A.) CGP 35348 (100 mg/kg, closed upward facing triangles, 320 mg/kg closed squares) does not significantly antagonize either GHB discriminative stimulus (open circles) or B.) rate-decreasing effects. C.) CGP 35348 (100 mg/kg, open upward facing triangles, 320 mg/kg open squares) antagonizes baclofen discriminative stimulus (closed circles) and D.) rate-decreasing effects. E.) Discriminative stimulus and F.) rate-decreasing effects of morphine (closed diamonds) and midazolam (open diamonds) in mice trained to discriminate 178 mg/kg GHB from saline. Top panels show drug-appropriate responding on the ordinates and drug dose in mg/kg (log scale) on the abscissae. Bottom panels show response rate normalized to saline control on the ordinates as function of drug dose in mg/kg (log scale) on the abscissae. All data points represent the mean and SEM of 8 independent determinations, except as listed in the top panels. These reduced animal numbers are also reflected in the respective lower panel data.