The benefit of combination of oximes for the neuroprotective efficacy of antidotal treatment of sarin-poisoned rats.

The potency of the oxime HI-6 and two combinations of oximes (HI-6 + trimedoxime, HI-6 + K203) to reduce sarin-induced acute neurotoxic signs and symptoms was evaluated in this study. Sarin-induced neurotoxicity and the neuroprotective effects of atropine alone or in combination with HI-6 alone and HI-6 combined with trimedoxime or K203 in rats poisoned with sarin at a sublethal dose (108 μg/kg i.m.

In vitro binding and in vivo biodistribution studies of the neuroprotective peptide humanin using [125I]humanin derivatives.

Humanin (HN) and HN-derivatives are a family of peptides first reported in the last decade with potent in vitro and in vivo neuroprotective activity, which is mediated through a not completely elucidated mechanism. Recently, our group has evaluated the effect of various HN-derivatives on the 3-quinuclidinyl benzilate (QNB)-induced impairment of spatial orientation and memory in rats, by employing the T-maze test. In the present work four new, tyrosine containing HN-derivatives were synthesized (Y-PAGASRLLLTGEIDLP, peptide I; Y-PAGASRLLLLTGEIDLP, peptide II; Y-SALLRSIPAPAGASRLLLTGEIDLP, peptide III; Y-SALLRSIPAPAGASRLLLLTGEIDLP, peptide IV).

The multiple T-maze in vivo testing of the neuroprotective effect of humanin analogues.

Humanin (HN) and its analogues have been shown to protect cells against death induced by various Alzheimer's disease (AD) genes and amyloid-beta-peptides in vitro; the analogues [Gly(14)]-HN and colivelin have also been shown to be potent in reversing learning and memory impairment induced by scopolamine or quinuclidinyl benzilate (QNB) in mice or rats in vivo using the Y-maze or multiple T-maze tests. This paper describes the activity of new peptides of the HN family, after i.p.

Effect of galantamine on acetylcholinesterase and butyrylcholinesterase activities in the presence of L-carnitine in rat selected brain and peripheral tissues.

Objectives: The alkaloid galantamine (GAL), which exhibits a combined anticholinesterase and direct parasympathomimetic mechanism of action, is employed in conjunction with therapeutic interventions in the stimulation of central cholinergic transfer in cognitive diseases. We attempted to achieve pharmacologically-induced enhancement of the parasympathomimetic activity of GAL in the key areas of rat brain, using an interactive combination of the alkaloid with the transmembrane enhancer L-carnitine (CAR).

Methods: We investigated activities of acetylcholinesterase (AChE) in brain areas (frontal cortex, basal ganglia, septum and hippocampus) and the hypophysis, and that of butyrylcholinesterase (BuChE) in plasma and liver.

Comparison of effects of different antidotes on tabun-induced cognitive impairment in rats using water maze.

In the past, scientists focused on the development of antidotes (mainly anticholinergics in combination with reactivators of inhibited acetylcholinesterase-oximes) to increase the number of surviving nerve agent-intoxicated individuals. Recently, they are interested in antidotes able not only to protect nerve agent-poisoned men from lethal toxic effects but also to improve their life quality by improvement of their central cognitive functions. In our study, the water maze was used to measure spatial working learning and memory in the case of tabun-induced cognitive impairment in albino Wistar rats.

The acute toxicity of acetylcholinesterase reactivators in mice in relation to their structure.

Oximes in combination with atropine, are an integral part of the treatment of acute intoxications with organophosphorus insecticides or with the nerve agents such as tabun, sarin, soman, cyclosarin or VX. Organophosphorus compounds are extremely potent inhibitors of the enzyme acetylcholinesterase (AChE, 3.1.

Strategy for the development of new acetylcholinesterase reactivators - antidotes used for treatment of nerve agent poisonings.

The mechanism of intoxication with organophosphorus compounds, including highly toxic nerve agents, is based on the formation of irreversibly inhibited acetylcholinesterase (AChE; EC 3.1.1.

Effectivity of new acetylcholinesterase reactivators in treatment of cyclosarin poisoning in mice and rats.

The present study was performed to assess and compare a therapeutic efficacy of obidoxime, HI-6, BI-6 and HS-6 administered in equimolar doses and combined with atropine in cyclosarin-poisoned mice and rats. It was demonstrated that all the therapeutic regimens tested, were able to decrease the cyclosarin-induced toxicity significantly - at least 1.5 times.

A comparison of the potency of newly developed oximes (K027, K048) and commonly used oximes (obidoxime, HI-6) to counteract tabun-induced neurotoxicity in rats.

The neuroprotective effects of newly developed oximes (K027, K048) and currently available oximes (obidoxime, HI-6) in combination with atropine in rats poisoned with tabun at a sublethal dose (170 microg kg(-1) i.m.; 80% of LD(50) value) were studied.

Comparison of ability of some oximes to reactivate sarin-inhibited brain acetylcholinesterase from different species.

The aim of this work was the comparison of reactivation potency of four oxime acetylcholinesterase (AChE) reactivators (pralidoxime, HI-6, K027 and K033) on three resources of the enzyme (human, pig and rat brain homogenate) inhibited by nerve agent sarin. The results demonstrate remarkable differences in the reactivation of inhibited brain AChE, depending on the oxime and species

Comparison of the potency of newly developed and currently available oximes to reactivate nerve agent-inhibited acetylcholinesterase in vitro and in vivo.

Reactivation potency of three newly developed oximes K027, K033 and K048 was tested using standard in vitro and in vivo reactivation tests. K027 and K048 seem to be efficacious reactivators of tabun-inhibited acetylcholinesterase. K033 is sufficient reactivator of cyclosarin-inhibited AChE.

Bispyridinium oximes as antidotal treatment of cyclosarin poisoning-in vitro and in vivo testing.

The mechanism of intoxication with organophosphorus compounds, including highly toxic nerve agents and less toxic pesticides, is based on the formation of irreversibly inhibited acetylcholinesterase, which causes cumulation of neuromediator acetylcholine in synaptic clefts and subsequent overstimulation of cholinergic receptors, that is followed by a generalized cholinergic crisis. Nerve agent poisoning is conventionally treated using a combination of a cholinolytic (atropine mostly) to counteract the accumulation of acetylcholine and acetylcholinesterase reactivators (pralidoxime or obidoxime) to reactivate inhibited acetylcholinesterase. In this study of cyclosarin poisoning treatment, oximes of different chemical structures (obidoxime, HI-6, BI-6, and HS-6) were tested in vitro on rat brain acetylcholinesterase (enzyme source: rat brain homogenate), and afterwards, they were tested in vivo in equimolar doses, in mice and rats.

New quaternary pyridine aldoximes as casual antidotes against nerve agents intoxications.

In this work, the ability of four newly synthesized oximes--K005 (1,3-bis(2-hydroxyiminomethylpyridinium) propane dibromide), K027 (1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide), K033 (1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide) and K048 (1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide) to reactivate acetylcholinesterase (AChE, EC 3.1.1.

In vitro reactivation potency of some acetylcholinesterase reactivators against sarin- and cyclosarin-induced inhibitions.

In our study, we have tested six acetylcholinesterase (AChE) reactivators (pralidoxime, obidoxime, HI-6, trimedoxime, BI-6 and Hlö-7) for reactivation of sarin- and cyclosarin-inhibited AChE using an in vitro reactivation test. We have used rat brain homogenate as the suitable source of enzyme. All oximes are able to reactivate sarin-inhibited AChE.

Therapeutic efficacy of different antidotal mixtures against poisoning with GF-agent in mice.

The toxicity of cyclohexyl methylphosphonofluoridate (GF-agent; cyclosarin) and therapeutic efficacy of four oximes (trimedoxime, methoxime, obidoxime and HI-6) in combination with atropine or benactyzine (BNZ) was studied in mice. The oxime therapy combined with anticholinergic drug was administered intramusculary (i.m.