Figure 1.

(a) CB₁ wild-type mice treated with physostigmine (0.1 mg kg⁻¹ i.p.) presented an enhancement in learning/memory evaluated in the active avoidance test (100-trial avoidance sessions per day for 5 days). Wild-type mice treated with scopolamine (0.5 mg kg⁻¹ i.p.) showed a decrease in the learning performance. Data are expressed as a ratio between conditioned changes and total changes. Data represent mean±s.e.m. n=10–20 mice per experimental group. (b) CB₁ knockout mice treated with scopolamine (0.5 mg kg⁻¹ i.p.) showed a decrease in learning/memory evaluated during the active avoidance test (100-trial avoidance sessions per day for 5 days). Data are expressed as a ratio between conditioned changes and total changes. Data represent mean±s.e.m. n=10–20 mice per experimental group.