Toxicity and anticholinesterase activity of organophosphorus compounds in Triatoma infestans

Abstract

1. A series of diethyl p -substituted phenyl phosphates, phosphorothionates and phosphorothiolates were examined for anticholinesterase activity and toxicity to Triatoma infestans. 2. The isolated central nervous systems (CNS) of T. infestans was used as a source of acetylcholinesterase (AChE) for the determination of bimolecular rate constants ( k i) of enzyme inhibition because histochemical studies did not show any differences between brain and thoracic ganglia as targets of organophosphorus intoxication. 3. A good linear correlation was obtained between phosphates free energy σ and π parameters and CNS AChE inhibition. 4. There was an excellent linear correlation between insect toxicity and insect acetylcholinesterase inhibition.