Reactivation of acetycholinesterase inhibited by the pesticide chlorpyrifos

Abstract

Organophosphorus pesticides such as parathion or chlorpyrifos are substances used worldwide for agricultural purposes. These compounds are able to inhibit an enzyme acetylcholinesterase (AChE; EC 3.1.1.7) by phosphorylation in its active site. AChE reactivators and anticholinergics are generally used as antidotes in the case of intoxication by these agents. In this work, the reactivation potency of nine structurally different AChE reactivators was tested in vitro. Chlorpyrifos was chosen as an appropriate member of the pesticide family. The result is that bisquaternary reactivators with two oxime groups in position four at the pyridinium rings (trimedoxime and K074) seem to be the most potent reactivators of chlorpyrifos-inhibited AChE.