Anticonflict action of sodium valproate. Interaction with convulsant benzodiazepine (Ro 5-3663) and imidazodiazepine (Ro 15-1788)

The possibility that Ro 15-1788, a specific benzodiazepine antagonist would reverse the anxiolytic effect of VPA (200 mg/kg) in the Geller-Seifter paradigm was tested, using male albino rats. VPA (200 mg/kg) induced disinhibition which was antagonized by a convulsant benzodiazepine, Ro 5-3663 (1 mg/kg), but not by imidazobenzodiazepine, Ro 15-1788 at doses of 10 mg/kg, or 30 mg/kg. However, Ro 15-1788 (30 mg/kg) did have a short lasting antagonistic effect on VPA when tested in a “condensed” form (see text) of the conflict test. The nature of the anticonflict potency of VPA is discussed.