Comparison of symptomatic and neurophysiological activities of enantiomers of the insecticide 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropane‐1‐carboxylate

摘要

AbstractThe insecticidal activities of optical isomers of 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropanecarboxylate and related compounds were measured with American cockroaches and their knockdown activities were evaluated with house flies. The activities of the S(−)‐isomer of the dichlorocyclopropanecarboxylate were higher than those of theR(+)‐isomer. The effects of the compounds on the inward membrane currents induced by a stepdepolarizing pulse in crayfish axonal membranes were examined under voltage clamp conditions by the sucrose gap method. The compounds induced a tail current upon step repolarization of the membrane. The tail current decayed to zero in each record, but developed with time after the start of application of the compound until a steady level was reached. The rate of decay of the tail current observed in axonal membranes treated with theS(−)‐isomer was slower than with theR(+)‐isomer. The rates of development of the tail current induced by the two isomers we