Memory facilitation with atropine: a paradoxical effect

The potential antiamnesic properties of atropine were investigated in the mouse passive avoidance test. Amnesia was induced by scopolamine (2 mg/kg i.p.) and by exposure to a hypoxic environment (5% O2 in water-saturated nitrogen) for 8 min. Atropine (1–10 mg/kg s.c.) completely prevented disrupted acquisition without improving learning in mice with memory deficiency. At the same doses atropine did not produce any behavioural side effects in mice.