A method for quantifying state-dependency with chlordiazepoxide in rats.

A state-dependency procedure is described in which changes from the chlordiazepoxide state yield a robust and dose-dependent response decrement in rats. The format of data that are obtained with this procedure permits that the response decrement following a state change be defined accurately in individual animals, and that transfer be quantified. Dose-response studies revealed 13 (7.4-22) mg/kg to be the ED50 of chlordiazepoxide at which transfer occurred in animals that had acquired the response with 40 mg/kg chlordiazepoxide; the ED50 acquisition dose of chlordiazepoxide at which transfer to saline failed to occur was 3.7 (2.2-6.4 mg/kg).