Mr. Moyaquiles et al., EFFECT OF THE PYRETHROID INSECTICIDE ALLETHRIN ON MEMBRANE FLUIDITY, Biochemistry and molecular biology international, 36(6), 1995, pp. 1299-1308
Allethrin is a widely used pyrethroid insecticide with an alkenylmethy
lcyclopentenolone group in its structure. We have analyzed its interac
tion with model and native membranes using DPH and its polar derivativ
e TMA-DPH fluorescence polarization. Allethrin modified the bilayer or
der in the temperature range of the phase transition when incorporated
into liposomes made with dimyristoyl-(DMPC), dipalmitoyl-(DPPC) and d
istearoyl-(DSPC) phosphatidylcholine. In DMPC:allethrin mixtures the p
yrethroid decreased the bilayer order in the gel phase, without alteri
ng the liquid-crystalline one. In native membranes, DPH and TMA-DPH fl
uorescence polarization remained unchanged after incubation with allet
hrin. The release of hemoglobin was notably facilitated by the incorpo
ration of allethrin into human erythrocytes. The results are discussed
in terms of a possible aggregation of the insecticide in the lipid bi
layer to create special domains with a consequent increase in membrane
instability.