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Sichler S, Höfner G, Nitsche V, Niessen KV, Seeger T, Worek F, Paintner FF, Wanner KT. Screening for new ligands of the MB327-PAM-1 binding site of the nicotinic acetylcholine receptor. Toxicol Lett 2024; 394:23-31. [PMID: 38387764 DOI: 10.1016/j.toxlet.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 01/08/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
Intoxications with organophosphorus compounds (OPCs) effect a severe impairment of cholinergic neurotransmission that, as a result of overstimulation may lead to desensitization of nicotinic acetylcholine receptors (nAChRs) and finally to death due to respiratory paralysis. So far, therapeutics, that are capable to address and revert desensitized neuromuscular nAChRs into their resting, i.e. functional state are still missing. Still, among a class of compounds termed bispyridinium salts, which are characterized by the presence of two pyridinium subunits, constituents have been identified, that can counteract organophosphate poisoning by resensitizing desensitized nAChRs. According to comprehensive modeling studies this effect is mediated by an allosteric binding site at the nAChR termed MB327-PAM-1 site. For MB327, the most prominent representative of the bispyridinium salts and all other analogues studied so far, the affinity for the aforementioned binding site and the intrinsic activity measured in ex vivo and in in vivo experiments are distinctly too low, to meet the criteria to be fulfilled for therapeutic use. Hence, in order to identify new compounds with higher affinities for the MB327-PAM-1 binding site, as a basic requirement for an enhanced potency, two compound libraries, the ChemDiv library with 60 constituents and the Tocriscreen Plus library with 1280 members have been screened for hit compounds addressing the MB327-PAM-1 binding site, utilizing the [2H6]MB327 MS Binding Assay recently developed by us. This led to the identification of a set of 10 chemically diverse compounds, all of which exhibit an IC50 value of ≤ 10 µM (in the [2H6]MB327 MS Binding Assay), which had been defined as selection criteria. The three most affine ligands, which besides a quinazoline scaffold share similarities with regard to the substitution pattern and the nature of the substituents, are UNC0638, UNC0642 and UNC0646. With binding affinities expressed as pKi values of 6.01 ± 0.10, 5.97 ± 0.05 and 6.23 ± 0.02, respectively, these compounds exceed the binding affinity of MB327 by more than one log unit. This renders them promising starting points for the development of drugs for the treatment of organophosphorus poisoning by addressing the MB327-PAM-1 binding site of the nAChR.
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Affiliation(s)
- Sonja Sichler
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Georg Höfner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Valentin Nitsche
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Karin V Niessen
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz F Paintner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Klaus T Wanner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
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Kaiser J, Gertzen CG, Bernauer T, Höfner G, Niessen KV, Seeger T, Paintner FF, Wanner KT, Worek F, Thiermann H, Gohlke H. A novel binding site in the nicotinic acetylcholine receptor for MB327 can explain its allosteric modulation relevant for organophosphorus-poisoning treatment. Toxicol Lett 2022; 373:160-171. [DOI: 10.1016/j.toxlet.2022.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/25/2022] [Indexed: 11/27/2022]
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Influence of Experimental End Point on the Therapeutic Efficacy of Essential and Additional Antidotes in Organophosphorus Nerve Agent-Intoxicated Mice. TOXICS 2022; 10:toxics10040192. [PMID: 35448453 PMCID: PMC9027337 DOI: 10.3390/toxics10040192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 02/04/2023]
Abstract
The therapeutic efficacy of treatments for acute intoxication with highly toxic organophosphorus compounds, called nerve agents, usually involves determination of LD50 values 24 h after nerve agent challenge without and with a single administration of the treatment. Herein, the LD50 values of four nerve agents (sarin, soman, tabun and cyclosarin) for non-treated and treated intoxication were investigated in mice for experimental end points of 6 and 24 h. The LD50 values of the nerve agents were evaluated by probit-logarithmical analysis of deaths within 6 and 24 h of i.m. challenge of the nerve agent at five different doses, using six mice per dose. The efficiency of atropine alone or atropine in combination with an oxime was practically the same at 6 and 24 h. The therapeutic efficacy of the higher dose of the antinicotinic compound MB327 was slightly higher at the 6 h end point compared to the 24 h end point for soman and tabun intoxication. A higher dose of MB327 increased the therapeutic efficacy of atropine alone for sarin, soman and tabun intoxication, and that of the standard antidotal treatment (atropine and oxime) for sarin and tabun intoxication. The therapeutic efficacy of MB327 was lower than the oxime-based antidotal treatment. To compare the 6 and 24 h end points, the influence of the experimental end point was not observed, with the exception of the higher dose of MB327. In addition, only a negligible beneficial impact of the compound MB327 was observed. Nevertheless, antinicotinics may offer an additional avenue for countering poisoning by nerve agents that are difficult to treat, and synthetic and biological studies towards the development of such novel drugs based on the core bispyridinium structure or other molecular scaffolds should continue.
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Kassa J, Hatlapatková J, Žďárová Karasová J, Hepnarová V, Caisberger F, Pejchal J. A Comparison of the Neuroprotective and Reactivating Efficacy of a Novel Bispyridinium Oxime K870 with Commonly Used Pralidoxime and the Oxime HI-6 in Tabun-Poisoned Rats. ACTA MEDICA (HRADEC KRALOVE) 2021; 64:145-152. [PMID: 34779379 DOI: 10.14712/18059694.2021.25] [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: 06/13/2023]
Abstract
AIM The comparison of neuroprotective and central reactivating effects of the oxime K870 in combination with atropine with the efficacy of standard antidotal treatment in tabun-poisoned rats. METHODS The neuroprotective effects of antidotal treatment were determined in rats poisoned with tabun at a sublethal dose using a functional observational battery 2 h and 24 h after tabun administration, the tabun-induced brain damage was investigated by the histopathological evaluation and central reactivating effects of oximes was evaluated by the determination of acetylcholinesterase activity in the brain using a standard spectrophotometric method. RESULTS The central reactivating efficacy of a newly developed oxime K870 roughly corresponds to the central reactivating efficacy of pralidoxime while the ability of the oxime HI-6 to reactivate tabun-inhibited acetylcholinesterase in the brain was negligible. The ability of the oxime K870 to decrease tabun-induced acute neurotoxicity was slightly higher than that of pralidoxime and similar to the oxime HI-6. These results roughly correspond to the histopathological evaluation of tabun-induced brain damage. CONCLUSION The newly synthesized oxime K870 is not a suitable replacement for commonly used oximes in the antidotal treatment of acute tabun poisonings because its neuroprotective efficacy is only slightly higher or similar compared to studied currently used oximes.
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Affiliation(s)
- Jiří Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic.
| | - Jana Hatlapatková
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
| | - Jana Žďárová Karasová
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
| | - Vendula Hepnarová
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
| | - Filip Caisberger
- Neurology, University Hospital Hradec Králové, Hradec Králové, Czech Republic
| | - Jaroslav Pejchal
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
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Kassa J, Timperley CM, Bird M, Green AC, Tattersall JEH. Influence of experimental end point on the therapeutic efficacy of the antinicotinic compounds MB408, MB442 and MB444 in treating nerve agent poisoned mice - a comparison with oxime-based treatment. Toxicol Mech Methods 2020; 30:703-710. [PMID: 32878547 DOI: 10.1080/15376516.2020.1817218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Therapeutic efficacy of antidotal treatment of acute poisoning by nerve agents is generally assessed by the evaluation of LD50 values of nerve agents over 24 h following poisoning without or with a single administration of antidotal treatment. In this study, LD50 values of four nerve agents (sarin, soman, tabun and cyclosarin) for non-treated and treated poisoning were evaluated in mice for two experimental end points - 6 h and 24 h. While the efficacy of atropine or oxime-based antidotal treatment was the same regardless of the experimental end point, the therapeutic efficacy of all three newly developed bispyridinium non-oxime compounds (MB408, MB442, and MB444) was mostly slightly higher at the 6 h end point compared to the 24 h end point, although the therapeutic efficacy of MB compounds was not superior to oxime-based antidotal treatment. These results contrast with a study in guinea-pigs using a structurally-related compound, MB327, which showed a striking increase in protection at 6 h compared to 24 h. It is suggested that the disparity may be due to pharmacokinetic differences between the two animal species.
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Affiliation(s)
- Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Christopher M Timperley
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (DSTL), Salisbury, United Kingdom
| | - Mike Bird
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (DSTL), Salisbury, United Kingdom
| | - A Christopher Green
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (DSTL), Salisbury, United Kingdom
| | - John E H Tattersall
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (DSTL), Salisbury, United Kingdom
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Amend N, Niessen KV, Seeger T, Wille T, Worek F, Thiermann H. Diagnostics and treatment of nerve agent poisoning—current status and future developments. Ann N Y Acad Sci 2020; 1479:13-28. [DOI: 10.1111/nyas.14336] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/25/2020] [Accepted: 03/05/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Niko Amend
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
| | - Karin V. Niessen
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
| | - Timo Wille
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology Munich Germany
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Wein T, Wanner KT, Rappenglück S, Sichler S, Niessen KV, Seeger T, Worek F, Thiermann H. New Resensitizers for the Nicotinic Acetylcholine Receptor by Ligand-Based Pharmacophore Modeling. Curr Comput Aided Drug Des 2019; 15:104-109. [PMID: 29968541 DOI: 10.2174/1573409914666180703120201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/12/2018] [Accepted: 06/21/2018] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Irreversible inhibition of the acetylcholinesterase upon intoxication with organophosphorus compounds leads to an accumulation of acetylcholine in the synaptic cleft and a subsequent desensitization of nicotinic acetylcholine receptors which may ultimately result in respiratory failure. A direct intervention at the nicotinic acetylcholine receptor (nAChR) was proposed as an alternative therapeutic approach to the treatment with atropine and oximes. METHODS The bispyridinium compound MB327 has been found to recover functional activity of nAChR thus representing a promising starting point for the development of new drugs for the treatment of organophosphate poisoning. Recent solid-supported membrane-based electrophysiological experiments have identified symmetrically substituted bispyridinium compounds e.g. MB327, MB583, and PTM0001 that are able to resensitize nAChR of Torpedo californica. In addition, six compounds have been found not to show any resensitizing potential and were thus classified as inactive. This set of active and inactive bispyridinium compounds was taken to develop a pharmacophore model and in silico screening of a virtual database of bispyridinium compounds to identify new compounds that are able to restore the functional activity of desensitized nAChR. RESULTS Screening of a virtual compound database of symmetrically substituted bispyridinium compounds with the derived pharmacophore yielded several promising compounds which satisfy the pharmacophore and ought to have the same or even better resensitizing effect on nAChR as the parent compound MB327.
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Affiliation(s)
- Thomas Wein
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universitat München, Butenandtstr, 5-13, 81377 Munich, Germany
| | - Klaus T Wanner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universitat München, Butenandtstr, 5-13, 81377 Munich, Germany
| | - Sebastian Rappenglück
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universitat München, Butenandtstr, 5-13, 81377 Munich, Germany
| | - Sonja Sichler
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universitat München, Butenandtstr, 5-13, 81377 Munich, Germany
| | - Karin V Niessen
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
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Kassa J, Timperley CM, Bird M, Williams RL, Green AC, Tattersall JEH. Some benefit from non-oximes MB408, MB442 and MB444 in combination with the oximes HI-6 or obidoxime and atropine in antidoting sarin or cyclosarin poisoned mice. Toxicology 2018; 408:95-100. [PMID: 30005893 DOI: 10.1016/j.tox.2018.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/27/2018] [Accepted: 07/09/2018] [Indexed: 11/15/2022]
Abstract
The effect of three newly developed bispyridinium non-oxime compounds (MB408, MB442, and MB444) on the therapeutic efficacy of a standard antidotal treatment (atropine in combination with the oxime HI-6 or obidoxime) of acute poisoning by two nerve agents (sarin and cyclosarin) in mice was studied. The therapeutic efficacy of atropine in combination with an oxime with or without one of the bispyridinium non-oximes was evaluated by determination of the 24 h LD50 values of the nerve agents studied and by measurement of the survival time after supralethal poisoning. Addition of all tested non-oximes increased the therapeutic efficacy of atropine in combination with an oxime against sarin poisoning; however, the differences were not significant. The non-oximes also positively influenced the number of surviving mice 6 h after supralethal poisoning with sarin. In the case of cyclosarin, they were also slightly beneficial in the treatment of acute poisoning. The higher dose of MB444 was able to significantly increase the therapeutic efficacy of standard antidotal treatment of poisoning with cyclosarin. The benefit of each bispyridinium non-oxime compound itself was obviously dose-dependent. In summary, the addition of MB compounds to the standard antidotal treatment of acute nerve agent poisoning was beneficial for the antidotal treatment of sarin or cyclosarin poisoning, although their benefit at 24 h after poisoning was not significant, with the exception of the higher dose of MB444 against cyclosarin.
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Affiliation(s)
- Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, Trebesska 1575, 500 01 Hradec Kralove, Czech Republic.
| | - Christopher M Timperley
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Mike Bird
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Rebecca L Williams
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - A Christopher Green
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - John E H Tattersall
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury SP4 0JQ, United Kingdom
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Scheffel C, Niessen KV, Rappenglück S, Wanner KT, Thiermann H, Worek F, Seeger T. Electrophysiological investigation of the effect of structurally different bispyridinium non-oxime compounds on human α7-nicotinic acetylcholine receptor activity—An in vitro structure-activity analysis. Toxicol Lett 2018; 293:157-166. [DOI: 10.1016/j.toxlet.2017.11.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/11/2017] [Accepted: 11/22/2017] [Indexed: 02/01/2023]
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Wein T, Höfner G, Rappenglück S, Sichler S, Niessen KV, Seeger T, Worek F, Thiermann H, Wanner KT. Searching for putative binding sites of the bispyridinium compound MB327 in the nicotinic acetylcholine receptor. Toxicol Lett 2018; 293:184-189. [DOI: 10.1016/j.toxlet.2017.10.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/18/2017] [Accepted: 10/29/2017] [Indexed: 01/14/2023]
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Niessen K, Seeger T, Rappenglück S, Wein T, Höfner G, Wanner K, Thiermann H, Worek F. In vitro pharmacological characterization of the bispyridinium non-oxime compound MB327 and its 2- and 3-regioisomers. Toxicol Lett 2018; 293:190-197. [DOI: 10.1016/j.toxlet.2017.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/29/2017] [Accepted: 10/08/2017] [Indexed: 11/27/2022]
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Rappenglück S, Sichler S, Höfner G, Wein T, Niessen KV, Seeger T, Paintner FF, Worek F, Thiermann H, Wanner KT. Synthesis of a Series of Structurally Diverse MB327 Derivatives and Their Affinity Characterization at the Nicotinic Acetylcholine Receptor. ChemMedChem 2018; 13:1806-1816. [DOI: 10.1002/cmdc.201800325] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/28/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Sebastian Rappenglück
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
| | - Sonja Sichler
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
| | - Georg Höfner
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
| | - Thomas Wein
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
| | - Karin V. Niessen
- Bundeswehr Institute of Pharmacology and Toxicology; Neuherbergstr. 11 80937 Munich Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology; Neuherbergstr. 11 80937 Munich Germany
| | - Franz F. Paintner
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology; Neuherbergstr. 11 80937 Munich Germany
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology; Neuherbergstr. 11 80937 Munich Germany
| | - Klaus T. Wanner
- Department of Pharmacy, Center for Drug Research; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 Munich Germany
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Scheffel C, Niessen KV, Rappenglück S, Wanner KT, Thiermann H, Worek F, Seeger T. Counteracting desensitization of human α7-nicotinic acetylcholine receptors with bispyridinium compounds as an approach against organophosphorus poisoning. Toxicol Lett 2017; 293:149-156. [PMID: 29248576 DOI: 10.1016/j.toxlet.2017.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 01/30/2023]
Abstract
Irreversible inhibition of acetylcholinesterase (AChE) resulting in accumulation of acetylcholine and overstimulation of muscarinic and nicotinic receptors accounts for the acute toxicity of organophosphorus compounds (OP). Accordingly, the mainstay pharmacotherapy against poisoning by OP comprises the competitive muscarinic acetylcholine receptor antagonist atropine to treat muscarinic effects and, in addition, oximes to reactivate inhibited AChE. A therapeutic gap still remains in the treatment of desensitized nicotinic acetylcholine receptors following OP exposure. Hereby, nicotinic effects result in paralysis of the central and peripheral respiratory system if untreated. Thus, these receptors pose an essential target for therapeutic indication to address these life-threatening nicotinic symptoms of the cholinergic crisis. Identification of ligands regulating dynamic transitions between functional states by binding to modulatory sites appears to be a promising strategy for therapeutic intervention. In this patch clamp study, the ability of differently substituted bispyridinium non-oximes to "resensitize" i.e. to recover the activity of desensitized human homomeric α7-type nAChRs stably transfected in CHO cells was investigated and compared to the already described α7-specific positive allosteric modulator PNU-120596. The structures of these bispyridinium analogues were based on the lead structure of the tert-butyl-substituted bispyridinium propane MB327, which has been shown to have a positive therapeutic effect due to a non-competitive antagonistic action at muscle-type nAChRs in vivo and has been found to have a positive allosteric activity at neuronal receptors in vitro. Prior to test compounds, desensitization of hα7-nAChRs was verified by applying an excess of nicotine revealing activation at low, and desensitization at high concentrations. Thereby, desensitization could be reduced by modulation with PNU-120596. Desensitization was further verified by dose-response profiles of agonists, carbamoylcholine and epibatidine in the absence and presence of PNU-120596. Although less pronounced than PNU-120596 and the lead structure MB327, bispyridinium compounds, particularly those substituted at position 3 and 4, resensitized the nicotine desensitized hα7-nAChRs in a concentration-dependent manner and prolonged the mean channel open time. In summary, identification of more potent compounds able to restore nAChR function in OP intoxication is needed for development of a putative efficient antidote.
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Affiliation(s)
- Corinna Scheffel
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Germany.
| | - Karin V Niessen
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | | | - Klaus T Wanner
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
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Sichler S, Höfner G, Rappenglück S, Wein T, Niessen KV, Seeger T, Worek F, Thiermann H, Paintner FF, Wanner KT. Development of MS Binding Assays targeting the binding site of MB327 at the nicotinic acetylcholine receptor. Toxicol Lett 2017; 293:172-183. [PMID: 29146291 DOI: 10.1016/j.toxlet.2017.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/09/2017] [Accepted: 11/12/2017] [Indexed: 02/06/2023]
Abstract
The bispyridinium compound MB327 has been shown previously to have a positive pharmacological effect against poisoning with organophosphorous compounds (OPCs). The mechanism by which it exerts its therapeutic effect seems to be directly mediated by the nicotinic acetylcholine receptor (nAChR). In the present study, the development of mass spectrometry based binding assays (MS Binding Assays) for characterization of the binding site of MB327 at the nAChR from Torpedo californica is described. MS Binding Assays follow the principle of radioligand binding assays, but do not, in contrast to the latter, require a radiolabeled reporter ligand, as the readout is in this case based on mass spectrometric detection. For [2H6]MB327, a deuterated MB327 analogue employed as reporter ligand in the MS Binding Assays, an LC-ESI-MS/MS method was established allowing for its fast and reliable quantification in samples resulting from binding experiments. Using centrifugation for separation of non-bound [2H6]MB327 from target-bound [2H6]MB327 in saturation and autocompetition experiments (employing native MB327 as competitor) enabled reliable determination of specific binding. In this way, the affinities for [2H6]MB327 (Kd=15.5±0.9μmolL-1) and for MB327 (Ki=18.3±2.6μmolL-1) towards the nAChR could be determined for the first time. The almost exactly matching affinities for MB327 and [2H6]MB327 obtained in the MS Binding Assays are in agreement with potencies previously found in functional studies. In summary, our results demonstrate that the established MS Binding Assays represent a promising tool for affinity determination of test compounds towards the binding site of MB327 at the nAChR.
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Affiliation(s)
- S Sichler
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - G Höfner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - S Rappenglück
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - T Wein
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - K V Niessen
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstr. 11, 80937 Munich, Germany
| | - T Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstr. 11, 80937 Munich, Germany
| | - F Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstr. 11, 80937 Munich, Germany
| | - H Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstr. 11, 80937 Munich, Germany
| | - F F Paintner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - K T Wanner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany.
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Kassa J, Timperley CM, Bird M, Williams RL, Green AC, Tattersall JEH. Evaluation of the Influence of Three Newly Developed Bispyridinium Anti-nicotinic Compounds (MB408, MB442, MB444) on the Efficacy of Antidotal Treatment of Nerve Agent Poisoning in Mice. Basic Clin Pharmacol Toxicol 2017; 122:429-435. [PMID: 29117635 DOI: 10.1111/bcpt.12935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/26/2017] [Indexed: 11/28/2022]
Abstract
The influence of three newly developed bispyridinium antinicotinic compounds (the non-oximes MB408, MB442 and MB444) on the therapeutic efficacy of a standard antidotal treatment (atropine in combination with an oxime) of acute poisoning by the organophosphorus nerve agents tabun and soman was studied in mice. The therapeutic efficacy of atropine in combination with an oxime with or without one of the bispyridinium non-oximes was evaluated by determination of the LD50 values of the nerve agents and measurement of the survival time after supralethal poisoning. Addition of all the tested non-oximes increased significantly the therapeutic efficacy of atropine in combination with an oxime against tabun poisoning. They also positively influenced the number of surviving mice 6 hr after supralethal poisoning with tabun. However, they were only slightly effective for the treatment of soman poisoning. The benefit of the tested bispyridinium non-oximes was dose-dependent. To conclude, the addition of bispyridinium non-oximes to the standard antidotal treatment of acute poisoning with tabun was beneficial regardless of the chosen non-oxime, but only slightly beneficial in the case of soman poisoning.
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Affiliation(s)
- Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, Hradec Kralove, Czech Republic
| | - Christopher M Timperley
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - Mike Bird
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - Rebecca L Williams
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - A Christopher Green
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - John E H Tattersall
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
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17
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Kassa J, Misik J, Hatlapatkova J, Zdarova Karasova J. A comparison of neuroprotective efficacy of two novel reactivators of acetylcholinesterase called K920 and K923 with the oxime K203 and trimedoxime in tabun-poisoned rats. Toxicol Mech Methods 2017; 27:236-243. [DOI: 10.1080/15376516.2016.1275907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czech Republic
| | - Jan Misik
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czech Republic
| | - Jana Hatlapatkova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czech Republic
| | - Jana Zdarova Karasova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czech Republic
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18
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Neumaier K, Worek F, Thiermann H, Wille T. Bispyridinium non-oximes: An evaluation of cardiac effects in isolated hearts and smooth muscle relaxing effects in jejunum. Toxicol In Vitro 2016; 35:11-6. [DOI: 10.1016/j.tiv.2016.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
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19
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An electric generator using living Torpedo electric organs controlled by fluid pressure-based alternative nervous systems. Sci Rep 2016; 6:25899. [PMID: 27241817 PMCID: PMC4886531 DOI: 10.1038/srep25899] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/22/2016] [Indexed: 11/08/2022] Open
Abstract
Direct electric power generation using biological functions have become a research focus due to their low cost and cleanliness. Unlike major approaches using glucose fuels or microbial fuel cells (MFCs), we present a generation method with intrinsically high energy conversion efficiency and generation with arbitrary timing using living electric organs of Torpedo (electric rays) which are serially integrated electrocytes converting ATP into electric energy. We developed alternative nervous systems using fluid pressure to stimulate electrocytes by a neurotransmitter, acetylcholine (Ach), and demonstrated electric generation. Maximum voltage and current were 1.5 V and 0.64 mA, respectively, with a duration time of a few seconds. We also demonstrated energy accumulation in a capacitor. The current was far larger than that using general cells other than electrocytes (~pA level). The generation ability was confirmed against repetitive cycles and also after preservation for 1 day. This is the first step toward ATP-based energy harvesting devices.
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20
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Kassa J, Pohanka M, Timperley CM, Bird M, Green AC, Tattersall JEH. Evaluation of the benefit of the bispyridinium compound MB327 for the antidotal treatment of nerve agent-poisoned mice. Toxicol Mech Methods 2016; 26:334-9. [DOI: 10.3109/15376516.2016.1162249] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Pharmacokinetic profile and quantitation of protection against soman poisoning by the antinicotinic compound MB327 in the guinea-pig. Toxicol Lett 2016; 244:154-160. [DOI: 10.1016/j.toxlet.2015.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/24/2015] [Accepted: 08/10/2015] [Indexed: 11/20/2022]
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22
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John H, Mikler J, Worek F, Thiermann H. Reversed-phase ion-pair chromatography-diode array detection of the bispyridinium compound MB327: plasma analysis of a potential novel antidote for the treatment of organophosphorus poisoning. Drug Test Anal 2015; 8:154-63. [PMID: 26041012 DOI: 10.1002/dta.1821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 05/12/2015] [Accepted: 05/12/2015] [Indexed: 11/08/2022]
Abstract
In the case of poisoning by organophosphorus nerve agents or pesticides, there is still a lack of pharmacological treatment of the cholinergic crisis selectively targeting the nicotinic acetylcholine receptor. Recently, the compound MB327 was identified as a potential novel lead structure to close this gap, thus demanding a quantitative assay for initial pharmacokinetic (PK) studies. MB327 is a salt consisting of the dicationic bispyridinium compound (BPC) 1,1´-(propane-1,3-diyl)bis(4-tert-butylpyridinium) and two iodide counter ions. Due to the permanent positive charge of the BPC, an isocratic reversed-phase ion-pair chromatographic separation (RPIPC) was developed using heptanesulfonic acid as ion-pairing reagent and 45% v/v methanol as organic modifier (1 mL/min). Selective UV-detection (230 nm) was done by a diode array detector (DAD) for reliable, rugged, precise (RSD < 7%) and accurate (96-104%) quantitative analysis of 50 μL swine plasma (linear range 1-1000 µg BPC/mL plasma, lower limit of quantification 2 µg/mL). During method validation, diverse parameters essential for the chromatographic process were investigated to generate van´t Hoff, van Deemter and width plots allowing calculation of thermodynamic data like the distribution constant K (5.7 ± 0.3), change in enthalpy, ΔH(0) : -23.66 kJ/mol, and entropy, ΔS(0) : -65 J/(mol*K). In addition, RPIPC-DAD analysis enabled calculation of molar absorptivities of the BPC, ε230 : 17 400 ± 1100 L/(mol*cm), and iodide, ε230 : 9900 ± 400 L/(mol*cm), which determination was hampered by interference with each other in conventional cuvette UV-spectrophotometric measurements. Finally, the RPIPC-DAD procedure was applied to samples from an in vivo study of swine.
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Affiliation(s)
- Harald John
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - John Mikler
- Defence Research and Development Canada-Suffield Research Station, Medicine Hat, Alberta, Canada
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
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Kassa J, Misik J, Zdarova Karasova J. Neuroprotective efficacy of newly developed oximes in comparison with currently available oximes in tabun-poisoned rats. J Appl Biomed 2015. [DOI: 10.1016/j.jab.2014.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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24
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Kassa J, Hatlapatková J, Žďárová Karasová J. The Evaluation of the Potency of Newly Developed Oximes (K727, K733) and Trimedoxime to Counteract Acute Neurotoxic Effects of Tabun in Rats. ACTA MEDICA (HRADEC KRÁLOVÉ) 2015; 58:135-43. [PMID: 26960827 DOI: 10.14712/18059694.2016.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AIM The ability of two newly developed oximes (K727, K733) to reduce tabun-induced acute neurotoxic signs and symptoms was evaluated and compared with currently available trimedoxime in rats. METHODS The neuroprotective effects of the oximes studied combined with atropine on Wistar rats poisoned with tabun at a lethal dose (380 µg/kg i.m.; 90% of LD50 value) were evaluated. Tabun-induced neurotoxicity was monitored by the functional observational battery consisting of 38 measurements of sensory, motor and autonomic nervous functions at 2 hours following tabun challenge. RESULTS All tested oximes combined with atropine enable tabun-poisoned rats to survive till the end of experiment. Both newly developed oximes (K727, K733) combined with atropine were able to decrease tabun-induced neurotoxicity in the case of lethal poisoning although they did not eliminate all tabun-induced acute neurotoxic signs and symptoms. CONCLUSION The ability of both novel bispyridinium oximes to decrease tabun-induced acute neurotoxicity was slightly lower than that of trimedoxime. Therefore, the newly developed oximes are not suitable for the replacement of commonly used oximes such as trimedoxime in the treatment of acute tabun poisonings.
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Affiliation(s)
- Jiří Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic.
| | - Jana Hatlapatková
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
| | - Jana Žďárová Karasová
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defense, Hradec Králové, Czech Republic
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Niessen K, Seeger T, Tattersall J, Timperley C, Bird M, Green C, Thiermann H, Worek F. Affinities of bispyridinium non-oxime compounds to [3H]epibatidine binding sites of Torpedo californica nicotinic acetylcholine receptors depend on linker length. Chem Biol Interact 2013; 206:545-54. [DOI: 10.1016/j.cbi.2013.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 01/20/2023]
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Thiermann H, Worek F, Kehe K. Limitations and challenges in treatment of acute chemical warfare agent poisoning. Chem Biol Interact 2013; 206:435-43. [PMID: 24091052 DOI: 10.1016/j.cbi.2013.09.015] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 02/02/2023]
Abstract
Recent news from Syria on a possible use of chemical warfare agents made the headlines. Furthermore, the motivation of terrorists to cause maximal harm shifts these agents into the public focus. For incidents with mass casualties appropriate medical countermeasures must be available. At present, the most important threats arise from nerve agents and sulfur mustard. At first, self-protection and protection of medical units from contamination is of utmost importance. Volatile nerve agent exposure, e.g. sarin, results in fast development of cholinergic crisis. Immediate clinical diagnosis can be confirmed on-site by assessment of acetylcholinesterase activity. Treatment with autoinjectors that are filled with 2mg atropine and an oxime (at present obidoxime, pralidoxime, TMB-4 or HI-6) are not effective against all nerve agents. A more aggressive atropinisation has to be considered and more effective oximes (if possible with a broad spectrum or a combination of different oximes) as well as alternative strategies to cope with high acetylcholine levels at synaptic sites should be developed. A further gap exists for the treatment of patients with sustained cholinergic crisis that has to be expected after exposure to persistent nerve agents, e.g. VX. The requirement for long-lasting artificial ventilation can be reduced with an oxime therapy that is optimized by using the cholinesterase status for guidance or by measures (e.g. scavengers) that are able to reduce the poison load substantially in the patients. For sulfur mustard poisoning no specific antidote is available until now. Symptomatic measures as used for treatment of burns are recommended together with surgical or laser debridement. Thus, huge amounts of resources are expected to be consumed as wound healing is impaired. Possible depots of sulfur mustard in tissues may aggravate the situation. More basic knowledge is necessary to improve substantially therapeutic options. The use of stem cells may provide a new and promising option.
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Affiliation(s)
- Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany.
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Königer C, Worek F, Thiermann H, Wille T. Effect of MB327 and oximes on rat intestinal smooth muscle function. Chem Biol Interact 2013; 204:1-5. [PMID: 23603452 DOI: 10.1016/j.cbi.2013.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/20/2013] [Accepted: 04/09/2013] [Indexed: 10/26/2022]
Abstract
Organophosphorous compounds (OP) are highly toxic compounds. Great efforts have been undertaken in the last decades to develop new reactivators of OP-inhibited acetylcholinesterase. So far, a broad-spectrum oxime bearing efficacy against all OP is still missing and alternative approaches are presently under investigation. Previous experiments demonstrated that the bispyridinium non-oxime MB327 was able to improve OP-impaired muscle force in human, rat and guinea pig respiratory muscles and to increase survival in soman, sarin and tabun poisoned guinea pigs. Recent studies indicate that MB327 exhibits a high affinity to muscarinic acetylcholine receptors but up to now, only scarce information is available on the effects of MB327 in isolated organs. Now, the antimuscarinic effect of MB327 was compared to that of established oximes and atropine in a rat jejunum smooth muscle model. MB327 showed a fully reversible smooth muscle relaxing effect at lower concentrations (EC₅₀≈ 6 μM) than all tested oximes. In fact, MB327 exhibited an antimuscarinic smooth muscle relaxing effect at concentrations which were shown to improve OP-impaired skeletal muscle force. Hence, it may be assumed that the antimuscarinic potency of MB327 may contribute to its therapeutic effect in OP poisoning.
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Affiliation(s)
- C Königer
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstraße 11, 80937 Munich, Germany
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28
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Soukup O, Jun D, Tobin G, Kuca K. The summary on non-reactivation cholinergic properties of oxime reactivators: the interaction with muscarinic and nicotinic receptors. Arch Toxicol 2012. [PMID: 23179755 DOI: 10.1007/s00204-012-0977-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Organophosphorus inhibitors (OP) of acetylcholinesterase (AChE) represent a group of highly toxic compounds. The treatment of OP intoxication is, however, insufficiently ensured. Currently, two main categories of drugs-anticholinergics and oxime reactivators- are employed as antidotes. Oximes have been reported to act at several levels of the cholinergic transmission, and among the non-reactivation effects, the interaction with cholinergic receptors stands out. This review addresses issues correlated with non-reactivating effects of oxime reactivators with a special focus on the muscarinic and nicotinic receptors, but involvement of other cholinergic structures such as AChE and choline uptake carriers are discussed too. It can be concluded that the oxime reactivators show a variation in their antagonistic effect on the muscarinic and nicotinic receptors, which is likely to be of significance in the treatment of OP poisoning. In vitro data reported oximes to exert higher efficacy on the muscarinic M2 subtype than on the AChE. However, this effect seemed to be subtype specific since the antagonistic M3 effect was lower. Also, and importantly, the antimuscarinic effect was larger than that on nicotinic receptors. Even though atropine showed a much higher muscarinic antagonism, it is supposed that non-reactivation properties of oxime reactivators play a significant role in the treatment of OP poisoning.
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Affiliation(s)
- O Soukup
- Biomedical Research Center, University Hospital of Hradec Kralove, Sokolska 581, 50005 Hradec Kralove, Czech Republic
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Seeger T, Eichhorn M, Lindner M, Niessen K, Tattersall J, Timperley C, Bird M, Green A, Thiermann H, Worek F. Restoration of soman-blocked neuromuscular transmission in human and rat muscle by the bispyridinium non-oxime MB327 in vitro. Toxicology 2012; 294:80-4. [DOI: 10.1016/j.tox.2012.02.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/02/2012] [Accepted: 02/04/2012] [Indexed: 11/17/2022]
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30
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Niessen KV, Tattersall JEH, Timperley CM, Bird M, Green C, Thiermann H, Worek F. Competition radioligand binding assays for the investigation of bispyridinium compound affinities to the human muscarinic acetylcholine receptor subtype 5 (hM5). Drug Test Anal 2012; 4:292-7. [DOI: 10.1002/dta.410] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 12/02/2011] [Accepted: 12/02/2011] [Indexed: 11/08/2022]
Affiliation(s)
- K. V. Niessen
- Bundeswehr Institute of Pharmacology and Toxicology; Munich; Germany
| | | | | | - M. Bird
- Detection Department; Dstl Porton Down; Salisbury; UK
| | - C. Green
- Biomedical Sciences Department; Dstl Porton Down; Salisbury; UK
| | - H. Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology; Munich; Germany
| | - F. Worek
- Bundeswehr Institute of Pharmacology and Toxicology; Munich; Germany
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Timperley CM, Bird M, Green C, Price ME, Chad JE, Turner SR, Tattersall JEH. 1,1′-(Propane-1,3-diyl)bis(4-tert-butylpyridinium) di(methanesulfonate) protects guinea pigs from soman poisoning when used as part of a combined therapy. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md00258b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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