EFFECTS OF ETHANOL ON RECOMBINANT GLYCINE RECEPTORS EXPRESSED IN MAMMALIAN-CELL LINES

We examined the effects of acute ethanol exposure on recombinant human glycine receptors transiently transfected into HEK 293 cells and stab ly transfected into Ltk(-) fibroblast-like cells. In our study of the effects of ethanol, we used the whole-cell patch-clamp configuration. Relatively low concentrations of ethanol (25 mM and 50 mM) did not aff ect glycine-gated currents in any of the cell lines studied. Higher co ncentrations of ethanol (100 mM and 200 mM) significantly potentiated glycine responses only in stably transfected Ltk(-) cells expressing a lpha(1) and alpha(2) subunits and in HEK 293 cells transiently express ing alpha(2) subunits. Cells stably expressing alpha(1) versus alpha(2 ) glycine receptors were modulated equally by ethanol. Both glycine al pha(1) and glycine alpha(1)beta receptors transiently expressed in HEK 293 cells were insensitive to all concentrations of ethanol tested; h owever, there was a trend toward potentiation at 100 and 200 mM ethano l concentrations. A population of cells (41-87%) that was sensitive to the potentiating effects of 100 and 200 mM ethanol (defined as more t han 10% potentiation) was identified in both cell lines tested. In the se sensitive cells, ethanol (100 and 200 mM) produced significant pote ntiation, independent of the cell line and the glycine receptor subuni t tested. Together with published results from studies with Xenopus oo cytes, these data indicate that the sensitivity of recombinant glycine receptors to ethanol depends upon the expression system.