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 investigate...

Background: It has been suggested that organophosphates may inhibit gamma-aminobutyric acid (GABA) metabolism in synaptosomal preparations. In the present investigation, we have assessed the interaction between paraoxon and the GABA system at synaptic level. Methods: Synaptosomes were prepared from male Wistar rats (200-250 g). Cerebral cortex was dissected and homogenized, then centrifuged at ...

Accuracy in measurement of plasma free fatty acids (FFA), and therefore prevention of the in vitro lipolysis, is a crucial step to understand the physiologic role of plasma FFA and their relationships in the pathogenesis of important metabolic disorders such as central obesity, insulin resistance, and diabetes mellitus. As lipoprotein triglyceride-fatty acids are elevated in these states, in vi...

Acetylcholinesterase (AChE) is an important enzyme in the control of the neuronal action potential and sensitive to organophosphate inhibition. Brain fish AChE is less sensitive to organophosphate inhibition than AChE from terrestrial animals, although this sensitivity is variable among species and has not yet been fully evaluated in fish species. In this setting, inhibition kinetic constants f...

Carboxylesterases from different strains of Myzus persicae were examined to try to understand their contribution to insecticide resistance. Preliminary evidence that they are involved comes from the good correlation between the degree of resistance and the carboxylesterase and paraoxon-degrading activity in aphid homogenates. Furthermore the carboxylesterase associated with resistance could not...

A-esterases are calcium-dependent hydrolases that can detoxify the active metabolites (oxons) of organophosphorus insecticides such as chlorpyrifos and parathion. A-esterases from rat liver have previously been shown to hydrolyze chlorpyrifos-oxon but not paraoxon at low substrate concentrations. Two A-esterases were extracted by ammonium sulfate fractionation from solubilized rat liver microso...

Serum paraoxonase1 (PON1), a high density lipoprotein (HDL)-linked enzyme, appears to have a role in the protection of low density lipoproteins from oxidative stress. PON1 enzyme activity for paraoxon as a substrate is modulated, along with others at the PON1 locus, by the PON1-192 polymorphism, which contains low paraoxon-activity and high paraoxon-activity alleles (Q and R, respectively). The...

Cyclodextrins are torus-shaped polymers of glucose that can bind organophosphorous compounds such as nerve agents and pesticides. We demonstrate here that cyclodextrin can bind up to two paraoxon molecules with a K(av) of 6775 M(-1). Molecular modeling shows that the paraoxon appears to bind in polar opposite orientation and have an average binding energy of -89 Kcals/mol. Published 2013. This ...

Human serum paraoxonase-1 (HuPON1) has the capacity to hydrolyze aryl esters, lactones, oxidized phospholipids, and organophosphorus (OP) compounds. HuPON1 and bacterially expressed chimeric recombinant PON1s (G2E6 and G3C9) differ by multiple amino acids, none of which are in the putative enzyme active site. To address the importance of these amino acid differences, the abilities of HuPON1, G2...