Brain levels of tofizopam in the rat and relationship with benzodiazepine receptors

Summary The effect of tofizopam on ³H-flunitrazepam binding was studied in rat hippocampus and cerebellum. Tofizopam (at a concentration of 10^–7M) increased ³H-Flu binding through a 30% rise in the B_max with no modification of K_d in either brain area.Similar results were obtained when the binding was measured in tofizopam (50 mg/kg p.o.) pretreated rats.Even though tofizopam has no anticonvulsive action against pentetrazol-induced convulsions, it significantly potentiated the action of diazepam but with no modification of brain diazepam levels and metabolism.The brain levels of tofizopam are reported and compared to plasma levels after oral administration of 5 and 50 mg/kg to rats.