The acetylcholinesterase (AChE) reactivators (e.g., obidoxime, asoxime) became an essential part of organophosphorus (OP) poisoning treatment, together with atropine and diazepam. They are referred to as a causal treatment of OP poisoning, because they are able to split the OP moiety from AChE active site and thus renew its function. In this approach, fifteen novel AChE reactivators were determined. Their molecular design originated from former K-oxime compounds K048 and K074 with remaining oxime part of the molecule and modified part with heteroarenium moiety. The novel compounds were prepared, evaluated in vitro on human AChE (HssAChE) inhibited by tabun, paraoxon, methylparaoxon or DFP and compared to commercial HssAChE reactivators (pralidoxime, methoxime, trimedoxime, obidoxime, asoxime) or previously prepared compounds (K048, K074, K075, K203). Some of presented oxime reactivators showed promising ability to reactivate HssAChE comparable or higher than the used standards. The molecular modelling study was performed with one compound that presented the ability to reactivate GA-inhibited HssAChE. The SAR features concerning the heteroarenium part of the reactivator's molecule are described.

• Klíčová slova
• acetylcholinesterase, in vitro, molecular docking, organophosphate, oxime, reactivation,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory toxicita   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• inhibiční koncentrace 50 MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie s uhlíkem 13C MeSH
• organofosforové sloučeniny toxicita   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• reaktivátory cholinesterázy chemická syntéza   chemie   farmakologie   MeSH
• rekombinantní proteiny metabolismus   MeSH
• simulace molekulového dockingu * MeSH
• techniky in vitro MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• organofosforové sloučeniny MeSH
• reaktivátory cholinesterázy MeSH
• rekombinantní proteiny MeSH

BACKGROUND: The aim of our study was to compare the ability of two combinations of oximes (HI-6 + trimedoxime and HI-6 + K203) with atropine to counteract acute sarin-induced brain damage with the efficacy of antidotal treatment involving single oxime (HI-6) and atropin using in vivo methods. METHODS: Brain damage and neuroprotective effects of antidotal treatment were evaluated in rats poisoned with sarin at a sublethal dose (108 μg/kg i.m.; 90% LD50) using histopathological, Fluoro-Jade B and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis 24 h after sarin administration. RESULTS: Both combinations of oximes reduce the number of rats that died before the end of experiment compared to non-treated sarin poisoning and sarin poisoning treated with HI-6 and atropine. In the case of treatment of sarin poisoning with HI-6 in combination with K203, all rats survived till the end of experiment. HI-6 with atropine was able to reduce sarin-induced brain damage, however, both combinations were slightly more effective. CONCLUSIONS: The oxime HI-6 in combination with K203 and atropine seems to be the most effective. Thus, both tested oxime combinations bring a small benefit in elimination of acute sarin-induced brain damage compared to single oxime antidotal therapy.

• Klíčová slova
• FluoraJadeB, HI-6, Histopathology, K203, Rats, Sarin, TUNEL, Trimedoxime,
• MeSH
• antidota terapeutické užití   MeSH
• kombinovaná farmakoterapie MeSH
• neurotoxické syndromy farmakoterapie   MeSH
• oximy terapeutické užití   MeSH
• potkani Wistar MeSH
• sarin otrava   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antidota MeSH
• oximy MeSH
• sarin MeSH

Four novel bisquaternary aldoxime cholinesterase reactivators differing in their chemical structure were prepared. Afterwards, their biological activity was evaluated for their ability to reactivate acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BuChE; EC 3.1.1.8) inhibited by paraoxon. Their reactivation activity was compared with standard reactivators--pralidoxime, obidoxime and HI-6--which are clinically used at present. As it resulted, none of the prepared compounds surpassed obidoxime, which is considered to be the most potent compound if used for reactivation of AChE inhibited by paraoxon. In case of BuChE reactivation, two compounds (K053 and K068) achieved similar results as obidoxime.

• MeSH
• acetylcholinesterasa účinky léků   metabolismus   MeSH
• butyrylcholinesterasa účinky léků   metabolismus   MeSH
• enzymové reaktivátory farmakologie   MeSH
• magnetická rezonanční spektroskopie MeSH
• oximy chemie   MeSH
• paraoxon farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• enzymové reaktivátory MeSH
• oximy MeSH
• paraoxon MeSH

Seven new oxime-based acetylcholinesterase reactivators were compared with three currently available ones (obidoxime, trimedoxime, HI-6) for their ability to lessen cholinesterase inhibition in blood and brain of cyclosarin-treated rats. Oximes were given at doses of 5% their LD(50) along with 21 mg/kg atropine five min before the LD(50) of cyclosarin (120 ug/kg) was administered. Blood and brain samples were collected 30 minutes later. The greatest difference between acetylcholinesterase inhibition in blood of cyclosarin-treated rats was found after administration of HI-6 (40%), compared to 22% for trimedoxime and 6% for obidoxime. Only two of the seven newly synthesized oximes had any effect (K203 at 7%, K156 at 5%). Effective oximes against cyclosarin-inhibited plasma butyrylcholinesterase were HI-6 (42%), trimedoxime (11%), and K156 (4%). The oximes were less effective in brain than in blood, with reactivation values for HI-6 30% against acetylcholinesterase and 10% against butyrylcholinesterase. Values for newly synthesized oximes were less than 10% for K206, K269 and K203.

• Klíčová slova
• acetylcholinesterase, butyrylcholinesterase, cyclosarin, oximes, reactivators,
• MeSH
• acetylcholinesterasa krev   metabolismus   MeSH
• atropin farmakologie   MeSH
• krysa rodu Rattus MeSH
• mozek účinky léků   enzymologie   MeSH
• organofosforové sloučeniny toxicita   MeSH
• oximy chemie   farmakologie   MeSH
• potkani Wistar MeSH
• reaktivátory cholinesterázy chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva 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
• atropin MeSH
• cyclohexyl methylphosphonofluoridate MeSH Prohlížeč
• organofosforové sloučeniny MeSH
• oximy MeSH
• reaktivátory cholinesterázy MeSH

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

• Klíčová slova
• acetylcholinesterase, antidote, nerve agent, organophosphates, prophylaxis, therapy,
• Publikační typ
• časopisecké články MeSH