Fig. 1 Figure 1: Glycine mediated inward currents in representative oocytes expressing alpha1or alpha2 subunits of the receptor are almost completely blocked by the selective glycine antagonist, strychnine. After 10 min of washout, recovery of responses is observed.

Fig.2 Figure 2: A concentration response curve was generated for alpha1 or alpha2 subunit expressing oocytes. Oocytes were perfused with glycine (5-1000uM) for 30 sec. Values are expressed as a percent of the maximal glycine (500 uM) response (n=5-15). An EC50 of 85 uM and a Hill coefficient of 2.5 were calculated for alpha1 subunit receptors, and an EC50 of 142 uM and a Hill coefficient of 2.29 were calculated for alpha2 subunit receptors, respectively.

Figure 3: Electrophysiological recordings of inward currents produced by glycine in oocytes containing alpha1 or alpha2 receptors in the absence and presence of ethanol. Oocytes were perfused with ethanol (100 mM) for 1 min prior to the application of ethanol (100 mM) plus glycine (alpha1: 25 uM) or glycine (alpha2: 50uM) for 30 sec.

Fig.4 Figure 4: Ethanol produces a concentration dependent stimulation of alpha1and alpha2 receptors. Oocytes were bath perfused with approximately equieffective concentrations (EC4) of glycine, 15uM (alpha1) and 50 uM (alpha2) for 30 sec. Oocytes were perfused with ethanol (50-200 mM) for 1 min prior to exposure to glycine plus ethanol. Values are expressed as a percent above the respective control glycine response (n=4-11).

Fig.5 Figure 5: Electrophysiological recordings of inward currents produced by glycine in oocytes containing alpha1 and alpha2 receptors in the absence and presence of butanol. Oocytes were perfused with butanol (5 mM) for 1 min prior to the application of butanol (5 mM) plus glycine (alpha1: 25 uM) or glycine (alpha2: 50 uM) for 30 sec.

Fig.6 Figure 6: Butanol produced a concentration dependent stimulation of alpha1 and alpha2 receptors. Oocytes were perfused with approximately equieffective concentrations (EC4) of glycine, 15uM (alpha1) and 50 uM (alpha2) for 30 sec. Oocytes were perfused with butanol (2.5-40 mM) for 1 min prior to exposure to glycine plus butanol. Values are expressed as a percent potentiation above the respective control glycine response (n=4-9).

Fig.7 Figure 7: Butanol increases the potency, but not the efficacy of glycine receptors. Oocytes (alpha1: upper panel, alpha2: lower panel) were perfused with glycine (15-500 uM) for 30 sec. Oocytes were perfused with butanol (10mM) for 1 min prior to application of glycine plus butanol for 30 sec. Values are expressed as a percent potentiation above the respective control glycine response (n=5-8).

Fig.8 Figure 8: Electrophysiological recordings of inward currents produced by glycine in oocytes containing alpha1 and alpha2 receptors in the absence and presence of halothane. Oocytes were perfused with glycine (alpha1: 25 uM) or glycine (alpha2: 50 uM) with or without halothane (0.32 mM) for 30 sec.

Fig.9 Figure 9: Halothane produced a concentration dependent stimulation of alpha1 and alpha2 receptors. Oocytes were perfused with glycine (50 uM) for 30 sec. Oocytes were then perfused with glycine plus halothane (0.16-2.5 mM) for 30 sec. Values are expressed as a percent potentiation above the respective control glycine response (n=4-5).

Fig.10 Figure 10: Halothane mediated stimulation of glycine receptors is dependent on glycine concentration. Oocytes (alpha1: upper panel; alpha2: lower panel) were treated with glycine (10-500 uM) for 30 sec. Oocytes were then treated with halothane (0.25 mM) plus glycine for 30 sec. Values are expressed as a percent potentiation above the respective control glycine response (n=4-5).