Effects of fenvalerate on membrane in fluidity in the cerebellum and cerebral cortex of rats

The effects of fenvalerate on rat cerebral cortex and cerebellum cell membrane fluidity were investigated using a fluorescence polarization technique. The study was performed in vitro and in vivo, producing different data according to the experimental conditions. In vitro, fenvalerate induced a significant concentration-dependent increase in membrane fluidity in both brain regions; in vivo the authors observed that membrane fluidity increased in a dose and time dependent manner in the cerebellum cells of rats treated with fenvalerate for 2, 5 or 30 days, whilst no change was found in cerebral cortex cells. This latter result could be explained by the increasing accumulation of fenvalerate and its metabolites in the cerebellum where the levels of conjugation activity appear to be very low.