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

Nerve agents pose a real threat to both the military and civil populations, but the current treatment of the poisoning is unsatisfactory. Thus, we studied the efficacy of prophylactic use of memantine alone or in combination with clinically used reversible acetylcholinesterase inhibitors (pyridostigmine, donepezil, rivastigmine) against soman. In addition, we tested their influence on post-exposure therapy consisting of atropine and asoxime. Pyridostigmine alone failed to decrease the acute toxicity of soman. But all clinically used acetylcholinesterase inhibitors administered alone reduced the acute toxicity, with donepezil showing the best efficacy. The combination of memantine with reversible acetylcholinesterase inhibitors attenuated soman acute toxicity significantly. The pretreatment administered alone or in combinations influenced the efficacy of post-exposure treatment in a similar fashion: (i) pyridostigmine or memantine alone did not affect the antidotal treatment, (ii) centrally acting reversible acetylcholinesterase inhibitors alone increased the antidotal treatment slightly, (iii) combination of memantine with reversible acetylcholinesterase inhibitors increased the antidotal treatment more markedly. In conclusion, memantine alone failed to decrease the acute toxicity of soman or increase post-exposure antidotal treatment efficacy. The combination of memantine with donepezil significantly increased post-exposure effectiveness (together 5.12, pretreatment alone 1.72). Both drugs, when applied together, mitigate soman toxicity and boost post-exposure treatment.

• Klíčová slova
• Donepezil, Memantine, Mice, Pyridostigmine, Rivastigmine, Soman,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antiparkinsonika aplikace a dávkování   MeSH
• cholinesterasové inhibitory aplikace a dávkování   toxicita   MeSH
• donepezil aplikace a dávkování   MeSH
• dopaminové látky aplikace a dávkování   MeSH
• kombinovaná farmakoterapie MeSH
• memantin aplikace a dávkování   MeSH
• myši MeSH
• preexpoziční profylaxe metody   MeSH
• soman toxicita   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• antiparkinsonika MeSH
• cholinesterasové inhibitory MeSH
• donepezil MeSH
• dopaminové látky MeSH
• memantin MeSH
• soman MeSH

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

Certain AChE reactivators, asoxime, obidoxime, K027, K048, and K075, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure the different organs. As a continuation of previously published data, in this study, Wistar rats have sacrificed 24 hrs and 7 days after single im application of 0.1LD50, 0.5LD50 and 1.0LD50 of each reactivator, and examinated tissue samples were obtained for pathohistological and semiquantitative analysis. A severity of tissue alteration, expressed as different tissue damage scores were evaluated. Morphological structure of examinated tissues treated with of 0.1LD50 of all reactivators was comparable with the control group of rats. Moderate injuries were seen in visceral tissues treated with 0.5LD50 of asoxime, obidoxime and K027. Acute damages were enlarged after treatment with 0.5LD50 and 1.0LD50 of all reactivators during the next 7 days. The most prominent changes were seen in rats treated with 1.0LD50 of K048 and K075 (P < 0.001 vs. control and asoxime-treated group). All reactivators given by a single, high, unitary dose regimen, have an adverse effect not only on the main visceral tissue, but on the whole rat as well, but the exact mechanism of cellular injury remains to be confirmed in further investigation.

• MeSH
• biopsie MeSH
• chemické bojové látky škodlivé účinky   chemie   toxicita   MeSH
• histocytochemie MeSH
• krysa rodu Rattus MeSH
• LD50 MeSH
• molekulární struktura MeSH
• orgánová specificita MeSH
• oximy aplikace a dávkování   škodlivé účinky   chemie   toxicita   MeSH
• plíce účinky léků   metabolismus   patologie   MeSH
• vnitřnosti účinky léků   patologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• žaludek účinky léků   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické bojové látky MeSH
• oximy 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 cholinesterasy 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 cholinesterasy MeSH