Organophosphorus compounds (OPs) involving life-threatening nerve agents (NA) have been known for several decades. Despite a clear mechanism of their lethality caused by the irreversible inhibition of acetylcholinesterase (AChE) and manifested via overstimulation of peripheral nicotinic and muscarinic acetylcholine (ACh) receptors, the mechanism for central neurotoxicity responsible for acute or delayed symptoms of the poisoning has not been thoroughly uncovered. One of the reasons is the lack of a suitable model. In our study, we have chosen the SH-SY5Y model in both the differentiated and undifferentiated state to study the effects of NAs (GB, VX and A234). The activity of expressed AChE in cell lysate assessed by Ellman's method showed 7.3-times higher activity in differentiated SH-SY5Y cells in contrast to undifferentiated cells, and with no involvement of BuChE as proved by ethopropazine (20 µM). The activity of AChE was found to be, in comparison to untreated cells, 16-, 9.3-, and 1.9-times lower upon A234, VX, and GB (100 µM) administration respectively. The cytotoxic effect of given OPs expressed as the IC50 values for differentiated and undifferentiated SH-SY5Y, respectively, was found 12 mM and 5.7 mM (A234), 4.8 mM and 1.1 mM (VX) and 2.6 mM and 3.8 mM (GB). In summary, although our results confirm higher AChE expression in the differentiated SH-SY5Y cell model, the such higher expression does not lead to a more pronounced NA cytotoxic effect. On the contrary, higher expression of AChE may attenuate NA-induced cytotoxicity by scavenging the NA. Such finding highlights a protective role for cholinesterases by scavenging Novichoks (A-agents). Second, we confirmed the mechanism of cytotoxicity of NAs, including A-agents, can be ascribed rather to the non-specific effects of OPs than to AChE-mediated effects.

• Klíčová slova
• Acetylcholinesterase, Cytotoxicity, Neuroprotection, Neurotoxicity, Organophosphates, SH-SY5Y,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nervová bojová látka * MeSH
• neuroblastom * MeSH
• neurotoxické syndromy * etiologie   MeSH
• protinádorové látky * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• nervová bojová látka * MeSH
• protinádorové látky * MeSH
• VX MeSH Prohlížeč

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.

• Klíčová slova
• MB327, atropine, mice, nerve agents, oximes,
• Publikační typ
• časopisecké články MeSH

Poisoning with organophosphorus compounds used as pesticides or misused as chemical weapons remains a serious threat to human health and life. Their toxic effects result from irreversible blockade of the enzymes acetylcholinesterase and butyrylcholinesterase, which causes overstimulation of the cholinergic system and often leads to serious injury or death. Treatment of organophosphorus poisoning involves, among other strategies, the administration of oxime compounds. Oximes reactivate cholinesterases by breaking the covalent bond between the serine residue from the enzyme active site and the phosphorus atom of the organophosphorus compound. Although the general mechanism of reactivation has been known for years, the exact molecular aspects determining the efficiency and selectivity of individual oximes are still not clear. This hinders the development of new active compounds. In our research, using relatively simple and widely available molecular docking methods, we investigated the reactivation of acetyl- and butyrylcholinesterase blocked by sarin and tabun. For the selected oximes, their binding modes at each step of the reactivation process were identified. Amino acids essential for effective reactivation and those responsible for the selectivity of individual oximes against inhibited acetyl- and butyrylcholinesterase were identified. This research broadens the knowledge about cholinesterase reactivation and demonstrates the usefulness of molecular docking in the study of this process. The presented observations and methods can be used in the future to support the search for new effective reactivators.

• Klíčová slova
• acetylcholinesterase, butyrylcholinesterase, docking studies, molecular modeling, organophosphates, reactivation process, reactivators,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• aktivace enzymů MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• fosfor chemie   MeSH
• katalytická doména MeSH
• konformace proteinů MeSH
• kvantová teorie MeSH
• lidé MeSH
• ligandy MeSH
• molekulární modely MeSH
• myši MeSH
• organofosfáty chemie   MeSH
• oximy chemie   MeSH
• proteosyntéza MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• sarin chemie   MeSH
• shluková analýza MeSH
• simulace molekulového dockingu * MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• fosfor MeSH
• ligandy MeSH
• organofosfáty MeSH
• oximy MeSH
• reaktivátory cholinesterasy MeSH
• sarin MeSH
• tabun MeSH Prohlížeč

The series of symmetrical and unsymmetrical isoquinolinium-5-carbaldoximes was designed and prepared for cholinesterase reactivation purposes. The novel compounds were evaluated for intrinsic acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) inhibition, when the majority of novel compounds resulted with high inhibition of both enzymes and only weak inhibitors were selected for reactivation experiments on human AChE or BChE inhibited by sarin, VX, or paraoxon. The AChE reactivation for all used organophosphates was found negligible if compared to the reactivation ability of obidoxime. Importantly, two compounds were found to reactivate BChE inhibited by sarin or VX better to obidoxime at human attainable concentration. One compound resulted as better reactivator of NEMP (VX surrogate)-inhibited BChE than obidoxime. The in vitro results were further rationalized by molecular docking studies showing future directions on designing potent BChE reactivators.

• Klíčová slova
• Acetylcholinesterase, butyrylcholinesterase, organophosphate, oxime, reactivator,
• MeSH
• acetylcholinesterasa účinky léků   MeSH
• butyrylcholinesterasa účinky léků   MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• isochinoliny chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• simulace molekulového dockingu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• isochinoliny MeSH
• reaktivátory cholinesterasy MeSH

The present work aimed to compare the small, neutral and monoaromatic oxime, isatin-3-oxime (isatin-O), to the commercial ones, pralidoxime (2-PAM) and obidoxime, in a search for a new potential reactivator for acetylcholinesterase (AChE) inhibited by the pesticide paraoxon (AChE/POX) as well as a novel potential scaffold for further synthetic modifications. The multicriteria decision methods (MCDM) allowed the identification of the best docking poses of those molecules inside AChE/POX for further molecular dynamic (MD) studies, while Ellman's modified method enabled in vitro inhibition and reactivation assays. In corroboration with the theoretical studies, our experimental results showed that isatin-O have a reactivation potential capable of overcoming 2-PAM at the initial moments of the assay. Despite not achieving better results than obidoxime, this molecule is promising for being an active neutral oxime with capacity of crossing the blood⁻brain barrier (BBB), to reactivate AChE/POX inside the central and peripheral nervous systems. Moreover, the fact that isatin-O can also act as anticonvulsant makes this molecule a possible multipotent reactivator. Besides, the MCDM method showed to be an accurate method for the selection of the best docking poses generated in the docking studies.

• Klíčová slova
• Ellman’s method, TOPSIS-AHP, acetylcholinesterase, molecular modeling, multicriteria decision making, neutral oxime,
• MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• erytrocyty účinky léků   enzymologie   MeSH
• molekulární modely * MeSH
• molekulární struktura MeSH
• oximy chemie   farmakologie   MeSH
• paraoxon chemie   farmakologie   MeSH
• reaktivátory cholinesterasy chemie   farmakologie   MeSH
• simulace molekulární dynamiky MeSH
• simulace molekulového dockingu MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cholinesterasové inhibitory MeSH
• oximy MeSH
• paraoxon MeSH
• reaktivátory cholinesterasy MeSH

BACKGROUND: Pharmaceuticals with targets in the cholinergic transmission have been used for decades and are still fundamental treatments in many diseases and conditions today. Both the transmission and the effects of the somatomotoric and the parasympathetic nervous systems may be targeted by such treatments. Irrespective of the knowledge that the effects of neuronal signalling in the nervous systems may include a number of different receptor subtypes of both the nicotinic and the muscarinic receptors, this complexity is generally overlooked when assessing the mechanisms of action of pharmaceuticals. METHODS: We have search of bibliographic databases for peer-reviewed research literature focused on the cholinergic system. Also, we have taken advantage of our expertise in this field to deduce the conclusions of this study. RESULTS: Presently, the life cycle of acetylcholine, muscarinic receptors and their effects are reviewed in the major organ systems of the body. Neuronal and non-neuronal sources of acetylcholine are elucidated. Examples of pharmaceuticals, in particular cholinesterase inhibitors, affecting these systems are discussed. The review focuses on salivary glands, the respiratory tract and the lower urinary tract, since the complexity of the interplay of different muscarinic receptor subtypes is of significance for physiological, pharmacological and toxicological effects in these organs. CONCLUSION: Most pharmaceuticals targeting muscarinic receptors are employed at such large doses that no selectivity can be expected. However, some differences in the adverse effect profile of muscarinic antagonists may still be explained by the variation of expression of muscarinic receptor subtypes in different organs. However, a complex pattern of interactions between muscarinic receptor subtypes occurs and needs to be considered when searching for selective pharmaceuticals. In the development of new entities for the treatment of for instance pesticide intoxication, the muscarinic receptor selectivity needs to be considered. Reactivators generally have a muscarinic M2 receptor acting profile. Such a blockade may engrave the situation since it may enlarge the effect of the muscarinic M3 receptor effect. This may explain why respiratory arrest is the major cause for deaths by esterase blocking.

• Klíčová slova
• Acetylcholine, acetylcholinesterase, muscarinic receptor subtypes, pharmacotherapy,
• MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• interakce mezi receptory a ligandy účinky léků   MeSH
• lidé MeSH
• receptory muskarinové účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• cholinesterasové inhibitory MeSH
• receptory muskarinové MeSH

Alpha7 nicotinic acetylcholine receptor (α7 nAChR) is an important part of the cholinergic nerve system in the brain. Moreover, it is associated with a cholinergic anti-inflammatory pathway in the termination of the parasympathetic nervous system. Antagonists of α7 nAChR are a wide group represented by conotoxin and bungarotoxin. Even Alzheimer's disease drug memantine acting as an antagonist in its side pathway belongs in this group. Agonists of α7 nAChR are suitable for treatment of multiple cognitive dysfunctions such as Alzheimer's disease or schizophrenia. Inflammation or even sepsis can be ameliorated by the agonistic acting compounds. Preparations RG3487, SEN34625/WYE-103914, SEN12333, ABT-107, Clozapine, GTS-21, CNI-1493, and AR-R17779 are representative examples of the novel compounds with affinity toward the α7 nAChR. Pharmacological, toxicological, and medicinal significance of α7 nAChR are discussed throughout this paper.

• Klíčová slova
• Alzheimer’s disease, agonist, antagonist, cholinergic anti-inflammatory pathway, cognitive disorder, inflammation, schizophrenia,
• MeSH
• acetylcholin farmakologie   MeSH
• agonisté excitačních aminokyselin * farmakologie   toxicita   MeSH
• alfa7 nikotinové acetylcholinové receptory agonisté   antagonisté a inhibitory   fyziologie   MeSH
• antagonisté excitačních aminokyselin * farmakologie   toxicita   MeSH
• antiflogistika farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie * MeSH
• lidé MeSH
• memantin farmakologie   terapeutické užití   MeSH
• mozek účinky léků   metabolismus   MeSH
• oximy farmakologie   terapeutické užití   MeSH
• pyridinové sloučeniny farmakologie   terapeutické užití   MeSH
• signální transdukce účinky léků   MeSH
• zánět metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• acetylcholin MeSH
• agonisté excitačních aminokyselin * MeSH
• alfa7 nikotinové acetylcholinové receptory MeSH
• antagonisté excitačních aminokyselin * MeSH
• antiflogistika MeSH
• asoxime chloride MeSH Prohlížeč
• memantin MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH

The toxic effect of organophosphates is attributed to irreversible inhibition of acetylcholinesterase (AChE; EC 3.1.1.7), the enzyme that hydrolyses the neurotransmitter acetylcholine. Inhibition potency in vivo of one of the most toxic nerve agents--Russian VX (RVX;N,N-diethyl-2-[methyl-(2-methylpropoxy)phosphoryl]sulfanylethanamine) (1 x LD(50) dose administered intramuscularly, i.m.) was studied in rats. AChE in blood was inhibited by 50%, 3 min after i.m. RVX. Butylcholinesterase (BChE; EC 3.1.1.8) in plasma was inhibited less rapidly and only by 10-20%, 20 min after RVX. AChE and BChE activities in diaphragm were reduced only 35% and 15% at 30 min. While AChE and BChE activities were reduced only about 20% and 15%, respectively, the decline in activity was rapid, occurring within 3 min. These findings indicate that RVX most potently inhibits ChE outside the central nervous system.

• MeSH
• acetylcholinesterasa krev   MeSH
• bránice účinky léků   enzymologie   MeSH
• časové faktory MeSH
• chování zvířat účinky léků   MeSH
• játra účinky léků   enzymologie   MeSH
• krysa rodu Rattus MeSH
• LD50 MeSH
• mozek účinky léků   enzymologie   MeSH
• organothiofosforové sloučeniny toxicita   MeSH
• potkani Wistar MeSH
• tkáňová distribuce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• organothiofosforové sloučeniny MeSH
• S-(N,N-diethylaminoethyl) isobutyl methylphosphothiolate MeSH Prohlížeč

The potency of newly developed bispyridinium compounds (K117, K127) to reduce tabun-induced acute neurotoxic signs and symptoms was compared with currently available oxime (obidoxime) using functional observational battery. The neuroprotective effects of atropine alone and atropine combined with one of three bispyridinium oximes (K117, K127, obidoxime) on rats poisoned with tabun at a sublethal dose (180 microg/kg i.m.; 80% of LD(50) value) were studied. Tabun-induced neurotoxicity was monitored using a functional observational battery and automatic measurement of motor activity at 24 h following tabun challenge. The results indicated that all tested oximes combined with atropine enabled tabun-poisoned rats to survive 24 h following tabun challenge while one tabun-poisoned rats died within 24 h after tabun poisoning when the rats were treated with atropine alone. Newly developed oxime K127 combined with atropine was the most effective in decreasing tabun-induced neurotoxicity in the case of sublethal poisonings among all oximes tested. Nevertheless, the differences of neuroprotective efficacy between K127 and obidoxime are not sufficient to replace obidoxime by K127 for the treatment of acute tabun poisonings.

• MeSH
• chemické bojové látky otrava   MeSH
• cholinesterasové inhibitory otrava   MeSH
• krysa rodu Rattus MeSH
• neuroprotektivní látky farmakologie   MeSH
• organofosfáty MeSH
• otrava organofosfáty * MeSH
• oximy farmakologie   MeSH
• pohybová aktivita účinky léků   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• chemické bojové látky MeSH
• cholinesterasové inhibitory MeSH
• K117 compound MeSH Prohlížeč
• K127 compound MeSH Prohlížeč
• neuroprotektivní látky MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• tabun MeSH Prohlížeč

The therapeutical efficacies of eleven oxime-based acetylcholinesterase reactivators were compared in an in vivo (rat model) study of treatment of intoxication caused by tabun. In this group there were some currently available oximes (obidoxime, trimedoxime and HI-6) and the rest were newly synthesized compounds. The best reactivation efficacy for acetylcholinesterase in blood (expressed as percent of reactivation) among the currently available oximes was observed after administration of trimedoxime (16%) and of the newly synthesized K127 (22432) (25%). The reactivation of butyrylcholinesterase in plasma was also studied; the best reactivators were trimedoxime, K117 (22435), and K127 (22432), with overall reactivation efficacies of approximately 30%. Partial protection of brain ChE against tabun inhibition was observed after administration of trimedoxime (acetylcholinesterase 20%; butyrylcholinesterase 30%) and obidoxime (acetylcholinesterase 12%; butyrylcholinesterase 16%).

• Klíčová slova
• Acetylcholinesterase, butyrylcholinesterase, oximes, pretreatment, reactivators,
• Publikační typ
• časopisecké články MeSH