Fig. 9. GABA^Areceptors play a smaller role in enflurane actions in cords from −/− than +/+ mice. (Top ) Protocol for assessing the interaction between enflurane and GABA^Areceptors. Data for enflurane alone are the same as those shown in figure 3. The excitatory effects of bicuculline were controlled for by making the responses in the presence of the antagonist the baseline against which enflurane effects were measured when bicuculline was present. The GABA^Areceptor antagonist bicuculline (1 μm) attenuated the actions of enflurane on the population excitatory postsynaptic potential (pEPSP;A ) and the slow ventral root potential (sVRP;B ) significantly (P < 0.05) in cords from +/+ animals but not from −/− mice (C  and D ). Enflurane concentrations were approximately 0.7 MAC for pEPSP, 0.18 MAC for sVRP. Data points are means of four to five experiments; error bars are SEM.