This article describes acetylcholinesterase (AChE), an enzyme involved in parasympathetic neurotransmission, its activity, and how its inhibition can be pharmacologically useful for treating dementia, caused by Alzheimer's disease, or as a warfare method due to the action of nerve agents. The chemical concepts related to the irreversible inhibition of AChE, its reactivation, and aging are discussed, along with a relationship to the current international legislation on chemical weapons.

• Klíčová slova
• Alzheimer’s disease, Chemical Weapons Convention, acetylcholinesterase, nerve agents,
• MeSH
• acetylcholinesterasa * metabolismus   MeSH
• Alzheimerova nemoc * farmakoterapie   enzymologie   MeSH
• chemická válka zákonodárství a právo   MeSH
• cholinesterasové inhibitory terapeutické užití   MeSH
• GPI-vázané proteiny antagonisté a inhibitory   metabolismus   MeSH
• lidé MeSH
• nervová bojová látka * MeSH
• stárnutí metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• acetylcholinesterasa * MeSH
• ACHE protein, human MeSH Prohlížeč
• cholinesterasové inhibitory MeSH
• GPI-vázané proteiny MeSH
• nervová bojová látka * MeSH

BACKGROUND: Based on in vitro and in vivo rat experiments, the newly developed acetylcholinesterase (AChE) reactivator, K203, appears to be much more effective in the treatment of tabun poisonings than currently fielded oximes. METHODS: To determine if this reactivating efficacy would extend to humans, studies were conducted in vitro using human brain homogenate as the source of AChE. The efficacy of K203 was compared with commercially available oximes; pralidoxime, obidoxime and asoxime (HI-6). RESULTS: Reactivation studies showed that K203 was the most effective reactivator with a second order kinetic constant (kr) of 2142 min- 1. M- 1, which was 51 times higher than that obtained for obidoxime (kr = 42 min- 1. M- 1). Both pralidoxime and asoxime (HI-6) failed to significantly reactivate tabun-inhibited human AChE. DISCUSSION: According to these results and previous studies, using K203, it appears that oxime K203 is the most effective reactivator of tabun-inhibited cholinesterase in several species including humans and should be considered as a possible medical countermeasure to tabun exposure.

• Klíčová slova
• Antidotes, Chemical warfare agents, Oxime, Poisoning, Reactivator, Treatment,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antidota metabolismus   MeSH
• cholinesterasové inhibitory metabolismus   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• mozek enzymologie   MeSH
• organofosfáty metabolismus   MeSH
• oximy metabolismus   MeSH
• pyridinové sloučeniny metabolismus   MeSH
• reaktivátory cholinesterasy metabolismus   MeSH
• simulace molekulového dockingu MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-(4-carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)but-2-ene MeSH Prohlížeč
• acetylcholinesterasa MeSH
• antidota MeSH
• cholinesterasové inhibitory MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč

The ability of two newly developed oximes (K305, K307) to protect tabun-poisoned rats from tabun-induced inhibition of brain acetylcholinesterase, acute neurotoxic signs and symptoms and brain damage was compared with that of the oxime K203 and trimedoxime. The reactivating and neuroprotective effects of the oximes studied combined with atropine on rats poisoned with tabun at a sublethal dose were evaluated. The reactivating efficacy of a newly developed oxime K305 is lower compared to the reactivating efficacy of the oxime K203 and trimedoxime while the ability of the oxime K307 to reactivate tabun-inhibited acetylcholinesterase (AChE) in the brain roughly corresponds to the reactivating efficacy of the oxime K203 and it is slightly lower compared to trimedoxime. In addition, only one newly developed oxime (K307) combined with atropine was able to markedly decrease tabun-induced neurotoxicity although it did not eliminate all tabun-induced acute neurotoxic signs and symptoms. These results correspond to the histopathological evaluation of tabun-induced brain damage. Therefore, the newly developed oximes are not suitable for the replacement of commonly used oximes (especially trimedoxime) in the treatment of acute tabun poisonings.

• Klíčová slova
• acetylcholinesterase, functional observational battery, histopathology, neurotoxicity, oximes, rats, tabun,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• atropin terapeutické užití   MeSH
• chemické bojové látky otrava   MeSH
• lidé MeSH
• mozek účinky léků   enzymologie   MeSH
• neuroprotektivní látky terapeutické užití   MeSH
• neurotoxické syndromy farmakoterapie   MeSH
• organofosfáty toxicita   MeSH
• otrava organofosfáty farmakoterapie   MeSH
• oximy terapeutické užití   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny terapeutické užití   MeSH
• reaktivátory cholinesterasy terapeutické užití   MeSH
• trimedoxim terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• atropin MeSH
• chemické bojové látky MeSH
• neuroprotektivní látky MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč
• trimedoxim MeSH

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

In this work, two oximes for the treatment of tabun-inhibited acetylcholinesterase (AChE; EC 3.1.1.7), K074 (1,4-bis(4-hydroxyiminomethylpyridinium)butane dibromide) and K075 ((E)-1,4-bis(4-hydroxyiminomethylpyridinium)but-2-en dibromide), were tested in vitro as reactivators of AChE. Comparison was made with currently used AChE reactivators (pralidoxime, HI-6, methoxime and obidoxime). Human brain homogenate was taken as an appropriate source of the cholinesterases. As resulted, oxime K074 appears to be the most potent reactivator of tabun-inhibited AChE, with reactivation potency comparable to that of obidoxime. A second AChE reactivator, K075, does not attain as great a reactivation potency as K074, although its maximal reactivation (17%) was achieved at relevant concentrations for humans.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• aktivace enzymů účinky léků   MeSH
• butany chemie   farmakologie   MeSH
• cholinesterasové inhibitory toxicita   MeSH
• lidé MeSH
• nucleus caudatus účinky léků   enzymologie   MeSH
• obidoxim chlorid chemie   farmakologie   MeSH
• organofosfáty toxicita   MeSH
• oximy chemie   farmakologie   MeSH
• pralidoximové sloučeniny chemie   farmakologie   MeSH
• pyridinové sloučeniny chemie   farmakologie   MeSH
• reaktivátory cholinesterasy chemie   farmakologie   MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,4-bis(4-hydroxyiminomethylpyridinium)butane dibromide MeSH Prohlížeč
• acetylcholinesterasa MeSH
• asoxime chloride MeSH Prohlížeč
• butany MeSH
• cholinesterasové inhibitory MeSH
• K075 compound MeSH Prohlížeč
• N,N'-monomethylenebis(pyridiniumaldoxime) MeSH Prohlížeč
• obidoxim chlorid MeSH
• organofosfáty MeSH
• oximy MeSH
• pralidoxime MeSH Prohlížeč
• pralidoximové sloučeniny MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč

INTRODUCTION: Organophosphorus nerve agents inhibit the enzyme, acetylcholinesterase (AChE; EC 3.1.1.7). AChE reactivators (also known as oximes) are generally used for the reactivation of an inhibited enzyme. METHODS: Two new AChE reactivators--K033 and K027--were tested for their in vitro reactivation of sarin-inhibited pig-brain AChE. Their reactivation potencies were compared with the commercially available AChE reactivators, pralidoxime, obidoxime, and HI-6. RESULTS: Of the oximes tested, the newly developed oxime K027 achieved the highest reactivation potency (100%; concentration of the oxime -10(-2) M). However, oxime HI-6 (33%) and obidoxime (23%) seem to be the best AChE reactivators for human relevant doses (10(-4) M and lower). CONCLUSION: For human relevant doses, newly developed oximes (K027 and K033) do not surpass the reactivation potency of the most promising oxime, HI-6.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antidota farmakologie   MeSH
• cholinesterasové inhibitory toxicita   MeSH
• mozek účinky léků   enzymologie   MeSH
• obidoxim chlorid farmakologie   MeSH
• oximy farmakologie   MeSH
• pralidoximové sloučeniny farmakologie   MeSH
• prasata MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• sarin toxicita   MeSH
• techniky in vitro MeSH
• výzkumný projekt MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• 1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium) propane dibromide MeSH Prohlížeč
• 1,4-bis(2-hydroxyiminomethylpyridinium)butane MeSH Prohlížeč
• acetylcholinesterasa MeSH
• antidota MeSH
• asoxime chloride MeSH Prohlížeč
• cholinesterasové inhibitory MeSH
• obidoxim chlorid MeSH
• oximy MeSH
• pralidoxime MeSH Prohlížeč
• pralidoximové sloučeniny MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH
• sarin MeSH

The influence of newly developed oximes, K027 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide] and K048 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) butane dibromide], or currently used oximes (pralidoxime, obidoxime, trimedoxime, HI-6) and anticholinergic drugs (atropine, benactyzine) on the ability of antidotal treatment to eliminate tabun-induced acute toxic effects was studied in mice. The therapeutical efficacy of trimedoxime and both newly developed oximes (K027, K048) is significantly higher than the potency of pralidoxime (regardless of the choice of anticholinergic drug), obidoxime (in the case of its combination with atropine) and the oxime HI-6 (in the case of its combination with benactyzine). All studied oximes with the exception of pralidoxime and the oxime HI-6, when combined with benactyzine, appear to be more efficacious in the elimination of toxic effects of the lethal dose of tabun than their combination with atropine. The findings support the hypothesis that the choice of acetylcholinesterase reactivators as well as the anticholinergic drug selection are important for the effectiveness of an antidotal mixture in the case of antidotal treatment of tabun-induced acute poisonings.

• MeSH
• antidota farmakologie   MeSH
• chemické bojové látky otrava   MeSH
• cholinergní antagonisté farmakologie   MeSH
• hodnocení léčiv MeSH
• LD50 MeSH
• lékové interakce MeSH
• myši MeSH
• organofosfáty antagonisté a inhibitory   MeSH
• otrava organofosfáty MeSH
• oximy farmakologie   MeSH
• reaktivátory cholinesterasy terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• antidota MeSH
• chemické bojové látky MeSH
• cholinergní antagonisté MeSH
• organofosfáty MeSH
• oximy MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč

We investigated the relationship between the chemical structure of acetylcholinesterase (AChE; EC 3.1.1.7) reactivators and their potency in reactivating this enzyme, after prior inhibition by VX (O-ethyl-S-(2-diisopropylaminoethyl)-methylthiophosphonate), tabun, sarin, and cyclosarin. The oximes, pralidoxime (2-PAM), HI-6 [1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-2-oxa-propane dichloride], obidoxime and HS-6 [1-(2-hydroxyiminomethylpyridinium)-3-(3-carbamoylpyridinium)-2-oxa-propane dichloride] were used as representatives of the group of AChE reactivators. Rat brain AChE was used as the appropriate source of the enzyme. Our results confirm that there is no single broad-spectrum oxime suitable for the treatment of poisoning with all highly toxic organophosphorus agents.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• aktivace enzymů účinky léků   fyziologie   MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• krysa rodu Rattus MeSH
• mozek účinky léků   enzymologie   MeSH
• organofosfáty farmakologie   MeSH
• oximy farmakologie   MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH