Intrinsic actions of benzodiazepine antagonists

RO 15–1788 (4–20 mg/kg), both alone and in combination with chlordiazepoxide (5 mg/kg), increased exploratory head-dipping in a holeboard above control levels. This intrinsic action of a benzodiazepine antagonist is not reversed, and is even augmented, by chlordiazepoxide. RO 15–1788 alone had no effect on locomotor activity, but antagonized the sedative effects of chlordiazepoxide. β-CCE (1 and 2 mg/kg) was without effect on locomotor activity, but the higher dose reduced head-dipping.