Objective Previously we have demonstrated that cyclothiazide (CTZ) could induce epilepitiform activity in hippocampal neurons both in vitro and in vivo.Here,we further report that CTZ dose-dependently induced seizure behavior in freely moving rats.Methods Adult male Sprague-Dawley rats were anaesthetized with sodium pentobarbital (60 mg/kg,i.p.),and a guide cannula was embedded into left cerebral ventricle at the sterotaxic coordination of 0.3 mm rostral,1.3 mm lateral and 4.0 mm in depth.Animals were allowed to recover from the surgery for at least one week before behavioral testing.CTZ (1 mol/L in DMSO) or vehicle DMSO was administered i.c.v.through the embedded guide cannula at 5 μL over 2 min.Animal behavior was then observed for 3 h immediately after drug application and at same time period at designated dates after drug application for at least 1 month.Doses of CTZ were given at 0.1,0.25,0.25 × 2,0.25 × 3 and 0.25 × 4 μmol.