Bioconcentration pyrethroid insecticides

Muir, D.C.G., B.R. Hobden, and M.R. Servos. 1994. Bioconcentration of pyrethroid insecticides and DDT by rainbow trout uptake, depuration, and effect of dissolved organic carbon. Aquat. Toxicol. 29 223-240. 

Pyrethroids, such as p,p -DDT, are toxic because they interact with Na+ channels of the axonal membrane, thereby disturbing the transmission of nerve action potential (Eldefrawi and Eldefrawi 1990, and Chapter 5, Section 5.2.4 of this book). In both cases, marked hydrophobicity leads to bioconcentration of the insecticides in the axonal membrane and reversible association with the Na+ channel. Consequently, both DDT and pyrethroids show negative temperature coefficients in arthropods increasing temperature brings decreasing toxicity because it favors desorption of insecticide from the site of action. 

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