Effects of non-neural mechanisms on pyrethroid structure-activity relationships.

Structural requirements for high insecticidal activity in pyrethroid insecticides are very stringent. Observed structure-activity relationships may arise either from specificity at the site of pyrethroid action in the nervous system, from selectivity in the pharmacokinetic processes governing the appearance and persistence of compounds at that site, or from a combination of these mechanisms. Recent studies of the metabolism of trans and cis isomers of pyrethroids in insect tissue preparations in vitro and of their pharmacokinetic behavior in insects in vivo permit an assessment of the impact of non-neural mechanisms on the toxicity differences observed between these isomers.