Two classes of pyrethroid action in the cockroach

摘要: Abstract Pyrethroids are divided into two classes (Types I and II) based on their effects the cercal sensory nerves recorded in vivo vitro symptomology they produce dosed cockroaches, Periplaneta americana . Type compounds include pyrethrins, S -bioallethrin, [1 R,cis ]resmethrin, kadethrin, 1 R,trans isomers of tetramethrin, phenothrin, permethrin, an oxime O -phenoxybenzyl ether. Electrophysiological recordings from individuals reveal trains spikes sometimes also spike motor CNS. Low concentrations these pyrethroids act to induce repetitive firing a nerve following single electrical stimulus. This measurement, standardized for evaluating structure-activity relationships, shows that only R , insecticidal highly effective neurotoxins. The most potent isolated ]- ]tetramethrin, each active at 3 × 10 −13 M poisoning symptoms restlessness, incoordination, hyperactivity, prostration, paralysis. II ,α ]cypermethrin, deltamethrin, [ S,S ]fenvalerate. These α-cyanophenoxybenzyl do not either or ; moreover, cause different symptoms, including pronounced convulsive phase. Two other with α-cyano substituent, i.e., fenpropathrin -α-cyanophenoxybenzyl ether, classified as action but resemble II. pyrethroid evident cockroach discussed relative neurophysiological organisms.