Mean SWD duration ± SEM of mGluR4^−/− and mGluR4^+/+ mice given either GHB or (−) baclofen. A, Mean SWD duration ± SEM in mGluR4^−/− and mGluR4^+/+ mice (n = 10 for each group) that received 100 mg/kg of GBL, the prodrug of GHB. There was no significant difference between mGluR4^−/−and mGluR4^+/+ mice in the duration of GHB-induced absence seizures (p > 0.1, ANOVA).B, Mean SWD duration ± SEM in mGluR4^−/− and mGluR4^+/+ mice (n = 10 for each group) that received 20 mg/kg of (−) baclofen. There was no significant difference between mGluR4^−/− and mGluR4^+/+ mice in the duration of (−) baclofen-induced absence seizures (p > 0.1, ANOVA).