Paralysis of skeletal muscles, which can lead to paralysis of respiratory muscles and death, is one of the most toxic effects of organophosphates (OPs), and oximes are the only available antidotes that can reverse or prevent such toxic effects. In the present study, the possible reversal or preventive effect of different concentrations of obidoxime (toxogonin) on changes induced by paraoxon (as...

Diethyl p-nitrophenyl phosphate (paraoxon) is the active toxic metabolite of parathion. Some evidences indicate that OPs affect the GABA system via noncholinergic mechanisms. The purpose of this study was to investigate the effects of paraoxon on K+-evoked [3H]-GABA release from cerebellar synaptosomes. Adult male rats (200 ± 30 g; 3-4 months old) were sacrificed by decapitation and the cerebel...

lnillbition experiments with paraoxon revealed two types of acetylcholinesterases in Panagrellus redivivus i.e. a fast (F-component) and a slow reacting component (S-component). The F-component was thermostable and inactivated by Triton-X100, while the S-component was thermolabile and insensitive for Triton-X-100. The bimolecular rate constant for inhibition by paraoxon was 25.5 x 103 M-1min' f...

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, obidoxi...

A simple approach is described for preparing poly-(ethylene glycol) hydrogel materials with encapsulated seminapthofluorescein (SNAFL)-organophosphorus hydrolase enzyme conjugates. Direct determination of enzyme-catalyzed neurotoxin hydrolysis is provided by the self-referencing, pH-sensitive dye SNAFL-1, whose emission spectrum changes at lambda = 550 in response to pH. Using spectrofluorimetr...

A flow-through biosensor consisting of a fixed bed bioreactor was employed to detect the insecticideparaoxon. Based on the inhibition of organophosphorous insecticide to the enzymatic activity of acetylcholinesterase (AChE), using paraoxon as a model compound, the condition for detection of the insecticide were optimized. The influence of enzyme loading on the packing surface was studied ...

Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification of paraoxon by phosphotriesterase (PTE). In the simulations, the PM3 parameters for the phosphorous atom were reoptimized. The equilibrated configuration of the enzyme/substrate complex showed th...

Diethyl p-nitrophenyl phosphate (paraoxon) is the active toxic metabolite of parathion. Some evidences indicate that OPs affect the GABA system via noncholinergic mechanisms. The purpose of this study was to investigate the effects of paraoxon on K+-evoked [3H]-GABA release from cerebellar synaptosomes. Adult male rats (200 ± 30 g; 3-4 months old) were sacrificed by decapitation and the cerebel...

Introduction: Compounds which are used to treat organophosphate (OP) poisoning are not able to fully alleviate long lasting effects. They are mainly used to antagonize cholinergic effects of Ops. However, non-cholinergic effects, such as interference with different neurotransmitter systems, especially GABA release and uptake, are recently attracting more attentions. We have tried to investi...