Effects of some monoterpenoids on [3h]-tbob binding to mouse gaba receptor

AGRO 37

Fan Tong, tongf@iastate.edu and Joel R. Coats, jcoats@iastate.edu. Department of Entomology, Iowa State University, 112 Insectary, Ames, IA 50011
In this study, four monoterpenoids (pulegone, thymol, α-terpineol, and linalool) were using to investigate their effects on [3H]-TBOB (t-butylbicycloorthobenzoate) binding to adult mouse GABA (γ-aminobutyric acid) receptors. Those four types of monoterpenoids have different patterns on modulating the binding of [3H]-TBOB to GABA receptor. Pulegone inhibited the binding of [3H]-TBOB with IC50 = 30mM. The other 3 monoterpenoids potentiated the [3H]-TBOB binding to the GABA receptor with the maximum potentiation of 143% (thymol), 127% (α-terpineol), and 156% (linalool). The data suggested that pulegone binds to GABA receptor as the same binding site as [3H]-TBOB, and pulegone may affect GABA receptor as a non-competitive antagonist. The increasing of [3H]-TBOB binding indicated the interaction of GABA receptor and the other three monoterpenoids, but the binding sites of them are different from the [3H]-TBOB.