title: Comparison of the delayed neurotoxicity of O-methyl and O-ethyl analogs of EPN, leptophos, and cyanofenphos.
abstract: Eight pairs of O-methyl and O-ethyl O-(substituted-phenyl) phenylphosphonothionates were evaluated with respect to their delayed neurotoxic activity in hens. O-methyl compounds were in all cases more active than their O-ethyl analogs. The neurotoxic potential of the O-methyl phenylphosphonothionates was 2,5-diCl greater than 4-NO2 greater than 2,4,5-triCl and 2,4,6-triCl greater than 2,4-diCl greater than 2,5-diCl-4-Br greater than 4-CN, when single oral doses were given. Both EPN-ethyl and leptophos-methyl were more neurotoxic in multiple dermal than multiple oral dosing regimens. LD50s for mice and flies were established.
mesh_terms: D000284:Administration, Oral; D000287:Administration, Topical; D000818:Animals; D001259:Ataxia / Q000139:chemically induced; D002645:Chickens; D004175:Diptera; D005260:Female; D007928:Lethal Dose 50; D051379:Mice; D009420:Nervous System / Q000187:drug effects*; D009943:Organophosphorus Compounds / Q000008:administration & dosage / Q000633:toxicity*; D013045:Species Specificity; D013997:Time Factors
chemical_list: D009943:Organophosphorus Compounds