Cyanofenphos

Cyanofenphos is an orally active organophosphate insecticide and brain AChE inhibitor with neurotoxicity. Cyanofenphos induces delayed neurotoxicity such as ataxia and paralysis. Cyanofenphos also causes symptoms including somnolence, reduced feed intake and weight loss in hens. Cyanofenphos has a unique self-antagonistic effect: repeated low-dose pre-treatment not only reduces subsequent acute toxicity, but also exacerbates delayed neurotoxicity and attenuates enzyme inhibition, with the protective effect peaking at 24 h after the last pre-treatment. Cyanofenphos is commonly used in studies related to delayed neurotoxicity^[1][2]. In Vivo:Cyanofenphos (10-20 mg/kg; p.o.; daily; 8 days) pretreatment significantly reduces the acute toxicity of subsequent high-dose cyanofenphos in hens, increasing the LD₅₀ from 700 to 1170 mg/kg and reducing 7-day mortality from 77% to 20% following a 1000 mg/kg challenge^[1].
Cyanofenphos (80 mg/kg; oral; single dose) induces delayed neurotoxicity in hens following cyanofenphos challenge doses, with higher neurotoxicity incidence observed for 200 mg/kg compared to 100 mg/kg challenge doses^[2].