Inhibitory avoidance

The apparatus was divided into two compartments: a larger one made of white Plexiglas, kept strongly illuminated and fitted at one end with a guillotine door, and a smaller one made of black Plexiglas (Panlab, Barcelona, Spain). A floor grid placed in the dark chamber received electrical current. On the training day each mouse was placed in the lit compartment, facing away from the dark compartment. Mice show a natural tendency to leave a well-lit chamber for a darkened one, and they do so after a short latency. When a mouse entered the dark compartment with all four paws 1 footshock (0.2 mA x 2”) was delivered. The time spent in the lit side (step-through latency) 24 hr later is the measure of ‘inhibitory avoidance’. A maximum step-through latency of 360 s was allowed in the test session (Brambilla et al., 1997).

Two doses of PD325901, 10 and 25 mg/kg, were given either at day 1 after training to interfere with the consolidation of fear memory or at day 2 to perturb the retrieval of that memory.