Adult dose-response-related behavioral effects of 4 different pesticides, after neonatal exposure

There are several different types of pesticides globally used, all with their own characteristics and toxicological potency. In the present study we have exposed male mice neonatally to different doses of four different types of pesticides, carbaryl (carbamate) chlorpyrifos (organophosphate), cypermethrin (pyrethroid) and endosulfan (organochlorine), and tested them for spontaneous behavior in a novel home environment at adult age. The doses used were 0.5 – 20 mg carbaryl/kg bw, 0.1 – 5.0 mg chlorpyrifos/kg bw, 0.1 – 5.0 mg cypermethrin/kg bw and 0.05 – 20 mg endosulfan/kg bw. All four pesticides induced adult disturbances in the spontaneous behavior in a novel home environment, affecting cognitive function, at 2 months of age. Carbaryl induced a dose-response related effect on spontaneous behavior from 5 mg/kg bw and up, while chlorpyrifos only induced a weak effect with the highest dose tested (5 mg/kg bw). The pyrethroid cypermethrin induced dose-response related neurotoxicity from 0.5 mg/kg bw and up. The organochlorine endosulfan also induced dose-response related neurotoxicity from 0.1 mg/kg bw and up These disturbances also persisted when the animals were re-observed at 4 months of age, indicating that these effects are long-lasting or even irreversible. From this study we conclude that endosulfan seem to be the most potent, of these four compounds, to induce cognitive behavioral effects in the adult after neonatal exposure, while carbaryl has the lowest potency to induce these types of neurotoxic effects.