Neurophysiological alterations in Caenorhabditis elegans exposed to dichlorvos, an organophosphorus insecticide

AChE inhibition is widely regarded as a good biomarker of exposure to organophosphorus insecticides (OPIs), suggesting increase in the cholinergic transmission and consequent accumulation of acetylcholine in the organism. This might lead to behavioral changes and create widespread disturbances in the normal physiology of an organism. In the present study we have employed the model organism Caenorhabditis elegans to evaluate the biochemical and behavioral alterations induced by dichlorvos, a well known OPI. Exposure of worms to dichlorvos (at sublethal concentrations: 5, 50, 100, 150 and 200 μM) induced a concentration and time dependent AChE inhibition, and accumulation of acetylcholine. Further, we also observed cessation in feeding (by 72%), shutting of pharyngeal pumping, inhibition of egg laying (34–55%), contraction of nose (45%) and significant paralysis (50%) after 4 h of exposure. Significant correlation was observed between biochemical effects and behavioral parameters clearly suggesting the implications of sublethal concentrations of dichlorvos on non-target invertebrate organism such as C. elegans. These data further suggest that assessment of subtle neurophysiological parameters may serve as useful indicators of OPI exposure.