDX-induced seizures.
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Chern CR, Lauková M, Schonwald A, Kudová E, Chodounská H, Chern CJ, Shakarjian MP, Velíšková J, Velíšek L. Novel neurosteroid pregnanolone pyroglutamate suppresses neurotoxicity syndrome induced by tetramethylenedisulfotetramine but is ineffective in a rodent model of infantile spasms. Pharmacol Rep 2023; 75:177-188. [PMID: 36422805 PMCID: PMC10785007 DOI: 10.1007/s43440-022-00437-1] [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: 09/05/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Neurosteroids are investigated as effective antidotes for the poisoning induced by tetramethylenedisulfotetramine (TMDT) as well as treatments for epileptic spasms during infancy. Both these conditions are quite resistant to pharmacotherapy; thus, a search for new treatments is warranted. METHODS In this study, we determined the efficacy of two novel neurosteroids, pregnanolone glutamate (PAG) and pregnanolone pyroglutamate (PPG), and tested these drugs in doses of 1-10 mg/kg (ip) against the TMDT syndrome and in our rodent model of infantile spasms. RESULTS Only PPG in doses 5 and 10 mg/kg suppressed the severity of the TMDT syndrome and TMDT-induced lethality, while the 1 mg/kg dose was without an effect. Interestingly, the 1 mg/kg dose of PPG in combination with 1 mg/kg of diazepam was also effective against TMDT poisoning. Neither PAG nor PPG were effective against experimental spasms in the N-methyl-D-aspartate (NMDA)-triggered model of infantile spasms. CONCLUSIONS While evidence suggests that PAG can act through multiple actions which include allosteric inhibition of NMDA-induced and glycine receptor-evoked currents as well as augmentation of ɣ-aminobutyric acid subtype A (GABAA) receptor-induced currents, the agent appears to neither have the appropriate mechanistic signature for activity in the infantile spasm model, nor the adequate potency, relative to PPG, for ameliorating the TMDT syndrome. The full mechanisms of action of PPG, which may become a potent TMDT antidote either alone or in combination with diazepam are yet unknown and thus require further investigation.
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Affiliation(s)
- Chian-Ru Chern
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
| | - Marcela Lauková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
- Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Science, Bratislava, Slovakia
| | - Antonia Schonwald
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
| | - Eva Kudová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Chodounská
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Chian-Jiang Chern
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
| | - Michael P Shakarjian
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
- Department of Public Health, Environmental Health Science Program, New York Medical College, Valhalla, NY, USA
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Ln W, Piscataway, NJ, 08854, USA
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
- Department of Obstetrics and Gynecology, New York Medical College, Valhalla, NY, USA
- Department of Neurology, New York Medical College, Valhalla, NY, USA
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA.
- Department of Neurology, New York Medical College, Valhalla, NY, USA.
- Department of Pediatrics, New York Medical College, Valhalla, NY, USA.
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The new synthesis of sulfuryl-bridged triazinane and its selective recognition to SO42−. RESEARCH ON CHEMICAL INTERMEDIATES 2021. [DOI: 10.1007/s11164-021-04585-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Calsbeek JJ, González EA, Boosalis CA, Zolkowska D, Bruun DA, Rowland DJ, Saito NH, Harvey DJ, Chaudhari AJ, Rogawski MA, Garbow JR, Lein PJ. Strain differences in the extent of brain injury in mice after tetramethylenedisulfotetramine-induced status epilepticus. Neurotoxicology 2021; 87:43-50. [PMID: 34478772 PMCID: PMC8595842 DOI: 10.1016/j.neuro.2021.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/28/2021] [Accepted: 08/29/2021] [Indexed: 11/30/2022]
Abstract
Acute intoxication with tetramethylenedisulfotetramine (TETS) can trigger status epilepticus (SE) in humans. Survivors often exhibit long-term neurological effects, including electrographic abnormalities and cognitive deficits, but the pathogenic mechanisms linking the acute toxic effects of TETS to chronic outcomes are not known. Here, we use advanced in vivo imaging techniques to longitudinally monitor the neuropathological consequences of TETS-induced SE in two different mouse strains. Adult male NIH Swiss and C57BL/6J mice were injected with riluzole (10 mg/kg, i.p.), followed 10 min later by an acute dose of TETS (0.2 mg/kg in NIH Swiss; 0.3 mg/kg, i.p. in C57BL/6J) or an equal volume of vehicle (10% DMSO in 0.9% sterile saline). Different TETS doses were administered to trigger comparable seizure behavior between strains. Seizure behavior began within minutes of TETS exposure and rapidly progressed to SE that was terminated after 40 min by administration of midazolam (1.8 mg/kg, i.m.). The brains of vehicle and TETS-exposed mice were imaged using in vivo magnetic resonance (MR) and translocator protein (TSPO) positron emission tomography (PET) at 1, 3, 7, and 14 days post-exposure to monitor brain injury and neuroinflammation, respectively. When the brain scans of TETS mice were compared to those of vehicle controls, subtle and transient neuropathology was observed in both mouse strains, but more extensive and persistent TETS-induced neuropathology was observed in C57BL/6J mice. In addition, one NIH Swiss TETS mouse that did not respond to the midazolam therapy, but remained in SE for more than 2 h, displayed robust neuropathology as determined by in vivo imaging and confirmed by FluoroJade C staining and IBA-1 immunohistochemistry as readouts of neurodegeneration and neuroinflammation, respectively. These findings demonstrate that the extent of injury observed in the mouse brain after TETS-induced SE varied according to strain, dose of TETS and/or the duration of SE. These observations suggest that TETS-intoxicated humans who do not respond to antiseizure medication are at increased risk for brain injury.
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Affiliation(s)
- Jonas J Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Eduardo A González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Casey A Boosalis
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Dorota Zolkowska
- Department of Neurology, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA, 95616, USA.
| | - Naomi H Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Abhijit J Chaudhari
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA, 95616, USA.
| | - Michael A Rogawski
- Department of Neurology, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, 63110, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
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Buchholz BA, Ahn KC, Huang H, Gee SJ, Stewart BJ, Ognibene TJ, Hammock BD. Pharmacokinetics, Metabolite Measurement, and Biomarker Identification of Dermal Exposure to Permethrin Using Accelerator Mass Spectrometry. Toxicol Sci 2021; 183:49-59. [PMID: 34460930 PMCID: PMC8404990 DOI: 10.1093/toxsci/kfab082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Impregnating military uniforms and outdoor clothing with the insecticide permethrin is an approach to reduce exposure to insect borne diseases and to repel pests and disease vectors such as mosquitos and sandflies, but the practice exposes wearers to prolonged dermal exposure to the pesticide. Key metabolite(s) from a low dose dermal exposure of permethrin were identified using accelerator mass spectrometry. Metabolite standards were synthesized and a high performance liquide chromatography (HPLC) elution protocol to separate individual metabolites in urine was developed. Six human subjects were exposed dermally on the forearm to 25 mg of permethrin containing 1.0 µCi of 14C for 8 h. Blood, saliva and urine samples were taken for 7d. Absorption/elimination rates and metabolite concentrations varied by individual. Average absorption was 0.2% of the dose. Serum concentrations rose until 12-24 h postdermal application then rapidly declined reaching predose levels by 72 h. Maximum saliva excretion occurred 6 h postdosing. The maximum urinary excretion rate occurred during 12-24 h; average elimination half-life was 56 h. 3-Phenoxybenzyl alcohol glucuronide was the most abundant metabolite identified when analyzing elution fractions, but most of the radioactivity was in still more polar fractions suggesting extensive degradative metabolism and for which there were no standards. Analyses of archived urine samples with the ultra performance liquid chromatography-accelerator mass spectrometry-mass spectrometry (UPLC-AMS-MS) system isolated a distinct polar metabolite but it was much diminished from the previous analyses a decade earlier.
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Affiliation(s)
- Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National laboratory, Livermore, California 94550, USA
| | - Ki Chang Ahn
- Department of Entomology, University of California, Davis, California, USA
| | - Huazhang Huang
- Department of Entomology, University of California, Davis, California, USA
| | - Shirley J Gee
- Department of Entomology, University of California, Davis, California, USA
| | - Benjamin J Stewart
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Ted J Ognibene
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National laboratory, Livermore, California 94550, USA
| | - Bruce D Hammock
- Department of Entomology, University of California, Davis, California, USA
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Mundy PC, Pressly B, Carty DR, Yaghoobi B, Wulff H, Lein PJ. The efficacy of γ-aminobutyric acid type A receptor (GABA AR) subtype-selective positive allosteric modulators in blocking tetramethylenedisulfotetramine (TETS)-induced seizure-like behavior in larval zebrafish with minimal sedation. Toxicol Appl Pharmacol 2021; 426:115643. [PMID: 34265354 PMCID: PMC8514104 DOI: 10.1016/j.taap.2021.115643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 11/19/2022]
Abstract
The chemical threat agent tetramethylenedisulfotetramine (TETS) is a γ-aminobutyric acid type A receptor (GABA AR) antagonist that causes life threatening seizures. Currently, there is no specific antidote for TETS intoxication. TETS-induced seizures are typically treated with benzodiazepines, which function as nonselective positive allosteric modulators (PAMs) of synaptic GABAARs. The major target of TETS was recently identified as the GABAAR α2β3γ2 subtype in electrophysiological studies using recombinantly expressed receptor combinations. Here, we tested whether these in vitro findings translate in vivo by comparing the efficacy of GABAAR subunit-selective PAMs in reducing TETS-induced seizure behavior in larval zebrafish. We tested PAMs targeting α1, α2, α2/3/5, α6, ß2/3, ß1/2/3, and δ subunits and compared their efficacy to the benzodiazepine midazolam (MDZ). The data demonstrate that α2- and α6-selective PAMs (SL-651,498 and SB-205384, respectively) were effective at mitigating TETS-induced seizure-like behavior. Combinations of SB-205384 and MDZ or SL-651,498 and 2–261 (ß2/3-selective) mitigated TETS-induced seizure-like behavior at concentrations that did not elicit sedating effects in a photomotor behavioral assay, whereas MDZ alone caused sedation at the concentration required to stop seizure behavior. Isobologram analyses suggested that SB-205384 and MDZ interacted in an antagonistic fashion, while the effects of SL-651,498 and 2–261 were additive. These results further elucidate the molecular mechanism by which TETS induces seizures and provide mechanistic insight regarding specific countermeasures against this chemical convulsant.
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Affiliation(s)
- Paige C Mundy
- Department of Molecular Biosciences, University of California, School of Veterinary Medicine, Davis, CA 95616, United States.
| | - Brandon Pressly
- Department of Pharmacology, University of California, School of Medicine, Davis, CA 95616, United States.
| | - Dennis R Carty
- Department of Molecular Biosciences, University of California, School of Veterinary Medicine, Davis, CA 95616, United States
| | - Bianca Yaghoobi
- Department of Molecular Biosciences, University of California, School of Veterinary Medicine, Davis, CA 95616, United States.
| | - Heike Wulff
- Department of Pharmacology, University of California, School of Medicine, Davis, CA 95616, United States.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, School of Veterinary Medicine, Davis, CA 95616, United States.
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Jiang J, Huang LX, Chen F, Sheng CW, Huang QT, Han ZJ, Zhao CQ. Novel alternative splicing of GABA receptor RDL exon 9 from Laodelphax striatellus modulates agonist potency. INSECT SCIENCE 2021; 28:757-768. [PMID: 32293803 DOI: 10.1111/1744-7917.12789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
The resistance to dieldrin gene (RDL) encodes the primary subunit of the insect ionotropic γ-aminobutyric acid (GABA) receptor (GABAR), which is the target of phenylpyrazole and isoxazoline insecticides. The splice variants in exons 3 and 6 of RDL, which have been widely explored in many insects, modulate the agonist potency of the homomeric RDL GABAR and potentially play an important role in the development of insects. In the present study, four splice variants of exon 9 were identified in RDL of the small brown planthopper, Laodelphax striatellus (LsRDL), resulting in LsRDL-9a, LsRDL-9a', LsRDL-9b, and LsRDL-9c. LsRDL-9a has one more amino acid (E, glutamic acid) compared with LsRDL-9a', and LsRDL-9b lacked two amino acids and had seven different amino acids compared with LsRDL-9c. Two-electrode voltage-clamp recording on LsRDLs expressed in Xenopus oocytes showed that alternative splicing of exon 9 has significant impact on LsRDL sensitivity to the agonists GABA and β-alanine, whereas no significant difference was observed in the potencies of the non-competitive antagonists (NCAs) ethiprole and fluralaner on the splice variants. Our results suggest that alternative splicing of RDL exon 9 broadens functional capabilities of the GABAR in L. striatellus by influencing the action of GABA.
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Affiliation(s)
- Jie Jiang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Li-Xin Huang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Feng Chen
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Cheng-Wang Sheng
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Qiu-Tang Huang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Zhao-Jun Han
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Chun-Qing Zhao
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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Antrobus S, Pressly B, Nik AM, Wulff H, Pessah IN. Structure-Activity Relationship of Neuroactive Steroids, Midazolam, and Perampanel Toward Mitigating Tetramine-Triggered Activity in Murine Hippocampal Neuronal Networks. Toxicol Sci 2021; 180:325-341. [PMID: 33483729 PMCID: PMC8599726 DOI: 10.1093/toxsci/kfab007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tetramethylenedisulfotetramine (tetramine or TETS), a potent convulsant, triggers abnormal electrical spike activity (ESA) and synchronous Ca2+ oscillation (SCO) patterns in cultured neuronal networks by blocking gamma-aminobutyric acid (GABAA) receptors. Murine hippocampal neuronal/glial cocultures develop extensive dendritic connectivity between glutamatergic and GABAergic inputs and display two distinct SCO patterns when imaged with the Ca2+ indicator Fluo-4: Low amplitude SCO events (LASE) and High amplitude SCO events (HASE) that are dependent on TTX-sensitive network electrical spike activity (ESA). Acute TETS (3.0 µM) increased overall network SCO amplitude and decreased SCO frequency by stabilizing HASE and suppressing LASE while increasing ESA. In multielectrode arrays, TETS also increased burst frequency and synchronicity. In the presence of TETS (3.0 µM), the clinically used anticonvulsive perampanel (0.1-3.0 µM), a noncompetitive AMPAR antagonist, suppressed all SCO activity, whereas the GABAA receptor potentiator midazolam (1.0-30 µM), the current standard of care, reciprocally suppressed HASE and stabilized LASE. The neuroactive steroid (NAS) allopregnanolone (0.1-3.0 µM) normalized TETS-triggered patterns by selectively suppressing HASE and increasing LASE, a pharmacological pattern distinct from its epimeric form eltanolone, ganaxolone, alphaxolone, and XJ-42, which significantly potentiated TETS-triggered HASE in a biphasic manner. Cortisol failed to mitigate TETS-triggered patterns and at >1 µM augmented them. Combinations of allopregnanolone and midazolam were significantly more effective at normalizing TETS-triggered SCO patterns, ESA patterns, and more potently enhanced GABA-activated Cl- current, than either drug alone.
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Affiliation(s)
- Shane Antrobus
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616, USA
| | - Brandon Pressly
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, California 95616, USA
| | - Atefeh Mousavi Nik
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616, USA
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, California 95616, USA
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616, USA
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Pressly B, Lee RD, Barnych B, Hammock BD, Wulff H. Identification of the Functional Binding Site for the Convulsant Tetramethylenedisulfotetramine in the Pore of the α 2 β 3 γ 2 GABA A Receptor. Mol Pharmacol 2020; 99:78-91. [PMID: 33109687 PMCID: PMC7746976 DOI: 10.1124/molpharm.120.000090] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/06/2020] [Indexed: 11/22/2022] Open
Abstract
Tetramethylenedisulfotetramine (TETS) is a so-called "caged" convulsant that is responsible for thousands of accidental and malicious poisonings. Similar to the widely used GABA receptor type A (GABAA) antagonist picrotoxinin, TETS has been proposed to bind to the noncompetitive antagonist (NCA) site in the pore of the receptor channel. However, the TETS binding site has never been experimentally mapped, and we here set out to gain atomistic level insights into how TETS inhibits the human α 2 β 3 γ 2 GABAA receptor. Using the Rosetta molecular modeling suite, we generated three homology models of the α 2 β 3 γ 2 receptor in the open, desensitized, and closed/resting state. Three different ligand-docking algorithms (RosettaLigand, Glide, and Swissdock) identified two possible TETS binding sites in the channel pore. Using a combination of site-directed mutagenesis, electrophysiology, and modeling to probe both sites, we demonstrate that TETS binds at the T6' ring in the closed/resting-state model, in which it shows perfect space complementarity and forms hydrogen bonds or makes hydrophobic interactions with all five pore-lining threonine residues of the pentameric receptor. Mutating T6' in either the α 2 or β 3 subunit reduces the IC50 of TETS by ∼700-fold in whole-cell patch-clamp experiments. TETS is thus interacting at the NCA site in the pore of the GABAA receptor at a location that is overlapping but not identical to the picrotoxinin binding site. SIGNIFICANCE STATEMENT: Our study identifies the binding site of the highly toxic convulsant tetramethylenedisulfotetramine (TETS), which is classified as a threat agent by the World Health Organization. Using a combination of homology protein modeling, ligand docking, site-directed mutagenesis, and electrophysiology, we show that TETS is binding in the pore of the α2β3γ2 GABA receptor type A receptor at the so-called T6' ring, wherein five threonine residues line the permeation pathway of the pentameric receptor channel.
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Affiliation(s)
- Brandon Pressly
- Departments of Pharmacology (B.P., R.D.L, H.W.) and Entomology and Nematology, and Comprehensive Cancer Center (B.B., B.D.H.), University of California, Davis, California
| | - Ruth D Lee
- Departments of Pharmacology (B.P., R.D.L, H.W.) and Entomology and Nematology, and Comprehensive Cancer Center (B.B., B.D.H.), University of California, Davis, California
| | - Bogdan Barnych
- Departments of Pharmacology (B.P., R.D.L, H.W.) and Entomology and Nematology, and Comprehensive Cancer Center (B.B., B.D.H.), University of California, Davis, California
| | - Bruce D Hammock
- Departments of Pharmacology (B.P., R.D.L, H.W.) and Entomology and Nematology, and Comprehensive Cancer Center (B.B., B.D.H.), University of California, Davis, California
| | - Heike Wulff
- Departments of Pharmacology (B.P., R.D.L, H.W.) and Entomology and Nematology, and Comprehensive Cancer Center (B.B., B.D.H.), University of California, Davis, California
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15
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Benkherouf AY, Eerola K, Soini SL, Uusi-Oukari M. Humulone Modulation of GABA A Receptors and Its Role in Hops Sleep-Promoting Activity. Front Neurosci 2020; 14:594708. [PMID: 33177986 PMCID: PMC7591795 DOI: 10.3389/fnins.2020.594708] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Humulus lupulus L. (hops) is a major constituent of beer. It exhibits neuroactive properties that make it useful as a sleeping aid. These effects are hypothesized to be mediated by an increase in GABAA receptor function. In the quest to uncover the constituents responsible for the sedative and hypnotic properties of hops, recent evidence revealed that humulone, a prenylated phloroglucinol derivative comprising 35-70% of hops alpha acids, may act as a positive modulator of GABAA receptors at low micromolar concentrations. This raises the question whether humulone plays a key role in hops pharmacological activity and potentially interacts with other modulators such as ethanol, bringing further enhancement in GABAA receptor-mediated effects of beer. Here we assessed electrophysiologically the positive modulatory activity of humulone on recombinant GABAA receptors expressed in HEK293 cells. We then examined humulone interactions with other active hops compounds and ethanol on GABA-induced displacement of [3H]EBOB binding to native GABAA receptors in rat brain membranes. Using BALB/c mice, we assessed humulone's hypnotic behavior with pentobarbital- and ethanol-induced sleep as well as sedation in spontaneous locomotion with open field test. We demonstrated for the first time that humulone potentiates GABA-induced currents in α1β3γ2 receptors. In radioligand binding to native GABAA receptors, the inclusion of ethanol enhanced humulone modulation of GABA-induced displacement of [3H]EBOB binding in rat forebrain and cerebellum as it produced a leftward shift in [3H]EBOB displacement curves. Moreover, the additive modulatory effects between humulone, isoxanthohumol and 6-prenylnaringenin were evident and corresponded to the sum of [3H]EBOB displacement by each compound individually. In behavioral tests, humulone shortened sleep onset and increased the duration of sleep induced by pentobarbital and decreased the spontaneous locomotion in open field at 20 mg/kg (i.p.). Despite the absence of humulone effects on ethanol-induced sleep onset, sleep duration was increased dose-dependently down to 10 mg/kg (i.p.). Our findings confirmed humulone's positive allosteric modulation of GABAA receptor function and displayed its sedative and hypnotic behavior. Humulone modulation can be potentially enhanced by ethanol and hops modulators suggesting a probable enhancement in the intoxicating effects of ethanol in hops-enriched beer.
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Affiliation(s)
| | | | | | - Mikko Uusi-Oukari
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland
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16
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Comparison of the toxicokinetics of the convulsants picrotoxinin and tetramethylenedisulfotetramine (TETS) in mice. Arch Toxicol 2020; 94:1995-2007. [PMID: 32239239 PMCID: PMC7303059 DOI: 10.1007/s00204-020-02728-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/26/2020] [Indexed: 12/15/2022]
Abstract
Acute intoxication with picrotoxin or the rodenticide tetramethylenedisulfotetramine (TETS) can cause seizures that rapidly progress to status epilepticus and death. Both compounds inhibit γ-aminobutyric acid type-A (GABAA) receptors with similar potency. However, TETS is approximately 100 × more lethal than picrotoxin. Here, we directly compared the toxicokinetics of the two compounds following intraperitoneal administration in mice. Using LC/MS analysis we found that picrotoxinin, the active component of picrotoxin, hydrolyses quickly into picrotoxic acid, has a short in vivo half-life, and is moderately brain penetrant (brain/plasma ratio 0.3). TETS, in contrast, is not metabolized by liver microsomes and persists in the body following intoxication. Using both GC/MS and a TETS-selective immunoassay we found that mice administered TETS at the LD50 of 0.2 mg/kg in the presence of rescue medications exhibited serum levels that remained constant around 1.6 μM for 48 h before falling slowly over the next 10 days. TETS showed a similar persistence in tissues. Whole-cell patch-clamp demonstrated that brain and serum extracts prepared from mice at 2 and 14 days after TETS administration significantly blocked heterologously expressed α2β3γ2 GABAA-receptors confirming that TETS remains pharmacodynamically active in vivo. This observed persistence may contribute to the long-lasting and recurrent seizures observed following human exposures. We suggest that countermeasures to neutralize TETS or accelerate its elimination should be explored for this highly dangerous threat agent.
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17
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Garrod MG, Rossow HA, Calvert CC, Miller JW, Green R, Buchholz BA, Allen LH. 14C-Cobalamin Absorption from Endogenously Labeled Chicken Eggs Assessed in Humans Using Accelerator Mass Spectrometry. Nutrients 2019; 11:nu11092148. [PMID: 31500393 PMCID: PMC6769442 DOI: 10.3390/nu11092148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 08/31/2019] [Accepted: 09/04/2019] [Indexed: 12/27/2022] Open
Abstract
Traditionally, the bioavailability of vitamin B-12 (B12) from in vivo labeled foods was determined by labeling the vitamin with radiocobalt (57Co, 58Co or 60Co). This required use of penetrating radioactivity and sometimes used higher doses of B12 than the physiological limit of B12 absorption. The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin. The eggs, which provided 1.4 to 2.6 μg of B12 (~1.1 kBq) per serving, were scrambled, cooked and fed to 10 human volunteers. Baseline and post-ingestion blood, urine and stool samples were collected over a one-week period and assessed for 14C-B12 content using AMS. Bioavailability ranged from 13.2 to 57.7% (mean 30.2 ± 16.4%). Difference among subjects was explained by dose of B12, with percent bioavailability from 2.6 μg only half that from 1.4 μg. The total amount of B12 absorbed was limited to 0.5–0.8 μg (mean 0.55 ± 0.19 μg B12) and was relatively unaffected by the amount consumed. The use of 14C-B12 offers the only currently available method for quantifying B12 absorption in humans, including food cobalamin absorption. An egg is confirmed as a good source of B12, supplying approximately 20% of the average adult daily requirement (RDA for adults = 2.4 μg/day).
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Affiliation(s)
- Marjorie G Garrod
- USDA, ARS Western Human Nutrition Research Center, Davis, CA 95616, USA.
| | - Heidi A Rossow
- Population Health and Reproduction, University of California, Davis, CA 95616, USA.
| | | | - Joshua W Miller
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Ralph Green
- Department. of Medical Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA 95817, USA.
| | - Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
| | - Lindsay H Allen
- USDA, ARS Western Human Nutrition Research Center, Davis, CA 95616, USA.
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18
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Moffett MC, Rauscher NA, Rice NC, Myers TM. Survey of drug therapies against acute oral tetramethylenedisulfotetramine poisoning in a rat voluntary consumption model. Neurotoxicology 2019; 74:264-271. [DOI: 10.1016/j.neuro.2019.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/30/2019] [Accepted: 08/05/2019] [Indexed: 12/12/2022]
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19
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Lauková M, Velíšková J, Velíšek L, Shakarjian MP. Tetramethylenedisulfotetramine neurotoxicity: What have we learned in the past 70 years? Neurobiol Dis 2019; 133:104491. [PMID: 31176716 DOI: 10.1016/j.nbd.2019.104491] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/27/2019] [Accepted: 06/05/2019] [Indexed: 12/21/2022] Open
Abstract
Tetramethylenedisulfotetramine (tetramine, TETS, TMDT) is a seizure-producing neurotoxic chemical formed by the condensation of sulfamide and formaldehyde. Serendipitously discovered through an occupational exposure in 1949, it was promoted as a rodenticide but later banned worldwide due to its danger to human health. However, exceptional activity of the agent against rodent pests resulted in its clandestine manufacture with large numbers of inadvertent, intentional, and mass poisonings, which continue to this day. Facile synthesis, extreme potency, persistence, lack of odor, color, and taste identify it as an effective food adulterant and potential chemical agent of terror. No known antidote or targeted treatment is currently available. In this review we examine the origins of tetramethylenedisulfotetramine, from its identification as a neurotoxicant 70 years ago, through early research, to the most recent findings including the risk it poses in the post-911 world. Included is the information known regarding its in vitro pharmacology as a GABAA receptor channel antagonist, the toxic syndrome it produces in vivo, and its effect upon vulnerable populations. We also summarize the available information about potential therapeutic countermeasures and treatment strategies as well as the contribution of clinical development of TMDT poisoning to our understanding of epileptogenesis. Finally we identify gaps in our knowledge and suggest potentially fruitful directions for continued research on this dangerous, yet intriguing compound.
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Affiliation(s)
- Marcela Lauková
- Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Pediatrics, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84505, Slovakia
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Obstetrics and Gynecology, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Neurology, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Neurology, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Pediatrics, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA
| | - Michael P Shakarjian
- Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Cell Biology and Anatomy, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Ln W, Piscataway, NJ 08854, USA.
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Buchholz BA, Carratt SA, Kuhn EA, Collette NM, Ding X, Van Winkle LS. Naphthalene DNA Adduct Formation and Tolerance in the Lung. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2019; 438:119-123. [PMID: 30631217 PMCID: PMC6322674 DOI: 10.1016/j.nimb.2018.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Naphthalene (NA) is a respiratory toxicant and possible human carcinogen. NA is a ubiquitous combustion product and significant component of jet fuel. The National Toxicology Program found that NA forms tumors in two species, in rats (nose) and mice (lung). However, it has been argued that NA does not pose a cancer risk to humans because NA is bioactivated by cytochrome P450 monooxygenase enzymes that have very high efficiency in the lung tissue of rodents but low efficiency in the lung tissue of humans. It is thought that NA carcinogenesis in rodents is related to repeated cycles of lung epithelial injury and repair, an indirect mechanism. Repeated in vivo exposure to NA leads to development of tolerance, with the emergence of cells more resistant to NA insult. We tested the hypothesis that tolerance involves reduced susceptibility to the formation of NA-DNA adducts. NA-DNA adduct formation in tolerant mice was examined in individual, metabolically-active mouse airways exposed ex vivo to 250 μΜ 14C-NA. Ex vivo dosing was used since it had been done previously and the act of creating a radioactive aerosol of a potential carcinogen posed too many safety and regulatory obstacles. Following extensive rinsing to remove unbound 14C-NA, DNA was extracted and 14C-NA-DNA adducts were quantified by AMS. The tolerant mice appeared to have slightly lower NA-DNA adduct levels than non-tolerant controls, but intra-group variations were large and the difference was statistically insignificant. It appears the tolerance may be more related to other mechanisms, such as NA-protein interactions in the airway, than DNA-adduct formation.
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Affiliation(s)
- Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Sarah A Carratt
- Center for Health and the Environment, University of California, Davis, CA USA
| | - Edward A Kuhn
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Nicole M Collette
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Xinxin Ding
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ USA
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California, Davis, CA USA
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21
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Garrod MG, Buchholz BA, Miller JW, Haack KW, Green R, Allen LH. Vitamin B12 Added as a Fortificant to Flour Retains High Bioavailability when Baked in Bread. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2019; 438:136-140. [PMID: 30555197 PMCID: PMC6290905 DOI: 10.1016/j.nimb.2018.05.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vitamin B12 deficiency and depletion are common world-wide, particularly in populations that consume low amounts of animal source foods. WHO and the Food Fortification Initiative recommend that wheat flour be fortified with vitamin B12 in regions where intake of B12 is low. The purpose of this pilot study in five participants was to determine if fortification of flour with B12 produced a bread product with intact B12 still present and to determine if healthy elderly absorb sufficient B12 from bread fortified in this manner. High-purity crystalline 14C-B12 was dissolved in water and added to flour (2 μg B12 /100 g flour) in a bread maker and made into rolls (average 1.17 kBq (31.5 nCi) 14C-B12 in a total of 0.8 µg B12 per roll). Excess 14C first appeared in plasma 4 h after ingestion of the 14C fortified bread and plasma levels returned almost to background by 72 h. Measurement of 14C in plasma verified that the dose was absorbed into the systemic circulation. The cumulative % dose recovered in urine was 4.8-37.0% (mean = 20.1%). Most of the 14C label in the stool appeared by day 4, and the cumulative % dose recovered in stool was 24.5- 43.0% (mean = 31.8%). Bioavailability among the 5 participants, calculated by subtracting the sum of urinary and fecal 14C excretion from the administered dose, was 28.4-63.7% (mean = 48.0%). This study showed that when B12 is added as a fortificant to flour it survives the fermentation and baking processes, and retains ~ 50% bioavailability when fed in small doses to healthy subjects. The Recommended Dietary Allowance of B12 for adults is 2.4 μg/d. This recommendation assumes that usual bioavailability of low doses of the vitamin in the crystalline form is 60%, while for the same amount in foods such as meat and fish it is 50%. Our pilot study shows that B12 added to bread as a fortificant in flour was absorbed as well as it is from endogenous food sources such as meat and fish.
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Affiliation(s)
- Marjorie G Garrod
- USDA, ARS Western Human Nutrition Research Center, Davis, California
| | - Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California
| | - Joshua W Miller
- School of Environmental and Biological Science, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Kurt W Haack
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California
| | - Ralph Green
- Dept. of Medical Pathology and Laboratory Medicine, University of California, Davis, California
| | - Lindsay H Allen
- USDA, ARS Western Human Nutrition Research Center, Davis, California
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22
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Hum NR, Martin KA, Malfatti MA, Haack K, Buchholz BA, Loots GG. Tracking Tumor Colonization in Xenograft Mouse Models Using Accelerator Mass Spectrometry. Sci Rep 2018; 8:15013. [PMID: 30302019 PMCID: PMC6178347 DOI: 10.1038/s41598-018-33368-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/24/2018] [Indexed: 12/12/2022] Open
Abstract
Here we introduce an Accelerator Mass Spectrometry (AMS)-based high precision method for quantifying the number of cancer cells that initiate metastatic tumors, in xenograft mice. Quantification of 14C per cell prior to injection into animals, and quantification of 14C in whole organs allows us to extrapolate the number of cancer cells available to initiate metastatic tumors. The 14C labeling was optimized such that 1 cancer cell was detected among 1 million normal cells. We show that ~1–5% of human cancer cells injected into immunodeficient mice form subcutaneous tumors, and even fewer cells initiate metastatic tumors. Comparisons of metastatic site colonization between a highly metastatic (PC3) and a non-metastatic (LnCap) cell line showed that PC3 cells colonize target tissues in greater quantities at 2 weeks post-delivery, and by 12 weeks post-delivery no 14C was detected in LnCap xenografts, suggesting that all metastatic cells were cleared. The 14C-signal correlated with the presence and the severity of metastatic tumors. AMS measurements of 14C-labeled cells provides a highly-sensitive, quantitative assay to experimentally evaluate metastasis and colonization of target tissues in xenograft mouse models. This approach can potentially be used to evaluate tumor aggressiveness and assist in making informed decisions regarding treatment.
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Affiliation(s)
- Nicholas R Hum
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Kelly A Martin
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA.,Georgetown University, Department of Biochemistry & Molecular Biology, Washington, DC, USA
| | - Michael A Malfatti
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Kurt Haack
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA
| | - Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Gabriela G Loots
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, Livermore, CA, USA. .,UC Merced, School of Natural Sciences, Merced, CA, USA.
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Tetramethylenedisulfotetramine: A Health Risk Compound and a Potential Chemical Warfare Agent. TOXICS 2018; 6:toxics6030051. [PMID: 30135374 PMCID: PMC6160919 DOI: 10.3390/toxics6030051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/04/2018] [Accepted: 08/16/2018] [Indexed: 01/03/2023]
Abstract
Tetramethylenedisulfotetramine (TETS, tetramine) is a toxic organic compound that is used as an effective rodenticide. However, this neurotoxin is not only toxic to rodents, it also causes poisoning in humans. Due to its high level of toxicity for humans, the use of TETS as a rodenticide has been banned and its production has been discontinued. Despite this, human poisoning by this substance is unfortunately still very common. The largest number of poisonings are reported in China, but in the United States, dozens of poisonings still happen annually. TETS is one of the most hazardous pesticides and also a possible chemical warfare agent with no known antidote. In this article, we aim to summarize the biochemical and toxicological data of TETS and hope to cast some light on the toxicological risk to human health.
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24
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Olsen RW. GABA A receptor: Positive and negative allosteric modulators. Neuropharmacology 2018; 136:10-22. [PMID: 29407219 PMCID: PMC6027637 DOI: 10.1016/j.neuropharm.2018.01.036] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/11/2022]
Abstract
gamma-Aminobutyric acid (GABA)-mediated inhibitory neurotransmission and the gene products involved were discovered during the mid-twentieth century. Historically, myriad existing nervous system drugs act as positive and negative allosteric modulators of these proteins, making GABA a major component of modern neuropharmacology, and suggesting that many potential drugs will be found that share these targets. Although some of these drugs act on proteins involved in synthesis, degradation, and membrane transport of GABA, the GABA receptors Type A (GABAAR) and Type B (GABABR) are the targets of the great majority of GABAergic drugs. This discovery is due in no small part to Professor Norman Bowery. Whereas the topic of GABABR is appropriately emphasized in this special issue, Norman Bowery also made many insights into GABAAR pharmacology, the topic of this article. GABAAR are members of the ligand-gated ion channel receptor superfamily, a chloride channel family of a dozen or more heteropentameric subtypes containing 19 possible different subunits. These subtypes show different brain regional and subcellular localization, age-dependent expression, and potential for plastic changes with experience including drug exposure. Not only are GABAAR the targets of agonist depressants and antagonist convulsants, but most GABAAR drugs act at other (allosteric) binding sites on the GABAAR proteins. Some anxiolytic and sedative drugs, like benzodiazepine and related drugs, act on GABAAR subtype-dependent extracellular domain sites. General anesthetics including alcohols and neurosteroids act at GABAAR subunit-interface trans-membrane sites. Ethanol at high anesthetic doses acts on GABAAR subtype-dependent trans-membrane domain sites. Ethanol at low intoxicating doses acts at GABAAR subtype-dependent extracellular domain sites. Thus GABAAR subtypes possess pharmacologically specific receptor binding sites for a large group of different chemical classes of clinically important neuropharmacological agents. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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25
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Witkin JM, Shenvi RA, Li X, Gleason SD, Weiss J, Morrow D, Catow JT, Wakulchik M, Ohtawa M, Lu HH, Martinez MD, Schkeryantz JM, Carpenter TS, Lightstone FC, Cerne R. Pharmacological characterization of the neurotrophic sesquiterpene jiadifenolide reveals a non-convulsant signature and potential for progression in neurodegenerative disease studies. Biochem Pharmacol 2018; 155:61-70. [PMID: 29940173 DOI: 10.1016/j.bcp.2018.06.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/18/2018] [Indexed: 11/17/2022]
Abstract
The 'neurotrophic sesquiterpenes' refer to a group of molecules derived from the Illicium genus of flowering plant. They display neurotrophic effects in cultured neuron preparations and have been suggested to be cognitive enhancers and potential therapeutics for neurodegenerative disorders and dementias. Recent synthetic advances generated sufficient quantities of jiadifenolide for in vivo investigation into its biological effects. Jiadifenolide did not induce convulsions in mice nor did it enhance or diminish convulsions induced by pentylenetetrazole. Other negative allosteric modulators of GABAA receptors, picrotoxin, tetramethylenedisulfotetramine (TETS), and bilobalide all induced convulsions. Either i.p. or i.c.v. dosing generated micromolar plasma and brain levels of jiadifenolide but only small effects on locomotion of mice. However, jiadifenolide decreased d-amphetamine-induced hyperlocomotion in mice, an antipsychotic-like drug effect. Jiadifenolide did not significantly alter body temperature or behavior in the forced-swim test in mice. Molecular simulation data suggested a potential site in the pore/M2 helix region that is at an overlapping, yet lower position than those observed for other 'cage convulsant' compounds such as TETS and picrotoxin. We hypothesize that a position nearer to the entrance of the pore channel may allow for easier displacement of jiadifenolide from its blocking location leading to lower potency and lower side-effect liability. Like jiadifenolide, memantine (Namenda), one of the few drugs used in the symptomatic treatment of dementias, occupies a unique site on the NMDA receptor complex that creates low binding affinity that is associated with its reduced side-effect profile. Given the potential therapeutic applications of jiadifenolide and its relatively inert effects on overt behavior, the possibility of clinical utility for jiadifenolide and related compounds becomes intriguing.
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Affiliation(s)
- Jeffrey M Witkin
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA.
| | - Ryan A Shenvi
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Xia Li
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - Scott D Gleason
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - Julie Weiss
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - Denise Morrow
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - John T Catow
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - Mark Wakulchik
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
| | - Masaki Ohtawa
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Hai-Hua Lu
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Michael D Martinez
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | | | - Timothy S Carpenter
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Felice C Lightstone
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Rok Cerne
- The Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
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26
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Sheng CW, Jia ZQ, Ozoe Y, Huang QT, Han ZJ, Zhao CQ. Molecular cloning, spatiotemporal and functional expression of GABA receptor subunits RDL1 and RDL2 of the rice stem borer Chilo suppressalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 94:18-27. [PMID: 29408355 DOI: 10.1016/j.ibmb.2018.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/19/2018] [Accepted: 01/22/2018] [Indexed: 06/07/2023]
Abstract
Insect γ-aminobutyric acid (GABA) receptor (GABAR) is one of the major targets of insecticides. In the present study, cDNAs (CsRDL1A and CsRDL2S) encoding the two isoforms of RDL subunits were cloned from the rice stem borer Chilo suppressalis. Transcripts of both genes demonstrated similar expression patterns in different tissues and developmental stages, although CsRDL2S was ∼2-fold more abundant than CsRDL1A throughout all development stages. To investigate the function of channels formed by CsRDL subunits, both genes were expressed in Xenopus laevis oocytes singly or in combination in different ratios. Electrophysiological results using a two-electrode voltage clamp demonstrated that GABA activated currents in oocytes injected with both cRNAs. The EC50 value of GABA in activating currents was smaller in oocytes co-injected with CsRDL1A and CsRDL2S than in oocytes injected singly. The IC50 value of the insecticide fluralaner in inhibiting GABA responses was smaller in oocytes co-injected with different cRNAs than in oocytes injected singly. Co-injection also changed the potency of the insecticide dieldrin in oocytes injected singly. These findings suggested that heteromeric GABARs were formed by the co-injections of CsRDL1A and CsRDL2S in oocytes. Although the presence of Ser at the 2'-position in the second transmembrane segment was responsible for the insensitivity of GABARs to dieldrin, this amino acid did not affect the potencies of the insecticides fipronil and fluralaner. These results lead us to hypothesize that C. suppressalis may adapt to insecticide pressure by regulating the expression levels of CsRDL1A and CsRDL2S and the composition of both subunits in GABARs.
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Affiliation(s)
- Cheng-Wang Sheng
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Zhong-Qiang Jia
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, 690-8504, Japan
| | - Qiu-Tang Huang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Zhao-Jun Han
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Chun-Qing Zhao
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
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27
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Lauková M, Velíšková J, Velíšek L, Shakarjian MP. Developmental and sex differences in tetramethylenedisulfotetramine (TMDT)-induced syndrome in rats. Dev Neurobiol 2018; 78:403-416. [PMID: 29411537 DOI: 10.1002/dneu.22582] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/15/2018] [Accepted: 02/01/2018] [Indexed: 12/21/2022]
Abstract
Tetramethylenedisulfotetramine (TMDT) is a synthetic neurotoxic rodenticide considered a chemical threat agent. Symptoms of intoxication include seizures leading to status epilepticus and death. While children and women have been often the victims, no studies exist investigating the neurotoxic effects of TMDT in developing individuals or females. Thus, we performed such an investigation in developing Sprague-Dawley rats of both sexes in order to identify potential age- or sex-dependent vulnerability to TMDT exposure. Subcutaneous injection was chosen as the preferred route of TMDT exposure. EEG recordings confirmed the seizure activity observed in both postnatal day 15 (P15) and adult rats. Additionally, P15 rats displayed greater sensitivity to TMDT than postnanatal day 25 or adult animals. Seizures were generally more severe in females compared to males. Barrel rotations accompanied convulsions in P25 and adult, but sparsely in P15 rats. Adults developed barrel rolling less frequently than P25 population. Neuronal cell death was not present in 24-h TMDT survivors at any age or sex tested. A seizure rechallenge with flurothyl 7 days following TMDT exposure demonstrated longer latencies to the first clonic seizure but a faster progression into the tonic-clonic seizure in P15 and adult survivors as compared to their vehicle-injected counterparts. In conclusion, the youngest age group represents the most vulnerable population to the TMDT-induced toxidrome. Females appear to be more vulnerable than males. TMDT exposure promotes seizure spread and progression in survivors. These findings will help to establish sex- and age-specific treatment strategies for TMDT-exposed individuals. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 403-416, 2018.
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Affiliation(s)
- Marcela Lauková
- Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, Valhalla, New York.,Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Obstetrics and Gynecology, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York.,Department of Pediatrics, New York Medical College, Valhalla, New York
| | - Michael P Shakarjian
- Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, Valhalla, New York.,Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey
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28
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GABA A receptor subtype selectivity of the proconvulsant rodenticide TETS. Arch Toxicol 2017; 92:833-844. [PMID: 29038840 PMCID: PMC5818616 DOI: 10.1007/s00204-017-2089-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/05/2017] [Indexed: 12/14/2022]
Abstract
The rodenticide tetramethylenedisulfotetramine (TETS) is a potent convulsant (lethal dose in humans 7–10 mg) that is listed as a possible threat agent by the United States Department of Homeland Security. TETS has previously been studied in vivo for toxicity and in vitro in binding assays, with the latter demonstrating it to be a non-competitive antagonist on GABAA receptors. To determine whether TETS exhibits subtype selectivity for a particular GABAA receptor combination, we used whole-cell patch-clamp to determine the potency of TETS on the major synaptic and extrasynaptic GABAA receptors associated with convulsant activity. The active component of picrotoxin, picrotoxinin, was used as a control. While picrotoxinin did not differentiate well between 13 GABAA receptors, TETS exhibited the highest activity on α2β3γ2 (IC50 480 nM, 95% CI 320–640 nM) and α6β3γ2 (IC50 400 nM, 95% CI 290–510 nM). Introducing β1 or β2 subunits into these receptor combinations reduced or abolished TETS sensitivity, suggesting that TETS preferentially affects receptors with α2/β3 or α6/β3 composition. Since α2β3γ2 receptors make up 15–20% of the GABAA receptors in the mammalian CNS, we suggest that α2β3γ2 is probably the most important GABAA receptor for the seizure-inducing activity of TETS.
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29
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Rice NC, Rauscher NA, Langston JL, Myers TM. Behavioral intoxication following voluntary oral ingestion of tetramethylenedisulfotetramine: Dose-dependent onset, severity, survival, and recovery. Neurotoxicology 2017; 63:21-32. [PMID: 28855111 DOI: 10.1016/j.neuro.2017.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 01/13/2023]
Abstract
Tetramethylenedisulfotetramine (tetramine, or TETS) is a highly toxic rodenticide that has been responsible for over 14,000 accidental and intentional poisonings worldwide. Although the vast majority of TETS poisonings involved tainted food or drink, the laboratory in vivo studies of TETS intoxication used intraperitoneal injection or gavage for TETS exposure. Seeking to develop and characterize a more realistic model of TETS intoxication in the present study, rats were trained to rapidly and voluntarily consume a poisoned food morsel. Initially, the overt toxic effects of TETS consumption across a large range of doses were characterized, then a focused range of doses was selected for more intensive behavioral evaluation (in operant test chambers providing a variable-interval schedule of food reinforcement). The onset of intoxication following voluntary oral consumption of TETS was rapid, and clear dose-dependent response-rate suppression was observed across multiple performance measures within the operant-chamber environment. At most doses, recovery of operant performance did not occur within 30h. Food consumption and body weight changes were also dose dependent and corroborated the behavioral measures of intoxication. This voluntary oral-poisoning method with concomitant operant-behavioral assessment shows promise for future studies of TETS (and other toxic chemicals of interest) and may be extremely valuable in characterizing treatment outcomes.
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Affiliation(s)
- Nathaniel C Rice
- United States Army Medical Research Institute of Chemical Defense, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, USA
| | - Noah A Rauscher
- United States Army Medical Research Institute of Chemical Defense, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, USA
| | - Jeffrey L Langston
- United States Army Medical Research Institute of Chemical Defense, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, USA
| | - Todd M Myers
- United States Army Medical Research Institute of Chemical Defense, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, USA.
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30
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Vasylieva N, Barnych B, Rand A, Inceoglu B, Gee SJ, Hammock BD. Sensitive Immunoassay for Detection and Quantification of the Neurotoxin, Tetramethylenedisulfotetramine. Anal Chem 2017; 89:5612-5619. [PMID: 28398746 PMCID: PMC5920647 DOI: 10.1021/acs.analchem.7b00846] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tetramethylenedisulfotetramine (TETS, tetramine) is a formerly used and highly neurotoxic rodenticide. Its lethality, recent history of intentional use for mass poisoning, and the absence of a known antidote raise public health concerns. Therefore, rapid, high throughput, and sensitive methods for detection and quantification of TETS are critical. Instrumental analysis method such as GC/MS is sensitive but not rapid or high throughput. Therefore, an immunoassay selective to TETS was developed. The assay shows an IC50 of 4.5 ± 1.2 ng/mL, with a limit of detection of 0.2 ng/mL, comparable to GC/MS. Performance of the immunoassay was demonstrated by a recovery study using known concentrations of TETS spiked into buffer and human and mouse serum matrices giving recoveries in the range of 80-120%. The assay demonstrated good correlation in TETS recovery with established GC/MS analysis. The immunoassay was then used to quantify TETS concentration in the serum of mice exposed to 2× LD50 dose of TETS and to monitor kinetics of TETS clearance from blood over a short period of time. TETS concentration in the serum reached 150 ng/mL without significant change over 4 h post-treatment. Results obtained with the immunoassay had good correlation with GC/MS analysis. Overall, this immunoassay is an important tool to rapidly detect and quantify levels of TETS from biological samples with high sensitivity. The assay can be adapted to multiple formats including field or hospital use.
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Affiliation(s)
- Natalia Vasylieva
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
| | - Bogdan Barnych
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
| | - Amy Rand
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
| | - Bora Inceoglu
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
| | - Shirley J Gee
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
| | - Bruce D Hammock
- Department of Entomology and Nematology and UCD Comprehensive Cancer Center, University of California Davis , Davis, California 95616, United States
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31
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Nik AM, Pressly B, Singh V, Antrobus S, Hulsizer S, Rogawski MA, Wulff H, Pessah IN. Rapid Throughput Analysis of GABA A Receptor Subtype Modulators and Blockers Using DiSBAC 1(3) Membrane Potential Red Dye. Mol Pharmacol 2017; 92:88-99. [PMID: 28428226 DOI: 10.1124/mol.117.108563] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/12/2017] [Indexed: 02/03/2023] Open
Abstract
Fluorometric imaging plate reader membrane potential dye (FMP-Red-Dye) is a proprietary tool for basic discovery and high-throughput drug screening for G-protein-coupled receptors and ion channels. We optimized and validated this potentiometric probe to assay functional modulators of heterologous expressed GABAA receptor (GABAAR) isoforms (synaptic α1β3γ2, extrasynaptic α4β3δ, and β3 homopentomers). High-resolution mass spectrometry identified FMP-Red-Dye as 5,5'-(1-propen-1-yl-3-ylidene)bis[1,3-dimethyl-2-thio-barbituric acid]. GABAAR-expressing cells equilibrated with FMP-Red-Dye exhibited depolarized equilibrium membrane potentials compared with GABAAR-null cells. The channel blockers picrotoxin, fipronil, and tetramethylenedisulfotetramine, and the competitive antagonist bicuculline reduced fluorescence near the levels in GABAAR-null cells indicating that FMR-Red-Dye, a barbiturate derivative, activates GABAAR-mediated outward Cl- current in the absence of GABA. GABA caused concentration-dependent increases in fluorescence with rank order of potencies among GABAAR isoforms consistent with results from voltage-clamp experiments (EC50 values for α4β3δ, α1β3γ2, and β3 homopentamers were 6 ± 1, 40 ± 11, and >18 mM, respectively), whereas GABAAR-null cells were unresponsive. Neuroactive steroids (NAS) increased fluorescence of GABAAR expressing cells in the absence of GABA and demonstrated positive allosteric modulation in the presence of GABA, whereas benzodiazepines only exhibited positive allosteric modulator (PAM) activity. Of 20 NAS tested, allopregnanolone, (3α,5α,20E)-3-hydroxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile, eltanolone, 5β-pregnan-3α,21-diol-20-one, and ganaxolone showed the highest potency. The FMP-Red-Dye-based assay described here provides a sensitive and quantitative method of assessing the activity of GABAAR agonists, antagonists, and PAMs on diverse GABAAR isoforms. The assay has a wide range of applications, including screening for antiseizure agents and identifying channel blockers of interest to insecticide discovery or biosecurity.
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Affiliation(s)
- Atefeh Mousavi Nik
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Brandon Pressly
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Vikrant Singh
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Shane Antrobus
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Susan Hulsizer
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Michael A Rogawski
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Heike Wulff
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine (A.M.N., S.A., S.H., I.N.P.), and Department of Pharmacology (B.P., V.S., M.A.R., H.W.), School of Medicine, University of California Davis, Davis, California; Department of Neurology, School of Medicine, University of California Davis, Sacramento, California (M.A.R.); and The Medical Investigation of Neurodevelopmental Disorders Institute, Sacramento, California (I.N.P.)
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Tian M, Zhang Q, Hua X, Tang B, Gao B, Wang M. Systemic stereoselectivity study of flufiprole: Stereoselective bioactivity, acute toxicity and environmental fate. JOURNAL OF HAZARDOUS MATERIALS 2016; 320:487-494. [PMID: 27585281 DOI: 10.1016/j.jhazmat.2016.08.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/13/2016] [Accepted: 08/16/2016] [Indexed: 06/06/2023]
Abstract
In this study, the stereoselectivity of flufiprole enantiomers in regards to their bioactivity, acute toxicity and environmental fate is reported for the first time. Four types of representative insects (Plutella xylostella, Nilaparvata lugens, Mythimna separata and Acyrthosiphon pisum) were used to investigate enantioselective bioactivity. Acute toxicities of flufiprole enantiomers toward two non-target organisms were also evaluated. Moreover, stereoselective degradation in four vegetables under field conditions was studied in response to food safety concerns. The bioactivity of (R)-flufiprole was 1.9-5.1 times higher than that of (S)-flufiprole. (R)-flufiprole also showed 3.7-5.7 times higher acute toxicity to Scenedesmus obliquus and Trichogramma japonicum Ashmead than (S)-flufiprole. Opposite stereoselective degradation of the two enantiomers was observed in pak choi, spinach cucumber, and tomato. (S)-flufiprole degraded faster in pak choi and spinach, resulting in an enrichment of (R)-isomer. By contrast, (R)-isomer was preferentially degraded in cucumber and tomato. Molecular simulation technology was used to illuminate the mechanism of enantioselective bioactivity. The Glide Score (-5.82kcal/mol) for (R)-isomer was better than that (-5.11kcal/mol) of (S)-isomer and this calculation showed (R)-flufiprole was more effective in pest control. Consequently, significant stereoselectivity of flufiprole enantiomers should be taken into account when assessing the environmental health risk of the pesticide.
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Affiliation(s)
- Mingming Tian
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, PR China
| | - Qing Zhang
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, PR China
| | - Xiude Hua
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, PR China
| | - Bowen Tang
- College of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, PR China
| | - Beibei Gao
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, PR China
| | - Minghua Wang
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, PR China.
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Cao Z, Xu J, Hulsizer S, Cui Y, Dong Y, Pessah IN. Influence of tetramethylenedisulfotetramine on synchronous calcium oscillations at distinct developmental stages of hippocampal neuronal cultures. Neurotoxicology 2016; 58:11-22. [PMID: 27984050 DOI: 10.1016/j.neuro.2016.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/18/2016] [Accepted: 10/18/2016] [Indexed: 12/20/2022]
Abstract
The spatial and temporal patterns of spontaneous synchronous Ca2+ oscillations (SCOs) regulate physiological pathways that influence neuronal development, excitability, and health. Hippocampal neuronal cultures (HN) and neuron/glia co-cultures (HNG) produced from neonatal mice were loaded with Fluo-4/AM and SCOs recorded in real-time using a Fluorescence Imaging Plate Reader at different developmental stages in vitro. HNG showed an earlier onset of SCOs, with low amplitude and low frequency SCOs at 4days in vitro (DIV), whereas HN were quiescent at this point. SCO amplitude peaked at 9 DIV for both cultures. SCO network frequency peaked at 12 DIV in HN, whereas in HNG the frequency peaked at 6 DIV. SCO patterns were associated with the temporal development of neuronal networks and their ratio of glutamatergic to GABAergic markers of excitatory/inhibitory balance. HN and HNG exhibited differential responses to the convulsant tetramethylenedisulfotetramine (TETS) and were highly dependent on DIV. In HN, TETS triggered an acute rise of intracellular Ca2+ (Phase I response) only in 14 DIV and a sustained decrease of SCO frequency with increased amplitude (Phase II response) at all developmental stages. In HNG, TETS decreased the SCO frequency and increased the amplitude at 6 and 14 but not 9 DIV. There was no acute Ca2+ rise (Phase I response) in any age of HNG tested with TETS. These data demonstrated the importance of glia and developmental stage in modulating neuronal responses to TETS. Our results illustrate the applicability of the model for investigating how caged convulsants elicit abnormal network activity during the development of HN and HNG cultures in vitro.
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Affiliation(s)
- Zhengyu Cao
- State Key Laboratory of Natural Medicines & Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China; Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 95616, United States.
| | - Jian Xu
- State Key Laboratory of Natural Medicines & Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China
| | - Susan Hulsizer
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 95616, United States
| | - Yanjun Cui
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 95616, United States
| | - Yao Dong
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 95616, United States
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 95616, United States.
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Pessah IN, Rogawski MA, Tancredi DJ, Wulff H, Zolkowska D, Bruun DA, Hammock BD, Lein PJ. Models to identify treatments for the acute and persistent effects of seizure-inducing chemical threat agents. Ann N Y Acad Sci 2016; 1378:124-136. [PMID: 27467073 DOI: 10.1111/nyas.13137] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/15/2016] [Accepted: 05/19/2016] [Indexed: 12/27/2022]
Abstract
Exposures to seizure-inducing chemical threat agents are a major public health concern. Of particular need is improved treatment to terminate convulsions and to prevent the long-term neurological sequelae in survivors. We are studying the organophosphorus cholinesterase inhibitor diisopropyl fluorophosphate (DFP) and the GABA receptor inhibitor tetramethylenedisulfotetramine (TETS), which arguably encompass the mechanistic spectrum of seizure-inducing chemical threats, with the goal of identifying therapeutic approaches with broad-spectrum efficacy. Research efforts have focused on developing translational models and translational diagnostic approaches, including (1) in vivo models of DFP- and TETS-induced seizures for studying neuropathological mechanisms and identifying treatment approaches; (2) in vivo imaging modalities for noninvasive longitudinal monitoring of neurological damage and response to therapeutic candidates; and (3) higher-throughput in vitro platforms for rapid screening of compounds to identify potential antiseizure and neuroprotective agents, as well as mechanistically relevant novel drug targets. This review summarizes our progress toward realizing these goals and discusses best practices and mechanistic insights derived from our modeling efforts.
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Affiliation(s)
- Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine
| | | | | | - Heike Wulff
- Department of Pharmacology, School of Medicine
| | | | - Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine
| | - Bruce D Hammock
- Department of Entomology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine.
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Shakarjian MP, Laukova M, Velíšková J, Stanton PK, Heck DE, Velíšek L. Tetramethylenedisulfotetramine: pest control gone awry. Ann N Y Acad Sci 2016; 1378:68-79. [PMID: 27384716 DOI: 10.1111/nyas.13120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/07/2016] [Accepted: 05/10/2016] [Indexed: 01/01/2023]
Abstract
Incidences of pesticide poisonings are a significant cause of morbidity and mortality worldwide. The seizure-inducing rodenticide tetramethylenedisulfotetramine is one of the most toxic of these agents. Although banned, it has been responsible for thousands of accidental, intentional, and mass poisonings in mainland China and elsewhere. An optimal regimen for treatment of poisoning has not been established. Its facile synthesis from easily obtained starting materials, extreme potency, and lack of odor, color, or taste make it a potential chemical threat agent. This review describes the toxicologic properties of this agent, more recent advances in our understanding of its properties, and recommendations for future research.
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Affiliation(s)
- Michael P Shakarjian
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, New York. .,Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York. .,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey.
| | - Marcela Laukova
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, New York.,Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Obstetrics and Gynecology, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York
| | - Patric K Stanton
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York
| | - Diane E Heck
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, New York
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.,Department of Neurology, New York Medical College, Valhalla, New York.,Department of Pediatrics, New York Medical College, Valhalla, New York
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Abstract
Covering: 1860-2016A mechanistic link may exist between convulsant plant substances typified by picrotoxinin, and 'neurotrophic' sesquiterpenes like jiadifenolide. Picrotoxinin elicits convulsion by anion blockade of the Cys-loop family of neurotransmitter-gated ion channels. These same receptors mediate neuronal development and neurite outgrowth prior to synapse formation. Due to its structural homology with picrotoxin and anisatin, it is possible that jiadifenolide enhances NGF-stimulated neurite outgrowth by modulation of the Cys-loop family of receptors.
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Affiliation(s)
- R A Shenvi
- The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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37
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Hooper-Bui LM, Kwok ESC, Buchholz BA, Rust MK, Eastmond DA, Vogel JS. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2015; 361:665-669. [PMID: 26504258 PMCID: PMC4615608 DOI: 10.1016/j.nimb.2015.06.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.
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Affiliation(s)
- L M Hooper-Bui
- Department of Environmental Science, Louisiana State University, Baton Rouge, LA 70803 ; Department of Entomology, University of California, Riverside, CA 92521
| | - E S C Kwok
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521
| | - B A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 ; Department of Environmental Toxicology, University of California, Davis, CA 95616
| | - M K Rust
- Department of Entomology, University of California, Riverside, CA 92521
| | - D A Eastmond
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521
| | - J S Vogel
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551
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Casida JE, Durkin KA. Novel GABA receptor pesticide targets. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2015; 121:22-30. [PMID: 26047108 DOI: 10.1016/j.pestbp.2014.11.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 06/04/2023]
Abstract
The γ-aminobutyric acid (GABA) receptor has four distinct but overlapping and coupled targets of pesticide action importantly associated with little or no cross-resistance. The target sites are differentiated by binding assays with specific radioligands, resistant strains, site-directed mutagenesis and molecular modeling. Three of the targets are for non-competitive antagonists (NCAs) or channel blockers of widely varied chemotypes. The target of the first generation (20th century) NCAs differs between the larger or elongated compounds (NCA-IA) including many important insecticides of the past (cyclodienes and polychlorocycloalkanes) or present (fiproles) and the smaller or compact compounds (NCA-IB) highly toxic to mammals and known as cage convulsants, rodenticides or chemical threat agents. The target of greatest current interest is designated NCA-II for the second generation (21st century) of NCAs consisting for now of isoxazolines and meta-diamides. This new and uniquely different NCA-II site apparently differs enough between insects and mammals to confer selective toxicity. The fourth target is the avermectin site (AVE) for allosteric modulators of the chloride channel. NCA pesticides vary in molecular surface area and solvent accessible volume relative to avermectin with NCA-IBs at 20-22%, NCA-IAs at 40-45% and NCA-IIs at 57-60%. The same type of relationship relative to ligand-docked length is 27-43% for NCA-IBs, 63-71% for NCA-IAs and 85-105% for NCA-IIs. The four targets are compared by molecular modeling for the Drosophila melanogaster GABA-R. The principal sites of interaction are proposed to be: pore V1' and A2' for NCA-IB compounds; pore A2', L6' and T9' for NCA-IA compounds; pore T9' to S15' in proximity to M1/M3 subunit interface (or alternatively an interstitial site) for NCA-II compounds; and M1/M3, M2 interfaces for AVE. Understanding the relationships of these four binding sites is important in resistance management and in the discovery and use of safe and effective pest control agents.
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Affiliation(s)
- John E Casida
- Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720-3112, United States.
| | - Kathleen A Durkin
- Molecular Graphics and Computation Facility, College of Chemistry, University of California, Berkeley, California 94720-1460, United States
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Shakarjian MP, Ali MS, Velíšková J, Stanton PK, Heck DE, Velíšek L. Combined diazepam and MK-801 therapy provides synergistic protection from tetramethylenedisulfotetramine-induced tonic-clonic seizures and lethality in mice. Neurotoxicology 2015; 48:100-8. [PMID: 25783504 DOI: 10.1016/j.neuro.2015.03.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/07/2015] [Accepted: 03/07/2015] [Indexed: 12/21/2022]
Abstract
The synthetic rodenticide, tetramethylenedisulfotetramine (TMDT), is a persistent and highly lethal GABA-gated Cl(-) channel blocker. TMDT is clandestinely produced, remains popular in mainland China, and causes numerous unintentional and deliberate poisonings worldwide. TMDT is odorless, tasteless, and easy to manufacture, features that make it a potential weapon of terrorism. There is no effective treatment. We previously characterized the effects of TMDT in C57BL/6 mice and surveyed efficacies of GABAergic and glutamatergic anticonvulsant treatments. At 0.4 mg/kg i.p., TMDT produced neurotoxic symptomatology consisting of twitches, clonic and tonic-clonic seizures, often progressing to status epilepticus and death. If administered immediately after the occurrence of the first clonic seizure, the benzodiazepine diazepam (DZP) effectively prevented all subsequent seizure symptoms, whereas the NMDA receptor antagonist dizocilpine (MK-801) primarily prevented tonic-clonic seizures. The latter agent, however, appeared to be more effective at preventing delayed death. The present study further explored these phenomena, and characterized the therapeutic actions of DZP and MK-801 as combinations. Joint treatment with both DZP and MK-801 displayed synergistic protection against tonic-clonic seizures and 24 h lethality as determined by isobolographic analysis. Clonic seizures, however, remained poorly controlled. A modification of the treatment regimen, where DZP was followed 10 min later by MK-801, yielded a reduction in both types of seizures and improved overall outcome. Simultaneous monitoring of subjects via EEG and videography confirmed effectiveness of this sequential regimen. We conclude that TMDT blockage at GABAA receptors involves early activation of NMDA receptors, which contribute to persistent ictogenic activity. Our data predict that a sequential combination treatment with DZP followed by MK-801 will be superior to either individual therapy with, or simultaneous administration of, these two agents in treating TMDT poisoning.
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Affiliation(s)
- Michael P Shakarjian
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, NY 10595, United States; Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, United States; Department of Medicine, Division of Pulmonary and Critical Care Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States.
| | - Mahil S Ali
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, NY 10595, United States.
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, United States; Department of Obstetrics and Gynecology, New York Medical College, Valhalla, NY 10595, United States; Department of Neurology, New York Medical College, Valhalla, NY 10595, United States.
| | - Patric K Stanton
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, United States; Department of Neurology, New York Medical College, Valhalla, NY 10595, United States.
| | - Diane E Heck
- Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, NY 10595, United States.
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, United States; Department of Neurology, New York Medical College, Valhalla, NY 10595, United States; Department of Pediatrics, New York Medical College, Valhalla, NY 10595, United States.
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40
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Olsen RW. Allosteric ligands and their binding sites define γ-aminobutyric acid (GABA) type A receptor subtypes. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:167-202. [PMID: 25637441 DOI: 10.1016/bs.apha.2014.11.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
GABAA receptors (GABA(A)Rs) mediate rapid inhibitory transmission in the brain. GABA(A)Rs are ligand-gated chloride ion channel proteins and exist in about a dozen or more heteropentameric subtypes exhibiting variable age and brain regional localization and thus participation in differing brain functions and diseases. GABA(A)Rs are also subject to modulation by several chemotypes of allosteric ligands that help define structure and function, including subtype definition. The channel blocker picrotoxin identified a noncompetitive channel blocker site in GABA(A)Rs. This ligand site is located in the transmembrane channel pore, whereas the GABA agonist site is in the extracellular domain at subunit interfaces, a site useful for low energy coupled conformational changes of the functional channel domain. Two classes of pharmacologically important allosteric modulatory ligand binding sites reside in the extracellular domain at modified agonist sites at other subunit interfaces: the benzodiazepine site and the high-affinity, relevant to intoxication, ethanol site. The benzodiazepine site is specific for certain GABA(A)R subtypes, mainly synaptic, while the ethanol site is found at a modified benzodiazepine site on different, extrasynaptic, subtypes. In the transmembrane domain are allosteric modulatory ligand sites for diverse chemotypes of general anesthetics: the volatile and intravenous agents, barbiturates, etomidate, propofol, long-chain alcohols, and neurosteroids. The last are endogenous positive allosteric modulators. X-ray crystal structures of prokaryotic and invertebrate pentameric ligand-gated ion channels, and the mammalian GABA(A)R protein, allow homology modeling of GABA(A)R subtypes with the various ligand sites located to suggest the structure and function of these proteins and their pharmacological modulation.
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Affiliation(s)
- Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
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Vito ST, Austin AT, Banks CN, Inceoglu B, Bruun DA, Zolkowska D, Tancredi DJ, Rogawski MA, Hammock BD, Lein PJ. Post-exposure administration of diazepam combined with soluble epoxide hydrolase inhibition stops seizures and modulates neuroinflammation in a murine model of acute TETS intoxication. Toxicol Appl Pharmacol 2014; 281:185-94. [PMID: 25448683 DOI: 10.1016/j.taap.2014.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/19/2014] [Accepted: 10/02/2014] [Indexed: 01/06/2023]
Abstract
Tetramethylenedisulfotetramine (TETS) is a potent convulsant poison for which there is currently no approved antidote. The convulsant action of TETS is thought to be mediated by inhibition of type A gamma-aminobutyric acid receptor (GABAAR) function. We, therefore, investigated the effects of post-exposure administration of diazepam, a GABAAR positive allosteric modulator, on seizure activity, death and neuroinflammation in adult male Swiss mice injected with a lethal dose of TETS (0.15mg/kg, ip). Administration of a high dose of diazepam (5mg/kg, ip) immediately following the second clonic seizure (approximately 20min post-TETS injection) effectively prevented progression to tonic seizures and death. However, this treatment did not prevent persistent reactive astrogliosis and microglial activation, as determined by GFAP and Iba-1 immunoreactivity and microglial cell morphology. Inhibition of soluble epoxide hydrolase (sEH) has been shown to exert potent anti-inflammatory effects and to increase survival in mice intoxicated with other GABAAR antagonists. The sEH inhibitor TUPS (1mg/kg, ip) administered immediately after the second clonic seizure did not protect TETS-intoxicated animals from tonic seizures or death. Combined administration of diazepam (5mg/kg, ip) and TUPS (1mg/kg, ip, starting 1h after diazepam and repeated every 24h) prevented TETS-induced lethality and influenced signs of neuroinflammation in some brain regions. Significantly decreased microglial activation and enhanced reactive astrogliosis were observed in the hippocampus, with no changes in the cortex. Combining an agent that targets specific anti-inflammatory mechanisms with a traditional antiseizure drug may enhance treatment outcome in TETS intoxication.
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Affiliation(s)
- Stephen T Vito
- Department of Entomology, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616, United States.
| | - Adam T Austin
- Department of Pediatrics, School of Medicine, University of California-Davis Medical Center, Sacramento, CA 95817, United States.
| | - Christopher N Banks
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, United States.
| | - Bora Inceoglu
- Department of Entomology, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616, United States.
| | - Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, United States.
| | - Dorota Zolkowska
- Department of Neurology, School of Medicine, University of California-Davis, Sacramento, CA 95817, United States.
| | - Daniel J Tancredi
- Department of Pediatrics, School of Medicine, University of California-Davis Medical Center, Sacramento, CA 95817, United States.
| | - Michael A Rogawski
- Department of Neurology, School of Medicine, University of California-Davis, Sacramento, CA 95817, United States.
| | - Bruce D Hammock
- Department of Entomology, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616, United States.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, United States.
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Olsen RW. Analysis of γ-aminobutyric acid (GABA) type A receptor subtypes using isosteric and allosteric ligands. Neurochem Res 2014; 39:1924-41. [PMID: 25015397 DOI: 10.1007/s11064-014-1382-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/30/2014] [Accepted: 07/02/2014] [Indexed: 11/30/2022]
Abstract
The GABAA receptors (GABAARs) play an important role in inhibitory transmission in the brain. The GABAARs could be identified using a medicinal chemistry approach to characterize with a series of chemical structural analogues, some identified in nature, some synthesized, to control the structural conformational rigidity/flexibility so as to define the 'receptor-specific' GABA agonist ligand structure. In addition to the isosteric site ligands, these ligand-gated chloride ion channel proteins exhibited modulation by several chemotypes of allosteric ligands, that help define structure and function. The channel blocker picrotoxin identified a noncompetitive channel blocker site in GABAARs. This ligand site is located in the transmembrane channel pore, whereas the GABA agonist site is in the extracellular domain at subunit interfaces, a site useful for low energy coupled conformational changes of the functional channel domain. Also in the trans-membrane domain are allosteric modulatory ligand sites, mostly positive, for diverse chemotypes with general anesthetic efficacy, namely, the volatile and intravenous agents: barbiturates, etomidate, propofol, long-chain alcohols, and neurosteroids. The last are apparent endogenous positive allosteric modulators of GABAARs. These binding sites depend on the GABAAR heteropentameric subunit composition, i.e., subtypes. Two classes of pharmacologically very important allosteric modulatory ligand binding site reside in the extracellular domain at modified agonist sites at other subunit interfaces: the benzodiazepine site, and the low-dose ethanol site. The benzodiazepine site is specific for certain subunit combination subtypes, mainly synaptically localized. In contrast, the low-dose (high affinity) ethanol site(s) is found at a modified benzodiazepine site on different, extrasynaptic, subtypes.
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Affiliation(s)
- Richard W Olsen
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Room CHS 23-120, 650 Young Drive South, Los Angeles, CA, 90095-1735, USA,
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