Experimental Data on the Neurotoxicity of Fenitrothion

Abstract

Abstract Fenitrothion, the indirect cholinesterase inhibitor organophosphorus insecticide, caused alteration in the conditioned avoidance reflex of rats. In trained rats (treated with 10 and 100 mg/kg fenitrothion) the number of conditioned responses diminished the latency period leghtened, and the tendency towards extinction was slower. The whole blood cholinesterase activity showed marked inhibition during the toxic effects. In rabbits, treated with 10 and 25 mg/kg fenitrothion daily, the conduction velocity of the sciatic nerve became slower. At the same time rabbits, poisoned with the higher dose, had marked signs of intoxication while others showed no signs at all. The histological findings showed destruction of the myelinated fibres of the sciatic nerve. Our results indicate that fenitrothion has a neurotoxic effect but the type and the mechanism of action is still obscure.