Neurotoxicity of organophosphorus and dithiocarbamate compounds

The neurotoxicity of organophosphorus compounds (OPs) including leptophos, TOCP and triphenyl phosphite and dithiocarbamate compounds were reviewed in this study. The major neurotoxicities of OPs were acute toxicity produced by the acetylcholine esterase (AChE) inhibiting action of OPs and delayed neurotoxicity produced by such OPs as leptophos and TOCP. The direct action of OP on the muscarinic and/or nicotinic acethylcholine receptors in the synaptic membranes have lately attracted attention in relation to acute toxicity. Delayed neurotoxicity is a delayed onset of prolonged locomotor ataxia resulting from a single or repeated exposure to an OP. Although neurotoxic esterase (NTE) inhibition might be related to the onset of organophosphate-induced delayed neurotoxicity (OPIDN), the precise mode of action is not yet clear. The effect of dithiocarbamates on the nervous system is also mentioned, because the compounds are currently suspected not only for neurotoxicity, but also as endocrine-disrupting chemicals. Although dithiocarbamates showed weak neurotoxicity in adult animals, we need to pay more attention to developmental neurotoxicity.