Single dose effects of chlorpyrifos and lead combination on neurobehavioural aspects in wistar rats.

ABSTRACT

Chlorpyrifos, a well known organophosphorus insecticide, and the heavy metal lead, were evaluated for their simultaneous interactive effects on neurobehavioural parameters in Wistar rats after single dose exposure via oral gavaging. The study comprised of functional observation battery and motor activity tests. The study was designed using two different dose levels of chlorpyrifos and lead acetate and grouped into seven groups; control (group 1), chlorpyrifos-5mg/kg (group 2), lead acetate- 100mg/kg (group 3), chlorpyrifos-5mg/kg + lead acetate- 100mg/kg (group 4), chlorpyrifos-50mg/kg (group 5), lead acetate-1000mg/kg (group 6) and chlorpyrifos-50mg/kg + lead acetate-1000mg/kg (group 7). Excitotoxicity and motor activity changes were evident in groups 5 and 7 animals. The animals treated with chlorpyrifos at 50mg/kg exhibited behavioural changes after 2–3 hours of oral gavaging and waned over 2 days. At 50mg/kg chlorpyrifos + 1000mg/kg lead acetate, severe cholinergic signs were noticed approximately 24 hours of exposure and symptoms regressed over 4 days. The incidence and severity of cholinergic behavioural changes were more pronounced in group 7 animals. Chlorpyrifos in the presence of lead delays the cholinergic effects which might be due to its chelating properties with metals and predominant behavioural changes suggest potentiating role of lead on excitotoxicity of chlopyrifos. The present study will be potentially relevant for physicians/scientists to decipher more about variability of action that could arise from accidental poisoning by these agents.