Fluorescence Spectroscopy Studies of the Effects f Prethroids on the DPPC Vesicles

The ineractions of pyrethroids with membrane lipids have been studied y means of fluorescent membrane probe DPH.Pyrethroids located in the interior hydrophobic regions of the lipid bilayer,differed in their effectiveness of lowering the phase transition temperature and in their ability to broaden the temperature range of this transition.With the increase in the concentrations of pyrethroids,the effects of disordering hydrocarbon packing were increased by pyrethroids.Fluorescence polarizations(P)were decreased in gel state,but not changed in fluid state by permethrin.The pyrethroids containing a cyano substitiute could not only disturb the hydrocarbon packing in the bilayer core,but also cause collisional quenching of DPH fluorescence in gel state,P were decreased,then were increased and at last were decreased slihtly again as the concentrations were increased.in fluid state P were not changed substantilally at low concentrations and were increased obviously when the concentrations were higher.