TK/TD relationships between GHB concentrations in whole brain and discrete brain regions and RRR. GHB (400, 600, or 800 mg/kg) was administered by intravenous bolus. When animals regained their righting reflex, brain regions [whole brain (right hemisphere) (A), frontal cortex (B), striatum (C), and hippocampus (D)] were obtained following exsanguination of anesthetized animals. Data are presented as mean ± S.D. (n = 7–8 for whole brain and n = 3–4 for discrete brain regions).